low-cost wastewater treatment technologies for
TRANSCRIPT
Low-cost wastewater treatment technlogies
for agricultural use
Study of the applicability of low-cost wastewater treatment effluents for the urban agricultural plots of Bhubaneswar city, Odisha (India)
MSc. Thesis by Eva Estevan Rodriguez
February 2014
Water Resources Management group
Sub-department of Environmental Technology
Low-cost wastewater treatment technlogies for agricultural use
Study of the applicability of low-cost wastewater treatment effluents for the urban agricultural plots of Bhubaneswar cty, Odisha (India)
Master thesis Water Resources Management submitted in partial fulfillment of the degree of Master of Science in International Land and Water Management at Wageningen University, the Netherlands
Eva Estevan Rodriguez
February 2014
Supervisor(s):
Ing. Harm Boesveld Dr.ir. Katarzyna Kujawa-Roeleveld Water Resources Management group Sub-department of Environmental Technology Wageningen University Wageningen University The Netherlands The Netherlands www.iwe.wur.nl/uk www.ete.wur.nl
Acknowledgements
This Master thesis was carried out at the Water Resource Management group in a close
collaboration with the Sub- Department of Environmental technology. I wish to express my
sincere gratitude to my supervisors Kasia and Harm for making this collaboration possible and
their entirely kindness, professionalism and willingness to support me during all the thesis
process. I would like to thank also my family, my life-long friends and my new friends for
encouraging me during my last few months of this exciting and difficult academic (life)
adventure. Thanks to all of you this experience was possible, nicer and totally unforgettable.
i Low-cost wastewater treatment technologies for agricultural use
Table of content
GLOSSARY OF TERMS .................................................................................................... 1
EXECUTIVE SUMMARY .................................................................................................. 3
1. INTRODUCTION .................................................................................................... 5
1.1 PROBLEM ANALYSIS ............................................................................................ 6
1.2 RESEARCH DESCRIPTION ..................................................................................... 7
1.2.1 Objective and questions .............................................................................. 7
1.2.2 Research phases .......................................................................................... 7
1.2.3 Research methodology ................................................................................ 8
2. BACKGROUND RESEARCH ................................................................................... 10
2.1DESCRIPTION OF THE AREA ................................................................................ 10
2.1.1 Location and demography ......................................................................... 10
2.1.2 Climate and rainfall.................................................................................... 11
2.1.3 Hydrography and topography ................................................................... 11
2.1.4 Study of the water context ........................................................................ 13
Water resources ................................................................................................. 13
Water scarcity ..................................................................................................... 13
Water regulations ............................................................................................... 14
Water and wastewater management ................................................................ 15
Agriculture and irrigation ................................................................................... 18
2.2 THE SCENARIO: WARD NUMBER 3 .................................................................... 20
2.2.1 Location ..................................................................................................... 20
2.2.2 Settlement description .............................................................................. 20
2.2.3. Energy utilities .......................................................................................... 22
2.2.4 Land availability ......................................................................................... 22
2.2.5 Agricultural characteristics ........................................................................ 22
2.2.6 Irrigation water resource ........................................................................... 23
2.3 STAKEHOLDERS ANALYSIS ................................................................................. 24
3. GUIDELINES AND STANDARDS OF WASTEWATER QUALITY FOR AGRICULTURAL
PURPOSES ................................................................................................................... 28
3.1 INDIAN REGULATION FOR IRRIGATION WATER QUALITY ................................. 28
ii Low-cost wastewater treatment technologies for agricultural use
3.2 INTERNATIONAL GUIDELINES REVIEW FOR HEALTH PROTECTION WHEN
WASTEWATER IS REUSED FOR IRRIGATION ............................................................ 28
3.3 EFFLUENT QUALITY STANDARDS AND MANAGEMENT RECOMMENDATIONS 30
4. LIST OF WASTEWATER TREATMENT SYSTEMS ................................................... 31
4.1REVIEW OF WASTEWATER TREATMENT SYSTEMS ............................................ 31
4.2TECHNOLOGIES FACT SHEETS ............................................................................ 34
4.2.1 Coarse screens (Bar racks) ......................................................................... 35
4.2.2 Sand traps (grit chamber) .......................................................................... 36
4.2.3 Grease traps ............................................................................................... 37
4.2.4 Septic tanks ................................................................................................ 38
4.2.5 Imhoff tank ................................................................................................ 38
4.2.6 Baffled reactor (anaerobic baffled reactor, ABR) ...................................... 39
4.2.7 Anaerobic Filter ......................................................................................... 41
4.2.8 Green filters ............................................................................................... 42
4.2.9 Soil biotechnology (SBT) or Constructed soil biofilter (CSB) or Constructed
soil filter (CSF) ..................................................................................................... 43
4.2.10 Anaerobic Stabilization ponds ................................................................. 44
4.2.11 Facultative ponds .................................................................................... 45
4.2.12 Aerobic stabilization ponds (Maturation ponds/Oxidation pond) .......... 46
4.2.13 Constructed wetlands. Free flow(surface) .............................................. 47
4.2.14 Horizontal subsurface flow constructed wetlands (HSF) ........................ 48
4.2.15 Vertical flow constructed wetlands (VF) ................................................. 49
4.2.16 Slow Sand Filter (SSF) .............................................................................. 50
5. ANALYSIS OF THE RESULTS ................................................................................. 51
5.1 SELECTION OF PRINCIPLES, CRITERIA AND INDICATORS .................................. 51
5.1.1 Principles ................................................................................................... 51
5.1.2 Criteria ....................................................................................................... 51
5.1.3 Indicators ................................................................................................... 52
Nutrient (N, P) content ....................................................................................... 52
Salinity reduction ................................................................................................ 52
Total Suspended Solids (TSS) reduction ............................................................. 53
Biochemical Oxygen Demand (BOD) .................................................................. 53
iii Low-cost wastewater treatment technologies for agricultural use
Heavy metals ...................................................................................................... 53
Pathogen removal .............................................................................................. 54
Size ...................................................................................................................... 54
Centralized or decentralized systems................................................................. 55
Design and construction cost. ............................................................................ 55
Simplicity of O & M. ............................................................................................ 55
Energy requirements .......................................................................................... 55
Robustness .......................................................................................................... 56
Environmental nuisances ................................................................................... 56
5.2 MULTI CRITERIA ANALYSIS ................................................................................ 57
5.2.1 Criteria weighting ...................................................................................... 57
5.2.2 Indicators rating technique ....................................................................... 58
5.2.3 Scoring matrix ............................................................................................ 61
6. DISCUSION .......................................................................................................... 65
7. CONCLUSION ...................................................................................................... 69
7.1 RECOMMENDATIONS ........................................................................................ 70
REFERENCES ................................................................................................................ 71
Personal communication(4th March, 2013) ............................................................ 82
ANNEX 1 ...................................................................................................................... 83
Institutions and Organizations: Online sources ...................................................... 83
Initiatives & Projects ............................................................................................... 84
ANNEX 2. Results ........................................................................................................ 85
Relative salinity tolerance of crops ......................................................................... 85
Domestic wastewater constituents ........................................................................ 86
Review of International guidelines of waste quality for irrigation ......................... 87
FAO Guidelines of waste quality for irrigation ........................................................ 89
Wastewater treatment technology cost comparison ............................................. 92
Water uses classification for the Indian Central Pollution Control Board .............. 93
Wastewater treated quality parameters for crop production ................................ 97
ANNEX 3. Maps of Bhubaneswar Ward n°3................................................................ 98
1 Low-cost wastewater treatment technologies for agricultural use
GLOSSARY OF TERMS
Centralized water management: Consist of conventional or alternative wastewater collection
systems (sewers), centralized treatment plants, and disposal/reuse of the treated effluent,
usually far from the point of origin (Tchobanoglous, 1996).
City: It refers to a big community (>2000 inh.).
Constructed wetland systems: Constructed wetlands are natural systems that imitate natural
depuration processes that take place in to rivers or lakes. The difference to the lagooning
systems is that aquatic vegetation is planted, taking in an important role in the treatment
performance.
Decentralized water management: Decentralized wastewater management (DWM) may be
defined as the collection, treatment, disposal and reuse of wastewater from individual homes,
clusters of homes, isolated communities, industries, or institutional facilities, as well as from
portions of existing communities at or near the point of waste generation (Tchobanoglous,
1996).
Domestic wastewater: The domestic effluents consist of black water (excreta, urine and
associated sludge) and grey water (kitchen and bathroom wastewater) (Raschid-Sally and
Jayakody, 2008). In this research it is also considered effluent from commercial establishments
and institutions, including hospitals (Van der hoek, 2004).
Household: It refers to a private house, building or plot occupied by a family or a group of
families (WSP, 2008).
Industrial wastewater: It is the wastewater generated by industrial processes and its
characteristics vary depending on the type of industry.
Lagooning systems (Stabilization ponds): Different terms are being used to name this kind of
process, stabilisation ponds, facultative ponds, anaerobic ponds or maturation ponds. All these
technologies are anthropogenic systems that imitate natural depuration processes that take
place in to rivers or lakes. The natural self depuration would consist of physical process of
sedimentation and flotation, chemical process of neutralization and oxidation and biological
process of microbiological degradation. Therefore, this chain of ponds completes a very
efficient treatment that complies, primary, secondary and tertiary treatment, however, pre-
treatment technologies are required at the beginning of the chain.
Neighbourhood: It refers to an area that comprise cluster of houses or buildings, around 10 to
200 households (WSP, 2008).
Pucca housing: Pucca housing (or pukka) refers to dwellings that are designed to be solid and
permanent. The term is applied to housing in South Asia built of substantial material such as
stone, brick, cement, concrete, or timber (Qadeer, 2006).
Settlement: It refers to an area with 200 to 1000 households. Inside a town or a city it could be
defined as a district or ward. These parts of the cities have often their own administrative
division area (WSP, 2008).
2 Low-cost wastewater treatment technologies for agricultural use
Soil based systems: Land application compiles various techniques that use soil as a filter. The
soil is the media where all the physical, chemical and biological processes take place. Therefore
it can perform as a primary and secondary treatment device. The organic matter is decayed by
soil bacteria in oxygen and anoxic processes.
Storm wastewater: Water from rainfall is not clean. It is affected by atmospheric pollution and
by sweeping along the street contaminants. The most common type of sewage system for this
type of water is the unitary, where water from urban runoff is mixed with domestic and
industrial effluents.
Total coliform: It is a measure to analyse the presence of pathogens in wastewater. Part of
coliform bacteria is naturally present in the intestines of mammals. The concentration of
coliform bacteria constitutes an indicative of faeces contamination. Total coliform is referred
both to faecal coliform and enteric coliform.
Urban wastewater: It is a combination of domestic wastewater, industrial wastewater and the
urban runoff and storm water (CENTA, 2007a).
Wastewater treatment technology: Wastewater treatment technology is defined as a group of
physical, chemical and biological processes, in order to treat wastewater by reducing or
removing its pollutants load.
3 Low-cost wastewater treatment technologies for agricultural use
EXECUTIVE SUMMARY
Urban farmers in India have few options to irrigate their crops. When precipitation is not
enough, tap water is too valuable therefore it is not a possible and affordable alternative.
Wastewater becomes the most logical input. In fact, wastewater is a potential input for
agriculture and can help to increase yields (Yadav, et al 2002). This research is part of
REOPTIMA project, Reuse options for marginal quality water in urban and peri-urban
agriculture and allied services in the ambit of WHO guidelines (New Indigo, 2011). This is an
initiative for the Development and Integration of Indian and European Research. The aim of
REOPTIMA is to create an expertise network on the development of integrated wastewater
management systems, and develop a roadmap for research on urban wastewater reuse in
Indian cities (New Indigo, 2011). The design of the present study comprises a study of the
scenario area, the city of Bhubaneswar.
Bhubaneswar is the overpopulated capital city of Odisha State in India. Its fast uncontrolled
growing pace make the urban planning unachievable, therefore the urban infrastructures
remain under dimensioned and the wastewater treatment capacity far behind the real
necessities. Water bodies suffer high loads of pollution. Although agriculture is a marginal
sector inside the city, it is still located in located in the bank of the city rivers. Urban farmers
have few options to irrigate their crops.
The high content of macronutrients as nitrogen and phosphorous and organic matter in
wastewater are beneficial and profitable for the agricultural production. However, other found
compounds in wastewater can create a health risk for farmers and consumers. Therefore in
order to use the municipal wastewater in agricultural plots, the treatment of not only
pathogens but also other pollutants (toxic compounds, heavy metals, etc) is necessary.
The goal of wastewater treatment plants is the improvement of water quality from an
environmental point of view, not for use in agriculture. The discharge of the effluent in the
existing water bodies or water drains is the main practice. Therefore, the wastewater
treatments use to focus in the reduction of the load of pollutants with the primary treatments
(to remove suspended solids by physical processes) and secondary treatments (to remove
colloidal and organic and inorganic constituents by biological processes). The removal of
pathogens by tertiary treatment is mainly applied in the case of direct reuse of the effluent, for
instance irrigation.
Furthermore, conventional technological treatments require high energy, chemical inputs,
skilled labour; infrastructure and maintenance works to work properly and therefore their
sustainability depends on economic aspects. Even in industrialized countries not all small
settlements can afford operating costs of modern wastewater treatment plants (Hophmayer-
Tokich, 2006). These preconditions make it difficult if possible to sustain high technological
wastewater treatment plants in developing countries. Therefore, high technical methods
would not be always the most suitable option in a long term perspective.
Consequently, urban farmers have to deal with a polluted source of water because the
treatment solution is not affordable for them.
4 Low-cost wastewater treatment technologies for agricultural use
The present study aims to devise a integrate approach to look for a technological feasible
solution for urban farmers of Bhubaneswar city. An in-depth study of the scenario area was
developed in order to integrate in the technologies assessment, the physical, social and
economical criteria of the local context. The research design involves also a description of the
low-cost wastewater treatment technologies. Following, there is selection of possible low cost
technologies for agricultural purposes for the studied case. The selection was made by a
scoring multi criteria evaluation process (MCA). In order to develop the MCA were defined
various principles, criterion and indicators that cover the aforementioned crucial aspects for
this research; (1) compliance with health protection (for consumers and farmers), (2)
compliance with crop production and (3) sustainable solutions for local context. Regarding to
each principle, the criteria were established to choose the technology. The criteria are further
divided into indicators that are characteristics of the technology and were used to assess the
adequacy of the technology. These indicators were related not only with the technical
characteristics but also with other local socioeconomic factors that might affect the success of
the implementation. Finally a technological solution is recommended for the urban agricultural
plots of Bhubaneswar.
5 Low-cost wastewater treatment technologies for agricultural use
1. INTRODUCTION
There is a trend of people migrating from the countryside to the cities creating new huge
metropolitan areas. The spatial reorganization of people to urban areas has also concentrated
food demands in cities (Jimenez et al, 2008, p 229). At the same time, the settlement of people
in the cities involves a rapid change of land use. As a consequence, the urban planning
becomes chaotic and the traditional rural agricultural plots suddenly coexist with high density
population settlements. Urban and peri-urban agricultural activities increasingly gain an
important role in the urban economy (reviewed by Jimenez et al, 2008, p 228), and become
essential to avoid problems of food security.
Water is an essential natural resource and is used in many human activities. Plants require
water and nutrients to grow, but in arid and semiarid areas water is a scarce resource. Where
rainfall is insufficient, irrigation is a necessary practice that ensures the production for the
farmers. However, the availability of fresh water for urban agricultural plots is decreased by
competing with an increasing domestic and industrial demand (Jimenez et al, 2008, p 199).
Driven by the new urban activities, the amount of wastewater is growing. Therefore, less fresh
water is available and reclaimed water is sometimes the only source available for the
agricultural plots located close to the city. Reclaimed water is widely used as a low-cost
alternative to conventional irrigation water (Scott et al 2004, p 1) because is a reliable source
of water supply.
Water closes a triangle of inter-dependences, in this report referred to as “Water-City-
Agriculture” (Figure 1).
The reuse of wastewater for agriculture is not a new practice. For centuries, urban wastewater
has been used as an input for agricultural plots, and today there are many examples of such
practices all over the world. For instance there are cases of direct use of untreated wastewater
in Dakar (Senegal) and Ghana (Scott et al, 2004), or treated wastewater from the cities as the
URBAN AGRICULTURE CITY Figure 1: Triangle of interdependence Water-City-Agriculture (self-designed)
6 Low-cost wastewater treatment technologies for agricultural use
case of El Mezquital in Mexico, were 250000 ha which are irrigated with wastewater from
Mexico City (Lazarova, et al 2005, p 345). In fact, wastewater is used extensively (20 million
ha.) and 10% of population worldwide consumes wastewater irrigated foods (Reoptima
workshop, 2012). This use brings both advantages and disadvantages to the farmers, as well as
to the consumers. For instance, the high nutrient concentration of the wastewater maximizes
yields; therefore, the possibility of irrigation with reclaimed water ensures the incomes of
households of urban farmers (Carr et al, 2004). On the contrary, wastewater not only contains
large quantities of nitrogen and phosphate, but in many cases also heavy metals,
pharmaceutical residues or other micro pollutants, viruses, bacteria, protozoa and helminths.
Adverse effects of surplus nutrients, toxic compounds and pathogens on the quality of the
crop are possible. Furthermore, beside the effects on the crops, a direct use of dirty and smelly
wastewater is not a pleasant work for the farmers. The use implies also high risk of waste
waterborne diseases like hook worm infection or intestinal nematode infection (Ensink et al
2005). Moreover, from the consumer’s perspective, the consequences of the consumption of
food with remains of toxic compounds or pathogens on human health can be fatal (WHO,
2006). Therefore, in order to use the municipal wastewater in agricultural plots, the treatment
of reclaimed wastewater has to assess all these factors.
1.1 PROBLEM ANALYSIS
In developed countries, the possible negative effects of wastewater reuse on human health
and environment have been overcome or minimised by implementation appropriate
wastewater treatment technologies that maximize water quality standards for safe discharge.
For example, municipal parks in the city of Madrid (Spain) are irrigated with reclaim water. To
minimize the health risk of citizens is treated with ultraviolet devices. Such highly technological
wastewater treatment is not what it is found in developing countries, where there is no access
to advanced treatment or even basic treatment. In many cases it results in the use of
untreated wastewater. Therefore, despite the possible negative effects on human health, with
the high risk of disease infection for the farmers (as hookworm, ascaris, Diarrhoeal disease,
giarda intestinalis infection), and food contamination (e.g. cholera, typhoid, ascaris infection)
(Carr et al, 2004), farmers are faced with polluted water as the only available input.
The use of treated and untreated wastewater in urban and peri-urban agriculture is a quite
common practice in India. Unfortunately, remains of toxic compounds and infectious
substances in wastewater irrigated food are common as well. However, the use of reclaimed
water for irrigation is not regulated by the Indian legislation, (New Indigo, 2011). Therefore,
wastewater management protocols and techniques should be developed based on sound
scientific knowledge to support farmers (New Indigo, 2011).
On the contrary, many organizations and institutions worldwide (WHO, FAO, etc.) have
developed guidelines that maximize the protection of human health and environment, so as
not to waste this important resource. They also propose some wastewater treatments in order
to achieve this. Nonetheless there is a need to identify wastewater treatment technologies
that not only reduce the health risks of wastewater use (Reoptima workshop, 2012) but also
keep the wastewater properties improve the growth of crops. The reason behind that is that
urban agricultural sector maintains and increases the socioeconomic and environmental
7 Low-cost wastewater treatment technologies for agricultural use
qualities of the cities (Van der Hoek, et al. 2002). This is not only a question of health security
but also food security.
1.2 RESEARCH DESCRIPTION
1.2.1 Objective and questions
The objective of this research is the identification of the most appropriate low cost
technological solutions for improving the wastewater quality, in order to irrigate urban
agricultural plots of the city of Bhubaneswar.
My main research question is what could be the most appropriate technological solutions to
upgrade wastewater in order to minimize the health risks and maximize crop benefits, in the
city of Bhubaneswar, Odisha (India).
1. Which are the criteria that will define the multi criteria analysis for the selection of the
solution?
2. Which factors would influence the performance or implementation of the wastewater
technology?
3. What are the required characteristics of reclaimed water that result beneficial and
profitable for agriculture?
4. Which are the current low cost wastewater treatments methods that are able to
supply water with beneficial characteristics for agriculture?
5. To what extent can low cost wastewater treatment reduce the health risk of
consuming reclaimed water irrigated crops?
6. What are the most suitable low cost wastewater treatment methods to minimize the
health risks for farmers?
1.2.2 Research phases
The research project is divided in the following stages:
Baseline analysis
The first phase of my research comprises a concise analysis of the area, regarding to the
geophysical characteristics, sociological aspects and water specific aspects (water resources,
water treatment, water infrastructure, water management, drinking water, types of
wastewater, etc.).
The objective of this first phase is to gather deep knowledge of the area, in order to make a
baseline that will be used to develop the further stages of my research.
Also during this phase, the definition of the specific quarter of the city is chosen.
8 Low-cost wastewater treatment technologies for agricultural use
Guidelines and standards of wastewater quality for agricultural purposes
The second part of this study is related to water quality standards, in terms of health and
agricultural purposes. During this phase the international guidelines for the reuse of
wastewater for agricultural purposes is studied. Also standards for the quality of water effluent
are analysed. A description of information on agricultural water standards from different
institutions is presented.
Inventory and categorization of low cost wastewater treatment technologies
The third part of this research consists of a list of technologies. First of all a general overview of
the conventional wastewater treatment processes is given. After the review of technologies,
the criteria indicators are described base on the agricultural reuse. A review of the existing
examples of low cost wastewater treatment plants in India and other countries is carried out,
followed by a selection of the technologies based on the criteria and indicators. A detailed
characterisation of each selected technology is then presented.
Multi criteria analysis
Finally, after the definition of the technologies the elaboration of multi criteria analysis is
achieved. Once the criteria indicators are defined and described for each selected technology,
the next step is to assess and put a value to each criteria indicator. The multi criteria model will
be chosen and adapted to the purpose of the research.
Selection
The selection of the most feasible technology for urban agriculture in Bhubaneswar will be
based on the results of the multi criteria analysis.
1.2.3 Research methodology
In order to address the research objective the methodology consists of:
Literature study.
The literature review studies relevant background information on quality standards for use
wastewater in agriculture, as well as the current wastewater treatment technologies in
application within the context of India and Bhubaneswar.
In order to gather as much information as possible, the collection of the data is done by
different sources:
-Documents: scientific books, journal articles, publications and expert reports, documents and
summaries.
- Official websites: State, regional and local institutions related to agriculture, environment,
water and administrative subjects, and research organizations and NGOs.
-REOPTIMA project: The thesis research topic is related to REOPTIMA project; reuse options
for marginal quality water in urban and peri-urban agriculture and allied services in the gambit
9 Low-cost wastewater treatment technologies for agricultural use
of WHO guidelines. The aim of REOPTIMA is to create an expertise network (Indian and
European researchers) and to develop a roadmap for research on urban wastewater reuse in
Indian cities (New Indigo, 2011). Information available from meetings, workshops, conferences
between the different counterparts of this project is consulted and used.
The literature study is specifically developed to find answers to the first four sub questions,
and also is used to back up the definition of the 5th and 6th sub questions.
Interviews.
The study area characteristic´s is defined with the assistance of the scientists from the
Directorate of Water Management. The local characteristics of the area related to: Geo-
hydrology, Agriculture, Rainfall, Climate and Topography are studied, therefore semi-
structured interviews were held to provide additional information on water quality and the
management context.
Although the aim of the REOPTIMA project is the wastewater management of the city, due to
the size of the area, it is essential to optimize the study, to reduce the unit of analysis to a
specific representative part of the city. The contacts and questionnaires are constructed as to
yield information about the city, and therefore are useful to answer the fifth research sub
question.
All the obtained data are triangulated in order to guarantee the transparency and reliability of
the information.
Multi criteria analysis.
The background information of Bhubaneswar ward will be reviewed. Based on the data
collected from the literature review, from the interviews and the assumptions of the missing
data, the assessment of the local situation will be developed. On the other side, criteria
indicators will be valued with a range of figures. The value of each indicator will change
depending of the local context. The total values of the indicators will be added to obtain a final
assessment of the criteria. The technology will be scored with the sum of the values of the
criteria indicators.
10 Low-cost wastewater treatment technologies for agricultural use
2. BACKGROUND RESEARCH
2.1DESCRIPTION OF THE AREA
2.1.1 Location and demography
Bhubaneswar is located in the district of Khordha of Odisha state (see Figure 2). It is the capital
city and the largest city of the state. By the Census of India 2011, Odisha had a population of
almost 42 million inhabitants in 2011. It is located in the eastern coastal area of India. It is
among the poorest and least developed states in the country (India today, 2008; Prakash et.al.
2011) and one of the least urbanized states with 14.97% of urban population (Sethy et al,
2007).
The metropolitan area of Bhubaneswar is merged with the nearby city of Cuttack. These two
cities conglomerate to a total population of 1.2 million people. The rapid growth of population,
driven by rural migration from the southern states, has resulted in a proliferation of slum
settlements. In 2001, Bhubaneswar had a total of 190 urban slums having 38142 households
spreading over 300 acres of land (Sethy, 2007), but nowadays according to Bhubaneswar
Municipal Corporation (BMC, 2013) there are already 377 slums settlements (see Figure 3).
Figure 2: Location map of Odisha, Khordha district and Bhubaneswar in India. (Self design base on: Antur, Wikipedia, 2013. Available at: http://en.wikipedia.org/wiki/File:OrissaKhordha.png)
Figure 3: Rising trend of slums in the city from 1994-2008. Department of Urban Poverty Alleviation. Bhubaneswar. (Source: Bhubaneswar Municipal Corporation website, 2013)
11 Low-cost wastewater treatment technologies for agricultural use
2.1.2 Climate and rainfall
Bhubaneswar is situated in a humid area and the climate is tropic template. The Indian
Meteorological Department defines the climate by four different periods: winter (cold) season
(January and February); pre-monsoon (summer)season (March, April and May); summer
monsoon season (June, July, August and September) and Post-monsoon season (October,
November and December). Precipitation is concentrated during monsoon period from 15th
June to the end of September (Government of Odisha, 2010). The overage annual rainfall is
1451.2mm. The temperature oscillates between the 15 o C in the winter months of January,
and maximum of almost 38 o C in the summer months of May (see Figure 4). There is a low
moderate risk of drought, and by contrary is highly vulnerable to Tropical Cyclones that form
during the monsoon season (Attri, et al, 2012).
Figure 4: Monthly mean maximum & minimum temperature (o C) and total rainfall based upon 1952-2000 period (49 years data). Station name: Bhubaneswar (A) (Source: self design adapted from IMD, 2012)
2.1.3 Hydrography and topography
Bhubaneswar is located in the coastal zone of the region, in the Mahanadi river delta. In the
near city of Cuttack Mahanadi River, third largest river of the Indian Peninsula (India WRIS,
2011), is divided in different branches before its mouth in Bengali Coast (see Figure 5: Map of
Khordha district, River and Drainage. Odisha, India. (Source: The District. Portal of Khordha,
2013)Figure 5).
Kuakhai River originates as a branch of Mahanadi and enters Bhubaneswar from the north and
it streams form the eastern boundary of the city. Likewise, at the south of the city Kuakhai
river is divided in two, originating the Daya River. Daya defines the south boundary of the city.
Therefore Bhubaneswar is bounded by Mahanadi River in the north, Kuakhai River in the east
and by Daya River in the south (see Figure 5).
12 Low-cost wastewater treatment technologies for agricultural use
Figure 5: Map of Khordha district, River and Drainage. Odisha, India. (Source: The District. Portal of Khordha, 2013)
The topography has been shaped by erosion of the laterite plateau over the one Bhubaneswar
lies on. So the city is rather hilly, with continuous raises and falls. However there is a clear
slope towards the eastern city parts from the upper western areas (CCIP, 2006). Therefore the
river Kuakhai on the east and the river Daya in the south define also the natural drainage
channels of the city the water runoff is split up in these two watersheds (Mishra, 2004).
Inside the city it is important to mention the Gangua Nallah stream. It flows from Gadakhan
village crossing the city towards south parallel to Daya River until they joint near Kanti village.
Despite Gangua Nallah is a natural canal form as rainwater drain, nowadays it has become the
main conveyor of city wastewater. This is due to at least 10 drains that run from west to east
of the city discharge their flows into Gangua Nallah stream (Van Beusekom, 2012; Kumar
Sabat, 2012). Chilika lake is located some kilometres at the south of the city (see Figure 5). This
water body is fed by different streams but the Daya River is one of the main tributaries.
Therefore the water quality and its environmental condition are totally influenced by the
Bhubaneswar wastewater discharges.
Figure 6: Location of water streams in Bhubaneswar, Odisha, India. (Source: Van Beusekom, 2012)
13 Low-cost wastewater treatment technologies for agricultural use
2.1.4 Study of the water context
Water resources
India is a large country with a geographical area of almost 3.3 million Km3. Its great size also
implies differences in rainfall, reaching over 11000mm at north east Meghalaya state, and only
100mm in western Rajasthan (Gulati et al, 2005). Nevertheless, not only exist areas drought
prone, but also there are areas under flood damage risk (CWC, 2010). Furthermore, there is an
uneven distribution of water not only in space but also in time. The main water resource of the
country results from the natural runoff that drains into the rivers (Gulati et al, 2005). It is
estimated of 1122 billion m3 usable water, surface water of 690 billion m3 and groundwater
432.94 billion m3 per year (CWC, 2010).
