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TRANSCRIPT
AINDUSTRIAL TRAINING REPORT
OnCONSTRUCTION OF SEWAGE TREATMENT PLANT
For the partial fulfillment of the award of the degree ofBachelor of Technology
At
DIESEL LOCOMOTIVE WORKS
SUBMITTED BY: - SUBMITTED TO:-SUJEET MAURYA CIVIL ENGINEERING DEPT.4th YEAR1229200030
1
ACKNOWLEDGEMENT
Any attempt at any level cannot be satisfactorily completed without the support and guidance of
learned people. I would like to extend my heartfelt thanks and deep sense of gratitude to all those
who helped me to complete this report.
I express my gratitude thanks towards the management of Diesel locomotive works, Varanasi
and especially thanks to Mr. Vivek Acharya (Principal, TTC DLW) for allowing me to the
summer training in this concern. I am also thankful to all the respected employee of this
organization under whose able direction I have completed my training.
Last but not the least, I am extremely thankful to my family members & my all friends for the
moral support, they provided without which I would have been unable to successfully complete
my vocational training.
Thanking you,
Yours sincerely
SUJEET MAURYA
2
CONTENTS
1. Abstract
1.1 List of Notations
2. Objective
3. Project
3.1 UASB Technology
4. History
5. Introduction
6. Chronological Training Diary
6.1Brief Description of Units
6.1.1Screener
6.1.2Gtit Chamber
6.1.3UASB Reactor
6.1.4Pre aeration Tank
6.1.5Polishing Pond
6.1.6Chlorine Contact Tank
6.1.7Sludge Drying Bed
6.1.8Filterate Sump
6.1.9Effluent Disposal
6.1.10Byepass Arrangement
6.1.11Resource Recovery
6.1.12Efflent Reuse
6.1.13Gas Utilization
6.2Apparatus
6.3Tests
6.4Process of Treatment
6.5Analysis Result
7. Plant Layout
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8. Flow Chart
9. Design
9.1 Basic Assumption
9.2 Materials of construction of UASB reactor
9.3 Operation & Maintenance
9.4 Evaluation of life cycle cost
10. Conclusion
11. Suggestion
12. Reference
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ABSTRACT
It’s nearly two decades since UASB (Upflow Anaerobic Sludge Blanket) concept for sewage
treatment was started in India and today it has taken an edge over the other developing countries
having similar climatic conditions in the use of this technology. At present, about 23 full scale
UASB plants are in operation at various places in India with total installed capacity of about
9,85,000 m3/day (985 mld) and about 20 number are in pipe line which are likely to be
commissioned within next 3-4 years. With financial assistance from international funding
agency, the National River Conservation Directorate (NRCD) under the ministry of
Environment & Forests (M0EF) ,Government of India (G0I) , formulated and launched a
comprehensive action plant project for conservation of river Yamuna under which 16 UASB
sewage treatment plants (STPs) were commissioned in the period of 1999-2002. Experience
shows that the present UASB reactor design & construction is quite different from the very first
module of 5 MLD treatment capacity that was constructed as a demonstration plant at Kanpur,
India under the Ganga Action Plan (GAP) in late 80’s. The discrepancies in the initial UASB
plants were recorded and now a new breed of UASB reactor is available with respect to the
design, operation and maintenance, and materials of construction. Initially, most of the UASB
plants were provided with final polishing ponds as post-treatment unit, but now other options for
the same are being explored to meet the stringent regulations. This paper reviews overall
implications of UASB technology in India. Institutional and technical aspects with special
reference to the Yamuna Action Plan (YAP) are presented. It also presents the potential of
UASB technology in other developing countries with its future within India as well as based on
the evaluation of Life cycle cost (LCC). Other sewage treatment technologies were also included
while evaluating LCC. The LCCE can be used as a tool for selecting appropriate technology
under similar climatic & economic conditions in other developing countries.LCC supports that
UASB as one of the most favorable methods of wastewater treatment from all respects.
5
L IST OF NOTATIONS
AF Anaerobic Filter
ASP Activated Sludge Process
BIOFOR Biological Filter Oxygenated Reactor
BOD Biochemical Oxygen Demand
CO2 Carbon Dioxide
COD Chemical Oxygen Demand
CRF Capital Recovery Factor
DJB Delhi Jal Board
DO Dissolved Oxygen
EAS Extended Aeration System
EGSB Expanded Granular Sludge Blanket
FAB Fluidized Aerobic Bed
FPU Final Polishing Unit
FRP Fiber Reinforced Plastic
GLSS Gas Liquid Solids Separator
GAP Ganga Action Plan
GOI Government of India
H2S Hydrogen Sulphide
IC Initial Cost
JBIC Japan Bank for International Corporation
LCC Life Cycle Cos
MBR Membrane Bioreactor
MBBR Moving Bed Bioreactor
6
MLD Million Liters per Day
MPN Most Probable Number
MOEF Ministry of Environment & Forest
MCD Municipal Corporation of Delhi
NRCD National River Conservation Directorate
O&M Operation & Maintenance
PIAS Project Implementing Agencies
PHED Public Health Engineering Department
RCC Reinforced Cement Concrete
R&D Research & development
Rs. Indian Rupees
SBR Sequencing Batch Reactor
SAFF Submerged Aeration Fixed Film Reactor
STPS Sewage Treatment Plants
TSS Total Suspended Solids
TAC Total Annual Cost
TF Trickling Filter
UPJN Uttar Pradesh Jal Nigam
UASB Upflow Anaerobic Sludge Blanket
VSS Volatile Suspended Solids
WSPs Waste Stabilization Ponds
YAP Yamuna Action Plan
7
OBJECTIVE
The principal object of waste water treatment is generally to allow human and industrial effluents
to be disposed off without damage to human health or unacceptable damage to the natural
environment.
Treatment of water within limits so as to suite the aquatic life and avoid soil pollution. To
improve the quality of treated water in that limit so that it may be us for irrigation and fishery
purpose and for drinking in future.
8
UASB TECHNOLOY
UASB technology is based on anaerobic process. Anaerobic process does not require oxygen
from outside for the stabilization of waste. Anaerobic treatment of waste water has a number of
advantages over aerobic treatment process, namely energy input of the system is low, as no
energy is required for oxygenation lower production of excess sludge per unit mass of organic
matter stabilized. Lower nutrient requirement due to lower biological synthesis and the
degradation of waste organic material leads to produce biogas, which is valuable source of
energy. However anaerobic process is considered slow process and is Dependent upon the
temperature and PH of waste water. Toxic materials also interfere the functioning of UASB
process.
UASB process has a special significance in India because of low energy requirement and
low capital and operation & maintenance cost with process.
The Upflow anaerobic sludge blanket (USAB) reactor maintains a high concentration of
biomass through formation of highly settable microbial aggregates. The wastewater flows
upwards through a layer of sludge. At the top of the sludge blanket layer phase separation
between gas-solid-liquid takes place. Any biomass leaving the reaction zones is directly
recalculated from the settling zone. The process is suitable for both soluble wastes and those
containing particulate matter.
This technology was adopted for the first time in India at Jajmau Kanpur for the 5 MLD
STP under Ganga action plan phase-I in the year 1988-89. The efficiency of this STP was about
65% to 70% since the desired BOD and TSS could not be achieved by UASB process alone, so it
was recommended to provide some additional treatment unit like polishing pond, aerated lagoons
etc. to achieve desired values of BOD, TSS and MPN for disposal into water body. At present
this technology followed by additional post treatment units by providing pre-aeration tank for
sulphide removal and polishing pond to obtain the BOD5 of the effluent less than 30 mg/l and
suspended solids less than 50 mg/l has been proposed for the 42 MLD sewage treatment plant at
DLW, Varanasi under Ganga action Plan Phase-I.
9
HISTORY
Worldwide presently over 200 full-scale UASB plants are in operation for the treatment of both
domestic and industrial wastewaters. However in India the UASB process is being widely
adopted for domestic wastewater and it can be claimed that 80% of total UASB reactors
worldwide for domestic wastewater treatment is in India. The basic approach towards selection
of technology for sewage was low capital costs. Low energy requirements, low O&M costs and
sustainability aspect. This was derived from the experience of Ganga action plan (Kanpur –
Mirzapur). Based on the successful result of 5 MLD demonstration plant was constructed at
Kanpur, Uttar Pradesh. Te experience GAP was mixed in terms of efficiency of treatment versus
energy consumption and cost of operation and maintenance. Drawing lessons from GAP, the
YAP opted for energy neutral and energy recovery technologies like anaerobic process for the
sewage treatment.gas and conventionally,, anaerobic process are to be used for the treatment of
high strength organic wastewaters. However, typical hydro-dynamic of UASB coupled with its
unique characteristic of holding high granular biomass (sunny et al, 2005) made is possible to
apply the anaerobic processes for the treatment of low strength wastewaters.