Water scarcity
Water scarcity can broadly be understood as the lack of access to adequate quantities of water
for human and environmental uses (White, 2012) Therefore the concept of water scarcity
could be approached from two different perspectives: Socio-economical and physical.
(1) Socio-economical scarcity could be understood as a result of growing population and
competing demands for water (Metha, 2007). The high pressure demands force to allocate
water among several stakeholders. Is predicted that the world population will increase within
the next fifty years, by 40-50% (WWC, 2012) and these figures are even more accentuated in
India. The growing population and its concentration in particular areas, stems a raise of water
needs. Furthermore, socioeconomic development and the increase of life standards trigger a
higher consumption of water in urban areas, and these activities compete with agriculture
whose yields, in addition, have also to guarantee food security. As it is indicated in Table 1 a
steady increase of water demand is predicted in the next few years. While agriculture will
increase from 16% (Standing Sub-Committee for assessment of availability and requirement of
water, MOWR) up to 55% (National Commission on Integrated Water Resources Development
,NCIWRD) until 2050, the foreseen increment of all the other types of uses is very much higher
as for example drinking water that will increase from 82% (MOWR) up to 164% (NCIWRD).
Table 1: Project water demand in India (by different uses) (Source: CWC, 2010, table 71)
SECTOR
Water Demand in Km3( or Billion Cubic Meter)
Standing Sub-Committee of availability and requirement of
water. (MOWR)
National Commission on Integrated Water Resources Development . (NCIWRD)
2010 2025 2050 2010 2025 2050
low High Low High Low High
Irrigation 688 910 1072 543 557 561 611 628 807
Drinking Water
56 73 102 42 43 55 62 90 111
Industry 12 23 63 37 37 67 67 81 81
Energy 5 15 130 18 19 31 33 63 70
Other 52 72 80 54 54 70 70 111 111
TOTAL 813 1093 1447 694 710 784 843 973 1180
14 Low-cost wastewater treatment technologies for agricultural use
Source: Basin Planning Directorate, CWC, XI Plan Document. Report of the Standing Sub-Committee on "Assessment
of Availability & requirement of Water for Diverse uses-2000"
(2) The term physical scarcity refers to a volumetric lack of water. Droughts or pollution are
factors that can trigger this problem and the consequences of the scarcity could be even more
severe if all of them overlap at the same period of time. However, droughts are natural
climatic phenomena produced by a shortage of rainfall during a long period of time. These
droughts have been a regular feature of India’s geo-physical profile since time immemorial. In
some parts of India, droughts occur almost every year (Jairath, et al. 2008, p.158). The south-
west monsoon (June – September) is a periodic phenomenon that produces the 73% of total
annual precipitation, therefore when monsoon fails, drought is originated (CMP, 2012). Indian
Government consider drought as a management issue, therefore they develop Crisis
Management Plans, Drought Prone Areas Programme (DPAP) where it is considered drought
management (CMP, 2012). Pollution is another factor that determines the reduction of the
physical water availability and therefore generates a rise of scarcity. Industrial activities and
urban development generates pollutants that reduce quality of water bodies, and therefore
diminish the directly usable quantity (Brands, et al 1997, p21). The pollution is cause by the
discharge of untreated or partly treated domestic (and industrial) wastewater from the fast
growing urban centres. In India, it is estimated that only 25-30% of the urban wastewater flow
receives some form of treatment (CUPS /70/2009-10) (New Indigo, 2011).
In Bhubaneswar, despite that there is a low risk of drought water scarcity could be triggered by
the high pressure over water resources. Although it is a humid region, the rainfall concentrates
only during the monsoon period. Bhubaneswar is located in an overpopulated river delta area.
During winter and summer season, there is an overexploiting of groundwater in the area
(Mishra, 2004), but also surface water bodies are threatened by huge loads of pollutants
released by upstream discharges. In case of scarcity, Odisha State Water Policy fulfil with the
National regulation. Water allocation priorities, are defined as following: Drinking water and
domestic use (human and animal consumption), Ecology, Irrigation, agriculture and other
related activities including fisheries, Hydro power, Industries including Agro Industries and
finally Navigation and other uses such as tourism (HLTC, 2007).
Water regulations
Bhubaneswar is regulated by Odisha´s policies (based on the Indian state regulation). The
national water policy developed by the government of India in 1988, was modified in 2002,
and recently change in 2012. It is a general regulation that is applied to all the states of the
country. Based on this, each state develops its own regulation. Odisha State created its own
State Water Policy in 1994 and the last adaptation was in 2007 (HLTC, 2007). With the new
National water policy, the main water management issues in the country and related to Odisha
are covered, it is worthy to mention the section 3.5 of State Water Policy, where it is aim
strengthened of water use infrastructure in north eastern regions. The policy is oriented to
prevent the pollution rather than invest in cleaning or remediation, as is shown in the section
8.5 of State Water Policy, sources of water and water bodies should not be allowed to get
polluted. It is much related to the aim of this research, the section 11.7 of State Water Policy
subsidies and incentives should be implemented to encourage recovery of industrial pollutants
and recycling / reuse, which are otherwise capital intensive. Therefore the regulation shows
the national government willingness to address the target of wastewater reuse. However, no
15 Low-cost wastewater treatment technologies for agricultural use
specific measures have been done so far. In fact, the regulation for water or wastewater is the
same and mainly related to environmental pollution (EBTC, 2011). The Central Pollution
Control Board (CPCB) is the institution in charge of controlling pollution in water bodies and
reports it to the Ministry of Environment and Forests (MoEF). In general, regarding to the
water bodies pollution, there are some environmental regulations (i.e. Act 1974) that forbid
the discharge of an effluent if it has not accomplished quality the standards required (CSE,
2011). CPCB control the performance of the wastewater treatment plants, but despite that,
there is no regulation that supervises the on-site treatment systems (EBTC, 2011).
Water and wastewater management
Indian water resources allocation is done at state level. In case of Bhubaneswar, it is done by
the Department of Water Resources of Odisha Government. This institution controls water
allocation among different users; Department of Agriculture, Urban water supply, etc.
The management of wastewater in Indian cities is done by local authority bodies that try to
face the uncontrolled increasing waste generation with a very short budget (CPCB, 2013). In
Bhubaneswar, the local sewage system and the wastewater treatment is built by the public
Odisha water supply and sewage board (OWSSB), from Odisha State. Once the infrastructure is
implemented, the Odisha Public Health Engineering Organization (OPHEO) is in charge of the
operation and maintenance. Drinking water supply to most parts of the City is also maintained
by the State, OPHEO. However the local authority, Bhubaneswar Municipal Corporation (BMC),
is providing water supply to certain fringe areas of the city mostly at the outskirts through well
production.
Sewage infrastructure
In Indian cities, the municipal sewer system does not cover the most part of the urban areas.
Furthermore, the infrastructure is unsuitable, deficient and in poor condition, aggravates the
problem. As a consequence, a large proportion of the domestic wastewater is either discharge
directly in natural drains or in some cases is directed to decentralized treatment systems. In
fact, it is estimated that about 29% of the India’s population uses septic tanks (USAID, 2010;
CSE, 2011). However, it should be stressed what has already been indicated by Water Aid India
(2005). In order to achieve the Millennium Development Goals (MDG), great investments in
sewerage and waste disposal infrastructure are needed in India. Furthermore, in case the MDG
would be accomplished, they also remarked on that slums population and the rural poor
people would be out of these measures. Therefore, Indian urban areas are complex frame to
work on. It is not only a question of implementing infrastructure but also dealing with the
inequalities of the poorest citizens settle in slums.
As a capital city of the state, Bhubaneswar has a high density population that implies a
production of huge volumes of wastewater. By the CSE (2011), the total sewage generated is
around 141 to 194 million Litres per day (see Figure 7 ). The existing infrastructure covers the
35% of all the districts of the city (Anon, 2011). But the households that are not cover by the
sewage system have their onsite facilities, septic tanks or soak pits (Mallick, 2012, Dr. S. K.
Rautaray and Dr. S. Raychaudhuri, personal communication, 4th March, 2013). The problem is
that untreated effluent from the septic tanks in the individual premises, overloaded due to lack
16 Low-cost wastewater treatment technologies for agricultural use
of any maintenance, is discharged into the natural drains, Kuakhai and Daya watersheds.
(Mishra, P, 2004). On the other hand, the uncontrolled and massive spread of the population
in the city of Bhubaneswar (see Figure 3) leads to unplanned slums settlements which makes it
rather difficult to set up the basic urban infrastructures in the new areas. The sewage
infrastructures that exist in these parts of the city consist on natural earthen drains for rainfall
that are used as a sewage system (Dr. S. K. Rautaray and Dr. S. Raychaudhuri, personal
communication, 4th March, 2013). Most of the drains are earthen basin. Only three of them
have concrete construction of walls. There are not gates or weirs in most of the major canals.
Consequently, the discharge of domestic wastewater is done into the natural drains. There are
not separated canals for rainfall and wastewater and, even so, it is not possible to separate
domestic and industrial effluents, hence rainfall runoff, domestic wastewater and industrial
wastewater end up in the natural drains. Urban farmers use these canals for watering their
crops. (Dr. S. K. Rautaray and Dr. S. Raychaudhuri, personal communication, 4th March, 2013).
Wastewater treatment
The existing centralized wastewater treatment plants are not able to keep pace of the growing
cities. That explains that in India only the 30% of municipal wastewater is treated (CPCB, 2013).
On the other hand, according to Centre Pollution Control Board (2013), the reason behind the
improper performance of WWTP is predominately due to lack of operation and maintenance.
Therefore, although big centralized wastewater systems were constructed in India during the
last few decades, their sustainability has being questioned (Kumar, 2012). Low cost for onsite
treatment seems to be an option to treat the huge volumes just at the point of generation
(Kumar, 2012). In the city of Bhubaneswar, there is not only a lack of sewage infrastructure but
also under dimensioned centralized treatment plants. For Bhubaneswar city there are two
wastewater treatment sites (Reoptima workshop, 2012). The wastewater treatment plant
located in the close city of Cuttack has a capacity of 33000 m3/day and consists of two pairs of
stabilisation ponds (anaerobic + facultative). The other site is located in Bhubaneswar for the
hospital wastewater treatment and has a capacity of 70 m3/ day. There are also various septic
tanks in the city but not in very good conditions as it is explained by Mishra, 2004. Water-
Excreta Survey 2005-06 (CSE, 2013) forecasted that it will be required an increase of 16% the
treatment capacity of the city (see figure 3.2.1). However, these figures are below the present
needs. Cuttack´s Plant could treat urban wastewater of an equivalent population of about
120000 people. City of Bhubaneswar is divided into 30 wards, under the Bhubaneswar
Municipal Corporation control, and there are also 204 more villages along the rural periphery
(Mishra, 2004) and the closer city of Cuttack. Only the two cities gather a population of about
1.2 million people. In order to treat the wastewater generated in these settlements a
treatment plant with 10 times higher capacity would be necessary, compared to the one
located in Cuttack (Reoptima workshop, 2012). Nonetheless, the main wastewater treatment
plant of the city is under dimensioned and does not work properly. As it was pointed out by
Nitya Jacob, director of CSE’s water programme (CSE, 2012) the sewage is discharged into
drains that flow through oxidation ponds or aeration lagoons, these do not function, but merely
act as flow-through systems. Despite that Stabilisation Pond it is perceived as a low-cost
wastewater treatment option, the fact that the efficiency of the plant should be checked,
make wonder if it is the best solution for the city.
17 Low-cost wastewater treatment technologies for agricultural use
Figure 7: Bhubaneswar wastewater portrait. (Source: Centre for Science and Environment, 2013. Available at: http://www.cseindia.org/content/excreta-matters-0)
18 Low-cost wastewater treatment technologies for agricultural use
Agriculture and irrigation
India is the second most populated country of the world after China, with more than 1.2 billion
inhabitants in 2011(World Bank, 2013). Although it represents the 18% of world population, in
India only the 2.3% of geographical area is used for agriculture (Icar, 2011). The economic
importance of agriculture in India (in terms of gross domestic product) is declining in the last
few decades. In 2008-09 reached 15.7% from about 30% in 1990-91 (NAAS, 2009) and
nowadays it is just the 8% Gross Domestic Product (Icar, 2011). During the last two decades
agriculture has been replaced by other sectors as industry and services (Icar, 2011).The most
common agricultural production in India consists of small landholdings managed by small
farmers (Icar, 2011). The types of crops and varieties depend on the region of India. The food
grain is an important production, highlighting rice, wheat and pulse, also sugarcane, cotton,
jute and mesta. (Agricultural census, 2012). Nevertheless, the production of fruits and
vegetables is the most noticeable, where India pose the second ranking in the world. It is
important to mention okra and pea production, but also fruits as mango, banana or papaya
(Department of Agriculture and Cooperation, 2013).
According to CWC, (2010, data of 2007-2008) in India there are in total 62.3 million hectare of
irrigated agriculture. The type of irrigation varies; there are 16.5 million hectares by canal
irrigation, 2.0 million hectare irrigate by tanks, 37.8 million hectare by wells and 6.0 million
hectare by others means. In urban irrigated agriculture the reuse of reclaimed water is
common. Although there is a lack of realistic wastewater irrigation data in India (Kumar, 2012),
the use of wastewater is reported in many cities, as for example: indirect use of wastewater
for 40500 ha. in the city of Hyderabad (Kumar, 2012; Buechler, et al. 2002) or 14576 ha. in the
city of Vadodara ( Kumar, 2012; Bhamoriya, V., 2002.).
Although agriculture provides employment, both direct and indirect, to about 64% of the total
workforce of the Odisha region (Government of Odisha, 2011), in the city of Bhubaneswar the
agriculture is a minor activity, less than 5% of the workforce. Most of the people are employed
in the service sector (Van Beusekom, 2012). Urban agriculture production is mainly to sell in
local markets, but also for self-consumption. The activity of the farmers is individual, but they
have some kind of collaboration. There is a water users association to use the pumped water
and they also decide the percentage of crops at community level land (Dr. S. K. Rautaray and
Dr. S. Raychaudhuri, personal communication, 4th March, 2013). According to the Agriculture
census (2012) in Bhubaneswar Municipality there are 2186 agriculture holdings that cover an
area of 1289 hectares. The 93% of the holdings are plots smaller than 2 hectares and the 60%
below 0.5 hectare. There is no agricultural plot in the city bigger than 5 hectares (see Figure 8).
However, the number of hectares for agriculture plots is diminishing due to the change of land
use. The farmers sell their plots that are converted to urban land (Dr. S. K. Rautaray and Dr. S.
Raychaudhuri, personal communication, 4th March, 2013). Majority of urban agriculture
remains located on the banks of the Daya and Kuakhai rivers.
19 Low-cost wastewater treatment technologies for agricultural use
Figure 8: Estimated area by size classes and land use. (Self design based on data available in Agricultural census, 2005-06. State)
There are not official data of wastewater irrigated plots in the city. However, this was studied
by Van Beusekom (2012) using satellite images from the dry season. The results of his study
revealed that 50 hectares in the city were identified as potential wastewater irrigated areas.
Nevertheless the irrigation is necessary only during few months. The irrigation period is from
November until May. Inside the city wastewater is a constant flow and very accessible stream.
The irrigation technique used is surface, furrow and flood (Dr. S. K. Rautaray and Dr. S.
Raychaudhuri, personal communication, 4th March, 2013). The Unit – V, Bhubaneswar Dean
Orissa University of Agriculture and Technology (OUAT) is the department responsible of
Bhubaneswar urban agriculture. The types of agricultural crops that are grown the most in the
urban agricultural plots of Bhubaneswar city are Rice (in June), vegetables (e.g. tomato,
cucumber, amaranth, spinach, okra, sugarcane, snap melon,etc) and ornamental plants (flower
production) (from November until April) (Dr. S. K. Rautaray and Dr. S. Raychaudhuri , personal
communication, 4th March, 2013). One of the objectives of the Annual plan Odisha 2012
(Government of Odisha, 2012, chap 6, p2) is the introduction of large scale vegetable
cultivation in peri-urban areas and encouraging off season vegetable cultivation thereby
increasing the income of the farmers.
20 Low-cost wastewater treatment technologies for agricultural use
2.2 THE SCENARIO: WARD NUMBER 3
2.2.1 Location
The ward number 3 of the city has being chosen as a representative quarter for this study (see
Figure 9). The selection was based on the research developed by Van Beusekom in 2012,
where this area was identified as a possible location of wastewater irrigation. Furthermore,
this ward is crossed by Gangua Nallah stream that was defined in the Chapter 2.2.3 as the main
drainage canal of the city, therefore an easy source of irrigation water for the farmers. In
addition the ward boundary is defined by the Kuakhai River on the East. The irrigation scheme
result very logical; use upstream Gangua Nallah Canal as irrigation water source and Kuakhai
River as down slope natural drainage. Furthermore, according to the Comprehensive
Development Plan for Bhubaneswar in 2030, the existing agricultural land use covers large part
of the ward (see Figure 10.).
Figure 9: Bhubaneswar Municipal Corporation Wards Map. (Source: BMC, 2013, accessed on July 11, 2013)
2.2.2 Settlement description
Ward number 3 is formed by the localities of Chakeisihani, Sameigadia, Kalaraput,
Mancheswar, Bhotapada and PHED colony. It is located in the eastern part of the city in a
relatively low density area (2262 inh. /km2) comparing the rest of the city (average 4800 inh.
/km2). The ward measures 5.05 km2 and has a population of 11421 inhabitants (CCIP, 2006).
The reason behind this low density is the presence of agricultural plots and also the fact that a
large part of the ward is occupied by the Kuakhai River and it is a flood prone plain (see Figure
10.). In the ward number 3, there are two large residential areas formed by residential plots
and independent houses, Chakeisihani (southwest) and Satya Vihar (south). The majority of
21 Low-cost wastewater treatment technologies for agricultural use
the households in Bhubaneswar are formed by nuclear families (non joint families) and most of
them low raise housing and the 70% in Pucca houses (IITK, 2008). The Chakeisiani slum
settlement is located on the south west border. Some other settlements are located out of the
ward, such as VSS Nagar (close to drain 2 an 3) and Garakana Slum (close to drain 4). One of
the largest industrial areas of the city, Mancheswar, is located in the ward number 6 close to
ward number 3, and there is no separation of industrial and domestic effluents in the sewage
system. Drinking water supply facilities do not cover all the extension of the ward; in the entire
city only the 34% of households have their own tap. There are public water stand post for
supply water and also ground water is been extracting by wells. The phreatic level of ground
water is 18-24 m. b. g. l. as an average in the city (IITK, 2008).
Figure 10: Existing land use in ward nº3, Bhubaneswar, Odisha.( (Source: Self-designed adapted from IITK, 2008).
22 Low-cost wastewater treatment technologies for agricultural use
2.2.3. Energy utilities
The power supply of Bhubaneswar city is done by three different power grids so the city is split
in three electrical areas (BCDD-I, BCDD-II and BED). The Central Electricity Supply Utility (CESU)
it is the private company in charge of power distribution. The network power´s infrastructure
is old and inefficient. Furthermore there are problems of power theft by illegal connections,
sporadic power outages and low voltage supply especially on the periphery of the city.
According to IITK (2008), in 2008 there was no electricity substation (11KV) in Sribantapur.
Sribantapur is the zone of the city where Ward number 3 is located. Power supply is deficient
and it is predicted and steady increasing of the electricity demand in all the districts of the city
(IITK, 2008).
2.2.4 Land availability
There is a mixture of different land uses in ward number 3. They are reported in the Figure 10.
However, the ownership is well defined. Mainly, the private land covers the greatest part of
the ward. Government land only occupies a few areas (see Figure 14, Annex 3). The existence
of available municipality land for the purpose of implementation of a wastewater treatment
plant is difficult to forecast. Basing on current land use, land ownership and the Bhubaneswar
development plan Vision 2030 (IIKT, 2008) it is assumed that there is a high probability of this
availability.
2.2.5 Agricultural characteristics
The agricultural specifications of the ward number 3 are the following.
Soil characteristics: Due to the proximity to the river, the ground in the ward is mainly alluvial,
and the soil condition is hard (CCIP, 2006; IITK, 2008). By definition, an alluvial soil located in a
flood plain of a river, is a soil with high fertility and low drainage capacity. The proximity to the
river makes the phreatic layer rather shallow in these areas (Carías et al, 2004). Beside the
general characteristic of alluvial soils, the local specifications of the soil located at the banks of
Kuakhai River were not found by literature review.
Crop typology: The specific crop production of Bhubaneswar city was not found by literature
research. According to the data obtained by the interviews (Dr. S. K. Rautaray and Dr. S.
Raychaudhuri, personal communication, 4th March, 2013) and the citation of different papers
(IIKT, 2008; EMP, 2003, CCIP, 2006), vegetables and paddy will be most likely crops cultivated
in ward number 3. Rainfall is not enough to irrigate the crops from November to May. The
irrigation season match exactly with vegetables growing period. I will assume then that
tomato, cucumber, amaranth, spinach, okra, sugarcane, snap melon and flower ornamental
will be irrigated with wastewater. All possible crops cultivated in the area are moderate
sensible to salinity according to FAO (see Table 13, Annex 2). Regarding to type of crop
consumption, in case of vegetables like cucumber, tomato, okra or spinach, they might be
eaten raw (Pescod, 1992).
The exact number and size of agricultural plots are unknown. Under the data from agricultural
census (2012) it is assumed that there are small plots about 0.5 to 1 ha.
23 Low-cost wastewater treatment technologies for agricultural use
Water users are not formally associated in the area however they collaborate within each
other in case of well water extraction or crop selection (Dr. S. K. Rautaray and Dr. S.
Raychaudhuri, personal communication, 4th March, 2013).
2.2.6 Irrigation water resource
The slope of the ground drains naturally towards the East. Although South Easter railway and
the Daya West Channel form a physical division, the existing crossings under both
infrastructures allow the drainage from the west uplands to the eastern lowlands (CCIP, 2006).
Gangua Nallah Canal crosses the ward from north to south. Four out of the 10 major drains of
the city (nº 1, nº. 2, nº. 3 and nº. 4) confluence with Gangua Nallah Canal before or inside the
ward, and conveys the upstream urban wastewater to it (TCGI, 2006). Although the minor
rivers of the area dry during some months of the year, the wastewater origin of the effluents
make the Gangua Nallah canal and its drains, a perennial water source. It is essential to remark
that Daya West Channel is an irrigation canal that defines the west border of the ward and the
agricultural plots are located far from it. I assumed that the use of this water would involve the
construction of a canal infrastructure, so this option would not be contemplated in this study.
Gangua Nallah effluent quality
The water quality of the Gangua Nallah is clearly determinated by the drains discharges.
Gangua Nallah enters into the ward already containing the Patia Nallahs (Drain number 1)
effluents. One third of the ward would be irrigated with this water. After around 2 km, Sainik
school Nallah (Drain number 2) and OAP Area Nallah (Drain number 3) together confluence to
Gangua Nallah. Only at the end of the ward, close to the industrial area of Mancheswar, the
Vanivihar Nallah (Drain number 4) outflow into the canal. The quality of the canal and its
principal drains has been monitored. The flowing Table 2 shows the wastewater quality of
theses drains.
Table 2: Wastewater quality and quantity of Drains number 1, 2, 3, 4 and Gangua Canal of Bhubaneswar city. (Source: Self-design based on data from EMP, 2003).
Sample point
PH SS(mg/l) TDS (mg/l)
BOD(mg/l) COD(mg/l) Cl-
(mg/l) NO3(mg/l) Total
Fe(mg/l) Average
discharge (ML/D)
Drainage Area Km2
A 7.6 100 200 60 120 34 - - 17 16.93
B 5.9 160 200 24 52 28 1.55 1.44
C 7.4 120 180 100 130 36 - - 3.55 3.31
D 7.4 140 490 20 180 699 0.0592 0.319
E 8.3 19 - 3 8.6 - 0.370 2.4
Average 2001 A. Drain nº 1; B. Drain nº 2; C. Drain nº 4; D Gangua Canal at Mancheswar Industrial area; E. Gangua canal
The samples of the drains were taken few km upstream before the confluence with Gangua
Canal. The drain number1 was sampled at Chandraeskapur. The drain number 2 was sampled
at Mancheswar, and drain number 4 at Acharya Vilhar settlement. The quality of Gangua Canal
has been monitored at the confluence with the Mancheswar industrial area, therefore with
the impact of the industrial effluent (See Figure 11).
24 Low-cost wastewater treatment technologies for agricultural use
Figure 11: Location of water quality sample points of drains number I, II, IV and Gangua Nallah (Source: Self-design adapted from EMP, 2003)
The exact wastewater quality of Gangua Nallah across the ward number 3 was not found by
literature review. The assumption of the quality has been done basing on the data of the
samples (see Table 3) and the location (see Figure 11). Due to the cultivated land is located
from the medium to the north part of the ward, the drain number IV will not be considered to
deduce irrigation water quality. In the Environmental Bhubaneswar Plan (2003) was reported
that the BOD levels of Gangua Nallah are directly linked with the domestic human waste, and
diminish by sedimentation with the long distance transportation. The COD are related to
industrial pollution. The total coliform and faecal coliform were really high in all the sample
points around 16000 MPN/100ml. Therefore the assumed wastewater quality of Gangua
Nallah is shown in the following table.
Table 3: Assumed water quality of Gangua Canal in the north part of the Ward number 3, Bhubaneswar city. (Source: Self-design).
PH SS (mg/l) TDS (mg/l) BOD(mg/l) COD(mg/l) Cl-(mg/l) FAECAL Coliform (MPN/100ml)
5.9-7.6 100-160 200 24-60 52-120 28-34 16000
Gangua Canal has a weak concentration of pollutants according to the classification of FAO
(Pescod, 1992) (See Table 16 Annex2).
2.3 STAKEHOLDERS ANALYSIS
The aim of this stakeholder analysis is to identify who are involved and what interest they have
in the results of this research. With this analysis a general view of stakeholders will be shown.
The following table summarize the stakeholder considered in this analysis.
25 Low-cost wastewater treatment technologies for agricultural use
Table 4: Stakeholder register (Source: Self design)
NAME POSITION ROLE
Bhubaneswar Directorate Of Water Management (BDWM)
Ministry of Agriculture. Indian Council of Agricultural Research (ICAR)
Water management technologies for sustainable agricultural production.
Odisha Public Health Engineering Organization (OPHEO)
Government of Odisha. Housing and urban development (H & UD) department.
Provides plans and executes projects related to urban water supply and sewerage systems
Odisha Water Supply And Sewage Board (OWSSB)
Is in charge of the operation and maintenance of the urban water supply and sewerage infrastructure
Bhubaneswar Municipal Corporation (BMC)
Municipality Provides basic amenities to its inhabitants
Engineering Department of BMC Creates & Maintain Civil Infrastructures
Health and Sanitation Department of BMC
Health control and food security
Regional Centre Of Development Cooperation.
Odisha NGO, located in Bhubaneswar.
Water management for domestic use
Informal water User Association (WUA)
- Wastewater users
Local Urban Farmers - Wastewater users
Residents - Products consumers
BHUBANESWAR DIRECTORATE OF WATER MANAGEMENT (BDWM). This organization depends
on ICAR. The Institute aims to develop improved water management technologies for
sustainable agricultural production and disseminate it amongst researchers, government
functionaries, NGOs and farmers. It is also one of the main partners of REOPTIMA project (see
ANNEX, initiatives & projects), that is linked to this research.
ODISHA PUBLIC HEALTH ENGINEERING ORGANIZATION (OPHEO) and ODISHA WATER SUPPLY
AND SEWAGE BOARD (OWSSB). Under the administrative control of Housing and Urban
Development (H & UD) Department of the Government of Odisha, these organisations provide
the city with the infrastructure and services for water supply and sewage collection and
treatment.
BHUBANESWAR MUNICIPAL CORPORATION (BMC). The aims and objectives of the
Bhubaneswar Municipal Corporation is to provide basic amenities to its inhabitants like health
and sanitation, maintenance of roads and drains, education, improvement of slum dweller,
relief at the time of natural calamities etc.
o Engineering department of Bhubaneswar Municipal Corporation, which
objectives are to create and maintain civil infrastructures of B.M.C area such
as drains and culverts?
o Health and Sanitation department of Bhubaneswar Municipal Corporation.
This department is the one that will be interested in health control and food
26 Low-cost wastewater treatment technologies for agricultural use
security. Among other activities, this department develops campaigns for food
hygienic and also for epidemic prevention and control of the mosquito
antifilaria.
REGIONAL CENTRE OF DEVELOPMENT COOPERATION. This is a NGO located in Bhubaneswar,
whose mission is “to play a facilitative role in the struggle for rights of the poor and
marginalised over resources, opportunities, institutions and processes”. This organization is
trying to facilitate the access of clean water and address problems of water contamination. It
provides consultancy services and support to campaigns of water safety measures, and also
works on the lack of mechanisms for operation and maintenance of water facilities.
JAPAN INTERNATIONAL COOPERATION AGENCY (JICA): It is an active agency in the area, that
have funded different projects in Bhubaneswar and Cuttack related to sewage and drainage
canals.
WATER USER ASSOCIATIONS (WUA). Although it is not clear the type of agreements and
negotiation between farmers, the existence of an informal farmer association, make the
involvement of the water user in the selection and implementation process of the technology,
an essential issue. The safe and beneficial use of the effluent will be assured by farmer’s
commitment with the correct performance of the system. They would get motivate to
participate if they see the reason behind (Singhirunnusorn, 2009). However, poor urban
farmers are probably not the higher social status, the literacy of farmers might not take it as
granted and might be also considered the possible illegality of the settlement. These factors
complicate their participation in the selection and implementation of the technology.
LOCAL URBAN FARMERS. Users of the wastewater canals. They are the main stakeholders of
this research. They have to confront the dilemma of using or not wastewater for irrigation.
Most of the times this is the only way to assure their livelihood.
RESIDENTS OF BHUBANESWAR. The citizens of Bhubaneswar have to deal with their own
excreta flowing open pit in the drains or overflowing from the septic tanks. The use of these
water streams as flood irrigation also implies a problem of odours. The onsite treatment might
suppose for them an improvement of life conditions. However, the implementation of
wastewater infrastructures sometimes implies the construction of noisy, smelly and
mosquito’s reservoirs facilities. Therefore, technology can also cause many nuisances for the
local dwellers.
FOOD CONSUMERS. Their interest might be high. Contaminated food implies a direct risk for
their health.
The Directorate of Water Management of Bhubaneswar is a research institute related to the
Ministry of Agriculture. Although it belongs to the ICAR (Indian Council of Agricultural
Research), it is possible to develop some kind of collaboration with the Sewage Board (Dr. S. K.
Rautaray and Dr. S. Raychaudhuri, personal communication, 4th March, 2013) in order use
reclaimed water for agriculture. There is awareness from the policy makers of the importance
of a good water management. In fact, there are many different initiatives within the State of
Odisha and also form Bhubaneswar municipality (see initiatives & projects, ANNEX):
27 Low-cost wastewater treatment technologies for agricultural use
In order to develop a better water and wastewater management. The annual plan 2012-13 of
Odisha government (Government of Odisha, 2012) considers: the implementation of
Integrated Watershed Development Programme (IWDP), Drought, Prone Area Program
(DPAP), Watershed development programme under Special and Plan for KBK districts and
Integrated Watershed Management Programme (IWMP).
There are many initiatives related to the sewage and sanitation of the city.
- For example the workshop on “Bhubaneswar’s Water and Sewage problems”
organized by the Centre for Science and Environment celebrated 14th June 2012.
- Also the Japan International Co-operation Agency (JICA) developed a project of sewage
Infrastructure for the city of Bhubaneswar. The project is related to dive a new
sewerage system in six districts of the city. Although was planned to be already
implemented in 2011, it is not developed yet.
Regarding specifically to sanitation in slums, there are different projects:
- Odisha Water Supply And Sewerage Board (OWSSB) is working in the comprehensive
sewerage project (CSP), but the project is very behind the schedule, meanwhile, the
department of Housing And Urban Development wants to create community toilets in
slums and areas not covered by CSP using integrated up-flow filter technology.
- Also public toilets in Bhubaneswar and Cuttack slums, has been funded by Bill and
Melinda Gates Foundation.
- The Samman project is another initiative to improve the sanitation in the slums of
Bhubaneswar and Cuttack cities. It is developed by a partnership of diverse group of
organizations and government entities united to tackle the sanitation and hygiene
crisis in India's urban slums.
28 Low-cost wastewater treatment technologies for agricultural use
3. GUIDELINES AND STANDARDS OF WASTEWATER
QUALITY FOR AGRICULTURAL PURPOSES
3.1 INDIAN REGULATION FOR IRRIGATION WATER QUALITY
The use of wastewater for irrigation is not specifically regulated by the Indian legislation.
However Indian Government has indirectly addressed this issue in several occasions by the
Ministry of Environment and Forests (MoEF). The pollution is regulated and controlled by the
Central Pollution Control Board (CPCB) of India. This board supports the MoEF with technical
advice to promote the environmental protection (Act 1974). They provided minimal national
standards to control pollutants discharges. The first approach to irrigation water standards was
mentioning in the Act, 1974. For preventing and controlling water pollution was set up some
water quality parameters according to different water uses or classes; “designated best use”
(DBU). The appropriate water quality for irrigation use was identified as use E; pH between 6.0
to 8.5, Electrical Conductivity at 25°C micro mhos/cm Max.2250, Sodium absorption Ratio
Max. 26, Boron Max. 2mg/l (see Table 20, Annex2). These criteria were only used as water
quality classification, as an assessment tool for Indian water bodies, in order to develop an
Indian Water Uses Map (CPCB, 2013b. pg 8). In 1999 was constituted a Committee by the
National River Conservation directorate. They not only recommended some standards for
treated wastewater discharge in water bodies. In this case it was considered the possible use
of land irrigation. For crops not eaten raw the recommended standards were: BOD <100 mg/L,
TSS <200mg/L and Fecal Coliform 1000-10000 MPN/100 ml. Although other recommendation
even more restricted were given during the last few years (i.e. Ministry of Urban Development
and Poverty, Committee 2004), all of them were related to the outfall into water bodies (CPCB,
2008). Therefore, these parameters will be taken into account as a reference in this research.
However an analysis of the international standards will be done in the following section in
order to have more complete guidelines.
3.2 INTERNATIONAL GUIDELINES REVIEW FOR HEALTH PROTECTION WHEN WASTEWATER IS REUSED FOR IRRIGATION
There are guidelines from World Health Organization (WHO), United States Environmental
Protection (USEPA), California Department of Public Health (CDPH), Food and Agriculture
Organization (FAO), etc. A review of the most influencing guidelines used worldwide for
wastewater use in agriculture, has been made (see Table 15. Annex 2). All the guidelines or
regulations take, as a starting point, the classification of the wastewater in terms of type use of
the wastewater. In the Table 15, Annex 2, are only shown and reviewed the types of crops that
could be found in the ward number 3 of Bhubaneswar. Although the infectious agent’s
concentration is considered in all guidelines, WHO (1989) recommend also some general
measures of health protection as for example; crop selection or restriction, different
wastewater application, human exposure control and wastewater treatment. However, the
WHO (1989) only consider E. Coli as a sign for significant human health treat, and as it was
indicated by Adhya, T.K. (Reoptima workshop, 2012) no other viruses and pathogens are
analysed. Scott (2004) remarked that in a situation of lack of infrastructure for treatment, the
achievement of WHO (1989), turns out completely unaffordable, and therefore the guidelines
29 Low-cost wastewater treatment technologies for agricultural use
turn into targets rather than norms to practise. Furthermore, the California water recycling
criteria entailed high technological treatments to achieve the water quality that is stipulated. It
makes that these standards become rather complicate to apply for low budget situation, as in
developing countries (Scott, et al 2004). On the other hand, physical and chemical parameters
are contemplated only for American and FAO regulations. Indeed, FAO guidelines are unique.
Not only are the health issues considered in these guidelines but also the importance of
wastewater quality for agricultural targets. They also proposed a table with the trace element
of toxic compounds that could contaminate the crop (see Table 16 and
Table 17, Annex2). The existing regulations or guidelines in many developed countries are
based on California guidelines or even WHO ,that are less restrictive, as is the case of some
countries of Mediterranean Europe (Lazarova et al, 2005, p73). But actually, the regulation for
the use of reclaimed water in agriculture varies among countries and even within regions of
the same country. Water quality restriction is set up depending on many different aspects:
crop choice, irrigation technique, wastewater treatment availability, economic input or health
protection (Lazarova et al, 2005, p.73). But the fact remains that, for the urban agriculture of
developing countries, the WHO guidelines (1989) result very strict (Lazarova et al, 2005, p.75)
and in many cases difficult to apply. The trade of agricultural products across boundaries
makes this issue an international concern (Carr, et al 2004.p 42). Have been done an effort by
the international agencies in order to develop effective guidelines for health and environment
protection. Hence, in 2006, due to the need to develop more flexible approach so adjust the
best to local circumstances, WHO, UNEP, and FAO issued the new guidelines basing on the
Australian National Guidelines for Water Recycling. This approach combines treatment and
post-treatment barriers compared to the old approach that relied solely on the treatment plant
as the only reliable control measures (Ardakanian et al., 2012). Consequently, the guidelines
and the parameters considered, have not only to deal with health protection but also with the
agricultural profit the two aspects that were pointed out in the objective of this research. WHO
2006 suggests a very complete guideline including both issues. According to Ardakanian
(2012), these guidelines approach the local socioeconomic conditions in an adaptive way. In
order to make the approach more specific, they not only assess the hazards but also include
diseases risk management. Primarily, they focus on the health risk derived of using the
wastewater. It is suggested to analyse the possible microbial risk of using the wastewater for
agriculture. This is developed by a Qualitative Microbial Risk Analysis (QMRA), were the
tolerable maximum load of disease is calculated in order to know the tolerable risk of
infection. To optimize the risk analysis the Monte Carlo simulation tool is used. Base on that it
is deduced the requirements of pathogens reducing. The risk study has a multiple approach,
considering not only treatment and post treatment measures, but also measures adopted with
no treated effluent. Once it is defined the required pathogen reduction, health protection
proposed measures will be related to; (1) wastewater treatment, (2) safe irrigation measures
and the possibility of restrict or even change the type of crop, (3) product manipulation post
harvesting and (4) in-kitchen product preparation (see
Table 18, Annex2).The framework proposed is quite complete and adapted to the local
conditions. However, the health risk assessment it is base on the measure of very specific
pathogens; rotavirus, Campylobacter and Cryptosporidium. The lack of information makes the
guideline not applicable for the scenario analysis.
30 Low-cost wastewater treatment technologies for agricultural use
3.3 EFFLUENT QUALITY STANDARDS AND MANAGEMENT RECOMMENDATIONS
Therefore, based on the recommended standards from Indian MoEF (see chapter 3.1), the
proposed guidelines by FAO and WHO in 1989 and USEPA in 1992 ( see Table 15, Annex 2) and
the recommendation for reducing health risk from WHO, World Bank and FAO 2006 (see
Table 18, Annex2) the following Table 5 was developed.
Table 5: Water Quality reference value according to different uses in agriculture (Source: self design base on Lazarova et al, 2005, WHO 2006b, World Bank, 2010)
PHYSICAL & CHEMICAL PARAMETERS
To preserve irrigation properties Recommendation (1,3) Moderate restriction of use (1)
Maximum (5)
Ecw1 (dS/m)- < 0.7 0.7 - 3.0 2.25
TDS (mg/l) < 450 450 - 2000 -
Sodium. Surface irrigation (SAR) < 3 3 - 9 -
Sodium. Sprinkler irrigation (me/I) < 3 > 3 -
BOD(mg/l) <10 - <100 mg/L
TSS (mg/l) <30- - <200mg/L
Chloride (Cl) Surface irrigation (me/I)
< 4 4 - 10 -
Chloride (Cl) Sprinkler irrigation(m
3/l)
< 3 > 3 -
Boron (B) (mg/l) < 0.7 0.7 - 3.0 -
Nitrogen (NO3-N)3 (mg/l) < 5 5 - 30 -
Bicarbonate (HCO3) (me/I) < 1.5 1.5 - 8.5 -
pH 6.5-8 > 8.5
BIOLOGICAL PARAMETERS
To avoid health problems Recommendation (1,2) Maximum (5) Intestinal nematodes Crops type A <1 Intestinal nematodes (nº eggs/L)- -
Intestinal nematodes Crops type B <1 Intestinal nematodes (nº eggs/L)- -
Faecal coliform Crops type A <1000 Faecal coliform (nº/100mL) 10000MPN/100mL
Faecal coliform Crops type B No standard recommended for Faecal coliform (nº/100mL)
10000MPN/100mL
RECOMENDED MEASURES Post treatment-health protection control measures recommendation (4) Furrow irrigation Crop density and yield may be reduced.
Low-cost drip irrigation 2-log unit reduction for low – growing crops, and 4-log unit reduction for high-growing crops.
Reduction of splashing Framers trained to reduce splashing when watering cans used (splashing ads contaminated soil particles on to crop surfaces which can be minimized)
Pathogen die off Die-off between last irrigation and harvest (value depends on climate, crop type, etc.)
Overnight storage in baskets Selling produce after overnight storage in baskets.
Produce separation prior to sale Rinsing salad crops, vegetables and fruits with clean water, running tap water or removing outer leaves.
Produce disinfection Washing salad crops, vegetables and fruit with appropriate disinfectant solution and rinsing with clean water.
Produce peeling Fruits, root crops.
Produce coking Option depends on local diet and preference for cooked food.
A: Irrigation of crops likely to be eaten uncooked, sport fields, public parks. B: Irrigation of cereal crops, industrial crops, fodder crops, pasture, and trees. 1. FAO 1989 guidelines; 2.WHO 1989 guidelines; 3.USEPA 1992 guidelines, 4.WHO 2006 guidelines (Note. The recommendations are done depending on the health risk assessment); 5.Indian Ministry of Environment and Forestry recommendations.
31 Low-cost wastewater treatment technologies for agricultural use
4. LIST OF WASTEWATER TREATMENT SYSTEMS
4.1REVIEW OF WASTEWATER TREATMENT SYSTEMS
Generally, the treatment of wastewater is described as a multistage system. The more stages are
made, the more level of treatment is done, according to the different substances that are removed
or separate from the water bulk. The most complex system template for wastewater treatment
would comprise four stages; pre-treatment, primary treatment, secondary treatment and tertiary
treatment. Each stage could be done by various processes and technologies. A review of the different
processes involve in wastewater treatment is done in the Table 6. Following there is a brief analysis
of the treatment stages.
(1) During pre-treatment or preliminary treatment, big solids are removed and grits and oil loads are
reduced. Preliminary processes prevent problems of equipment clogging or erosion. Therefore this
stage supports and optimizes the subsequent treatment stages.
(2) The primary treatment involves physical and chemical operations, like flocculation coagulation or
sedimentation. These processes are induced in order to remove solid particles not easy to settle. This
stage removes up to 25-50% of BOD, 70% of suspended solids (SS) and 65% of grease (Armenante,
1999).
(3) The secondary stage consists of processes that remove biologically the organic matter. Afterwards
use to be done sedimentation of suspended solids. Therefore, the secondary treatment aims to
remove the 90% of the organic matter dissolved and the 80% of the suspended solids by biological
processes (Armenante, 1999).
(4) The tertiary treatment is applied to produce an effluent with very low level of organic matter and
suspend solids. This stage is an additional treatment that guarantees quite acceptable quality of
effluent. Beside organic matter also toxic compounds, pathogens and odours are removed. Indeed
these processes are the one recommended for a safety reuse of the effluents (in terms of health
protection).
The kind of treatment will depend on the characteristics of wastewater. Wastewater is generated by
human activities. These activities determine the quantity and the quality of produced wastewater.
Urban wastewater comprises domestic wastewater, industrial wastewater and urban runoff.
Domestic wastewater would consist of black (toilet) and grey water (kitchen and bathroom).
Therefore they would contain organic matter, fats, salts, tens active compounds, nutrients, solids,
pathogens, etc. However industrial wastewater composition is not possible to standardize and it
varies depending on the industry type. Likewise, urban runoff characteristics could differ according to
the surface pollution. In an urban area it could contains different solids, sediments, oils and heavy
metals deriving from roads (CENTA, 2007a). The wastewater collection system and the possible
separation of industrial and domestic effluents, by separate sewage system, is a factor to consider.
Besides the quality, wastewater volume is also an essential factor that influences the selection and
design of the technology. In small and medium size settlements, wastewater generation is not that
constant the fluctuations of quantity ensue more extreme. As a consequence, wastewater quality is
related with the quantity. In small settlements, wastewater volumes are smaller and therefore the
water pollutants are less diluted.
32 Low-cost wastewater treatment technologies for agricultural use
On the other hand, when it is designed a wastewater treatment system, there is a choice between
centralized, semi-centralized and decentralized systems.
The definitions of centralized and decentralized water treatment are often blurry. Depending on the
specific situation (presence and /or cost effectiveness of a sewage system, topography, population
density, etc.), both offer advantages and disadvantages. Centralized systems are characterized by
collective wastewater treatment so they treat wastewater of medium to large scale communities
(Tchobanoglous, 1996). They have upscale sewage systems to conduct wastewater in to a central site
of treatment. The collection sometimes involves conduction over large distances therefore high
investments in infrastructure. However centralized systems are used worldwide in many cities. The
fact that they are able to cover higher population demands makes them a good alternative to access
high tech for a relatively low cost per inhabitant. Furthermore the monitoring and control of larger
amount of wastewater is simplified in a single point of discharge (Crites, et al 1998). As an example,
for big settlements, centralized systems would use mechanical systems like activated sludge,
oxidizing beds, membrane technology or lagooning (Seto, 2005). By the contrary, decentralized
systems are aimed for individual or low scale communities; households, neighbourhoods or spread
settlements. Therefore they do not have connection to a centralized sewage system. They consist of
alternative wastewater collection systems (i.e. septic tanks) and the disposal (reuse) of the treated
effluent is close to the point of origin. As an example, for small or spread settlements would be used
soil based systems or package plants (Seto, 2005). These decentralized systems can use high
technology but more often they use simple natural technologies that require relatively low energy or
even no energy (CSE, 2013b). Yet, it should be mention that there are many situations in between.
Small settlements, or even dispersed households could be interconnected forming what is called
semi-centralized treatment sites. Tuning the attention on the decentralized systems, mention should
be made of the spreading use in India. The suitability of these systems for Indian urban contexts was
mentioned by Kumar (Reoptima workshop, 2012), and the Centre for Science and Environment
reports various examples of successful implementation in cities like for example at Kachpura slum
near Mehtab Bagh in the city of Agra. (CSE, 2013b). Decentralized onsite systems are closely related
to sanitation treatments. Onsite treatment (at the point of generation) allows also the separation of
wastewater streams of various origins and therefore a better control of wastewater quality inlets.
Moreover, it has been proved that the treatment of black and grey water separately reduces the
energy, materials and emissions cost of the treatment process (Balkema, et al. 2002)
33 Low-cost wastewater treatment technologies for agricultural use
Table 6: Summary of processes of wastewater treatment (Source: self-design base on World Bank, 2013; Armenante, 1999; CENTA 2007a, Card, 2005)
PROCESSES DEVICES
PRE-TREATMENT or PRELIMINARY Removal of coarse easy separable solids, fat –grease- oil separation and equalization of flow
Removal of coarse solids
Grit removal Screens: Coarse screening (Bar racks), Medium screening (Inclined rotary screens, drum rotary screens, rotary disk screens), fine screening (drum rotary screens, rotary disk screens, centrifugal screens, micro strainer. Grinders: Vertical screens, semicircular cutting disks, cutting blades, conical shaped screen grid. Grit chambers (sand trap): Sedimentation tank (horizontal, aerated, or vortex)
Fat/grease/oil separation
Separation of free oil by gravity or flotation Grease trap (Sedimentation tank). Air flotation devices (diffusers, blowers)
Separation of emulsified oil De-emulsifying agents addition
Equalization of flow rate and pollutant concentration Tank (reservoir)
PRIMARY TREATMENT Physical-chemical operations to remove organic and inorganic solids and separation solids from solid-liquid suspension
Sedimentation of solids Clarifiers (Sedimentation tank): magnetite, vortex separators. Thickeners (Sedimentation tank)
Filtration of solids Mechanical straining
Sedimentation on filter
SECONDARY TREATMENT Biological process to remove dissolved organic matter and separation of suspended solids
Bio
logi
cal c
on
sum
pti
on
of
OM
Aerobic process
Activated sludge treatment (several chambers) Sequence batch reactors (one chamber)
Reactor tank. Air diffusers (Oxygen blowers). Sludge pumps.
Trickling filtration/ biofilter/ biological filter (rotating) / oxidation beds/ filter beds (carbonized coal is called oxidation bed)
Septic tank for fermentation or raw water tank. Bioreactor containment, Filter for biofilm. Air diffusers (Oxygen blowers). Sludge pumps. Percolation ponds. Treated water tank.
Soil based filter technology/ terrestrial system
Soil biotechnology (SBT)/ (trickling filtration using soil as a filter)
Land filter: Land application. Leach field. Soak pit( soak away) Green filter: trees or crops.
Aerobic reactors (rotating biological contactors)
Tank. Rotating disks
Ponds/Lagoons/ stabilization ponds /oxidation ponds or lagoons
Earthen basin or tank. Measurement devices. Sampling systems. Pumps
Constructed wetlands Earthen basin or tank. Phytoremediators (reed beds, ...)
Anaerobic process
Anaerobic digesters (reactors) that produce septic treatment/Anaerobic activated sludge process/.Up flow anaerobic sludge blanket digestion (UASB)/ Expanded granular sludge bed digestion (EGSB).
Tanks. (Imhoff tank. Anaerobic baffled reactor (ABR). Anaerobic clarigester. Anaerobic expanded-bed reactor. Anaerobic filter. Anaerobic fluidized bed. Anaerobic MBRs. Continuous stirred-tank reactor (CSTR). Anaerobic migrating blanket reactor. Batch system anaerobic digester. Internal circulation reactor (IC). One-stage anaerobic digester. Plug-flow anaerobic digester) Pumps
Anaerobic lagoons or ponds/ stabilization ponds
Earthen basin. Measurement devices. Sampling systems. Pumps
Secondary sedimentation Sedimentation tank (clarifier)
Drum rotary screen. Centrifugal screen
TERTIARY TREATMENT (Polishing) Remove toxic or recalcitrant organic pollutants (halogenated, not easy biodegradable, Phosphorus, Nitrogen...) and disinfection
Filtration or Adsorption. Odour removal Sand tank. Activated carbon tank. Lagooning: Earthen basin or tank. Membrane filtration
Nutrient removal (N and P). De-nitrification tanks (anoxic tanks) with mixers
Disinfection. Pathogen removal. Chorine addition. Ozone addition. U.V. lamp. Lagooning.
34 Low-cost wastewater treatment technologies for agricultural use
4.2TECHNOLOGIES FACT SHEETS
Base on the criteria indicators, the following list of technologies are preselected due to the simplicity
of the devices, easy to operate, low or non energy requirements and already tested locally.
(1) Pre-treatment devices could be very simple in terms of operation and maintenance works, can be
operated without energy supply and cleaned manually (e.g. some screens, grease traps or grits
traps). However, in some occasions to remove emulsified oil or fat droplets are required air blowers
or de-emulsifying chemical agents that complicate the operation and increase the maintenance
costs. In order to remove solids, fine screens have not being considered because the small light hole
could be easily clogged. This complicates the O&M works in terms of cleaning and reparations. The
screening systems that require energy to work as rotary screen or centrifugal are also rejected.
Grinders are not considered because it is a mechanical device for removing coarse solids and can be
substituted by a manual device like bar racks.
(2) Selection of primary treatment devices. As far as agriculture concern, during
coagulation/flocculation phase, some phosphates could be removed by precipitation during the
addition of the coagulants. This phosphate removal is not that positive for a possible agricultural
reuse.
(3) Selection of secondary treatment devices. Activated sludge is the most common biological
process use worldwide (CENTA, 2007a). However a constant supply of energy is required for the use
of blowers or diffusers to produce the oxygen that microorganisms need or pumps that transfer
sludge back to the biological reactor. In order to reduce the energy requirements, other biological
treatments, as lagooning or constructed wetlands are taken into consideration. The oxygen in that
cases are is supply by plant roots. (4) Selection of tertiary treatment devices. Polishing processes
produce very acceptable effluent characteristics that in case of reuse of effluent turn out decisive.
Mechanical devices as UV lamps or chemical agents as ozone are not considered. Facultative or
maturation lagooning and sand filters seem to be the most economically feasible process.
To summarize, the selection of the technologies was made upon the recommendations proposed by
Sasse (1998) to define low maintenance wastewater treatment devices for developing countries.
Therefore, despite the proven efficiency in other socio-economical context, all processes that depend
on; chemical additions (coagulation), aeration (flocculation), recirculation (activated sludge
processes), membrane (desalination) and therefore; skilled labour, constant energy and chemical
supply and expensive materials were not included in the list. In the scenario, ward number 3,
wastewater source is a sewage drain. Therefore, it is considered as a semi-centralized situation. For
this case study, it would not be possible to use onsite sanitation systems as treatment option; like pit
systems, or urine storage tank (for more information consult Tilley, 2008). However, due to the
existence of septic tanks in the city (IITK, 2008), as part to the urban sewage facilities, they have been
included in the technology selection. Besides that, all the technologies selected are known locally or
have been already implemented in India.
The fact sheets attempt to synthesize and examine the information compiled from several authors. In
the content there is a brief description of the device and working principle besides the outline of the
characteristics, advantages and limitations.
35 Low-cost wastewater treatment technologies for agricultural use
4.2.1 Coarse screens (Bar racks)
This device retains coarse materials of large size (6 to 150mm). It consists of a series of parallel bars (straight or curved) that form a screen. They are placed vertical to the water flow at an angle of 25o to 50o. In some cases is an essential device in order to protect pumps, valves and pipes in subsequent treatment stages.
Design criteria.
Hydraulic retention time (HRT): No retention time. The wastewater passes through the bars without stopping. Although the removal performance improves at low velocities, that also produce solid settlement. To avoid this problem the design of the system should allow a velocity through the bars < 0.3 m/s. Dimensions: Bar dimensions: width: 5 to 15mm. length: 25 to 37.5 mm. Bars clear opening is 15-50mm. Construction. Bar tracks are installed in wastewater canal. Therefore, in order to drive the flow through the screen, a canal should be part of the system. Canal with rectangular profile shape is the most common. Materials: Steel, stainless steel
O & M REQUIREMENTS
Operation. Simple operation. Wastewater can flow by gravity in to the canal and throw the screen. Maintenance. The maintenance consists of cleaning of the bars and also removal of sediments from the bottom of the canal. This should be done periodically (even daily) and maximizing during rain periods. Mechanical cleaning devices are used for large systems however they require power supply and periodical greasing. Spare parts (bars or screens) are easy to find at local markets.
CONSIDERATIONS
Advantages. Low capital cost investment. Good efficiency for coarse solids reduction. Limitations. It is a preliminary unit that does not reduce pollutants and pathogens loads, only removes large particles. The cleaning task results unpleasant for the operators. A disposal for removed solids is required.
TECHNICAL DESIGN
PRELIMINARY TREATMENT
Input Domestic wastewater/ Urban wastewater Household/Neighbourhood/City
Effluent BOD reduction 0% TSS reduction 0% Pathogen reduction 0% TN reduction 0% TP reduction 0%
(Source. CENTA, 2007b;www.aboutcivil.org)
36 Low-cost wastewater treatment technologies for agricultural use
4.2.2 Sand traps (grit chamber)
The sand trap also called grit chamber consists of a static sedimentation tank. This device aims to remove small particles bigger than 0.2mm, in order to protect pumps, canals or pipes from deposit of sediments and erosion. Sand, gravel, mineral particles, and organic materials not easy broke down (seeds, eggs, bones, grains) are removed. In many occasions grease and sand traps are combined at the same device (see figure of grease trap). In some cases is an essential device to avoid
problems of clogging in the subsequent treatment stages.
TECHNICAL DESIGN Design criteria. Hydraulic retention time (HRT): 45 to 90 seconds. Dimensions: Rectangular or square tank, with trapezoidal or parabolic profile. Wastewater flows horizontally throw the chamber at 0.3 m/s. Spillways are required to prevent problems of overloads. In small treatment plants sand is removed by hand, so the canal should have accumulation capacity of 4 -5 days. Construction. It is a very simple system to build and O&M, that allows solid removals with high rates of performance Materials. Simple tank construction of concrete, brick or plastic. Prefabricated tanks are available but might increase the cost. Although parabolic shape is most suitable, it is difficult to build. Therefore trapezoidal section is the most used. O & M REQUIREMENTS
Operation. Simple operation. Wastewater flows horizontally by gravity in to the tank and not extra energy supply is required. Maintenance. The maintenance is easy and does not need qualified personal. Consist of cleaning by removal of sediments from the bottom of the tank. There is no need of spare parts and other equipment replacements. CONSIDERATIONS
Advantages. Low capital cost investment. Good efficiency for solids reduction. Remove eggs Practically the total of the large inorganic particles are removed. Prevent blockages and erosion of irrigation systems. Limitations. Effluent properties do not change from the input. It is a preliminary unit that does not reduce pollutants and pathogens loads, only removes large particles.
PRELIMINARY TREATMENT
Input Domestic wastewater/ Urban wastewater Household/Neighbourhood/City
Effluent BOD reduction COD≤20%
TSS reduction ≤20%
Pathogen reduction 0%
TN reduction ≤10%
TP reduction ≤10%
(Source. CENTA, 2007b, Morel et al, 2006)
37 Low-cost wastewater treatment technologies for agricultural use
4.2.3 Grease traps
The grease trap consists of a static sedimentation tank. The device aims to remove floating fat droplets. Once wastewater enters into the tank, substances with lower density than water remain floating at the surface. The rest of the fluid flows away by the bottom of the device. The tank could be also used to remove grits by sedimentation. In some cases is a basic or essential device in order to avoid problems in further treatment stages.