After studying the performance of the demonstration plant for a few years, a full scale
UASB plant of 14 MLD was constructed at Mirzapur for treating the domestic wastewater
(Draaijer et al, 1992) in view of the fact that the USAB effluent does not meet discharge
standards, the plants were used in conjection with a setting pond called “final polishing unit’ to
achieve desired BOD and suspend solids reduction these being pilots and experimental plants
their performances were varied. However they were found to be promising In terms of energy
consumption, biogas yield and reduced requirements for sludge disposal.
The key factors that influenced selection process against the conventional aerobic
systems were their high energy requirements, unreliable power supply situation in the states, and
higher O&M costs; while those in favour of UASB were their robustness. Low or no dependence
on electricity, low cost of O&M. moreover the possibility of resource recover from biogas and
aquaculture respectively also influenced the selection process among the large capacity plants
under YAP, in all 28 STPs comprising 16 UASBs, 10 waste stabilization ponds (WSPs) and 2
10
BIOFOR technology STPs with aggregate capacity of 722 MLD were constructed. UASBs
accounted for an overwhelmingly high 83% of the total created capacity.
The state of Haryana almost entirely opted for UASB and WSP technology where 10 out there
was a balance in terms of numbers of STPs based on UASB and WSP technologies. Generally
for large flows UASBs were considered while for smaller flows WSPs were adopted. Summary
of technology distribution of various STPs Created under YAP are presented in table1.
Table - : Technology Wise Distribution of STP Capacity Created Under YAP
Technology No. of plants STP capacity, mld % of total in YAP
UASB 16 598 83
WSP 10 104 14
BIOFOR 2 20 3
TOTAL 28 722 100
Preference for WSPs in up could be attributed to state’s experience with complex and energy
intensive activated sludge process based plants during GAP-I as well as with the pilot UASBs at
Kanpur.
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INTRODUCTION
Sewage treatment is not a cheap proposition. Public bodies have to think twice before making
substantial investments particularly in developing countries where environmental issues could
not be given due priority due to financial constraints. Over the years, treatment related issues are
becoming expensive as governments are not only giving emphasis to treat wastewater in order to
protect their resources but the concept of reuse and recycling is also becoming an important
aspect. Not only this, residues emanating there from, and other treatment by-products are also
being included in the overall wastewater management system. On the other hand, emphasis is
also being given to clean technologies to minimize waste production. However, in countries like
India, the treatment issue is dominant and receiving due attention these days.
During the past two decades, several new sewage treatment technologies have been
developed and are being adopted in many developing countries particularly in the South-East
Asian region including India. Some of the technologies are Fluidized Aerobic Bed (FAB),
Anaerobic Filter (AF), Expanded Granular Sludge Blanket (EGSB), Sequencing Batch Reactor
(SBR), Membrane Bioreactor(MBR), Fluidized Aerated Bed Reactor (FAB), Submerged
Aeration Fixed Film Reactor (SAFF), BIOFOR (Biological Filter Oxygenated Reactor), Upflow
anaerobic sludge blanket (UASB) process etc. every technology has its pros and cons and
therefore has to be applied in accorda0nce to the local conditions.
In India, where the government has felt a need to prevent pollution of its rivers and
preserving natural resources, a major action plan has been formulated under which a good
number of towns and cities has been identified by the national river conservation direct rate
under the ministry of environment and forest (MoEF), government of India. The objective of
river action plan is to conserve the river water bodies. Within this framework, the Ganga action
plan (GAP) was incepted and implemented in mid 80s. After the implementation of GAP IN
FEW STATES,
Yamuna action plan (YAP) WAS FORMULATED in early 1990 for the states of
Uttarpradesh, Haryana and Delhi where major parts of Yamuna river flows. The YAP was
founded by JBIC under a soft loan bilaterally agreed arrangement. The total expenditure incurred
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under YAP phase 1 and 2 was Rs.6820 million, under which a sewage treatment capacity of 753
MLD has been created (moef, 2006).
In many countries UASB has been applied for the treatment of high strength wastewater,
but in India, it has been employed for the treatment of domestic wastewater (Lucas seghezzo et
al 1998). Brazil and Columbia are the other two countries in the world where this technology has
been used. It is now being used and gaining popularity in other countries like in Ras-Al-Khaimah
(UAE), Angola, Indonesia etc.
With respect to the application of UASB technology, the experience gained in India is
unique and diverse. India is one of the leading countries in terms of the amount of sewage
volume treated by the UASB process. It has been recognized as one of the most cost effective
and suitable sewage treatment process considering the environmental requirement in India. At
present about 23 number of sewage treatment plants with total installed capacity of 985mld
based on the UASB are in operation and about 20 number are in pipeline which are likely to be
commissioned within next 3-4 years under various river catchments i.e., GAP from Himalayan
region to the Bay of Bengal , Sabarmati in the state of Gujarat etc. However, the present study
focuses on the Yamuna action plan. In this study, efforts have been made to present the
experience to treat 985 mld sewage wastewater using UASB with respect to its design, operation
and maintenance , material of construction, effluent quality, post-treatment options etc, and its
potential in other developing countries having similar climatic conditions.
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CHRONOLOGICAL TRAINING DIARY
BRIEF DESCRIPTION OF UNITS
SCREEN
Pre-treatment is done in screens and grit chamber. For each stream of 115 MLD 2 no.
mechanical screens of 3mm opening has been devised to screen the extraneous and foreign
material. 1 No. mechanical screen and 1 no. manual screen has also been proposed as standby. It
is expected most of the unwanted material like polythene and other pouches will be trapped at
the screen level.
Mechanical Screener
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GRIT CHAMBER
Grit in swage consists of coarse particles of sand, ash and clinkers, eggshells, bone chips and
many inert materials inorganic in nature. The specific gravity of grit is usually in the range of 2.4
to 2.65. Grit is nonputrescible and possesses a higher hydraulic subsidence value than organic
solids. Hence separation of gritting material from organic solids is necessary. 2 No. mechanical
grit chambers have been provided to degrit the sewage with 1 no. manual grit chamber as
standby.
Mechanical Gritter
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UASB REACTOR
30 No. reactor of 11-50 MLD capacity have been proposed for the 345 MLD sewage treatment
plan. The size of reactor has been designed in such a way to accommodate the down ward
distribution pipes carrying swage to reactor and to collect the biogas produced by the biological
action and allow sludge blanket formation in the reactor. The water height of the reactor has been
designed keeping in view the height of the digested sludge storage and height of active biomass
called sludge blanket and solid liquid separation.
UASB Feed Box UASB Channels
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PRE AERATION TANK
Pre aeration tank has been proposed to aerate the effluent from UASB reactor to release the
trapped gases. Aeration will remove sulphide. The pre aeration may also be useful to change the
anaerobic nature of effluent of UASB to aerobic.
22-06-2015
POLISHING POND
As the effluent after UASB reactor has BOD5, TSS and COD more than the permissible limit for disposal into water body, hence polishing pond has been proposed in two stages.
1. First compartment of polishing pond with half day detention period and water depth of
3.0 m. this compartment will act as aerated lagoon by providing sufficient floating
aerators for the removal of sulphide and BOD.
2. Second compartment of polishing pond will be of shallow depth 1.50 m and one day
detention period. This compartment will act as final polishing pond. Weirs have also been
proposed in this pond for stream line flow & resulting improvement in D.O. of waste
water in the polishing pond.
Polishing Pond with Aerator
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CHLORINE CONTACT TANK
The effluent received after polishing pond will be disinfected in chlorine contact tank with a dose
of approximately 5.0 mg/I of chlorine gas dosing. The chlorine contact time has been kept about
30 minutes. The chlorine gas will come in contact with the treated sewage and will be capable to
remove the faucal coliform by chemical reaction (disinfection). It is hoped that MPN will reduce
below 104 per 100 ml by the application of chlorine gas.