TECHNICAL DESIGN Design criteria. The design should follow two criteria: - Proper HRT. Wastewater has to stay in the tank enough time to cool down. Thus, in cooler wastewater fat droplets emulsify easier. - Minimum turbulence: This is necessary in order to avoid the flush of grease and grits in to the next device. Hydraulic retention time (HRT): Minimum 15 to 30 min. Dimensions. Enough depth is required to difference the two layers of substances. I.e. for individual households the common dimensions are: length 1.3 – width 2.0, minimum volume 200-300l. Construction. Materials. Simple tank construction of concrete, brick or plastic. Prefabricated tanks are available but might increase the cost. O & M REQUIREMENTS
Operation. Manual device. The management is easy and does not need qualified personal. Wastewater can flow by gravity in to the tank and not extra energy supply is required. Maintenance. Manual cleaning. The oil and the scum should be removed periodically. The fat is scooped by hand. Minimum a monthly revision is required. No need of spare parts and other equipment replacements. CONSIDERATIONS
Advantages. The oil and grease removal could reach 70%. Limitations. Requires frequent maintenance. Not covered (sealed) tanks could produce odours. The cleaning task results unpleasant for the operators
PRELIMINARY TREATMENT
Input Domestic wastewater/ Urban wastewater Household/Neighbourhood/City
Effluent BOD reduction COD≤20%?
TSS reduction ≤20%
Pathogen reduction 0%
TN reduction ≤10%
TP reduction ≤10%
(Source. CENTA, 2007b; Morel et al, 2006)
38 Low-cost wastewater treatment technologies for agricultural use
4.2.4 Septic tanks
It is a sedimentation tank use for primary treatment. It is an underground system that received the WW by gravity. It is used to remove TSS by sedimentation. The solids sink and accumulate at the bottom of the tank mineralizing by anaerobic reactions. The tank is divided in to row chambers (usually 2-3). At the first chamber, the particles of highest density settle out at the bottom forming the sludge. The less dense particles (oil and fat) remain floating at the surface forming a scum layer. Clarified water pass to the other chamber by a hole located under the water level. The same process occurs at the second chamber. The reason behind this is processed in at least 2 chambers, is because bubbles produced by anaerobic digestion disturb the sedimentation of small particles. The second chamber contains less sludge, fewer burbles are produced and it allows sedimentation of lighter particles.
TECHNICAL DESIGN
Design criteria. Hydraulic retention time (HRT): The size should let hydraulic load retention of at least one day. There is a potential risk of dangerous gases release; therefore tanks should be designed with vent holes. Dimensions: The dimension design of the tank depend on many factors like temperature, wastewater quantity, wastewater quality and frequency of desludging. Considering these entire factor, the volume of the tank will be calculate for the maximum sludge storage capacity and scum accumulation. The first chamber use to be bigger than the second, 50 to 65%. Tank height around 2.5 m and length should be twice width. I.e. Normal size of septic tank is calculated for around 250 – 300 l /inhab. Construction. The construction is not simple and requires experience labour. Materials: The tank could be made of different materials, concrete, plastic, PVC or fibreglass. There are buried systems therefore the construction requires excavations. These earthworks could raise the costs. The construction could be on site, but there are also prefabricate systems that are transport to the specific location. Spare parts are required but there are easy to find in local market.
O & M REQUIREMENTS
Operation. Manual device. The management is easy and does not need qualified personal. Wastewater can flow by gravity in to the tank and not extra energy supply is required. No electrical consumption. The system has to be desluged periodically. This requires a truck with a pumping device. Maintenance. Maintenance costs are very low. Periodic monitoring is needed to check if the tank is working correctly. The system has to be clean and desluged regularly. The floating solids, oil and the scum should be removed periodically. In case of WW contains non biodegradable items (napkins, tampons) cleaning operations are more often required. Desludging requires a truck with a pumping device. A manual desludging is not recommended because the hazardous pathogen content of the sludge. Sludge formed in the chambers suffers anaerobic decay process, mineralizing and reducing it volume. Sludge accumulation rate is 70 to 100 litres per year. Due to this, tanks can keep the sludge for long term. Desludge frequency varies from 2 to 5 years. Overloading of tanks is the most common result of mismanagement.
CONSIDERATIONS
Advantages. Small size. Compact systems and underground, small land areas are required. The removal of SS is variable with a max of 60%, let good performance of agricultural devices. The effluent contains high amount of nitrogen therefore it is completely available for the crops. No flies or odorous problems if the tank is well sealed and maintenance. Long term device services than with well maintenance could last many decades. Limitations The infrastructure for transport the effluent is required as well as enough space to vacuum truck operation. Regarding to the health aspects, pathogens contents of the effluent is very high. In colder climate the treatment efficiency is reduced. The sludge generated is odorous. Risk of ground water pollution by percolation if not constructed properly. Not suitable if phreatic surface is shallow (<4m) or in areas with flood tendency. Low robustness. No adaptation to load fluctuations. The system is designed for certain volume of WW. If there is a sudden change of this volume (from rainfall or increase of WW) the device will overload and the process fails. Despite the good quality of sludge that can be used as fertilizer, it has high pathogens content therefore the sludge should be treated, appropriately disposed or managed.
PRIMARY TREATMENT Input Domestic wastewater
Household
Effluent BOD reduction COD 30%-50% TSS reduction 40-60% Pathogen reduction 0% TN reduction Low TP reduction 20-30% (sedimentation)
Source. Tilley, et al, 2008;CENTA 2007b, Morel, et al. 2006)
4.2.5 Imhoff tank
39 Low-cost wastewater treatment technologies for agricultural use
The Imhoff tank is a variation of septic tank. The Imhoff tanks consist on a unique deposit divided in two parts. Process characteristics of this device are similar to septic tank. Sedimentation is developed at the upper part meanwhile anaerobic digestion of sludge is produced at the bottom part. Tank´s zones design aims burbles do not enter into sedimentation area. Likewise the fluid part of the liquor, barely get in contact with the sludge. Generally these systems are used to treat domestic wastewater; black and grey wastewater for small buildings or houses.
TECHNICAL DESIGN
Design criteria There is a potential risk of dangerous gases release, therefore tanks should be designed with vent holes. Hydraulic retention time (HRT): Sedimentation zone are sized for hydraulic loads of 1 to 4 hours. For digestion zone 0.3m
3 / inhab., for 6 months of sludge retention.
Dimensions: Although there are circular tanks, the most common shape is rectangular. Tank height use to be around 2.5 m and the length 3 to 5 time’s width. Construction. The construction is more complicated than a standard septic tank and requires experience labour. Materials: The tank could be made of different materials, concrete, plastic, PVC or fibreglass. There are buried systems therefore the construction requires excavations. The construction could be on site, but there are also prefabricate systems that are transport to the specific location.
O & M REQUIREMENTS
Operation. Manual device the management is easy and does not need qualified personal. Wastewater can flow by gravity in to the tank and not extra energy supply is required. No electrical consumption. Maintenance. Maintenance costs are very low. Periodic monitoring is needed to check if the tank is working correctly. The system has to be clean and desluged regularly. The floating solids, oil and the scum should be removed, or brake it to allow gas releases. Sometimes solids have to be pushed to the sludge accumulation area through the slot. This could be done manually with a simple hand tools like a squeegee. Sludge settle at the bottom of the chambers suffers anaerobic decay process, mineralizing and reducing it volume. However, comparing to a septic tank, the desludging is easier and more accessible. Imhoff tanks have a pipe with a valve to drain the sludge. The removal is more frequently made. The normal sludge storage capacity is 3 to 12 month comparing to 2-5 years in a normal septic tank.
CONSIDERATIONS
Advantages. The specific baffle walls designed on this tank remains the effluent separated from the sludge. Therefore the outflow effluent is odourless and fresher than the one from a septic tank. Packed systems of small size and underground, do not large land required Applicable for decentralized systems. Low cost, works by hydraulic gradient, no need of energy supply Limitations. The cleaning task results unpleasant for the operators. Risk of ground water pollution by percolation. Low robustness. No adaptation to load fluctuations. The system is designed for certain volume of WW. If there is a sudden
change of this volume (from rainfall or increase of WW) the device will overload and the process fails.
Despite the good quality of sludge that can be used as fertilizer, it has high pathogens content therefore the sludge should be treated, appropriately disposed or managed.
PRIMARY TREATMENT
Input Domestic wastewater Household/Neighbourhood
Effluent BOD reduction 15-35%
TSS reduction 40-65%
Pathogen reduction 0%
TN reduction Low
TP reduction 20-30% (sedimentation)
(Source. CENTA, 2007b; Morel et al, 2006, Crock et al, WUTAP, 2007)
4.2.6 Baffled reactor (anaerobic baffled reactor , ABR)
40 Low-cost wastewater treatment technologies for agricultural use
Baffled reactor is an improved variation of septic tank. Instead of one single chamber device it consists of a sequence of 2 or 3 chambers. Wastewater is force to pass by each baffled chamber up flowing, so that wastewater keep contacting sludge layer every time it moves to the other chamber. This extra contact provides additional digestion of organic matter. Generally these systems are used to treat domestic wastewater; black and grey wastewater for small buildings or group of houses. WW should have controlled characteristics due to some chemicals like caustic soda, pesticides, paints, etc can damage the tank.
TECHNICAL DESIGN
Design criteria. Hydraulic retention time (HRT): Sedimentation zone are sized for hydraulic loads from few hours up to 48 to 72 hours. Dimensions: There are systems designed for capacities from 2 to 200 m3 / day wastewater inflow. There is a potential risk of dangerous gases release, therefore tanks should be designed with vent holes. Construction. The design and construction is not simple and requires experience labour. Materials: The tank could be made of different materials, concrete, plastic, PVC or fibreglass. There are buried systems therefore the construction requires excavations. The construction could be on site with available local materials.
O & M REQUIREMENTS
Operation. Manual device. The management is easy and does not need qualified personal. Wastewater can flow by gravity in to the system and not extra energy supply is required. No electrical consumption. Maintenance. Maintenance costs are very low. Periodic monitoring is needed to check if the tank is working correctly. The system has to be clean and desluged regularly. The floating solids, oil and the scum should be removed periodically. In case of WW contains non biodegradable items (napkins, tampons) cleaning operations are more often required. Desludging requires a truck with a pumping device. A manual desludging is not recommended because the hazardous pathogen content of the sludge. Sludge formed in the chambers suffers anaerobic decay process, mineralizing and reducing it volume. Desludge frequency varies every 2 to 3 years. Overloading of tanks is the most common result of mismanagement.
CONSIDERATIONS
Advantages Small size. They are really compact systems and underground, small land areas are required. No flies or odorous problems if the tank is well sealed and maintenance. Long term device service than with well maintenance could last many decades. Applicable for decentralized systems. Low cost, works by hydraulic gradient, no need of energy supply Limitations. The infrastructure for transport the effluent is required as well as enough space to vacuum truck operation. In colder climate the treatment efficiency is reduced. Risk of ground water pollution by percolation. Not suitable if phreatic surface is shallow (<4m) or in areas with flood tendency. It requires a relatively constant flow of wastewater. Regarding to the health aspects, pathogens contents in effluent is very high. Low robustness for volume fluctuations. The system is designed for certain volume of WW. If there is a sudden change of
this volume (from rainfall or increase of WW) the device will overload and the process fails.
Despite the good quality of sludge that can be used as fertilizer, it has high pathogens content therefore the sludge should be treated, appropriately disposed or managed.
PRIMARY TREATMENT
Input Domestic wastewater Household/Neighbourhood
Effluent BOD reduction 80-90% TSS reduction 50-90% Pathogen reduction 0% TN reduction 0% TP reduction 0%
(Source. Tilley et al, 2008; Morel et al, 2006)
41 Low-cost wastewater treatment technologies for agricultural use
4.2.7 Anaerobic Filter
Consist of one sedimentation chamber (similar to a septic tank) follow by several filtration chambers (normally from 1 to 3). The filter materials allow higher contact area for the bacteria with the wastewater promoting physical, chemical and biological processes to break down the organic matter. Therefore the biofilter increase the surface area for biological processes comparing with a normal septic tank or baffled reactor. Around 90 to 300 m2 per 1m3 of reactor. In order to guarantee a correct performance, water level might cover the filter.
TECHNICAL DESIGN
Design criteria. Hydraulic retention time (HRT): retention times from 0.5 to 1.5 days. Dimensions: There is a potential risk of dangerous gases release therefore tanks should be designed with vent holes. Construction. The design and construction is not simple and requires experience labour. Materials: The biofilter can be made by gravel, rocks, cinder or plastic material, depending on the local availability. The size of the filter elements varies from 12 to 55mm diameter, and is disposed in different layers. The tank could be made of different materials, concrete, plastic, PVC or fibreglass. It is often a buried system (not always) therefore the construction requires excavations. The construction can be on site with available local materials.
O & M REQUIREMENTS
Operation. The operation is simple, not skilled labour is needed to operate the system. Wastewater can flow by gravity in to the pit and not extra energy supply is required. No electrical consumption Maintenance. Maintenance costs are very low. Periodic monitoring is needed to check if the device is working correctly. When the layer of microorganisms becomes too thick the filter can clog, therefore, cleaning is needed. The cleaning consists of backwashing or removing biomass materials and refilling again. The floating solids, oil and the scum should be removed periodically. In case of WW contains non biodegradable items (napkins, tampons) cleaning operations are more often required. Desludging requires a truck with a pumping device. A manual desludging is not recommended because the hazardous pathogen content of the sludge. Sludge formed in the chambers suffers anaerobic decay process, mineralizing and reducing it volume. Tanks can keep the sludge for long term. Desludge frequency varies from 2 to 5 years. Overloading of tanks is the most common result of mismanagement.
CONSIDERATIONS
Advantages Small size. They are really compact systems and underground, small land areas are required. Adaptable to fluctuations of load. No flies or odorous problems if the tank is well sealed and maintenance. Long term device service than with well maintenance could last many decades. The effluent contains high amount of nitrogen therefore it is completely available for the crops. Applicable for decentralized systems. Low cost, works by hydraulic gradient, no need of energy supply Limitations. The cleaning task results unpleasant for the operators. It requires a relatively constant flow of wastewater. Requires inflows with low load of TSS. Not suitable for wastewater with high load of suspended solids. Long start up period: from 6 to 9 months. Risk of ground water pollution by percolation. Not suitable if phreatic surface is shallow (<4m) or in areas with flood tendency. Low robustness for volume fluctuations. The system is designed for certain volume of WW. If there is a sudden change of this volume (from rainfall or increase of WW) the device will overload and the process fails. Moderate robustness for organic load fluctuation. In order to avoid problems of clogging in the filter, pre treatment processes might be done. Despite the good quality of sludge that can be used as fertilizer, it has high pathogens content therefore the sludge should be treated, appropriately disposed or managed.
PRIMARY AND SECONDAY TREATMENT
Input Domestic wastewater Household/ Neighbourhood
Effluent BOD reduction 50-90% TSS reduction 50-90% Pathogen reduction Low TN reduction 15% TP reduction Low
(Source. Tilley et al, 2008; Morel et al, 2006)
42 Low-cost wastewater treatment technologies for agricultural use
4.2.8 Green filters
Green filter is a land application or soil based system where wastewater is applied superficially on the land. The media is formed by the ecosystem soil-plants-water. Wastewater irrigates the land that is cover with vegetation. The irrigation technique is flood or furrow. Once wastewater is treated is not re usable, because the filtrated effluents end up in the ground water bodies. Lysimeters are used to control effluent quality at different depths. Wastewater is treated preliminary to remove coarse solids
TECHNICAL DESIGN
Design criteria Hydraulic load depend on soil permeability and nitrogen concentration. Therefore infiltration capacity of the soil and the vegetal species will define the dimensions of the plantation. Dimensions: The quantity of wastewater to treat depends on the dimension of the plant. But these systems are design to treat the wastewater of small communities, with hydraulic loads ‹ 0.02-0.05m
3/m
2.d
Construction. Vegetation. Species with; high capacity of nutrient and water absorption, low sensibility of wastewater micro compounds, minimum management requirements is used. I.e. grass (Lolium s.p.; Gram s.p) or forest trees (Populus sp., Eucaliphtus sp.) are commonly used. Mechanical devices. The wastewater is applied by gravity over the land Therefore no pumping system is required. The construction expenses as very low in terms of capital cost. Construction costs consist of implementation of the plantation.
O & M REQUIREMENTS
Operation The operation is simple, not skilled labour is needed to operate the plant. The operation might assure irrigation in turns in order to let the soil dry. Wastewater irrigate by gravity (furrow or flood) therefore not extra energy supply is required. Other irrigation techniques would require pumping and electrical consumption. Maintenance. Maintenance costs are very low. Mechanical devices like valves and irrigation gates require grease. Tillage of land could be recommended to break the possible formed crust. Eventually biological state of trees should be analysed in order to prevent pest and diseases. Non sludge removal is need.
CONSIDERATIONS
Advantages. The operation in very simple reduced of the pre-treatment phase and the irrigation control scheme. From the agricultural aspects, wastewater keeps all the properties. Phosphorus and Nitrogen is available. However, it also contains many other micro pollutants than could result toxic for the plants. Limitations Large land surfaces. Therefore, the main capital cost of the system is the cost of the land that in urban areas could be high. Appropriate soil permeability. Very permeate soil will percolate the wastewater releasing the effluent without enough treatment. Non permeable soils will produce water collapse of the system. Possible problems of ground water pollution. Pre-treatment and primary stages do not achieve the minimum health protection requirements. Health aspects acceptance is not reached. Not suitable for high rainfall areas because only low volumes of wastewater can be treated. Aim for urban settlements of very small or very small volumes of wastewater size.
SECONDAY AND TERTIARY TREATMENT
Input Domestic wastewater/ Urban wastewater Household/Neighbourhood/City
Effluent BOD reduction high
TSS reduction high
Pathogen reduction 99% total coliform
TN reduction high
TP reduction high
(Source. Bustamante, 1990, Tilley, et al, 2008, Shankar, unknown date, Crites, et al. 2000; CENTA, 2007b; CPCB, 2008)
43 Low-cost wastewater treatment technologies for agricultural use
4.2.9 Soil biotechnology (SBT) or Constructed soil biofilter (CSB) or Constructed soil filter (CSF)
Soil biotechnology is a land application or soil based system where wastewater is applied superficially on the land to be treated. The filter media is formed by the ecosystem soil-plants-water that includes soil macro and micro organisms, geophagus worms, soil minerals and plants as bioindicators. Wastewater irrigates the land that is cover with vegetation. The difference between other land application systems is that once wastewater is treated the effluent is collected in a tank and effluent can be reused afterwards. The system is made up of 2tanks (raw and treated effluent), the bioreactor (soil media + plants) and the pumping system.
TECHNICAL DESIGN
Design criteria Hydraulic retention time: 0.6 to 2 hours. Dimensions: The quantity of wastewater to treat depends on the dimension of the plant. But these systems are design to treat the wastewater of small communities with hydraulic loads ‹ 0.4- 0.6 m
3/m
2.
Construction. Material soil and additives as a filter media, vegetation, 2 tanks. Mechanical devices. Pipes and pumps. The construction expenses might be high because it requires civil engineer construction of tanks, bioreactors and pump site.
O & M REQUIREMENTS
Operation The operation is simple but some knowledge is needed to operate the plant. Training is required. The operation is related to the pumping equipment and vegetation control (pruning and maintaining). In some occasions, is needed a recirculation of the effluent to increase the retention time of the effluent. This operation requires the use of pumps. However no oxygen devices are required because the soil is the natural supplier for the system. Therefore, relatively low electrical consumption for wastewater comparing to conventional systems. Maintenance. Maintenance costs are very low. Mechanical devices like valves and pumps require grease. Although non sludge removal is needed, a crust of solids is formed over the soil surface. This might be frequently manually scraped (daily or weekly). Periodical cleaning of tanks is also required.
CONSIDERATIONS
Advantages. Systems with pleasant appearance that create nice landscape. No odour problems. No pre-treatment is required. No mosquito reservoir. No sludge production. High reduction of turbidity, <5NTU. Pathogen removal capacity increase with the time of operation, are maturing systems. Limitations. In colder climate the treatment efficiency is reduced, in that case a greenhouse is built over the system. Large land surfaces are required. Energy consumption, around 40 to 50 Kwh per 1000m3 treated.
High electrical conductivity produce a reduction of the performance of the system, maximum admissible salinity <2500 mg/L.
SECONDAY AND TERTIARY TREATMENT
Input Domestic wastewater/ Urban wastewater Household/Neighbourhood/City
Effluent BOD reduction 85-90%
TSS reduction 85-95%l
Pathogen reduction 99% total coliforms (<103 CFU/100 mL.)
TN reduction High
TP reduction High
(Source. Bustamante, 1990; Tilley, et al, 2008, Shankar, unknown date; Kadam, et al. 2008a; Kadam, et al. 2008b; Crites, et al. 2000; CENTA, 2007b; CPCB, 2008)
44 Low-cost wastewater treatment technologies for agricultural use
4.2.10 Anaerobic Stabilization ponds
Anaerobic pond is a lagooning system. In case it is part of a series of pond would be located at the beginning of the treatment chain. Aside the shallow surface layer of water, anoxic conditions are in the rest of the pond. The reason behind this is that they receive high O.M loads (›100gBOD/m
3·d), so the dissolved oxygen that supplies wastewater is
fast consumed. Sulphates are reduced to sulphur compounds that are dark (not suitable for photosynthesis) and toxic to micro algae. Sedimentation is done at the bottom of the pond. Biogas is produced and methane and carbon dioxide burbles are release. Sedimentation of the solids and stabilization of sludge is the aim of this performance.
TECHNICAL DESIGN
Design criteria. Hydraulic retention time (HRT): 1 to 7 days. Dimensions: 2-5m depth. In order reduce the oxygen exchange layer from the surface; the ponds are designed deeper than wider. Relation length - width: 2/1 or 4/1. Square shape is the most usual. Sloping banks (horizontal vertical) 2:1. Construction The construction requires earthworks and ground compaction processes. Experience labour during construction phase is required. Materials: Concrete (small) or earthen basin (large). In case of earthen basin, the terrain might be impermeable otherwise compacted clay layer or plastic sheet (geotextile) are required. Specifications Flow meter is required to control the inflow, and also an outlet control for outflow regulation. To prevent scum coveys to the subsequence process and outflow baffle might be designed. For large ponds several inlets and outlets will be available.
O & M REQUIREMENTS
Operation The operation is simple but some knowledge is needed to operate the plant. Two different phases, acidogenesis and methanogenesis, should be done in a balance way to avoid problems of surface microalgae growing. Wastewater can flow by gravity in to the basin and not extra energy supply is required. No electrical consumption. Maintenance. Maintenance costs are very low. Periodic monitoring is needed to check if the pond is working correctly. The system has to be clean and desluged regularly. The floating solids, oil and the scum should be removed periodically. This could be scooped by hand. The sludge that is accumulated at the bottom at the same time is broken down and mineralized reducing the volume. Therefore desludge is required every 5-10 years. The correct isolation of the impermeable layer should be regularly checked to avoid leakages. The removal of the growing vegetation on the pond banks might be done periodically to prevent mosquito reservoirs.
CONSIDERATIONS
Advantages Low capital cost in construction and O&M. Easy sludge management. Sludge does not need any treatment before disposal. Beside lagooning, anaerobic ponds can be used as a primary treatment for other treatment technologies to facilitate and simplify sludge management. Limitations Odour problems (biogas realising) In colder climate the treatment efficiency is reduced. Large land surfaces requirement. Risk of ground water pollution by percolation. Possible mosquito (vector disease) reservoir. Proper maintenance works minimizes the risk.
PRIMARY TREATMENT
Input Urban wastewater Neighbourhood/City
Effluent BOD reduction 50-80% TSS reduction 60-80%% Pathogen reduction 100 % total coliform (Tc ≤2- 3 log.)
80-100% Helminths eggs
TN reduction 5-10 %( N is break down in to Ammonium Compounds)
TP reduction 0-5 %
(Source. Tilley, et al, 2008; Shilton, 2005 , WUTAP, 2007; CPCB, 2008)
45 Low-cost wastewater treatment technologies for agricultural use
4.2.11 Facultative ponds
Facultative pond is a lagooning system. In case it is part of a series of pond, would be located after the anaerobic ponds as a second stage of the treatment chain. They combine aerobic conditions (at the surface) and anaerobic condition (at the bottom). Three different layers are formed in theses ponds. (1) At the surface, they develop aerobic conditions by the oxygen produce by microalgae and air movement. During the night, photosynthesis activity decrease therefore the thickness of this layer is reduced. During spring and summer season these layers increase. (2) At the bottom they have anaerobic condition due to the mineralization of the sediment. If the pond received and overload of organic matter, this layer could extend over all pond volume. (3)An intermediate zone is formed with variable conditions and facultative bacteria. Aerobic, anaerobic and facultative microorganisms are found in these ponds. Protozoa, purple sulphur bacteria and microalgae develop photosynthetic processes.
TECHNICAL DESIGN
Design criteria Hydraulic retention time (HRT): Between 5 to 120 days (30 days required for pathogen removal).Dimensions: 1-2 m depth. Relation length - width: 2/1 or 4/1. Rectangular, curve or kidney shape. Sloping banks (horizontal vertical) 3:1. Construction The construction requires earthworks and ground compaction processes. Experience labour during construction phase is required. Materials: Earthen basin. The terrain might be impermeable otherwise compacted clay layer or plastic sheet (geotextile) is required. Specifications: Flow meter is required to control the inflow, and also an outlet control for outflow regulation. To prevent scum coveys to the subsequence process and outflow baffle might be designed. For large ponds several inlets and outlets will be available.
O & M REQUIREMENTS
Operation The operation is simple but some knowledge is needed to operate the plant. High rate of suspended solids could be an operation problem due to the high microalgae growing. Wastewater can flow by gravity in to the basin and not extra energy supply is required. No electrical consumption. Maintenance. Maintenance costs are very low. Periodic monitoring is needed to check if the pond is working correctly. The system has to be clean and desluged regularly. The floating solids, oil and the scum should be removed periodically. This could be scooped by hand. The sludge that is accumulated at the bottom at the same time is broken down and mineralized reducing the volume. Therefore desludge is required every 12-24 years. The correct isolation of the impermeable layer should be regularly checked to avoid leakages. The removal of the growing vegetation on the pond banks might be done periodically to prevent mosquito reservoirs.
CONSIDERATIONS
Advantages Low capital cost in construction and O&M. High microalgae concentration that is a value input for agriculture.(as fertilizers, humus soil and increasing soil hydraulic retention) Limitations Odour problems. Large land surfaces requirement. In colder climate the treatment efficiency is reduced. Risk of ground water pollution by percolation. High microalgae concentration is a risk of clogging for drip and sprinkler irrigation. Possible mosquito (vector disease) reservoir. Proper maintenance works minimizes the risk.
SECONDAY TREATMENT
Input Urban wastewater Neighbourhood/City
Effluent BOD reduction 60-90% TSS reduction 0-70%
Pathogen reduction 100 % total coliform (Tc ≤2- 3 log.) 100% Helminths eggs
TN reduction 30-60 TP reduction 0-30%
(Source. Tilley, et al, 2008; Shilton, 2005; CPCB, 2008)
46 Low-cost wastewater treatment technologies for agricultural use
4.2.12 Aerobic stabilization ponds (Maturation ponds/Oxidation pond)
Maturation pond is a lagooning system. In case it is part of a series of ponds would be located at the end of the treatment chain. The maturation pond is shallow to allow light entry and ensure photosynthesis reactions. Aerobic microorganisms are found in these ponds. Therefore it keeps aerobic conditions The inflow is a low organic load influent. And the treatment removes suspended solids, organic matter, nutrients and pathogens. It is a final polishing treatment.
TECHNICAL DESIGN
Design criteria. Hydraulic retention time (HRT): 21 to 30 days. Dimensions: 1-2 m depth. Relation length - width: 2/1 or 4/1. Rectangular, curve or kidney shape. Sloping banks (horizontal vertical) 3:1. Construction. The construction requires earthworks and ground compaction processes. Experience labour during construction phase is required. Materials: Earthen basin. The terrain might be impermeable otherwise compacted clay layer or plastic sheet (geotextile) is required. Specifications: Flow meter is required to control the inflow, and also an outlet control for outflow regulation. To prevent scum coveys to the subsequence process and outflow baffle might be designed. For large ponds several inlets and outlets will be available.
O & M REQUIREMENTS
Operation. The operation is simple but some knowledge is needed to operate the plant. Wastewater can flow by gravity in to the tank and not extra energy supply is required. No electrical consumption. Maintenance. Maintenance costs are very low. Periodic monitoring is needed to check if the pond is working correctly. The system has to be clean and desluged regularly. The floating solids, oil and the scum should be removed periodically. This could be scooped by hand. The sludge that is accumulated at the bottom at the same time is broken down and mineralized reducing the volume. Therefore desludge is required every 10-20 years. The correct isolation of the impermeable layer should be regularly checked to avoid leakages. The removal of the growing vegetation on the pond banks might be done periodically to prevent mosquito reservoirs.
CONSIDERATIONS
Advantages. Low odour problems. Low capital cost in construction and O&M. Total pathogen removal. Disinfection system due to the long retention times. Limitations. In colder climate the treatment efficiency is reduced. Large land surfaces requirement. Risk of ground water pollution by percolation. Possible mosquito (vector disease) reservoir. Proper maintenance works minimizes the risk.
TERCIARY TREATMENT
Input Urban wastewater Neighbourhood/City
Effluent BOD reduction 75-85% TSS reduction 40-80% Pathogen reduction
100 % total coliform (Tc ≤2- 3 log.) 100% helminths eggs.