SLUDGE DRYING BED
The digested sludge will be sent to sludge sump by piping and finally pumped to sludge drying
beds for drying and removal purpose. A sludge drying and disposal cycle of 10 days has been
taken with a sludge application thickness of 25 cm on drying beds.
FILTRATE SUMP
The filtrate of the sludge drying bed will be recycled to STP at the outlet of grit chamber before
UASB reactors by pumping at filtrate sump.
25-06-2015
EFFLUENT DISPOSAL
The final effluent of 345 MLD UASB STP will be disposed through gravity pipe to river Ganga
near Lonapur village. It is also under consideration to pump the treated waste water into the
Varuna. Canal situated approximately 2 km. from the STP site for irrigation purpose, if its
feasibility is worked out with the U.P. irrigation department in near future.
BYEPASS ARRANGEMENT
The design of STP in 3 streams has been proposed keeping in mind to meet out the any
eventually if one stream is closed for O/M purpose, however a purpose however a provision of
bypass has also been made for emergency break downs.
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RESOURCE RECOVERY
Two bye products will be received after sewage treatment namely biogas & dried sludge cakes.
The biogas expected is approximately 400 m3 / hr and the dry sludge cakes about 100 tons/day.
The biogas will be utilized for the generation of electricity by (duel fuel/gas) engine. It is
expected that biogas will produce more than 1500 KVA electricity and will be utilized at the STP
campus for operation of screens, degriting units, sludge pumps, aerator & lighting of campus and
laboratory cum workshop. If biogas production is more than demand then the extra biogas will
be sold to the market. The dried sludge will be utilized as manure for agriculture and horticulture
purpose. Besides this it may also be used as land filling purpose.
28-06-2015
EFFLENT REUSE
At present the effluent will be disposed directly to river Ganga near Lonapur village about 2.0
km from STP site. As the quantity of treated sewage is huge, it will be advantages to reuse it for
the agriculture purpose, provided the agricultural land is available in the vicinity of STP site.
After the commissioning of STP and seeing the quality of effluent utilization of effluent will be
finalized, agriculture and horticulture, fisheries department and other related field to decide the
best possible reuse of this treated effluent either to use for agricultural land or to pump into
irrigation canal of U.P irrigation department and to earn revenue by sale of effluent water and to
make the plant sustainable in long run.
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GAS UTILIZATION
This bio gas obtained by the UASB process is highly rich in methane content. In general about
75% biogas is CH4 and approximately 10- 20% is carbon dioxide and about 1% is H2S. H2 S gas
is harmful for the process also. Hence H2S scrubber has been proposed to get rid of H2S, it is
expected that nearly 400 m3 biogas will be produced per hour. However seeing the actual
production, its best use is finalized. The biogas will be used for electricity generation by use of
(duel fuel/gas) engines.
Gas Dome
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01-07-2015
APPARATUS
Following apparatus are used to carry out the tests to know the hydraulic parameter of treated
water:
1. Digital PH meter.
2. Conductivity meter.
3. Magnet stirrer
4. Nephelo meter.
5. Water distillation unit.
6. COD reflux unit.
7. Hot air oven.
8. BOD incubator.
9. Auto clave.
Autoclave Digital Temperature Controller
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C.O.D Reflux Unit Water Distillation Unit
Digital Nephelo Meter Magnetic Stirrer
Digital Balance Digital PH Meter
22
Following are the tests to know the hydraulic parameters of treated water:
05-07-2015
1. PH value-
It indicates the logarithm of reciprocal of hydrogen ion concentration present in water. It is thus
an indicator of the acidity or the alkalinity of water. Water quality and pH are often mentioned
in the same sentence. The pH is a very important factor, because certain chemical processes can
only take place when water has a certain pH. For instance, chlorine reactions only take place
when the pH has a value of between 6, 5 and 8.
The pH is an indication for the acidity of a substance. It is determined by the number of free
hydrogen ions (H+) in a substance. Acidity is one of the most important properties of water.
Water is a solvent for nearly all ions. The pH serves as an indicator that compares some of the
most water-soluble ions. The outcome of a pH-measurement is determined by a consideration
between the number of H+ ions and the number of hydroxide (OH-) ions. When the number of
H+ ions equals the number of OH- ions, the water is neutral. It will then have a pH of about 7.
The pH of water can vary between 0 and 14. When the pH of a substance is above 7, it is a basic
substance. When the pH of a substance is below 7, it is an acid substance. The further the pH lies
above or below 7, the more basic or acid a solution is. The pH is a logarithmic factor; when a
solution becomes ten times more acidic, the pH will fall by one unit. When a solution becomes a
hundred times more acidic the pH will fall by two units. The common term for pH is alkalinity.
The word pH is short for "pondus Hydrogenium". This literally means the weight of hydrogen.
De pH is an indication for the number of hydrogen Did you know that the pH of Coca-Cola is
ions. It consisted when we discovered about 2? And did you know that it is that water consists of
hydrogen ions (H+) useless to measure the pH of RO-water or demiwater? Both demiwater and
RO-water and hydroxide ions (OH-). The pH does not have a unit; it is merely do not contain
any buffer ions. This means expressed as a number. When a solution that the pH can be as low as
four, but it can also be as high as 12. Both kinds of is neutral, the number of hydrogen ions
equals the number of hydroxide ions. Water is not readily usable in their natural form. They are
always mixed when the number of hydroxide ions is higher, the solution is basic. When the
before application! number of hydrogen ions is higher, the solution is acid.
23
1. BOD Test-Biochemical oxygen demand or B.O.D. is a chemical procedure for
determining the amount of dissolved oxygen needed by aerobic biological organisms in a
body of water to break down organic material present in a given water sample at certain
temperature over a specific time period. It is not a precise quantitative test, although it is
widely used as an indication of the organic quality of water. It is most commonly
expressed in milligrams of oxygen consumed per liter of sample during 5 days of
incubation at 20 °C and is often used as a robust surrogate of the degree of organic
pollution of water.BOD can be used as a gauge of the effectiveness of wastewater
treatment plants.
2. COD Test-Chemical Oxygen Demand (COD) is defined as the quantity of a specified
oxidant that reacts with a sample under controlled conditions. The quantity of oxidant
consumed is expressed in terms of its oxygen equivalence. COD is expressed in mg/L.
COD is often measured as a rapid indicator of organic pollutant in water. It is normally
measured in both municipal and industrial wastewater treatment plants and gives an
indication of the efficiency of the treatment process. COD is measured on both influent
and effluent water. The efficiency of the treatment process is normally expressed as COD
Removal, measured as a percentage of the organic matter purified during the cycle. Both
organic and inorganic constituents of the sample are subject to oxidation; however the
organic component predominates and is of greater interest. COD is a defined test;
digestion time, reagent strength and sample COD concentration all affect the extent of
sample oxidation. COD is often used as a measurement of pollutants in natural and waste
waters and to assess the strength of waste such as sewage and industrial effluent waters.
COD has further applications in power plant operations, chemical manufacturing,
commercial laundries, pulp & paper mills, environmental studies and general education.
In potable drinking water plants, COD values should be less than 10 mg/L 0 2 at the end
of the treatment cycle.
24
09-07-2015
3. TSS Test- The total suspended solids ’TSS testing measures the total concentration of
suspended (non-soluble) solids in the aeration stabilization basin (ASB) or in effluents.
The total suspended solids (TSS) data is critical in determining the operational behavior
of a waste treatment system. It is usually a permitted test and solids must be kept at a
minimum. The total permissible amount of solids in water is generally limited to 500
ppm, although higher amounts up to 1000 ppm are also sometimes permitted, but are
likely to produce certain psychological effects on human system.
4. Alkalinity Test- Alkalinity or A T measures the ability of a solution to neutralize acids
to the equivalence point of carbonate or bicarbonate. The alkalinity is equal to the
stoichiometric sum of the bases in solution. In the natural environment carbonate
alkalinity tends to make up most of the total alkalinity due to the common occurrence and
dissolution of carbonate rocks and presence of carbon dioxide in the atmosphere. Other
common natural components that can contribute to alkalinity include borate, hydroxide,
phosphate, silicate, nitrate, dissolved ammonia, the conjugate bases of some organic acids
and sulfide. Solutions produced in a laboratory may contain a virtually limitless number
of bases that contribute to alkalinity. Alkalinity is usually given in the unit mEq/L
(milliequivalent per liter). Commercially, as in the pool industry, alkalinity might also be
given in the unit ppm or parts per million.