TN reduction 35-80% TP reduction 1-60%
(Source. Tilley, et al, 2008; Shilton, 2005, Card, 2005; CPCB, 2008, Von Sperling et al 2005)
47 Low-cost wastewater treatment technologies for agricultural use
4.2.13 Constructed wetlands. Free flow(surface)
The free flow constructed wetland is the wetland treatment system most similar to the processes that occur in a natural water body. The bottom of the basin is cover with gravel, rocks and the roots of plants forming the ground of the wetland. The ground has mainly anaerobic conditions although some oxygen is realised from the roots of the plants. A shallow (10-50cm) layer of wastewater flow free over the ground. The slowly flow of wastewater throw the basin allow efficient treatment of the inflow, with physical, chemical and biological processes (filtration, precipitation, nitrification, predation, etc.). Therefore toxic compounds, suspended solids, nutrients, organic load and pathogens are reduced by process of decantation and by the action of microorganisms and plants.
TECHNICAL DESIGN
Design criteria. An important design part is the wastewater inlet because a correct distribution of the wastewater will assure the performance of the system. Construction: The construction is complicated and might be expensive depending of the materials availability and the size. Experience labour during construction phase is required. Materials: Local materials. Earthen basin. The basin is compound of several layers with different material’s permeability like rocks, gravel and clay. Vegetation. Native plants species are required (reeds, rushes…). Specifications: Flow meter is required to control the inflow, water level and also an outlet control for outflow regulation.
O & M REQUIREMENTS
Operation. The operation is simple, not skilled labour is needed to operate the plant. Wastewater can flow by gravity in to the basin and not extra energy supply is required. No electrical consumption. Vegetation might be prune and cut regularly. Maintenance: Maintenance costs are very low. Periodic technical monitoring is needed to check if the wetland is working correctly and prevent blockages or short-circuits. In case of clogging, the wetland might be drained out.
CONSIDERATIONS
Advantages. Low capital cost in construction and O&M. Adaptable technology for flow fluctuations. Sub products: grown vegetation could be reuse as biomass of for feeding animals. Systems with pleasant appearance that create nice landscape. No odour problems with proper maintenance works No energy consumption. Easier to operate than subsurface systems. Limitations. Large land surfaces requirement. Possible mosquito (vector disease) reservoir. Limited to low polluted wastewater. In colder climate the treatment efficiency is reduced (low biological activity). In order to avoid problems of clogging in the filter, pre treatment processes might be done.
PRIMARY & SECONDAY TREATMENT & TERCIARY
Input Domestic wastewater/ Urban wastewater Household/Neighbourhood/District
Effluent BOD reduction 80%-90% TSS reduction 30-45% Pathogen reduction 100 % total coliform
(Tc ≤2- 3 log.) TN reduction 15-40% TP reduction 30-45%
(Source. Tilley, et al, 2008; Tanaka, et al. 2011, WUTAP, 2007; CPCB, 2008; Palm2010 EPA 2004)
48 Low-cost wastewater treatment technologies for agricultural use
4.2.14 Horizontal subsurface flow constructed wetlands (HSF)
The constructed wetland with horizontal subsurface flow (HSF) is a wetland system where wastewater flow horizontally throw a porous media. The basin is filled up with the porous material, gravel or sand (3 to 30 mm diameter). These materials allow higher contact area with the wastewater flow, therefore an efficient treatment with physical, chemical and biological processes (filtration, precipitation, nitrification, predation, etc.) is done. In order to guarantee the horizontal subsurface flow, water level might be kept around 5 to 15cm below the surface of the porous media. The effluent treated is drained to an outlet pie located at the bottom of the basin.
TECHNICAL DESIGN
Design criteria. Hydraulic retention time (HRT): from 3 to 7 days. Dimensions: Porous media depth around 70cm. The reason behind this is to avoid anoxic conditions, assuring a water level of 60 cm and maintaining a top layer of 5 to 15 cm of media without water. However, to assure the oxygen transfer wastewater inflow might be small and the wetland surface large. Construction. The construction is complicated and might be expensive depending of the materials availability and the size. The basin is compound of several layers with different permeability. Experience labour during construction phase is required. Materials: Earthen basin, gravel, clay. Pipes. Plants (reed bed like Phragmites sp.). Specifications: Flow meter is required to control the inflow, water level and also an outlet control for outflow regulation.
O & M REQUIREMENTS
Operation. The operation is simple, not skilled labour is needed to operate the plant. Anaerobic conditions should be avoided by reducing load or resting the system. Aerobic conditions are easy to detect by odour. If the slope of the basin is correctly design (and possible by topography conditions), wastewater can flow by gravity in to the basin and not extra energy supply is required. No electrical consumption. Vegetation might be pruned and cut regularly. Maintenance: Maintenance costs are very low. Periodic technical monitoring is needed to check if the wetland is working correctly and prevent blockages or short-circuits. In case of clogging, the wetland might be drained out.
CONSIDERATIONS
Advantages. Systems with pleasant appearance that create nice landscape. No odour problem (subsurface system). No health risk because of mosquito reservoir if the maintenance is correct. Land requirements are lower than for free surface wetlands (for the same wastewater volumes). No sludge production. Limitations. More complicate to operate than a free flow wetland system.
Large land surfaces requirement. Grease clogging could be a problem. In order to avoid problems of clogging, pre treatment processes is required.
PRIMARY & SECONDAY TREATMENT & TERCIARY
Input Domestic wastewater/ Urban wastewater Household/Neighbourhood/District
Effluent BOD reduction 80-90% TSS reduction 80-95% Pathogen reduction 100 % total coliform
(Tc ≤2- 3 log.) TN reduction 15-40% TP reduction 30-45%
(Source. Tilley, et al, 2008; Tanaka, et al. 2011; CPCB, 2008, Hoffmann, 2011)
49 Low-cost wastewater treatment technologies for agricultural use
4.2.15 Vertical flow constructed wetlands (VF)
The constructed wetland with vertical flow (VF) it is a wetland system where wastewater flow vertically throw a porous media. The basin is filled up with the porous material, gravel or sand. These materials allow higher contact area with the wastewater flow, therefore an efficient treatment with physical, chemical and biological processes (filtration, precipitation, nitrification, predation, etc.) is done. The pre-treated wastewater is spread over the filter media flowing vertically through it. The effluent treated is drained to an outlet pie located at the bottom of the basin.
TECHNICAL DESIGN
Design criteria Hydraulic retention time (HRT): The applications are made intermittently from 4 to 12 times per day. Dimensions: 1 to 4m2 per population equivalent. Construction: The construction is complicated and might be expensive depending of the materials availability and the size. Experience labour during construction phase is required. The basin is compound of several layers with different permeability. The wastewater distribution system should be designed. Materials: Earthen basin, gravel, clay. Pipes. Plants (reed bed like Phragmites sp.). Specifications: Flow meter is required to control the inflow, water level and also an outlet control for outflow regulation.
O & M REQUIREMENTS Operation. The operation is simple, not skilled labour is needed to operate the plant. In order to apply the inflow vertically, a pump or siphon is required. The application is intermittent to assure oxygen transfer. Wastewater can flow by gravity in to the basin and not extra energy supply is required. No electrical consumption. Vegetation might be pruned and cut regularly. Maintenance: Maintenance costs are very low. Periodic technical monitoring is needed to check if the wetland is working correctly and prevent blockages or short-circuits. In case of clogging, the wetland might be drained out. The emptying process might be done with proper health risks prevention measures.
CONSIDERATIONS
Advantages. Systems with pleasant appearance that create nice landscape. No odour problem (subsurface system). No health risk because of mosquito reservoir. Land requirements are lower than for free surface wetlands (for the same wastewater volumes). No sludge production. Limitations. Energy is required to pump the inflow. More complicate to operate than a free flow wetland system.
Large land surfaces requirement. Grease clogging could be a problem. In order to avoid problems of clogging, pre treatment processes might be done.
PRIMARY & SECONDAY TREATMENT & TERCIARY
Input Domestic wastewater Household/Neighbourhood
Effluent BOD reduction 75-90% TSS reduction 65-85% Pathogen reduction 100 % total coliform
(Tc ≤2- 3 log.) TN reduction <60% TP reduction <35%
(Source. Tilley, et al, 2008; Tanaka, et al. 20;,CPCB,2008, Hoffmann, 2011)
50 Low-cost wastewater treatment technologies for agricultural use
4.2.16 Slow Sand Filter (SSF)
Slow sand filtration is a typical wastewater purification system use for drinking water purposes. Consist of a vessel, chamber, tank or reservoir filled up with sand. Therefore the system is based on using the sand as a filter. The sand increase the contact surface with the effluent, promoting physical and chemical processes, moreover the biological process is done by the microbiota settle on the upper layers of the sand. . It is quiet effective to reduce turbidity and pathogenic compounds.
TECHNICAL DESIGN Design criteria Hydraulic retention time (HRT): Hydraulic loads ≤ 0.1-0.05m3/h.m2. Dimensions: no specific dimensions. For gravity filters, certain high is required. Construction: The construction is very simple. Not experience labour during construction phase is required. Materials: Simple tank construction of concrete, brick or plastic. Sand filter is made by sand of different size and gravel, locating the coarses at the bottom and the finest sand at the upper layers. Gravity provides enough pressure to make water cross the filter (Pumps can also be used).
O & M REQUIREMENTS Operation. The operation is simple, not skilled labour is needed to operate the device. Wastewater flow by gravity through the tank and not extra energy supply is required. No electrical consumption. Maintenance: Maintenance costs are very low during all working life of the device. When the layer of microorganisms becomes too thick the filter can clog, therefore, periodic cleaning is needed every few week or months. The cleaning consists of draining the tank and scrapping the surface layer of sand. Backwashing is also possible but requires energy supply.
CONSIDERATIONS Advantages Aim for medium size settlements or district level. Low capital cost in construction and O&M. Robust system relatively adaptable to effluent fluctuations. Limitations No odour removal. High turbidity of inflow effluent (>30NTU) limits the use because the high risk of clogging. Hence, it is a system use for the treat of fresh water, the use for wastewater as a polishing treatment, requires a relatively good quality of effluent. In order to avoid problems of clogging, pre treatment processes might be done. Slow filter, water moves 100 to 300 litres per hour. In colder climate the treatment efficiency is reduced. Large land surfaces requirement.
TERTIARY.
Input Treated effluent. Neighbourhood/Settlements/District
Effluent BOD reduction Low TSS reduction 80% Pathogen reduction 90-99% pathogens and heavy metals
TN reduction Low TP reduction Low
(Source: Tilley, et al, 2008 LDWQ, 2013; Brikke et al, 2003, EWB, 2010;Huisman
et al,1974)
51 Low-cost wastewater treatment technologies for agricultural use
5. ANALYSIS OF THE RESULTS
5.1 SELECTION OF PRINCIPLES, CRITERIA AND INDICATORS
5.1.1 Principles
In the previous chapter a general review of wastewater treatment processes has been done.
But not all the described processes are suitable to be used by local farmers, assuring health
protection and crop production with minimum cost. The concept and the scope of the
selection might cover technical, socioeconomically, agricultural and health aspects. Therefore
are defined the following principles.
Principle 1. Compliance with crop production. The treated effluent might represent an input to
enhance agricultural productivity without threaten the future production or damaging soil
conditions.
Principle 2. Compliance with health protection. Ensure the achievement and maintenance of a
minimum level of health protection for farmers and for consumers. Depending on the type of
crop, the irrigation techniques, the consumption of the crop (raw or cooked), the effluent
quality requirements for the farmers are different. Hence treatment technology has to achieve
certain effluent qualities (previously mentioned, see Table 5).
Principle 3. Integration of the technology in the local context. The technology has to be
adapted to the socio economical context. There are some parameters of local conditions or
availability of resources that assure the sustainability of the technique in terms of robustness,
energy dependency, operation and maintenance requirements.
5.1.2 Criteria
The criteria outline the overarching aim of each principle, driving the attention to the local
characteristics of the scenario. Therefore the technological criteria are the following:
Crop production efficiency: The first criterion is related the effluent quality. Water is an input
for agricultural production. Wastewater has compounds that can whether enhance or harm
the crop production. The different wastewater components and their properties could
influence in the performance of the yield. Therefore the parameters commonly analysed to
check the performance of the wastewater technologies will be use as indicators for crop
production.
Health protection efficiency: The second criterion is not only related to the effluent quality
but also with the irrigation techniques, product management and local climate conditions. In
compliance with health protection principle, the efficiency of the technology in terms of
effluent quality is pointed out (see Table 20, Annex2). The reduction of pathogens is usually
achieved by the wastewater treatment to some extent. The less pathogen the less risk for
farmers and consumers. Moreover, there is a risk of creation a reservoir for vectors of
waterborne disease; this is related to the geographical location. It will be also assessed the
irrigation technique. For instance, drip irrigation might reduce drastically the water contact
with the product and farmers however it will required higher effluent quality in order to avoid
clog up the drips.
52 Low-cost wastewater treatment technologies for agricultural use
The third principle involves many different aspects. Aside technological characteristics for
agricultural or health compliance there are some other socio-economic, political,
environmental and institutional factors necessary to analyse. They could represent key issues
for success of the implementation of certain technologies. Some features make the technology
easy to integrate in the local practices. Therefore, regarding to the integration capacity of the
technology to the local context, the affordability, and sustainability and environmentally
friendly characteristics will be considered.
5.1.3 Indicators
To assess the criteria are defined the indicators. The indicators are characteristic of the
technology. In the Figure 12 are represented the technology criteria. The indicators are
characteristics of the technology that will be used to assess its adequacy. They were deduced
driving the attention to the local context (See Figure13).
Nutrient (N, P) content
Nitrogen in wastewater is found in organic (mainly proteins) and inorganic compounds
(Ammonium Ion) dissolved or forming solid particles. In anaerobic treatment processes organic
nitrogen is transformed into inorganic compound by the action of bacteria and proteolytic
microorganisms. Therefore sometimes after the treatment the effluent has higher
concentration of Ammonium compounds. During the aerobic process ammonium compounds
are transformed in nitrate by microorganism. Both nitrates and ammonium ions are
compounds easy to assimilate by plants. Phosphates are either found dissolved in wastewater
or forming solid particles. Solid phosphates use to settle in the sediments and be reduced by
microorganisms to orthophosphates forms that are easy to decay. Therefore, orthophosphates
remain in the sludge giving to this product an added value for agricultural input (CENTA,
2007b). Irrigation with untreated wastewater will produce a long term increase of the amount
of carbon and macronutrients in the soil (Yadav, et al 2002). Nutrients (N and P) are required
by the crops therefore a high nutrient content of effluent is a quality objective. They are
normally removed from the bulk, but in that case the water would loss the added value for the
crops. However, certain limits have to be considered, because too high concentration of
Nutrients might cause negative effects on the crops, such as delaying fruit formation in fruit
trees or developing weak stems in grain crops. The tolerance rate is up to the sensibility of the
crop, for example, high sensible with 5 mg N/l, to high tolerant 30mgN/l. Furthermore, might
also cause illness to animals that feed with excess N fodder (Palm, 2010).
Salinity reduction
Not all the crops are tolerant to high load of salinity (see Table 13, Annex 2). Furthermore, high
salinity in the irrigation water will produce long term effects on soil hydraulic conductivity and
reduce the C available for the plants (Setiaa, et al 2013). It could become a great hazard for the
future of the land regarding to the soil properties deterioration. However, as was argued by
Patterson (2000), aside industrial pollution, domestic wastewater is the most common origin
of chemical compounds in the sewage. Inorganic salts are added to the wastewater by the use
of soaps, detergents, rests of food, paper and feces. Patterson (2000) valued as an average of
63m/L (equivalent of 158kg/ML of sodium chlorine) the increase of sodium compounds in
53 Low-cost wastewater treatment technologies for agricultural use
wastewater due to domestic contamination. Sodium salts are very soluble and the
conventional wastewater treatment plants are not able to remove them (Harussia, et al 2001).
The only way to remove them is with a desalination process for instance by reverse osmosis
process (Patterson, 2000). Therefore, soil salinity is a big hazard of reclaimed water use.
Unfortunately, the high energy and equipment cost of these treatments will leave this problem
uncover with the proposed techniques (no economical feasibility). Therefore as far as salinity
reduction concerns, the irrigation management is crucial. Martinez (1999) proposed a
guideline to manage saline water in a sustainable way for the agriculture. Good agricultural
practices and measures like leaching would reduce the harm effects of high salinity irrigation
water (WHO, 2006a).
Total Suspended Solids (TSS) reduction
Wastewater only contains 0.07 % of solids. They are dissolved or suspended in the water bulk
that forms the 99.93% rest. The solids are organic and inorganic particles (in half to half
proportions). The importance of removing them is because many pollutants are in solid state,
as for example nutrients or heavy metals. Treatment technologies aim to make solids settle
and remove them by the sludge (Ellis, 2005). TSS is a normal parameter use to assess the
efficiency of the treatment therefore it is easy to measure. Furthermore, total suspended
solids may cause clogs in irrigation facilities, overall for drip and sprinkler irrigation. For
instance, according to Capra (2007) for drippers is not possible to use wastewater with TSS
>50mg/l without compromising the performance of the system. With surface irrigation
techniques (furrow or flood) the high TSS will affect to the soil saturated hydraulic
conductivity. This was checked out by a lab experiment carried by Viavini (2004), where the
infiltration capacity was reduced and the formation of a scaled layer over the surface. This
effect was increased noticeable in clay type soils.
Biochemical Oxygen Demand (BOD)
Biochemical oxygen demand (BOD) is a normal parameter use to assess the efficiency of the
treatment therefore it is easy to measure. BOD represents the oxygen need by bacteria to
break down the organic compounds of the water. Around 10% of the organic compounds are
toxic pollutants like pesticides, phenols, phthalates, polynuclear aromatic hydrocarbons
(PAHs). They can be removed by secondary treatment technologies (Petrasek, et al 1983).
However, irrigation with high oxygen demand water (high load of organic compounds) could
affect soil properties, causing problems of soil tilth and decreasing infiltration capacity (Oster,
1994). Furthermore, if waters with high oxygen demand are used for irrigation, they will cause
changes in soil pH, EC, NO3 and NH4, modifying the nitrification and other aerobic process that
normally take place in the soil (Nashikkar , 1993).
Heavy metals
If toxic compounds like heavy metals (Ni, Mn, Cu, Pb, Zn, Fe or Cd,) are present in the irrigation
effluent in high loads might be absorbed by the crops and become a hazard to consumer’s
health (see Table 16, Annex 2). The accumulation of heavy metals differs between crops. For
instance, in a research developed by Singh (2010), in crops irrigated with reclaimed water, the
higher levels of heavy metals were found in vegetables, since cereals and milk had less
54 Low-cost wastewater treatment technologies for agricultural use
concentration. However the potential risk is higher with dietary food like rice because of the
higher consumption. On the other hand, heavy metals could have phytotoxicity effects on the
crops (Fuentes, 2004; Ernst, 1996). Depending on crop sensibility, certain concentrations could
produce crop reductions. The level of crop damage is closely related to uptake availability
(FAO, 1985). Therefore heavy metals might represent also a hazard for the agricultural land
because of their long term accumulation (ICON, 2001). It is worthy to mention that, heavy
metals are, at certain concentration, also toxic for microorganisms in charge of biological
treatment. Domestic wastewater usually has low loads of heavy metals (Omu, 2009; ICON,
2001). Heavy metals usually end up in sewage streams as a consequence of industrial
wastewater discharges or because of the runoff from oils road´s pollutants. Depending on the
precipitation rate, heavy metals are partly accumulated in the sediments (majority) and partly
remain in the liquid phase of the effluent (around 20%) (ICON, 2001). Wastewater treatment
technologies aim to remove heavy metals by sedimentation and filtration. The settlement is
triggered with chemical and physical processes and with microbiological process (Kulbat,
2003).The variation of pH is a factor that influence in the precipitation of the sediments.
Anaerobic processes have high heavy metals removals rates due to reactions produce by
hydrogen sulphide compounds that makes them precipitate and settle (CENTA, 2007b). In
order to know the removal efficiency of heavy metals the sludge load is normally analysed.
However, in the absence of this data, as the polluting load is transferred by sedimentation, the
efficiency of suspended solids removal could be used to measure it (ICON, 2001).
Pathogen removal
Pathogens microorganisms are regularly found in urban wastewater. Water quality has to
ensure health protection for consumers and workers. Therefore, it will differ from the farmer
(as hookworm, ascaris, Diarrhoeal disease, giarda intestinalis infection) and for the consumers
of the products (e.g. cholera, typhoid ascaris infection) (Carr et al, 2004). In case of helminths
eggs or protozoa cysts, they stay latent and they can survive for a long period outside the host.
They become a high risk for consumers and farmers (World Bank, 2010, pg 33). However, they
settle easily, therefore sedimentation or filtration are the most basic processes to remove
them (CENTA, 2007b).The removal of virus or bacteria in the wastewater treatment plants
depend on two factors, the time that stay in the process and the time requires to kill them
(Curtis, 2003). Viruses are unable to multiply outside their host, but they can survive in the
wastewater for a short while. Bacteria are able to multiply out of the host, and persist in the
wastewater for a medium-long term. Both involve high risk for consumers (World Bank, 2010,
pg 33). Pathogen removal is a common parameter measured and reduced in the treatment
plants in order to prevent the transmission of wastewater borne diseases.
Size
It is evident that in urban environment land may be expensive. To reduce capital costs, small
and compact systems could seem the most appropriate technology for urban sites, where
there is no room available and the price of the land is high. However, CENTA (2007a) stated
that energy requirements are inversely proportionate to the size of the plant. Therefore small
plants could spend 5-6 times more energy than the big ones. Furthermore, wastewater
systems that occupies large surfaces as wetlands and pond could result cheaper in terms of
55 Low-cost wastewater treatment technologies for agricultural use
operational and maintenance. The dimension of the system and it relatio to the cost will be
assessed.
Centralized or decentralized systems
Centralized treatment plants require the transport of wastewater over larger distances.
Therefore it involves high investments in infrastructure for wastewater transport from
wastewater production to the site-of treatment. Furthermore in rural areas a longer length of
the infrastructure is required to connect dispersed households. According to Seto (2005), the
collection system implies the 70% of the cost per capita meanwhile 30% is the cost of the
treatment. Therefore, also due to the fact that they cannot benefit of from the economy of
scale, the inhabitants from small villages might pay 2 or 3 times as much as a resident of a big
city (Hophmayer-Tokich, 2006). Decentralization involves local/onsite treatments that reduce
the investment costs for implementation and maintenance of large sewage infrastructure.
These onsite treatments let a better control of wastewater type and even with possibility of
separation different effluents (black water, grey water, urban water, etc). However, the
particular case of ward number 3 allows considering the infrastructure as granted. Gangua
Nallah can be considered a large sewage canal. No separation of sewage is possible in this
case.
Design and construction cost.
A proper design could simplify the performance of the system so this phase results essential. In
many occasions has being confused simplicity of maintenance and working with simplicity of
treatment plant design and implementation. Enough attention has to be paid in design and
implementation phases (CENTA, 2007a). Local technologies that has being already proved and
successfully implemented in the area, would assure the long term life of the project.
Acknowledge and availability of the construction material or spare parts is required for the
sustainable performance of the technology (Hellströma, 2000). In case of underground
systems and earth basin designs, especially in rugged terrains, earth works can be rather
extensive. Therefore the topography might be also a factor to consider.
Simplicity of O & M.
While the design and construction of the treatment last few months, operation and
maintenance (O&M) remains during useful life of the Plant. At the local context, the O&M of
the treatment plant would be done by a public institution, private or in case of agriculture
reuse by water user association. Depending on that, the possibility of skilled labour
employment varies. Looking at the technology, simplicity and minimized costs will guarantee
the correct performance. In other terms, low levels of sophistication and high robustness and
trustfulness are aimed. Complicated systems require the hire of skilled labour, the use of
chemical additives, expensive and fragile devices (membranes, pumps or filters) and
availability of spare parts therefore are more costly.
Energy requirements
The requirement of energy supply is an important criteria indicator. Energy supply is expensive
so energy consumption should be minimized or non existing. Furthermore it may also be kept
56 Low-cost wastewater treatment technologies for agricultural use
in mind the importance of energy supply reliability. Electricity is not always fully ensured in
many cities. Bhubaneswar suffers of continuous electrical power failures (see chapter 2.3.3).
Therefore, with random power breakdowns, plant operation should not depend on energy.
One third of the O&M costs are related to the energy requirements. Electromechanical devices
could result very expensive, as an example aeration devices consume up to 75% of the total
energetic cost (CENTA, 2007a). Manual devices that do not depend on external energy supply
to work may reduce this cost.
Robustness
Bhubaneswar is steady growing and developing. The high developing rate of the city makes
difficult to set figures of wastewater generated from a specific area. Furthermore, there is a
time discrepancy among the actions and plans than local authorities develop and the city
growing requirements. At the end result barely impossible to keep the pace of the city.
Therefore the most appropriate solution for the farmers, perhaps also change accordingly
(Balkema, et al, 2002). An important indicator is the robustness of the technology in terms of
adaptability of load and flow fluctuations. The quality and quantity of the stream that flow
through the drains will change over the time in an unpredictable way and the capacity to adapt
is essential.
Environmental nuisances
The implementation of the technology is associated to additional outcomes that might impact
the local environment of users or workers. Therefore concepts like odour, landscape,
mosquitoes or noise are by-products to contemplate. There is also necessary to keep in mind
the possibility of overflowing of devices and tanks that could cause a threat for groundwater
bodies pollution. The interrelation between local parameters, principle, criteria and indicators
is shown in the following Figure 12).
Figure 12: Principles and criteria for the selection of wastewater treatment technology and the related indicator (Self-design).
57 Low-cost wastewater treatment technologies for agricultural use
5.2 MULTI CRITERIA ANALYSIS
The Multi Criteria Analysis (MCA) is a methodology widely used to support the decision making
processes. The tool allows clearing up complicated dilemma with multi-faceted characteristics.
This is made by assessing the different elements of the problem and afterwards classifying
them according to their relevance. Therefore, the MCA provides to the decision makers a
comparison and evaluation of the elements of the processes. MCA are not only able to
compare quantitative and qualitative aspect but also to compensating possible conflicts of
contradictory criteria (Singhirunnusorn, 2009). There are plenty of different MCA
methodologies based on complex mathematical models. For this study it will be used the
Scoring Rating model. This model was chosen because of its simplicity. The analysis is based on
a scoring comparison. In the Scoring Rating model, the criteria of the different solutions are
assessed with a score. The criteria are previously weighted by the level of importance.
Therefore the result of the model is a matrix with the scored criteria of the different solutions,
the weight of the criteria and the final score of the different options. The model allows using a
large amount of criteria in a simple and flexible way. However, as was argued by
Singhirunnusorn (2009), the pitfall of this model is that the inter connection of the criteria is
barely achieved.
5.2.1 Criteria weighting
Commonly, during the technology selection process, the criteria weight is backed up with
expert’s surveys or stakeholder´s interviews. In the absence of this information I based the
weighting highlighting the importance of the 2 first principles of the study, “wastewater
treatment to assure the health protection and crop production”. The reason behind that is that
the aim of this research is to find out a useful technology for the local farmers. The usefulness
of the technology is only achieved by the 2 first principles. The third principle, “Contextualise”,
would lose its value whether the other two were not accomplished.
Base on the indications reported by Fischer (2008), the weight among each criterion was
calculated as following. First of all, the criteria were compared two by two according to the
level of importance (see Table 7).
Table 7: Scale level of importance of criteria for technology selection
Level of Importance
No preference 1
Slight preference 2
Some preference 3
Significant preference 4
Very strong preference 5
For instance, to emphasize health protection over environmental friendly characteristics,
health protection was assessed with a very strong preference, value 5. (See Table 8, cell; first
column, fifth row). However health protection and crop production were equally considered.
Assessed with 1 means that there is no preference over the other. (See Table 8, cell; first
column, second row). The total importance of each criterion is calculated by the sum of the
58 Low-cost wastewater treatment technologies for agricultural use
each comparison. Once the total importance of each criterion is obtained, the weight (relative
values) is calculated. The relative values were calculated dividing the individual rating criteria
between the total importance of each criterion. (see table 8).
Table 8: Rating criteria (Self-desinged base on Fischer, 2008)
RATING CRITERIA Health protection
Crop production
Affordability Sustainability Environmental
Friendly TOTAL
Importance
Health protection 1,000 1,000 0,250 0,250 0,200 2,700
Crop production 1,000 1,000 0,250 0,250 0,200 2,700
Affordability 4,000 4,000 1,000 1,000 0,333 10,333
Sustainability 4,000 4,000 1,000 1,000 0,333 10,333
Environmental Friendly
5,000 5,000 3,000 3,000 1,000 17,000
RELATIVE VALUES
Health protection 0,370 0,370 0,093 0,093 0,074 1,000
Crop production 0,370 0,370 0,093 0,093 0,074 1,000
Affordability 0,387 0,387 0,097 0,097 0,032 1,000
Sustainability 0,387 0,387 0,097 0,097 0,032 1,000
Environmental Friendly
0,294 0,294 0,176 0,176 0,059 1,000
RANKING OF IMPORTANCE WEIGHT
0,362 0,362 0,111 0,111 0,054 1,000
5.2.2 Indicators rating technique
The different indicators were assessed by a rating technique. The sum of the scores of all the
indicators for each criterion might be 100, therefore the weight between indicators is
considered. The total criterion score (X) will obtained by summing the points of the indicators
(W), therefore: 0 ≤ wji ≤ 100
X= Σwji = 100
Where W: indicator score and X: criterion score (Singhirunnusorn, 2009).
Each indicator was analysed previously in the chapter 5.1. However, the importance varies
depending on the local context. For instance, a technology that could be a possible mosquito
reservoir, is an important factor to consider in regions where exists the risk of vector born
diseases (i.e. Malaria). Based on that, a score has been assigned. The indicator´s maximum
score assigned base on Bhubaneswar conditions is explained in Table 9. A more detailed
explanation in explained in Table10.
In this context, the following should be pointed out:
-Salinity reduction will not be addressed by the technologies selected.
-Heavy metals removal is assessed by the TSS reduction.
-There is no need of sewage implementation, Gangua Canal is already built. It is considered a
constant flow of urban sewage as the water inflow.
59 Low-cost wastewater treatment technologies for agricultural use
-Due to the variable characteristics of the crops cultivated in the area, the importance of the
indicators related to effluent efficiency, has been assessed base on the most sensible, risky and
least adapted crop. i.e. Pathogen removals has been consider high important due to possible
cultivation of vegetables to eat raw.
- All the technologies selected are known and has been implemented in India urban context.
Therefore the construction methods ability has been assessed by; (1) The need of skilled
labour for the design and the implementation of the device, and (2) the complexity of the civil
works that involves the construction of the technology. The reason behind is that this would
rise the financial requirements of the technology.
-Ground water threat and odour problems are two indicators that can easily be produced
normally or as a consequence of mismanagement of the system. The mismanagement risk is
considered in the assessment.
Table 9: Ranting of different indicators based on the local conditions (Source: self-design)
Milestones of Ward Number 3 Related Indicators/criteria SCORE RANGE
PRINCIPLE1: AGRICULTURE Crop production efficiency Total 100
Crop characteristics
Crops are moderate sensitive to salinity concentration. Nutrient crop requirements.
The soil composition is alluvial with low filtration capacity.
Nutrients 40
Crop sensibility Salinity* 0
Soil characteristics
BOD 20
TSS 20
Heavy Metals 20
PRINCIPLE 2: HEALTH Health protection efficiency Total 100
Crop consumption Crops type A by WHO 1989 (see table 3.2a, Annex2) The
wastewater is applied by furrow irrigation. Bhubaneswar is located in a tropic template area, very humid with high risk
of mosquito vector diseases as malaria.
Heavy Metals 20
Pathogens removal 40 Irrigation techniques
Vector-borne diseases Mosquito reservoir 40
PRINCIPLE 3: CONTEXTUALITY Affordability Total 100
Land availability
There are not financial resources available. Gangua Nallah considered as a sewage facility. There is not municipal land property in the ward (although it is contemplated to make a
green belt area for the vision 2030 plan). As a capital city, material and construction ability is not a problem.
Size 60
Financial resources
Centralized or decentralized** 0 Sewage infrastructure
Local material and construction methods knowledge
Correct design and construction 40
PRINCIPLE 3: CONTEXTUALITY Sustainability TOTAL 100
WUA The skill labour availability is assured; however financial resources to pay them are not clear. Odisha annual plan, as
well as Bhubaneswar Municipal planning consider urban and peri-urban activities as part of their plans. There is an
informal water user association (WUA).
Simple O&M
10
Institutional initiatives 15
Skill labour availability 5
Spare parts availability 5
Financial resources 5
Energy supply in the city is not covering all the areas and suffer of cut offs frequently.
Energy requirements
10
Energy supply infrastructure 10
Energy reliability 15
Fluctuation of volume of wastewater
High risk of wastewater fluctuation due to, the fat growing of the city, changing of land use and lack of separated
sewage system. Robustness
5
Fluctuation of load of pollutants
15
PRINCIPLE 3: CONTEXTUALITY Environmentally friendly Total 100
Geomorphology Deep phreatic surface (18-24m.b.g.l.). Ground water is
commonly used as a drinking water source. Ground water threat 50
Proximity to residential areas Lower population density than the city average. Mixed land use although agriculture plot occupy a large compact part
of the north of the ward.
Odour problem 25
Landscape impact Pleasant infrastructure 25
(*) Salinity reduction will not be addressed by the technology. (**) There is no need of sewage implementation, Gangua Canal is already built.
60 Low-cost wastewater treatment technologies for agricultural use
Table 10: Detailed scoring of indicators (Source: self-design)
INDICATORS CRITERIA Score Range Total score
CROP PRODUCTION EFFICIENCY Partial score 100
Nutrients 50-100% Nutrients removal 0 40 25%-50% Nutrients removal 20
Low/No nutrient removal 40
BOD No BOD reduction 0 20 25%-50% BOD reduction 10
50-100% BOD reduction 20
TSS No TSS reduction 0 20 25%-50% TSS reduction 10
50-100% TSS reduction 20
Heavy Metals Low removal of heavy metals 0 20 High removal of heavy metals 20
HEALTH PROTECTION EFFICIENCY Partial score 100
Heavy Metals Low removal of heavy metals 0 20 High removal of heavy metals 20
Pathogens removal No removal 0 40 Partial removal ( of most of pathogens) 20
Total removal of pathogens (helminths, viruses, protozoa and bacteria) 40
Mosquito reservoir No possibility of mosquito reservoir 0 40 Risk of mosquito reservoir if missmanagement 20
Possible mosquito reservoir 40
AFFORDABILITY Partial score 100
Size Large systems 0 60 Small system 60
Correct design and construction
Difficult construction, requires hire skilled labour for the design and implementation 0 30 Simple construction, does not require to hire skilled labour for the design and implementation 30
Construction methods knowledge and availability
of local materials
No local ability and material for construction. 0 10 Local ability and material for construction 10
SUSTAINABILITY Partial score 100
Skilled labour Technology requires skilled labour in order to be managed. No possible management by WUA members.
0 15
No requirement of skilled labour or small training is enough for the correct management of the system. Possible management by WUA members
15
Financial resources or initiatives for implementing
the project
Requires large financial investment or institutional initiatives to be implemented and promote the project.
0 15
Requires the existence of small budget, loan, charity capital, NGO funds, etc. 15
Spare parts No spare parts availability at local market 0 5 Spare parts availability at local market 5
Energy requirements Requirement of energy supply 0 35 Non requirement of energy supply 35
Robustness No flexible, no adaptable to changes of volume 0 5 Flexible, adaptable to moderate changes of volume 5
No flexible, no adaptable to changes of pollutants load 0 15 Flexible, adaptable to moderate changes of pollutants load 15
ENVIRONMENTALLY FRIENDLY CHARACERISTICS Partial score 100
Ground water threat High risk of pollution 0 50 Some possibility risk of ground water pollution 20
No risk of ground water pollution 50
Odour problem Produce odours 0 25 Some possibility of odour release 10
No odour production 25
Pleasant infrastructure Do not contribute to create a pleasant view for landscape 0 25 Contribute to create a pleasant view for landscape 25
61 Low-cost wastewater treatment technologies for agricultural use
5.2.3 Scoring matrix
In the Table 11, the scoring matrix is shown. These are the results of the technologies
evaluation by the scoring comparison. The evaluation has been carried out analysing each
indicator one by one according to the Table 10. It should be mentioned the Direct Use as a non
treatment situation. The Direct Use evaluation has been assessed considering the use of
untreated wastewater, with all content of nutrients and pollutants. The sustainability,
affordability and environmental friendly criteria has been scored base on the "Green filter"
technology (further details see Table 11). The final score of the criterion of each technology
and the final score of the technologies is shown in the Table 12. The technologies in the Table
12 have been classified by their treatment stage. However, note that this final score cannot be
used to compare all the technologies. As it was discussed in the chapter 4.1, the technologies
are usually part of treatment processes chain (see Figure 13). They work combined in order to
achieve a complete treatment. Multiple combinations of technologies are possible. Therefore,
the evaluation result is a reference to compare technologies that develop similar stage of the
process.
A sensibility analysis was made in order to verify the uncertainty grade of the results. Giving
the maximum score to the health protection and crop production criteria, and making the local
context criterion zero, the technology would obtain a 72.4 final score. This means that this
method would assume that a very expensive technology, difficult to manage and non
environmental friendly will be chosen rather than a technology easy to manage that get an
effluent of less quality. Therefore, the scoring comparison is a supporting tool but should not
be considered the selection method.
62 Low-cost wastewater treatment technologies for agricultural use
Table 11: Detailed scoring of technology (Source: self-design).
INDICATORS TOTAL SCORE
Direct Use
Coarse screen
Sand traps
Grease traps
Septic tank
Imhoff tank
Baffed reactor
Anaerobic filter
Soil biotechnolog
y
Anaerobic ponds
Facultative ponds
Maturation ponds
Free flow CW
Horizontal flow CW
Vertical flow CW
Sand filter
Crop production efficiency
100 40 40 40 40 90 100 100 100 60 100 60 60 60 80 80 60
1 40 40 40 40 40 40 40 40 40 0 40 20 0 20 20 20 40
2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
3 20 0 0 0 0 10 20 20 20 20 20 20 20 20 20 20 0
4 20 0 0 0 0 20 20 20 20 20 20 10 20 10 20 20 0
5 20 0 0 0 0 20 20 20 20 20 20 10 20 10 20 20 20
Health protection efficiency
100 40 40 40 40 40 40 40 40 100 40 50 60 70 80 80 80
5 20 0 0 0 0 20 20 20 20 20 20 10 20 10 20 20 20
6 40 0 0 0 0 0 0 0 0 40 20 40 40 40 40 40 40
7 40 40 40 40 40 20 20 20 20 40 0 0 0 20 20 20 20
Affordability 100 100 100 100 100 70 70 70 70 10 10 10 10 10 40 40 100
8 60 60 60 60 60 60 60 60 60 0 0 0 0 0 30 30 60
9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
10 30 30 30 30 30 0 0 0 0 0 0 0 0 0 0 0 30
11 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
Sustainability 100 100 100 100 100 75 75 75 75 25 80 65 95 95 90 40 105
12 15 15 15 15 15 15 15 15 15 0 0 0 15 15 15 15 15
13 10 10 10 10 10 5 5 5 5 0 5 5 5 5 0 0 15
14 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
15 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 50 50 50 50 50 50 50 50 50 0 50 50 50 50 50 0 50
17 5 5 5 5 5 0 0 0 0 5 5 5 5 5 5 5 5
15 15 15 15 15 0 0 0 0 15 15 0 15 15 15 15 15
Environmentally friendly
100 35 75 75 75 60 75 75 75 85 75 60 75 85 100 100 60
18 50 0 50 50 50 25 25 25 25 50 50 50 50 50 50 50 50
19 25 10 25 25 25 10 25 25 25 10 25 10 0 10 25 25 10
20 25 25 0 0 0 25 25 25 25 25 0 0 25 25 25 25 0
TOTAL SCORE 53.05 55.21 55.21 55.21 66.395 70.825 70.825 70.825 66.395 64.72 51.385 59.145 63.305 77.75 72.2 76.675
63 Low-cost wastewater treatment technologies for agricultural use
Note. Direct use of wastewater has been assessed base on the green filter characteristics in terms of design and O&M. The effluent characteristics were considered as non treated effluent therefore: 0% nutrients removal, BOD reduction, TSS reduction, heavy metals reduction and pathogen reduction. As the technology does not exist the affordability and sustainability score are maximized. 1-Nutrients: (0) 50-100% Nutrients removal. (20) 25%-50% Nutrients removal. (40) Low/No nutrient removal. 2-Salinty: (0) Not considered. 3-BOD reduction: (0) <25% BOD reduction. (10) 25%-50% BOD reduction. (20) 50-100% BOD reduction. 4-TSS reduction: (0) <25%TSS reduction. (10) 25%-50% TSS reduction. (20) 50-100% TSS reduction. 5-Heavy metals reduction: (0) <25%TSS reduction. (10) 25%-50% TSS reduction. (20)50-100% TSS reduction. 6-Pathogens removal: (0) No removal. (20) Partial removal (of most of pathogens). (40) Total removal of pathogens 99% (helminths, viruses, protozoa and bacteria). 7-Mosquito reservoir: (0) Possible mosquito reservoir. (20) Risk of mosquito reservoir if mismanagement. (40) No possibility of mosquito reservoir 8-Size: (0) Large systems. (30) Medium size. (60) Small system. 9- Centralized or decentralized: (0) Not considered. 10-Correct design and construction: (0) Difficult construction, requires hire skilled labour for the design and implementation. (30) Simple construction does not require hiring skilled labour for the design and implementation. 11-Local ability and material for construction: (0) No local ability and material for construction. (10) Local ability and material for construction. 12-Skilled labour: (0) Technology requires skilled labour in order to be managed. No possible management by WUA members. (15) No requirement of skilled labour or small training is enough for the correct management of the system. It is possible to be managed by WUA members. 13-Financial resources or initiatives for implementing the project: (0) Requires large financial investment or institutional initiatives to be implemented and promote the project. (10) Requires the existence of small budget, loan, charity capital, NGO funds, etc. 14-Spare parts and local materials: (0) No spare parts availability at local market. (5) Spare parts availability at local market 15-Construction methods knowledge: (0) Not considered. 16-Energy requirements: (0) Requirement of energy supply. (60) Non requirement of energy supply. 17-Robustness: (0) No flexible, no adaptable to changes of volume. (5) Flexible, adaptable to changes of volume. (0) No flexible, no adapting to changes of pollutants load. (15) Flexible, adaptable to moderate changes of pollutants load. 18-Ground water pollution threat: (0) Buried systems, risk of ground water pollution. (40) No risk of ground water pollution. 19-Odour problem: (0) Produce odours. (10) Some possibility of odour release. (20) No odour production. 20-Pleasant infrastructure: (0) does not contribute to create a pleasant view for landscape. (20) Contribute to create a pleasant view for landscape.
64 Low-cost wastewater treatment technologies for agricultural use
Figure 13: Classification of the selected technologies according to the treatment stage.
The ranking matrix of the technologies selected with the final scored is the following:
Table 12: Scoring matrix of the different technologies regarding to the five criteria assessed.
TREATMENT STAGE
TECH. Crop production
efficiency Health protection
efficiency Affordability Sustainability
Environmentally friendly
TOTAL SCORE
Max. Score 100 100 100 100 100 100
ALL DIRECT USE 40 0 100 100 35 53.05
PRE-TREAT.
Coarse screen 40 40 100 100 75 55.21
Sand traps 40 40 100 100 75 55.21
Grease traps 40 40 100 100 75 55.21
PRIMARY TREATMENT
Septic tank 90 40 70 75 60 66.395
Imhoff tank 100 40 70 75 75 70.825
PRIMARY/ SECONDARY TREATMENT
Baffled reactor 100 40 70 75 75 70.825
Anaerobic filter 100 40 70 75 75 70.825
ALL Soil
biotechnology 60 100 10 25 85 66.395
ALL
PRIMARY TREATMENT
Anaerobic ponds
100 40 10 80 75 64.72
SECONDARY TREATMENT
Facultative ponds
60 50 10 65 60 51.385
TERTIATY TREATMENT
Maturation ponds
60 60 10 95 75 59.145
SECONDARY TREATMENT
TERTIATY TREATMENT
Free flow CW 60 70 10 95 85 63.305 Horizontal flow
CW 80 80 40 90 100 77.75
Vertical flow CW
80 80 40 40 100 72.2
TERCIATY TREATMENT
Sand filter 60 80 100 105 60 76.675
65 Low-cost wastewater treatment technologies for agricultural use
6. DISCUSION
Bhubaneswar is an overpopulated city, in which urban infrastructures remain under
dimensioned behind the fast growing pace of the city. Gangua canal, a natural topographical
drain, has become the main sewage stream of the city due to the lack of any sewage
infrastructure in the 70% of the urban area. Located in a tropical climate, the uneven
distribution of rain during the year and the increasing demand makes water a scarce resource
form a socioeconomic and a physic point of view.
Agriculture is a marginal sector but still located in the urban banks of the eastern and southern
rivers. The ward number 3 of Bhubaneswar has a large urban agricultural area, located in the
bank of Kuakhai river. Despite the high potential change of land use in to urban plots, the
development plans of the city for 2030 consider part of this area as agricultural land. The
urban settlement expansion of the city is not considered in this area that remains as a green
belt for urban planners. Although there is no irrigation infrastructure, watering is required for
vegetables and flower production from November to May. The irrigation is made by flood.
Gangua canal crosses the ward from north to south. There is a continuous flow stream of
urban wastewater in Gangua Canal. This is the cheapest and the most affordable source of
water for the local farmers.
Quality parameters of wastewater for irrigation
Wastewater use for irrigation is not yet covered by Indian regulation. The situation regarding
the availability and quality of water in India, has been reported for years by the Central
Pollution Control Board. Although there are no registered data of wastewater irrigation in
Indian cities, the use is reported by several authors (Van Beusekom, 2012; Kumar, 2012). These
activities are potential health hazards for the dwellers. Some recommendations regarding to
water quality parameters for irrigation were given by the National River Conservation
Directorate. The Indian government also included in the last water law of 2012, some quotes
about incentives of wastewater reuse. However these initiatives are not feasible measures,
and represent a timid response to the scope of the problem.
Worldwide there is increasing use of urban wastewater for irrigation. This fact makes this issue
to be an international concern. The last international guidelines were proposed in 2006 by
FAO, WHO and World Bank. Although the measures suggested are flexible and adaptable to
the local context, the calculations are complex and the required water quality data very
specific. The lack of data makes these guidelines to be inapplicable in the analysis of
Bhubaneswar scenario. Therefore, during this study, in order to have a reference of water
quality parameters for irrigation, a summary of the recommended standards was done. Indian
MoEF, FAO and WHO in 1989, USEPA 1992 and the reducing health risk recommendation of
WHO, World Bank and FAO 2006 were considered.
Water quality of Gangua Canal is not good. Base on the above mentioned guidelines, the direct
use of Gangua water for irrigation overcomes the recommended limits regarding to suspended
solids, BOD, chloride and faecal coliforms. On the contrary, the water quality parameters
revealed a low concentration of pollutants according to the wastewater quality classification of
66 Low-cost wastewater treatment technologies for agricultural use
Pescod (1992). This could be due to the dilution suffered by the pollutants in the water stream.
However it is unknown the period of the year when the data were collected, therefore this
assumption is not possible to verify.
Urban wastewater is normally characterized by high loads of organic and inorganic
compounds. Some of these compounds are plant´s macronutrients such as Nitrogen or
Phosphorous. Nitrogen is highly present in wastewater, however only the inorganic forms
(Nitrate and ammonium) can be directly absorbed by plants. During the treatment process,
organic N is transformed into inorganic N. Phosphorous is also a valuable macronutrient of
wastewater. Solid phosphates either are dissolved or are formed solid particles. Therefore are
partially concentrated in the sludge formed during the treatment processes. Sludge spreading
is a frequent agricultural practice. Phosphates are decayed by natural, physical and
microbiological processes in the soil and assimilated by the crops afterwards. Regarding to
macronutrients, a direct use (untreated) of wastewater can produce a long term increase of
the amount of carbon and macronutrients in the soil (Yadav, et al 2002). Reliable data of
macronutrient content of Gangua Canal were not available.
Wastewater contains also other organic and inorganic compounds that are not beneficial for
the crop production. Heavy metals (Ni, Mn, Cu, Cr, Se, Pb, Zn, Fe or Cd) are frequently found in
urban wastewater mainly from industrial discharge and road´s runoff. The heavy metal´s
concentration in urban wastewater is usually low. Although the use of (untreated) wastewater
for irrigation does not have immediate effect on soils, however there are potential long term
effects because of the accumulation over the time. High loads of certain compounds are toxic
for soil microorganism and crops and can affect to crop yields and human health. Heavy metals
are usually removed by precipitation and sedimentation. This is normally enhanced by
anaerobic processes. Therefore heavy metals are accumulated in the sludge.
Additionally, urban wastewater is characterized by the high content of salts. Inorganic salts are
added to the wastewater by the use of soaps, detergents, rests of food, paper, urine and feces.
Sodium compounds in wastewater are very soluble. Crops have different tolerance to salinity
and this could be a determining factor of crop production failure. Furthermore, the continued
use of high salinity irrigation causes long term effect on soil properties, such as hydraulic
conductivity and carbon availability. Despite the great hazard of soil salinization due to the use
of reclaimed water, wastewater desalinization requires high energy and costly equipment.
Nowadays there is no low cost treatment solution for this problem.
Urban wastewater contains high loads of pathogens. The wastewater borne disease risk due to
the use of wastewater is high. The direct use of reclaimed water (not treated) implies health
hazard both to the farmer that manage the water and to the consumers that eat the products.
However, the extent of risk of disease transmission is variable and related to many external
factors; irrigation techniques, crop consumption, local habits, hygienic customs, etc
(Ardakanian, 2012). Therefore, the treatment of Ganghua water before use it for irrigation
seems to be a logical solution.
Wastewater treatment technology
67 Low-cost wastewater treatment technologies for agricultural use
Wastewater treatment technologies are designed for environmental purposes. The possible
use of the effluent as reclaimed water for irrigation is only consider as a possibility not as a
target. Their purpose is environmental water protection with no agricultural consideration.
However, for this study the main purpose of the water treatment system is the improvement
of the wastewater quality, in order to enable poor urban farmers to benefit from it. In fact, the
final quality of the effluent is linked with the treatment process.
While wastewater treatment technologies and drinking water technologies are disciplines
clearly defined. Agriculture water treatment is not considered as a discipline only as a marginal
potential use of water. However irrigation is not a marginal use and the potential use of
reclaimed water for agriculture is exponentially increasing. It results paradoxical that over
decades the environmental technologists have been developing treatment methods to treat
water in order to make it suitable for human activities such as drinking, industry and
environmental protection, but not for agriculture. Although, agriculture is an ancient practise
developed by humans in prehistoric era, and irrigation is used for crop production since more
that 2000 years. The agricultural sector is the human activity totally ignored by water quality
technicians. The biggest wastewater user has been totally sidetracked for the wastewater
treatment methods. Crop production has to use technologies designed for environmental
measures that bear no relation to the agricultural sector.
The fact is that wastewater technology is aimed to get an effluent quality that ensures
compliance with the environmental standards. These standards are completely different to the
agricultural ones. The eutrophication risk of water bodies, pushes to reduce the nitrogen and
phosphorus concentration of the effluents before discharges them into water bodies.
Regarding to the health protection, wastewater treatment technologies only cover health
issues when direct reuse of effluent is considered. In that case tertiary treatments are
implemented as a complementary treatment stage at the end of the process chain. Therefore
these polishing technologies are designed to treat a pre-treated effluent. This means that has
already reduced nutrient loads, therefore it is against the crop production if using the current
technologies available.
On the other hand, although wastewater´s high tech treatment plants have spread in India
over the last few decades, the performance was not as satisfying as initially intended (CPCB,
2013). The low performance of the plants leads to drain effluents with high COD and
pathogen´s loads. The reason behind this has been reported by researchers like Sato (2006)
and also by local institutions like Sankat Mochan Foundation (1993) and the CPCB (2013). The
mismanagement of conventional treatment plants was pointed out as the main reason. The
high demand of operating cost, lack of qualified staff and the inability of spare parts
replacement are the scope of the problems.
Low cost and water quality are the main targets of any wastewater treatment project. Aside
from goals and standards towards water quality, the technology has to be appropriate for the
local situation and the social context regarding to land availability, local materials, construction
and operation know-how or skill labour availability. On the other hand some studies
(Singhirunnusorn, 2009) suggest that low investment and operating costs are of great
importance to guarantee the sustainability of the system. Other fingers pointed directly
68 Low-cost wastewater treatment technologies for agricultural use
towards decentralized solutions (Sasse, 1998) and stakeholder participation (Van Buuren,
2010). However, even in these cases, in many occasions, the implementation of any of the
proposed solutions looks far from feasible considering the investment required. In case of the
ward number 3, the cost of infrastructure implementation does not constrain the selection of
the technology. This is because Ganghua Canal becomes a sewage infrastructure itself.
Technology selection process
All the above mentioned factors and limitations were taken into account when the
technologies were analysed. Furthermore, due to the large amount of characteristics
(indicators) that could influence the suitability of the technology, a multi criteria analysis tool
was used to support the selection process of the technology. The scoring comparison method
results a very simple and feasible tool for the process.
The preliminary devices obtained the same score. The aim of these devices is to facilitate the
performance of the other technologies. Therefore, the low compliance regarding to health and
agronomic properties is not taken into consideration. Any of them would be suitable because
of the high affordability and sustainability features. Therefore the selection among them
would be done according to the requirements of the following technologies. Although the
relation health protection/crop production achieved by soil biotechnology is very acceptable,
the final score is not that optimal because of the low sustainability and affordability. This is due
to the dependency of energy in order to be operated, the large land requirements and the high
capital cost for implementation. The combined typologies of septic tanks (septic tank, Imhoff
tank, baffled reactor and anaerobic filter) have a good performance for crop production;
however the health risk remains non-covered. Between the different primary and secondary
treatment technologies, the combined typologies of septic tanks are higher scored over
anaerobic stabilization ponds. Although the score is similar regarding to crop protection and
crop production, the septic tank typologies obtained higher punctuation regarding to
affordability and sustainability. This difference is due to the size of the system. Urban land is
expensive and ponds technologies require larger land. A combination of stabilization ponds
would optimize the performance regarding to health protection. However, despite the high
rates of sustainability and environmental respect, a combination of three large ponds in an
urban area results a solution barely affordable. By contrary, despite the large land required,
horizontal constructed wetland has been scored the highest. Comparing with the other
constructed wetland technologies, free flow wetland requires larger land and vertical flow
implies the use of energy and increase the risk of mosquito reservoir. Horizontal flow
constructed wetlands have risk of clogging because of grease, and therefore completing the
system with a pre-treatment device of grease/sand trap, will result the most appropriate
system for wastewater irrigation in ward number 3 of Bhubaneswar.
69 Low-cost wastewater treatment technologies for agricultural use
7. CONCLUSION
-Horizontal subsurface constructed wetland is a suitable technology for treating the water of
Gangua Canal at the north part of Ward number 3. This technology provides an effluent that
keeps at least the 60% of nutrients. The effluent final quality minimizes the risk of pathogen
transmission to the farmers and the products. Furthermore, the system is easy to manage and
does not create potential vector disease reservoirs because of the subsurface flow of the
wastewater. In order to avoid clogging problems, a grease/sand trap might be installed as a
pre-treatment device.
-The criteria used for the selection of the technology; health protection efficiency, crop
production efficiency, affordability, sustainability and the environmental friendly
characteristics provide a very complete and representative analysis.
-The defined indicators; nutrient (N,P) content, salinity reduction, total suspended solid (TSS)
reduction, biochemical oxygen demand (BOD), heavy metals, pathogens removal, size, design
and construction cost, energy requirements, simplicity of operating and maintenance,
robustness and environmental nuisances, are representative for the criteria. Most of them
result easy to identify and to analyse because they are parameters commonly used by
environmental technicians.
-There are various socio, economical, political and physical factors that influence in the
implementation and performance of a wastewater treatment technology for the treatment of
urban agricultural wastewater. These are:
- Agricultural characteristics: Irrigation requirements, crop consumption.
-Social context: Existence of water user association, skilled labour availability.
-Political: land availability, institutions initiatives, financial support.
-Physical: energy reliability, sewage infrastructure.
-The high content of macronutrients as Nitrogen and Phosphorous, and organic matter in
wastewater are beneficial and profitable for the agricultural production. However, heavy
metals and a high content of inorganic salts might be also present in urban wastewater and
can be a hazardous for agricultural production.
- Aerobic processes of treatment technologies break down the nitrogen into compounds highly
assimilated by plants, like nitrates and ammonium. Therefore this treatment could be used to
enhance the assimilation capability of plants. Regarding to phosphorus, during the primary
treatments, phosphorus is partially settled down with the solid part forming the sludge. The
spread of the sludge over the fields is a common way of phosphorus utilization in agriculture.
- Due to the lack of chemical and energy devices, low cost disinfection is based on the longer
retention times of the technologies. The reduction of viruses, that are not able to survive long
time without be hosted, is ensured. Bacteria can persist in the wastewater multiplying for a
medium-long term period, the correct removal requires therefore longer time of treatment.
70 Low-cost wastewater treatment technologies for agricultural use
However, the reduction of helminths eggs or protozoa cysts can be achieved in previous stages
by simple sedimentation processes.
-There are low cost wastewater treatment technologies that can achieve the polishing
treatments with a high rate of reliability. Maturation stabilization ponds, free flow, horizontal
and vertical constructed wetlands and sand filters are technologies suitable for a low cost
requirement.
7.1 RECOMMENDATIONS
There are several low cost technologies that could be applied successfully to the case study.
The missing information triggered high amount of uncertainties and data assumptions during
all the study process. These results must be considered as a recommendation and further
studies should be done. It is highly recommended to look for reliable data regarding to water
quality of Gangua Canal. In case this data are not available or feasible, it is recommended to
take samples and analyse them manually.
Further research regarding to wastewater treatment specifically designed for agricultural use
are recommended.
Agricultural plots can be considered as a wastewater treatment themselves. Technologies as
Soil biotechnology, Land application, Green filters or Constructed Wetlands are in fact cases of
wastewater treatment in a soil -plant system. On the other hand, health risk can be minimized
by appropriate irrigation and management techniques. Base on the fact that non treatment
would be an acceptable option. However, crops and soil can be affected by some wastewater
compounds. Further research might be done about to what extent in some occasions the
treatment is really required.
High salinity is a common characteristic of urban wastewater. Inorganic salt end up in the
sewage from the soap, detergents and food preparation. Desalinization technologies use to be
high energy demanding. Irrigation management techniques and tolerant crops selection seem
to be the only manner to deal with the use water. Further research about low cost energy
technologies should be promoted in order to prevent irreversibly damage to urban agricultural
soil.
Although in this study stakeholder’s participation has not been analysis, much research point
out participatory approach as key factor for the sustainability of the implementation of
technology. In case of agriculture use of reclaimed water, water user association could play an
important role. During the review, many literature has been found regarding to participatory
approach of stakeholders in sanitation selection processes or participatory processes of water
user association in order to implement irrigation systems. Farmers are concerned of health
risks because the use of wastewater. However, I barely found articles of farmer’s participatory
approach for the selection of wastewater treatment technologies in with agricultural targets.
71 Low-cost wastewater treatment technologies for agricultural use
REFERENCES
Agricultural census, 2005-06. State : Orissa. District: khurda. Tehsil: Bhubaneswar Municipality.
Social group: all social groups. Department of Agriculture and Cooperation. Ministry of
Agriculture. Government of India 2013.
Agriculture census, 2012. Online database. All India report on number and area of operational
holdings (agriculture census2010-2011). Department of Agriculture & cooperation.
Ministry of Agriculture, Government of India. Available at: http://agcensus.nic.in/
Anon, 2011. Excreta Matters. 71- Cities Water-Excreta Survey 2005-06. Centre for Science and
Environment. New Delhi. Available at:
http://www.cseindia.org/themes/CSE/excretamatters/pdf/Bhubaneshwar.pdf
Ardakanian, R, Sewilam, H. and Liebe, J.2012. A Collaboration of UN-Water Members &
Partners FAO, WHO, UNEP, NU-INWEH, UNW-DPC, ICID IWMI UN-Water Decade
Programme on Capacity Development (UNW-DPC) Mid-Term-Proceedings on Capacity
Development for the Safe Use of Wastewater in Agriculture. Available at:
http://www.ais.unwater.org/ais/pluginfile.php/62/course/section/29/proceedings-no8-
web.pdf
Armenante, P.M. 1999. Course notes for: Industrial Waste Control I: Physical and Chemical
treatment. CHE 685. Lecture notes. New Jersey Institute of Technology Department of
Chemical Engineering, Chemistry, and Environmental Science Newark, NJ 07102-1982
ASAG, 2012. Agricultural Statistics at a glance 2012. Directorate of Economics and statistics.
Department of Agriculture and Cooperation. Ministry of Agriculture, Government of India.
Attri, et al, 2012. Attri S. D. and Ajit Tyagi Climate Profile Of India. Met Monograph No.
Environment Meteorology-01/2010. Government of India. India Meteorological
Department
Balkema, A. J; Preisig, H. A.; Otterpohl, R; Lambert, F. J.D. 2002. Indicators for the sustainability
assessment of wastewater treatment systems. Urban Water vol. 4 (2) p. 153-161
Ballabh, V. and Singh, K. 1997. Competing demands for water in Sabarmati Basin: Present and
Potential Conflicts. Paper presented at the Indo Dutch Program on Alternatives in
Development Seminar, Amersfoort, The Netherlands. Reprinted in A. Vaidyanathan and
H.M. Oudshoom (Eds.), Managing Water Scarcity: Experiences and Prospects (pp 49-74).
New Delhi: Manohar Publications, 2003.
Bhamoriya, V., 2002. Wastewater and welfare: pump irrigation economy of peri-urban
Vadodara. IWMI-TATA Water Policy Research Program Annual Partners' Meet, 2002
Brans, E.H.P.; de Haan, E.J. ; Nollkaemper, A. and Rizema, J. 1997. The Scarcity of Water.
Emerging Legal and Policy Responses. International Environmental Law & Policy Series.
72 Low-cost wastewater treatment technologies for agricultural use
Brikke, F.; Bredero, M. 2003. Linking technology choice with operation and maintenance in the
context of community water supply and sanitation. A reference document for planners
and project staff. Geneva: world health organization and IRC water and sanitation centre.
Bryson, J.M. 2003. What To Do When Stakeholders Matter: A Guide to Stakeholder
Identification and Analysis Techniques. Hubert H. Humphrey Institute of Public Affairs 245
Humphrey Center University of Minnesota. Minneapolis.
Buechler, S. and. Devi G., 2002. Livelihoods and Wastewater Irrigated Agriculture. Musi River in
Hyderabad City, Andhra Pradesh, India. In: Urban
Burjia, J. S. 2006. Groundwater Resources in India: The National water policy. Chapter 2 in:
Water and sanitation. Institutional Challenges in India. Sijbesma, C. and Van Dijk, M. P.
2006.
Bustamante, I. 1990. Land Aplication: its effectiveness in purification of urban and industrial
wastewater in La Mancha (Spain). Environ. Geol.Water Science Vol16, n3,pp.179-185.
Capra, A. and Scicolone, B. 2007. Recycling of poor quality urban wastewater by drip irrigation
systems. Journal of Cleaner Production (2007). Volume: 15, Issue: 16, Pages: 1529-1534
Card, H. 2005. Municipal wastewater treatment: A review of treatment technologies.
Wastewater workshop 2005. Municipal wastewater management: Theory and practices
.Water Resources Division. Department of Environment and Conservation. Province of
Newfoundland and Labrador. Canada.
Carías, B. E.; Chacón, E.T. and Martinez, M. A. 2004. Validación de metodologías para el cálculo
de caudales máximos en El Salvador. Universidad Centroamericana “José Simeón Cañas”.
Facultad de ingeniería y arquitectura. Octubre 2004. San Salvador
Carr, R.M., Blumenthal, U.J. and Mara, D.D. 2004. Health guidelines for the use of wastewater
in agriculture: Developing realistic guidelines. Chapter 4 In: Wastewater use in irrigated
agriculture. Confronting the Livelihood and Environmental realities. Scott, C.A.; Faruqui,
N. I. and Rachid-Sally, L. 2004. International Development Research Centre. International
Water Management Institute.
CDPH, 2013. California water recycling criteria & Agency. Recycled Water: Regulations and
Guidance 2013.
http://www.cdph.ca.gov/healthinfo/environhealth/water/pages/waterrecycling.aspx
CENTA, 2007a. Manual de tecnologías no convencionales para la depuración de aguas
residuales.Capitulo I. Generalidades. Fundación centro de nuevas tecnologías del agua.
Sevilla,2007.
CENTA, 2007b. Manual de tecnologías no convencionales para la depuración de aguas
residuales.Capitulo II. Aplicación al terreno. Fundación centro de nuevas tecnologías del
agua. Sevilla,2007.
73 Low-cost wastewater treatment technologies for agricultural use
Central Pollution Control Board (CPCB), 2008. Performance of Sewage Treatment Plants -
Coliform Reduction. Control of urban pollution. Series : CUPS/ 69 /2008.Central Pollution
Control Board. Ministry Of Environment & Forests. Government of India
Central Pollution Control Board (CPCB), 2013a. Water Quality/ Pollution. Status of STPs
(Sewage Treatment Plants). Ministry of Environment & Forests. Government of India.
Available at: http://cpcb.nic.in/statusSTP.php
Central Pollution Control Board (CPCB), 2013b. Status of water Quality in India-2011.
Monitoring of Indian National aquatic resources. Series; Minars 35 /2013-14. Parivesh
Bhawan, East Arjun Nagar, Delhi 110 32. Ministry of Environment & Forests. Government
of India.
Central Water Commission (CWC), 2010. Water and related statistics, December 2010. Water
resources statistics. Information System Organization. New Delhi. Available in:
http://www.cwc.nic.in/ISO_DATA_Bank/ISO_Home_Page.htm
Centre for Science and Environment (CSE), 2011. Policy paper on septage management in
India. New Delhi. Available at:
http://www.urbanindia.nic.in/programme/uwss/slb/SeptagePolicyPaper.pdf (accessed on
May 12, 2013).
Centre for Science and Environment (CSE), 2013a. Water Management. Excreta Matters
newsletter. Excreta matters home. Available at:
http://www.cseindia.org/content/excreta-matters-0
Centre for Science and Environment (CSE), 2013b. Decentralized wastewater treatment.
Available at: http://www.cseindia.org/node/3798 (accessed on July 15, 2013).
Centre for Science and Environment (CSE). 2012. Bhubaneswar lacks any sewage treatment.
June 14, 2012. Excreta Matters: Workshop on Bhubaneswar’s Water and Sewage
problems 14th June Xavier Institute of Management, Bhubaneswar. Water Management.
Excreta Matters newsletter. Excreta matters home. Available at:
http://www.cseindia.org/node/4274
Community consulting India Private Limited. (CCIP), 2006. Bhubaneswar city development plan
report under JnNURM. Annexure 2. Ward-wise population and density pattern. June,
2006. )
Crisis management plan (CMP), 2012. Drough. National. 2012. Drought Management Division.
Department of Agriculture and Cooperation. Ministry of Agriculture, Government of India.
Crites, R., and Tchobanoglous, G., 1998. Small and Decentralized Wastewater Management
Systems, WCV/Mc Graw-Hill.
Crites, R., Middlebrooks, E. y Reed, S. 2006. Natural Wastewater Treatment Systems. CRC
Press,Taylor & Francis Group.
74 Low-cost wastewater treatment technologies for agricultural use
Crites, R., Sherwood C. R., Robert B., 2000. Land treatment systems for municipal and
industrial wastes. McGraw-Hill Press.
Crock, C., Lammers, A., Long, B., Raak, A. 2010. Project design report. Team 5. Wastewatchers.
19th april 2010. Calvin college.
Curtis, T. 2003. 30 - Bacterial pathogen removal in wastewater treatment plants. Handbook of
Water and Wastewater Microbiology (2003).Publisher: Academic Press, Pages: 477-490
Department of Agriculture and Cooperation, 2013. Horticulture division. Department of
Agriculture & cooperation. Ministry of Agriculture, Government of India. Available at:
http://agricoop.nic.in/divisions.html
Drechsel, P.; Scott, C.A.; L Raschid-Sally, Redwood, M. and Bahri, A. 2009. Wastewater
irrigation and Health. Assessing a mitigating risk in Low-Income countries. International
Development Research Centre. International Water Management Institute.
EBTC, 2011. Snapshot. Water and wastewater in India. European Business and technology
centre, New Delhi. ww.ebtc.eu.
Ellis, T. G. 2005. Chemistry of Wastewater. Environmental and ecological chemistry . Vol. II.
Encyclopedia of Life Support Systems. (EOLSS). UNESCO-EOLSS Sample chapters.
EMP, 2003. Environmental Management Plan (EMP) for Bhubaneswar. Chapter-3. The city
structure. Department of Forests & Environment. Government of Odisha. Available at:
http://www.odisha.gov.in/forest&environment/ Accessed 10 September 2013.
Engineers Without Borders (EWB), 2010. Construction of a slow sand filter. Easton: Engineers
without Borders. Lafayette Chapter, Lafayette College.
Ensink, J.H.; van der Hoek, W.; Mukhtar, M.; Tahir, Z.; Amerasinghe, F.P. 2005. High risk of
hookworm infection among wastewater farmers in Pakistan. Trans R Soc Trop Med Hyg,
2005; 99(11):809-18
Ernst, W.H.O. 1996. Phytotoxicity of heavy metals. Fertilizers and Environment Developments
in Plant and Soil Sciences Volume 66, 1996, pp 423-430
European Commission, 2001. Extensive wastewater treatment processes adapted to small and
medium sized communities, International Office for Water, Luxembourg.
FAO. 1985. Water quality for agriculture. R.S. Ayers and D.W. Westcot. FAO Irrigation and
Drainage Paper 29, Rev. 1. FAO, Rome. 174 p.
Faruqui, N. I.; Scott, C.A. and Rachid-Sally, L. 2004. Confronting the realities of wastewater use
in irrigated agriculture: Lessons learned and recommendations. Chapter 16 in :
Wastewater use in irrigated agriculture. Confronting the Livelihood and Environmental
realities. International Development Research Centre. International Water Management
Institute. 173-185.
75 Low-cost wastewater treatment technologies for agricultural use
Fischer, D. 2008. Multiple criteria decisions: opening the black BOX. Department of Estate
Management. Universiti Malaya, Kuala Lumpur. April, 2008.
Fuentes , A.; Lloréns, M. et al 2004. Phytotoxicity and heavy metals speciation of stabilised
sewage sludges. Journal of Hazardous Materials Volume 108, Issue 3, 20 May 2004, Pages
161–169
Garfì, M and Ferrer-Martí, L. 2011. Decision-making criteria and indicators for water and
sanitation projects in developing countries. Environmental Engineering Division,
Department of Hydraulic, Maritime and Environmental Engineering, Research Group on
Cooperation and Human Development (GRECDH), Technical University of Catalonia.
Water Science & Technology Vol 64 No 1 pp 83–101.
Government of Odisha, 2010. Odisha Agriculture Statistics 2008-2009. Directorate of
agriculture & food production. Odisha, Bhubaneswar. Government of Odisha, April 2010.
Available at: http://www.agriorissa.org/Directorate_Agri/statistics/A.Stat.pdf
Government of Odisha, 2012. Annual Plan 2012-13. Odisha. Volume I. Chapter6. Agriculture
and allied sector. Planning & Coordination Department. Bhubaneswar. Government of
Odisha, April 2012. Available at:
http://www.odisha.gov.in/p&c/Download/Annual_Plan_2012_13/Vol_I/CHAPTER-
6%20(Agriculture)%20(F).pdf
Gulati, A.; Meinzen-Dick, R. and Rayu, K.V. 2005. Institutional Reforms in Indian Irrigation.
Internationa Food Policy Research Institute (IFPRI).
Guyer, P. J., P.E., R.A., Fellow ASCE, Fellow AEI, 2011. Introduction to Secondary Wastewater
Treatment. Course No: C04-022. CED Continuing Education and Development, Inc.
Available at:
http://www.cedengineering.com/upload/Secondary%20Wastewater%20Treatment.pdf
Harussia, Y.; Rom, D. and Galil, N. and Semiat, R. 2001. Evaluation of membrane processes to
reduce the salinity of reclaimed wastewater. Desalination Volume 137, Issues 1–3, 1 May
2001, Pages 71–89
Hellströma,D. 2000. A framework for systems analysis of sustainable urban water
management. Assessment Methodologies for Urban Infrastructure. Environmental Impact
Assessment Review. Volume 20, Issue 3, June 2000, Pages 311–321
High Level Technical Committee (HLTC), 2007. Report of the High Level Technical Committee to
Study Various Aspects of Water Usage for Hirakud Reservoir. Water Resources
Department. Government of Odisha. August, 2007.
Hoffmann, H.; Platzer, C.; Winker, M.; Von Muench, E. 2011. Technology Review of
Constructed Wetlands. Subsurface Flow Constructed Wetlands for Greywater and
Domestic Wastewater Treatment. Eschborn: Deutsche Gesellschaft fuer Internationale
Zusammenarbeit (GIZ) GmbH.
76 Low-cost wastewater treatment technologies for agricultural use
Hophmayer-Tokich, S. 2006. Wastewater Management Strategy: centralized v. decentralized
technologies for small communities.The Center for Clean Technology and Environmental
Policy, University of Twente, at the Cartesius Institute, Zuidergrachtswal 3, 8933 AD
Leeuwarden, The Netherlands.
Huisman, L.; Wood, W.E. 1974. Slow Sand Filtration. World Health Organisation (WHO).
Geneva. 1974.
ICON, 2001. Pollutants in urban wastewater and sewage sludge. Directorate General
Environment. European Comission. Icon Consulting. London.
India Meteorological Department (IMD), 2012. Ministry of Earth Sciences, Government of
India. See at: http://www.imd.gov.in/
India WRIS, 2011. India-WRIS Wiki. Water resources Information System of India. River
information. See at: http://india-wris.nrsc.gov.in/wrpinfo/index.php?title=River_Info
Indian Council for Agricultural Research (ICAR), 2011. Vision 2030. Published by the Project
Director, Directorate of Knowledge Management in Agriculture (formerly DIPA Indian
Council of Agricultural research. January 2011, New Delhi. 110 012.
Indian Institute of Technology Kharagpur (IITK), 2008. Comprehensive development plan for
Bhubaneswar development plan area. Draft Proposal. Vision 2030. Department of
Archtecture and regional planning. Indian Institute of Technology Kharagpur. August,
2008.
Jairath, J. and Ballabh, V. 2008.Droughts and the integrated water resource management in
South Asia. Issues, alternatives and futures. Water in South Asia. Volume 2. SaciWATERs.
Sage publications.
Jiménez, B. and T. Asano. 2008. Water reclamation and reuse around the world. In B. Jimenéz
and T. Asano, eds., Water Reuse: An International Survey of Current Practice, Issues and
Needs. London: IWA Publishing.
Kadam, A. M.; Oza, G. H.; Nemade, P. D.; Shankar, H. S. 2008a. Pathogen removal from
municipal wastewater in Constructed Soil Filter. Ecological Engineering vol. 33 (1) p. 37-44
Kadam, A.; Oza, G.; Nemade, P.; Dutta, S. and Shankar, H. 2008b. Municipal wastewater
treatment using novel constructed soil filter system. Chemical Engineering Department,
Indian Institute of Technology-Bombay, Powai, Mumbai. India. Chemosphere vol. 71 (5)
p. 975-81
Karvelas, M.; Katsoyiannis, A. and Samara, C. 2003. Occurrence and fate of heavy metals in the
wastewater treatment process. Chemosphere. Volume 53, Issue 10, December 2003,
Pages 1201–1210
Kulbat, E.; Olańczuk-Neyman, K.; Quant, B.; Geneja, M.; Haustein, E. 2003. Heavy Metals
Removal in the Mechanical-Biological Wastewater Treatment Plant “Wschód” in Gdańsk.
Polish Journal of Environmental Studies Vol. 12, No. 5 (2003), 635-641.
77 Low-cost wastewater treatment technologies for agricultural use
Kumar Sabat, A. 2012. Analysis of the underlying causes of environmental degradation in
Bhubaneswar city. International journal of engineering research and applications (ijera)
issn: 2248-9622 www.ijera.com vol. 2, issue 2,Mar-Apr 2012, pp.210-214
Kumar, A. 2012. Urban Wastewater in India. Director presentation of workshop New Indigo.
Director & Project Coordinator (REOPTIMA). Indian Council of Agricultural Research,
Bhubaneswar. India. October 2012.
Lazarova, V. and Bahri, A. 2005. Water reuse for Irrigation: agriculture, landscapes, and turf
grass. CRC Press.
LDEQ, 2013. Lousiana Department of Environmental Quality, non-point solution program. Online source.
Available at: http://www.abbey-associates.com/splash-splash/blue_standards/sand_filter.html,
accesed 11,11,2013.
Leeuwis, C. 2006. Co-operation across scientific disciplines end epistemic communities. In:
Communication for Rural Innovation. Rethinking Agricultural Extension. Third Edition,
Oxford: Blackwell Science, pp. 350-361.
Mallick, R. K. 2012. Bhubabeswar City Sanitation- Situation Analysis. Presentation of WASH
Consultant. During Workshop on Bhubaneswar’s Water and Sewage problems 14th June
2012. Xavier Institute of Management, Bhubaneswar. Excreta matters. Centre for Science
and Environment. Available at:
http://www.cseindia.org/userfiles/bhubaneswar_city_sanitation.pdf
Mar nez, J. 1999. Irrigation with saline water: benefits and environmental impact. Agricultural
Water Management. Volume 40, Issues 2–3, May 1999, Pages 183–194
Mendoça, S. R., 2000. Sistemas de lagunas de estabilizacion. Como utilizar aguas residuales
tratadas en sistemas de regadio. McGraw-Hill Interamericana, Santa Fe de Bogotá
(Colombia).
Metha, L. 2007. Whose scarcity? Whose property? The case of water in western India Institute
of Development Studies, University of Sussex, Brighton BN1 9RE, UK. Land Use
Policy.Volume 24, Issue 4, October 2007, Pages 654–663. Exploring New Understandings
of Resource Tenure and Reform in the Context of Globalisation.
Mishra, P. 2004. Water Resource (groundwater resource) Mapping Using Remote Sensing and
GIS: A Case Study of Bhubaneswar, Odisha, India. B.Arch, M.U.D.P. (Master of Urban
Development Planning. Planning Officer, Delhi Development Authority, New Delhi.
Member of Winning Team – Map India Best Poster Award,2004. Available at:
http://www.gisdevelopment.net/proceedings/mapindia/2006/water%20resources%20pla
nning/mi06wat_82.htm
Molle, F. 2002. To Price or Not to price? Thailand and the Stigmata of “Free Water”. Paper
presented at the Workshop irrigation Water Policies: Macro and Micro Considerations.
Agadir, Morocco.
78 Low-cost wastewater treatment technologies for agricultural use
Morel, A.; Diener, S. 2006. Greywater Management in Low and Middle-Income Countries,
Review of different treatment systems for households or neighbourhoods. Duebendorf:
Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation
in Developing Countries (SANDEC).
Murray, A. and Buckley, C. 2009. Designing Reuse-oriented sanitation infrastructure: The
design for service planning approach. Chapter 15 in: “Wastewater irrigation and Health.
Assessing a mitigating risk in Low-Income countries”. International Development Research
Centre. Drechsel, P.; Scott, C.A.; L Raschid-Sally, Redwood, M. and Bahri, A. 2009.
Nashikkar, V.J. 1993. Effect of reuse of high-BOD wastewaters for crop irrigation on soil
nitrification. National Environmental Engineering Research Institute, Nehru Marg, Nagpur
-440 020, India. Environment International. Volume 19, Issue 1, 1993, Pages 63–69
New Indigo, 2011. Networking Pilot Programme on Water Related Challenges. Full Project
Proposal. New INDIGO Initiative for the Development and Integration of Indian and
European research. REOPTIMA, reuse options for marginal quality water in urban and
peri-urban agriculture and allied services in the gambit of WHO guidelines. Bhubaneswar.
Omu, A. 2009. Identification of the Sources of Heavy Metal in Urban Wastewater. Centre for
Environmental Policy, Imperial College London. 2009.
Oster, J. D. 1994. Irrigation with poor quality water. Agricultural Water Management (1994).
Volume: 25, Issue: 3, Pages: 271-297
Ostrom, E.; Fung Lam, W.; Pradhan, P and Shivakoti, G. 2011.Improving Irrigation in Asia.
Sustainable performance of an innovative intervention in Nepal. Edward Edgar.
Palm, A. 2010. Sustainable and affordable water and wastewater solutions for a low -income
housing cooperative in Master of Science Thesis in the Master’s Programme Industrial
Ecology Cochabamba, Bolivia. Department of Civil and Environmental Engineering Division
of Water Environment Technology CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg,
Sweden, 2010. Master’s Thesis. 2010:139
Patterson, R.A. 2000. Wastewater Quality Relationships with Reuse Options in Proceedings of
1stWorld Water Congress of the International Water Association. 3-7 July 2000. Paris,
France. Conference Preprint Book 8, pp 205-212.
Pescod, M. B. 1992. Wastewater treatment and use in agriculture – FAO irrigation and
drainage paper 47. Food and Agriculture Organization of the United Nations. Rome, 1992.
Petrasek, A.C.; Kugelman, I.J.; Austern, M.B.; Pressley, T.A.; Winslow, L.A. and Wise, R.H. 1983.
Fate of toxic organic compounds in wastewater treatment plants. Research Journal of
Water Control Pollutant Federation. Vol. 55.No. 5,Oct. 1983.
Phocaides, A. 2008. Handbook on pressurized irrigation techniques. Chapter 7: water quality
for irrigation. FAO, Rome, 2007.
79 Low-cost wastewater treatment technologies for agricultural use
Prakash, A.; Saravanan, V.S. and Chourey, J. 2011. Interlacing water and human health. Case
studies from South Asia. (Water in South Asia). Sage India.
Qadeer, M. A. 2006. Pakistan: Social and Cultural Transformations in a Muslim Nation . pp. 54–
55.
Ratna Reddy, V. and Mahendra Dev, S. 2006. Drinking water and sanitation in India: Need for
demand management structures. Chapter 4 in: Water and sanitation. Institutional
Challenges in India. Sijbesma, C. and Van Dijk, M. P. 2006.
Reoptima workshop, 2012. Proceedings of the International Inception Workshop under new
Indigo Project “REOPTIMA“. Minutes. August 2012. Bhubaneswar. Odisha. India.
Sankat Mochan Foundation. 1993. Ganga action plan failure report. Available at:
http://en.wikipedia.org/wiki/Sankat_Mochan_Foundation (accessed on August 02, 2013).
Sasse, L. 1998. DEWATS. Decentralized wastewater treatment in developing countries. BORDA.
Bremen overseas research and development association.
Sato, N.; Okubo, T.; Onodera, T.; Ohashi, A. and Harada,H. 2006. Prospects for a self-
sustainable sewage treatment system: A case study on full-scale UASB system in India's
Yamuna River Basin. Journal of Environmental Management. Volume 80, Issue 3, August
2006, Pages 198–207
Scott, C.A.; Faruqui, N. I. and Rachid-Sally, L. 2004. Wastewater use in irrigated agriculture.
Confronting the Livelihood and Environmental realities. International Development
Research Centre. International Water Management Institute. Cabi publishing. water
consultant, Sri Lank. June 2004 / Paperback /208 pages. Available at:
http://hdrnet.org/364/1/
Sethy, P. G. S.; Bulliyya, G.; Mallick, G.; Swain, B.K. and Kar, S. K. 2007. Iodine deficiency in
urban slum in Bhubaneswar. Regional medical research centre, Indian council of medical
research, Bhubaneswar, India.
Setiaa, R.; Gottschalkc, P.; Smithd, P.; Marschnera, P.; Baldocka, J.; Setiaa, D. and Smithd, J.
2013. Soil salinity decreases global soil organic carbon stocks. Science of The Total
Environment. Soil as a Source & Sink for Greenhouse Gases. Volume 465, 1 November
2013, Pages 267–272.
Seto, P. 2005. Wastewater treatment for small communities. Wastewater workshop 2005.
Municipal wastewater management: Theory and practices .Water Resources Division.
Department of Environment and Conservation. Province of Newfoundland and Labrador.
Canada.
Shankar, H.S. (unknown date). Soil Biotechnology of Indian Institute of technology, Bombay.
Department of Chemical Engineering. IIT-Bombay.
Shilton, A. 2005. Pond treatment Technology. IWA Publishing, London, UK.
80 Low-cost wastewater treatment technologies for agricultural use
Sijbesma, C. and Van Dijk, M. P. 2006. Water and sanitation. Institutional Challenges in India.
Indo-Dutch Programme on Alternatives in Development. Manohar, 2006. New Delhi.
Singh, A.; Sharma, R.K.; Agrawal, M.; Marshall, F.M. 2010. Health risk assessment of heavy
metals via dietary intake of foodstuffs from the wastewater irrigated site of a dry tropical
area of India. Food and Chemical Toxicology. Volume 48, Issue 2, February 2010, Pages
611–619
Singhirunnusorn, W. 2009. An Appropriate Wastewater Treatment System in Developing
Countries:Thailand as a Case Study. Dissertation for degree Doctor of Philosophy in Civil
Engineering University Of California Los Angeles.
Tanaka, N; Ng, W.J. and Jinadasa, K.B.S.N. 2011. Wetlands for tropical applications.
Wastewater Treatment by Constructed Wetlands. Imperial College Press.
TCGI, 2006. Preparation of city development plan report: Bhubaneswar, Orissa. Indo- USAID
Financial institutions reform and expansion project- Debt & Infrastrcuture component
(FIRE-D Project). TCGI-AECOM. October, 2006.
Tchobanoglous, G. 1996. Appropriate technologies for wastewater Treatment and Reuse,
Australian Water & Wastewater Association, Water Journal, Vol. 23, No. 4.
Tilley, E., Lüthi, C., Morel, A., Zurbrügg , C. and Schertenleib, R. 2008. Compendium of
Sanitation Systemsand Technologies. Swiss Federal Institute of Aquatic Science and
Technology (Eawag). Dübendorf, Switzerland.
Van Beusekom, L. 2012. Significance of urban wastewater irrigation in farmers' livelihood’ in
Bhubaneswar, India. BSc. Thesis International Land and Water Management. August 2012.
Wageningen University. The Netherlands.
Van Buuren, J. C. L. 2010. Sanitation choice involving stakeholders: A participatory multi-
criteria method for drainage and sanitation system selection in developing cities applied
in Ho Chi Minh City, Vietnam. Thesis. Wageningen University.
Van der Hoek, W. 2004. A Framework for a Global Assessment of the extent of wastewater
irrigation: the need for a common wastewater typology. International Water
Management Institute (IWMI), Bierstalpad, the Netherlands. Chapter 2 In: Wastewater
use in irrigated agriculture. Confronting the Livelihood and Environmental realities. Scott,
C.A.; Faruqui, N. I. and Rachid-Sally, L. 2004. International Development Research Centre.
International Water Management Institute.
Van der Hoek, W. et al. 2002. Urban wastewater: a Valuable Resource for Agriculture. A Case
study from Haroonabad, Pakistan. IWMI 2002.
Van Haandel, A.C. and Lettinga, G. 1994. Anaerobic sewage treatment. A practical guide for
regions with a hot climate, John Wiley & Sons Ltd., Chichester. UK.
81 Low-cost wastewater treatment technologies for agricultural use
Viviani, G and Iovino, M. 2004. Wastewater Reuse Effects on Soil Hydraulic Conductivity.
Journal of Irrigation and Drainage Engineering Asce (2004). Volume: 130, Issue: 6, Pages:
476-484
Von Sperling M. 1996. Comparison among the most frequently used systems for wastewater
treatment in developing countries. Wat. Sci. Tech., 33 (1996), pp. 59–72
Von Sperling M.; Bastos, R.K.X. and Kato, M. T. 2005. Removal of E. coli and helminth eggs in
UASB: polishing pond systems in Brazil. Water Science & Technology Vol 51 No 12 pp 91–
97.
Water and Sanitation Program (WSP), 2008. A Guide to decision making. Technology Options
for Urban Sanitation in India. Ministry of Urban Development Nirman Bhawan.
Government of India. September, 2008.
Wateraid India, 2005. Drinking water and sanitation. Coverage, financing and emerging
concerns. WaterAid India. New Delhi.
White, 2012. Understanding water scarcity: definitions and measurements. Discussion paper
1217. Australian National University, Australia. May 2012.
World Bank, 2003. Population, total. Web page.
http://data.worldbank.org/indicator/SP.POP.TOTL/countries?order=wbapi_data_value_2
011%20wbapi_data_value%20wbapi_data_value-last&sort=desc&display=default.
Accessed 17 May 2013.
World Bank, 2010. Improving Wastewater Use in Agriculture: An Emerging Priority. Energy,
transport and water department. Water Partnership program. June 30, 2010
World Bank, 2013. Sanitation, Hygiene and Wastewater Resource Guide. Infrastructure.
Introduction to wastewater treatment process. Web page.
http://water.worldbank.org/shw-resource-guide/infrastructure/menu-technical-
options/wastewater-treatment Accessed 23 July 2013.
World Health Organization (WHO), 1989. Health guidelines for the use of wastewater in
agriculture and aquaculture. Technical Report Series, No. 778. Geneva. Available at:
http://whqlibdoc.who.int/trs/WHO_TRS_778.pdf.
World Health Organization, Food and Agriculture Organization, and United Nations
Environment Programme (WHO), 2006a. Guidelines for the safe use of wastewater,
excreta and greywater: Volume 2: Wastewater use in agriculture. Geneva: WHO. Available
at: http://www.who.int/ water_sanitation_health/wastewater/gsuww/en/index.html.
World Health Organization, Food and Agriculture Organization, and United Nations
Environment Programme, 2006b. Guidelines for the safe use of wastewater, excreta and
greywater: Volume 4: Excreta and greywater use in agriculture. Geneva: WHO. Available
from: http://www.who.int/water_sanitation_health/wastewater/gsuww/en/index.html.
82 Low-cost wastewater treatment technologies for agricultural use
World Water Council (WWC), 2010. World Water Forum 2012. Available at
http://www.worldwatercouncil.org/index.php?id=25
WUTAP, 2007. Wastewater Systems Operator Certification Study Manual. Water Utilities
Technical Assistance Program. Doña Ana Community College, New Mexico State
University. November, 2007 Version 1.1
Yadav, R.K.; Goyal, B.; Sharma, R.K.; Dubey, S.K. and Minhas, P.S. 2002. Post-irrigation impact
of domestic sewage effluent on composition of soils, crops and ground water—A case
study. Environment International. vol. 28 (6) p. 481-486.
Personal communication(4th March, 2013)
Dr. S. K. Rautaray
Directorate of water management. Bhubaneswar Principal Scientist (Agronomy) Email: [email protected]
Dr. S. Raychaudhuri.
Directorate of water management. Bhubaneswar Sr. Scientist (Soil Fert./Che./Microbio.) Email: [email protected]
83 Low-cost wastewater treatment technologies for agricultural use
ANNEX 1
Institutions and Organizations: Online sources
INDIA (State Level) Web site link
Ministry of water resources http://wrmin.nic.in/
Water quality assessment authority (WQAA) http://wqaa.gov.in/
Central Water Commission (CWC) http://cwc.gov.in/
Central ground water board (CGWB) http://cgwb.gov.in/
Central water and power (CPRS) http://cwprs.gov.in/
National Water Development Agency (NWDA)* http://nwda.gov.in/
Agri Census Portal/ Agricultural census http://agcensus.nic.in/
Agrimet, Pune www.imdagrimet.org
Centre for Science and Environment www.cseindia.org
Department of Agriculture &Cooperation. Ministry of Agriculture. www.agricoop.nic.in
India Meteorological Department www.imd.gov.in
Indian Council for Agricultural Research http://www.icar.org.in
Central Pollution Control Board http://cpcb.nic.in/
Indian sanitation portal Indian sanitation portal.org
Ministry of Home Affairs (Disaster Management)
www.ndmindia.nic.in
National Centre for Medium Range Weather Forecasting www.ncmrwf.gov.in
State Government’s website http://goidirectory.nic.in/stateut.htm
ODISHA (Regional Level) Website link
Government of Odisha http://www.odisha.gov.in/portal/default.asp
Department of water resources. Government of Odisha http://www.dowrorissa.gov.in/
Directorate of Agriculture & Food Production. Government of Odisha
http://www.agriorissa.org/Directorate_Agri/
Directorate of Economics & Statistics, D/o Agriculture & Cooperation
www.agricoop.nic.in/Agristatistics.htm
Odisha Water Supply And Sewage Board (OWSSB) http://urbanorissa.gov.in/water_supply_sewerage_board.html
Odisha Public Health Engineering Organization (OPHEO) http://urbanorissa.gov.in/OPHEO.html
Odisha Platform to discuss infrastructure developments http://www.orissalinks.com/orissagrowth/
The District. Portal of Khorda, 2013 http://www.ordistricts.nic.in/district_home.php?did=kdh
The district portal of khordha http://www.ordistricts.nic.in/district_home.php?did=kdh
Regional centre of development cooperation http://rcdcindia.org/
BHUBANESWAR (City level) Website link
Bhubaneswar municipal corporation http://bmc.gov.in/
Bhubaneswar development authority http://bdabbsr.in/
Directorate of water management. Bhubaneswar http://www.dwm.res.in/ (*) Autonomous society
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Initiatives & Projects
Programs, Initiatives and Projects related to wastewater treatment, sewage infrastructure, sanitation and reclaim water use in the city of Bhubaneswar, Odisha (India).
Samman project. http://projectsammaan.com/ It is a project to improve the sanitation in the slums of Bhubaneswar and Cuttack cities. It is developed by a partnership of diverse group of organizations and government entities united to tackle the sanitation and hygiene crisis in India's urban slums. Drought Prone Areas Programme (DPAP) http://dolr.nic.in/dolr/dpap.asp
Rajiv Awas Yojana (RAY) program Inside Bhubaneswar Municipal Corporation the RAY for the slum dwellers and the urban poor envisages a ‘Slum-free India’ through encouraging States/Union Territories to tackle the problem of slums in a definitive manner. It calls for a multi-pronged approach focusing on: Bringing existing slums within the formal system and enabling them to avail of the same level of basic amenities as the rest of the town. Redressing the failures of the formal system that lie behind the creation of slums; and Tackling the shortages of urban land and housing that keep shelter out of reach of the urban poor and force them to resort to extra-legal solutions in a bid to retain their sources of livelihood and employment. Rajiv Awas Yojana envisages that each State would prepare a State Slum-free Plan of Action (POA). The preparation of legislation for assignment of property rights to slum dwellers would be the first step for State POA. The POA would need to be in two parts; Part-1 regarding the up gradation of existing slums andPart-2 regarding the action to prevent new slums Total Sanitation Campaign (TSC). http://orissa.ngoregistry.com/2011/01/total-sanitation-campaign-tsc-project.html The objective of this project is to bring about an improvement in the general quality of life in the rural areas working on the sanitation coverage
Eco cities India http://ecocityindia.org/Ecocity.aspx In the year 2002, as a part of the X Plan activities, the Eco-City Program was initiated by the Central Pollution Control Board with the grants-in-aid from the Ministry of Environment & Forests, Government of India. The program received technical assistance from the German Technical Cooperation (GTZ) under the Indo-German Environment Program on "Advisory Services in Environmental Management" (ASEM). Japanese program http://www.orissalinks.com/orissagrowth/topics/urban-renewal/bhubaneswar/integrated-sewerage The project has been planned to be implemented by 2011, housing and urban development minister KV Singhdeo said that the detailed project report (DPR) of the project was presented to the ministry of urban development, Government of India, Japan Bank for International Cooperation and 12th Finance Commission of Government of India for funding. The new has been planned by diving the city are into six sewerage districts that shall be provided with an independent sewerage network, pumping system, sewage treatment and disposal system. Reoptima Project Reuse options for marginal quality water in urban and peri-urban agriculture and allied services in the ambit of WHO guidelines (New Indigo, 2011). This project is part of an initiative for the Development and Integration of Indian and European Research. The aim of REOPTIMA is to create an expertise network on the development of integrated wastewater management systems, and develop a roadmap for research on urban wastewater reuse in Indian cities (New Indigo, 2011). In this network project are involved several researchers and institutes as: Bhubaneswar Directorate of Water Management (Indian Council of Agricultural Research, India), Irrigation and Water Engineering Department and Sub-department of Environmental Technology ( Wageningen University and Research Centre, The Netherlands), Institute of Soil Science and Land Evaluation (Universitaet Hohenheim, Germany) and Irrigation Department (Centro de Edafologia y Biología Aplicada del Segura, CEBAS-CSIC, Spain). Information available
from meetings, workshops, conferences between the different counterparts of this project is consulted and used.
Experts meetings. Excreta Matters: Workshop on Bhubaneswar’s Water and Sewage problems.14th June 2012. http://www.cseindia.org/node/4274 Organized by the Centre for Science and Environment in order to discuss on Bhubaneswar’s water and sewage problems
85 Low-cost wastewater treatment technologies for agricultural use
ANNEX 2. Results
Relative salinity tolerance of crops
Table 13: Relative salt tolerance of herbaceous crop – vegetables and fruit crops (Source; Phocaides, 2008, Maas 1990)
Common name Botanical name Threshold dS/m Slope % per dS/m
Rating
Artichoke cynara scolymus - - MT*
Asparagus asparagus officinalis 4.1 2.0 T
Bean phaseolus vulgaris 1.0 19.0 S
Bean, mung vigna radiata 1.8 20.7 S
Beet, red beta vulgaris 4.0 9.0 MT
Broccoli brassica oleracea botrytis 2.8 9.2 MS
Brussels sprouts b. oleracea gemmifera - - MS*
Cabbage b. oleracea capitata 1.8 9.7 MS
Carrot daucus carota 1.0 14.0 S
Cauliflower brassica oleraca botrytis - - MS*
Celery apium graveolens 1.8 6.2 MS
Corn, sweet zea mays 1.7 12.0 MS
Cucumber cucumis sativa 2.5 13.0 MS
Eggplant solanum melongena esculentum 1.1 6.9 MS
Kale brassica oleracea acephala - - MS*
Kohlrabi b. oleracea gongylode - - MS*
Lettuce lactuca sativa 1.3 13.0 MS
Muskmelon cucumis melo - - MS
Okra abelmoschus esculentus - - S
Onion akkium cepa 1.2 16.0 S
Parsnip pastinaca sativa - - S*
Pea pisum sativa - - S*
Pepper capsicum annuum 1.5 14.0 MS
Potato solanum tuberosum 1.7 12.0 MS
Pumpkin cucurbita pepo pepo - - MS*
Radish raphanus sativus 1.2 13.0 MS
Spinach spinacia oleracea 2.0 7.6 MS
Squash scallop curcubita melo melopepo 3.2 16.0 MS
Squash zucchini curcubita melo melopepo 4.7 9.4 MT
Strawberry fragaria sp. 1.0 33.0 S
Sweet potato ipomoea batatas 1.5 11.0 MS
Tomato lycopersicon lycopersicum 2.5 9.9 MS
Tomato cherry l.esculentum var cerasiforme 1.7 9.1 MS
Turnip brassica rapa 0.9 9.0 MS
Watermelon citrullus lanatus - - MS* *: Ratings are estimates.
Notes: − S sensitive, MS moderately sensitive, MT moderately tolerant, T tolerant. The above data serve only as a guideline to relative tolerance among crops. Absolute tolerance varies, depending upon climate, soil conditions, and cultural practices. − In gypsipherus soils, plants will tolerate an ECe about 2 dS/m higher than indicated.
86 Low-cost wastewater treatment technologies for agricultural use
Domestic wastewater constituents
Table 14: Major constituents of typical domestic wastewater. (Source; Pescod, 1992)
Constituents Concentration (mg/l)
Strong Medium Weak
Total solids 1200 700 350
Dissolved solids(TDS)
850 500 250
Suspended solids 350 200 100
Nitrogen (as N) 85 40 20
Phosphorus 20 10 6
Chloride(1) 100 50 30
Alkalinity (as CaCo3)
200 100 50
Grease 150 100 50
BOD5(2) 300 200 100
(1) The amounts of TDS and chloride should be increased by the concentrations of these constituents in the carriage water. (2) BOD5 is the biochemical oxygen demand at 20°C over 5 days and is a measure of the biodegradable organic matter in the wastewater.
87 Low-cost wastewater treatment technologies for agricultural use
Review of International guidelines of waste quality for irrigation
Table 15: Review of guidelines and regulations of water reuse for food crops. (Source: self-design based on Lazarova et al, 2005; WHO, 1989; WHO, 2006b)
Location (International Institution or
Country)
Review of guidelines or regulations
Categorization Parameters Group of health risk
Treatment
Type of use. Crops and irrigation. Physical & Chemical biological
WHO (1989) A: Irrigation of crops likely to be eaten uncooked, sport fields, public parks
- <1 Intestinal nematodes (nº eggs/L) <1000 Faecal coliforms (nº/100mL)
Workers, consumers, public
A series of stabilization ponds designed to achieve the microbioical quality indicated, or equivalent treatment.
B: Irrigation of cereal crops, industrial crops, fodder crops, pasture, and trees
- <1 Intestinal nematodes (nº eggs/L) No standard recommended for Faecal coliforms (nº/100mL)
Workers Retention in stabilization ponds for 8-10 days or equivalent helminths and faecal coliform removal.
USEPA (1992) Agricultural reuse-food crops commercially processed. Surface irrigation of orchards and vineyards
pH 6-9 ≤30mg/L BOD ≤30mg/L SS Consult recommended agricultural (crop) limits for metals. High nutrient levels may adversely affect some crops during certain growth stages.
Reclaimed water should not contain measurable levels of pathogens. ≤200 faecal coli/100mL ≥1mg mg/L Cl2 residual
Setback distances 90 m potable water supply wells 30 m to areas accessible to the public
Secondary Disinfection (provide treatment reliability)
Agricultural reuse-food crops not commercially processed. Surface or spray irrigation of any food crop, including crops eaten raw
pH 6-9 ≤10mg/L BOD ≤2NTU® Consult recommended agricultural (crop) limits for metals. Chemical (coagulant and/or polymer) addition prior to filtration may be necessary to meet water quality recommendations. High nutrient levels may adversely affect some crops during certain growth stages.
Reclaimed water should not contain measurable levels of pathogens. No detectable faecal coli/100mL ≥1mg mg/L Cl2 residual Higher chlorine residual and/or a longer contact time may be necessary to assure that viruses and parasites are inactivated or destroyed.
Setback distances 15 m potable water supply wells
Secondary Filtration Disinfection (provide treatment reliability)
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Location (International Institution or
Country)
Review of guidelines or regulations
Categorization Parameters Group of health risk
Treatment
Type of use. Crops and irrigation. Physical & Chemical biological
CDPH (2000) Irrigation of pasture for milking animals, landscape areas, ornamental nursery stock
- Total coliform limits: ≤23/100mL (maximum)
Secondary Disinfection
Irrigation of food crops (no contact between reclaimed water and edible portion of crop).
- Total coliform limits: ≤2.2/100mL ≤23/100mL in more than one sample in any 30 day period
Secondary Disinfection
Irrigation of food crops (contact between reclaimed water and edible portion of crop: includes edible root crops) and open access landscape areas (parks, playgrounds, schoolyards, residential landscaping, unrestricted access golf courses, and other uncontrolled access irrigation areas.
- Total coliform limits: ≤2.2/100mL
- Secondary
FAO (1989) WHO* (See table 16 ) WHO* WHO* WHO*
WHO, FAO, and UNEP (2006)
Unrestricted irrigation: consumption of wastewater irrigated salad crop (lettuce and onion as
references)
Determination of risk and tolerance. Use of “reference” pathogens to calculate the health risk assessment: Viral pathogens ( norovirus), Bacterial pathogen (Campylobacter), protozoan pathogen (Cryptosporidium) <1 Intestinal nematodes (nº eggs/L)**
Workers Wastewater treatment
Restricted irrigation: involuntary ingestion of wastewater saturated soil. Two scenarios: labour
intense or highly mechanize
Workers and consumers
Wastewater treatment and post treatment-health protection
control measures
®NTU. Nephelometric turbidity units WHO* FAO follow WHO guidelines of 1989. ** According to World Bank (2010) a new estimation of helminths has been proposed similar to the risk simulation for viruses, bacteria and protozoa.
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FAO Guidelines of waste quality for irrigation
Table 16: Guidelines for interpretation of water quality for irrigation (FAO, 1985)
Potential irrigation problem
Degree of restriction on use
None Slight to moderate Severe Salinity Ecw
1 (dS/m) < 0.7 0.7 - 3.0 > 3.0 TDS (mg/l) < 450 450 - 2000 > 2000 Infiltration SAR2 = 0 - 3 and ECw > 0.7 0.7 - 0.2 < 0.2 3 -6 > 1.2 1.2 - 0.3 < 0.3 6-12 > 1.9 1.9 - 0.5 < 0.5 12-20 > 2.9 2.9 - 1.3 < 1.3 20-40 > 5.0 5.0 - 2.9 < 2.9 Specific ion toxicity Sodium (Na) Surface irrigation (SAR) < 3 3 - 9 > 9 Sprinkler irrigation (me/I) < 3 > 3 Chloride (Cl) Surface irrigation (me/I) < 4 4 - 10 > 10 Sprinkler irrigation(m3/l) < 3 > 3 Boron (B) (mg/l) < 0.7 0.7 - 3.0 > 3.0 Trace Elements (see Table 5.2.c) Miscellaneous effects Nitrogen (NO3-N)3 (mg/l) < 5 5 - 30 > 30 Bicarbonate (HCO3) (me/I) < 1.5 1.5 - 8.5 > 8.5 pH Normal range 6.5-8 1
ECw means electrical conductivity in deci Siemens per metre at 25°C 2 SAR means sodium adsorption ratio
3 NO3-N means nitrate nitrogen reported in terms of elemental nitrogen
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Table 17: Threshold levels of trace elements for crop production (FAO, 1985)
Element Recommended maximum
concentration (mg/l)
Remarks
Al (aluminium) 5.0 Can cause non-productivity in acid soils (pH < 5.5), but more alkaline soils at pH > 7.0 will precipitate the ion and eliminate any toxicity.
As (arsenic) 0.10 Toxicity to plants varies widely, ranging from 12 mg/l for Sudan grass to less than 0.05 mg/l for rice.
Be (beryllium) 0.10 Toxicity to plants varies widely, ranging from 5 mg/l for kale to 0.5 mg/l for bush beans.
Cd (cadmium) 0.01 Toxic to beans, beets and turnips at concentrations as low as 0.1 mg/l in nutrient solutions. Conservative limits recommended due to its potential for accumulation in plants and soils to concentrations that may be harmful to humans.
Co (cobalt) 0.05 Toxic to tomato plants at 0.1 mg/l in nutrient solution. Tends to be inactivated by neutral and alkaline soils.
Cr (chromium) 0.10 Not generally recognized as an essential growth element. Conservative limits recommended due to lack of knowledge on its toxicity to plants.
Cu (copper) 0.20 Toxic to a number of plants at 0.1 to 1.0 mg/l in nutrient solutions.
F (fluoride) 1.0 Inactivated by neutral and alkaline soils.
Fe (iron) 5.0 Not toxic to plants in aerated soils, but can contribute to soil acidification and loss of availability of essential phosphorus and molybdenum. Overhead sprinkling may result in unsightly deposits on plants, equipment and buildings.
Li (lithium) 2.5 Tolerated by most crops up to 5 mg/l; mobile in soil. Toxic to citrus at low concentrations (<0.075 mg/l). Acts similarly to boron.
Mn (manganese) 0.20 Toxic to a number of crops at a few-tenths to a few mg/l, but usually only in acid soils.
Mo (molybdenum) 0.01 Not toxic to plants at normal concentrations in soil and water. Can be toxic to livestock if forage is grown in soils with high concentrations of available molybdenum.
Ni (nickel) 0.20 Toxic to a number of plants at 0.5 mg/l to 1.0 mg/l; reduced toxicity at neutral or alkaline pH.
Pd (lead) 5.0 Can inhibit plant cell growth at very high concentrations.
Se (selenium) 0.02 Toxic to plants at concentrations as low as 0.025 mg/l and toxic to livestock if forage is grown in soils with relatively high levels of added selenium. As essential element to animals but in very low concentrations.
Sn (tin)
Ti (titanium) - Effectively excluded by plants; specific tolerance unknown.
W (tungsten)
C (vanadium) 0.10 Toxic to many plants at relatively low concentrations.
Zn (zinc) 2.0 Toxic to many plants at widely varying concentrations; reduced toxicity at pH > 6.0 and in fine textured or organic soils.
1 The maximum concentration is based on a water application rate which is consistent with good irrigation practices (10 000 m3 per hectare per year). If the water application rate greatly exceeds this, the maximum concentrations should be adjusted downward
accordingly. No adjustment should be made for application rates less than 10 000 m3 per hectare per year. The values given are for water used on a continuous basis at one site
91 Low-cost wastewater treatment technologies for agricultural use
Table 18: Health protection control measures and associated pathogen reduction (WHO, 2006b)
Control measure Pathogen Reduction (log units)
Notes
Wastewater treatment 1-7
Pathogen reduction depends on type and degree of treatment selected.
On-farm options
Crop restriction (i.e., no food crops eaten uncooked)
6-7
Depends on (a) effectiveness of local enforcement of crop restriction, and (b) comparative profit margin of the alternative crop(s).
On-farm treatment:
Three-tank system 1-2
Simple sedimentation 0.5-1 Sedimentation for ~18hours
Simple filtration 1-3 Value depends on filtration system used
Method of wastewater application
Furrow irrigation 1-2 Crop density and yield may be reduced
Low-cost drip irrigation 2-4
2-log unit reduction for low-growing crops, and 4-log unit reduction for high-growing crops.
Reduction of splashing
1-2
Farmers trained to reduce splashing when watering cans used (splashing adds contaminated soil particles on to crop surfaces which can be minimized)
Pathogen die-off 0.5-2 per day
Die-off between last irrigation and harvest (value depends on climate, crop type, etc.)
Post-harvest options at local markets
Overnight storage in baskets
0.5-1
Selling produce after overnight storage in baskets (rather than overnight storage in sacks or selling fresh produce without overnight storage)
Produce preparation prior to sale 1-2
Rinsing salad crops, vegetables and fruit with clean water.
2-3 Washing salad crops, vegetables and fruit with running tap water
1-3 Removing the outer leaves on cabbages, lettuces, etc.
In-kitchen produce-preparation options
Produce disinfection 2-3
Washing salad crops, vegetables and fruit with an appropriate disinfectant solution and rinsing with clean water.
Produce peeling 2 Fruits, root crops
Produce cooking 5-6
Option depends on local diet and preference for cooked food.
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Wastewater treatment technology cost comparison
Table 19: Summary of Wastewater treatment technologies and cost comparison (CSE, 2013b)
Name of the technology
Treatment Method
Treatment capacity
Capital cost (RS/KLD)
O&M Cost (Rs/KLD/year)
Reuse of treated wastewater
Decentralised wastewater treatment (DWWT)
Sedimentation, anaerobic digestion, filtration and phyto- remediation
1- 1000 KLD
35000- 70000 1000-2000 Horticulture Biogas generation
Soil Bio technology
Sedimentation, filtration, biochemical process
5KLD- tens of MLD
10,000-15,000 1000-1500 Horticulture Cooling systems
Biosanitatizer/ eco chip
Bio-catalyse-breaking the toxic. Organinc contents
100mg/KLD Chip cost Rs. 10000 excluding civil /construction cost
Not available In situ treatment of water bodies, horticulture
Soil scape filter Filtration through biologically activated medium
1-250KLD 20000-30000 1800-2000 Horticulture
Ecosanitation zero discharge toilets
Separation of fecal matter and urine
Individual and community level
40000 – 50000 (excluding the cost of toilet construction)
Not available Flushing Horticulture Composting
Nualgi technology
Phycoremediation (use of micro/ macro algae)- fix CO2, remove nutrients and increase DO in water
1Kg treats upto M L
Rs. 350 / MLD 9000- 10000/MLD
In situ treatment of lakes/ ponds, Increase in fish yield
Bioremediation Decomposition of organic matter using Persnickety 713 (biological product )
1 billion CFU/ml
2.25 – 3.0 lakhs/ MLD
2-2.5 Lakhs/MLD
In situ treatment of lakes/ ponds,
Green bridge technology
Filtration, sedimentation, bio-digestion and biosorption by microbes and plants
50 – 200 KLD/ sq m
200-500 20-50 In situ treatment if water bodies
Note: 1. Cost of the technologies for lakes and water bodies remediation have been indicated in per MLD per year. 2. Costs have been estimated on the basis of the year of implementation of listed case studies. The current cost involved may vary
93 Low-cost wastewater treatment technologies for agricultural use
Water uses classification for the Indian Central Pollution Control Board
Table 20: Water Quality Criteria according to different uses. (Source: CPCB, 2013b)
Designated best use (DBU) Class of Water
Criteria
Drinking Water Source without conventional treatment but after disinfection
A - Total Coliforms Organism MPN/100ml shall be 50 or less
- pH between 6.5 and 8.5 - Dissolved Oxygen 6mg/l or more - Biochemical Oxygen Demand 5 days 20°C
2mg/l or less
Outdoor bathing (Organised) B - Total Coliforms Organism MPN/100ml shall be 500 or less
- pH between 6.5 and 8.5 - Dissolved Oxygen 5mg/l or more - Biochemical Oxygen Demand 5 days 20°C
3mg/l or less
Drinking water source after conventional treatment and disinfection
C - Total Coliforms Organism MPN/100ml shall be 5000 or less
- pH between 6 to 9 - Dissolved Oxygen 4mg/l or more - Biochemical Oxygen Demand 5 days 20°C
3mg/l or less
Propagation of Wild life and Fisheries D - pH between 6.5 to 8.5 - Dissolved Oxygen 4mg/l or more - Free Ammonia (as N) 1.2 mg/l or less
Irrigation, Industrial Cooling, Controlled Waste disposal
E - pH between 6.0 to 8.5 - Electrical Conductivity at 25°C micro
mhos/cm Max.2250 - Sodium absorption Ratio Max. 26 - Boron Max. 2mg/l
Bellow-E Not Meeting A, B, C, D & E Criteria
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Wastewater treated quality parameters for crop production
Table 21: Effluent quality importance. Information required on effluent supply and quality (Source: Pescod, 1992)
Information Decision on irrigation management
Effluent supply
The total amount of effluent that would be made available during the crop growing season.
Total area that could be irrigated.
Effluent available throughout the year. Storage facility during non crop growing period either at the farm or near wastewater treatment plant and possible use for aquaculture.
The rate of delivery of effluent either as m3 per day or litres per second.
Area that could be irrigated at any given time, layout of fields and facilities and system of irrigation
Type of delivery: continuous or intermittent, or on demand.
Layout of fields and facilities, irrigation system, and irrigation scheduling.
Mode of supply: supply at farm gate or effluent available in a storage reservoir to be pumped by the farmer.
The need to install pumps and pipes to transport effluent and irrigation system
Effluent quality
Total salt concentration and/or electrical conductivity of the effluent.
Selection of crops, irrigation method, leaching and other management practices.
Concentration of cations, such as Ca++, Mg++ and Na+.
To assess sodium hazard and undertake appropriate measures.
Concentration of toxic ions, such as heavy metals, Boron and Cl-.
To assess toxicities that are likely to be caused by these elements and take appropriate measures.
Concentration of trace elements (particularly those which are suspected of being phyto-toxic).
To assess trace toxicities and take appropriate measures.
Concentration of nutrients, particularly nitrate-N.
To adjust fertilizer levels, avoid over fertilization and select crop.
Level of suspended sediments. To select appropriate irrigation system and measures to prevent clogging problems.
Levels of intestinal nematodes and faecal coliforms.
To select appropriate crops and irrigation systems.
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ANNEX 3. Maps of Bhubaneswar Ward n°3
Figure 14: Existing land property in the ward no3, Bhubaneswar, Odisha.(Source: Self-design adapted from IITK, 2008)
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Figure 15: Existing natural sewage drains in the ward number 3, Bhubaneswar, Odisha.(Source: Self-design adapted from IITK, 2008).