5. Dissolved Test-All the gasses of the atmosphere are soluble in water to some degree.
Both nitrogen & oxygen are classed as poorly soluble, and since they do not react with
water chemically, their solubility is directly proportional to their partial pressures. Hence,
Henry’s law may be used to calculate their amounts present at saturation at any given
temperature. The amount of oxygen found dissolved in given water at a given
temperature and pressure is known as the D.O value. The saturation D.O value is the
maximum dissolved oxygen which given water can contain at the temperature and
pressure. The saturation D.O decreases with an increase in temperature and it increases
with increase in pressure, & reduce with increase of chloride concentration in water. It is
expressed in mg/l.
25
15-07-2015
PROCESS OF TREATMENT
The sewage in the main pumping station (MPS) at Ghulari culvert is pumped through a 2100mm
diameter cast iron pipe and exposed at the inlet of 345mld STP, Bharwara.
The process of treatment takes place in two stages:
1. Pre-treatment unit.
(a) Screening,
(b) Griting.
2. Final treatment unit.
(a) Anaerobic process in UASB,
(b) Pre-aeration,
(c) Aeration in polishing pond-1 and
(d) Chlorination.
26
Preliminary treatment
The objective of preliminary treatment is the removal of coarse solids and other large materials
often found in raw wastewater. Removal of these materials is necessary to enhance the operation
and maintenance of subsequent treatment units. Preliminary treatment operations typically
include coarse screening, grit removal and, in some cases, communication of large objects.
a. Primary treatment
The objective of primary treatment is the removal of settleable organic and
inorganic solids by sedimentation, and the removal of materials that will float (scum) by
skimming.
b. Secondary treatment
The objective of secondary treatment is the further treatment of the effluent from primary
treatment to remove the residual organics and suspended solids. In most cases, secondary
treatment follows primary treatment and involves the removal of biodegradable dissolved
and colloidal organic matter using aerobic biological treatment processes. Aerobic
biological treatment is performed in the presence of oxygen by aerobic microorganisms
(principally bacteria) that metabolize the organic matter in the waste water, thereby
producing more microorganisms and inorganic end-products (principally CO2, NH3, and
H2 O). Several aerobic biological processes are used for secondary treatment differing
primarily in the manner in which oxygen is supplied to the microorganisms and in the
rate at which organisms metabolize the organic matter. Common high-rate processes
include the activated sludge processes, trickling filters or bio filters, oxidation ditches,
and rotating biological contractors (RBC). A combination of two of these processes in
series (e.g. bio filter followed by activated sludge) is sometimes used to treat municipal
wastewater containing a high concentration of organic material from industrial sources.
27
Analysis result of treated water at 345 MLD STP, Diesel locomotive works, Varanasi.
Dated: 05-07-2015
S. No. Parameter CB Parameter
Analysis Result Final Outlet
Remarks
Inlet Outlet
Inlet Reactor Outlet
1. PH 6-8 - 7.52 7062 8.012. BOD (mg/l) 150-
250<30 69 - 22 All Results
3. COD (mg/l) 200-500
- 220 110 74 Observed
4. TSS(mg/l) 300-600
<50 177 - 15 Within
5. Sulphide - <2.0 3.6 - Nil Permissible6. D.O(mg/l) - - Nil - Nil Limit.
7. VFA(mg/l) - - 0.51 0.41 Nil
8. Alkalinity (mg/l)
- - 9.1 9.4 -
Dated: 06-07-2015
S. No. Parameter CB Parameter
Analysis Result Final Outlet
Remarks
Inlet Outlet Inlet Reactor Outlet
1. PH 6-8 - 7.22 7068 8.102. BOD (mg/l) 150-
250<30 70 - 24 All Results
3. COD (mg/l) 200-500
- 222 108 72 Observed
4. TSS(mg/l) 300-600
<50 180 - 17 Within
5. Sulphide - <2.0 3.9 - Nil Permissible6. D.O(mg/l) - - Nil - Nil Limit.
7. VFA(mg/l) - - 0.57 0.41 Nil
8. Alkalinity - - 9.70 9.51 -
28
Dated: 08-07-2015
Sl. No. Parameter CB Parameter
Analysis Result Final Outlet
Remarks
Inlet Outlet Inlet Reactor Outlet
1. PH 6-8 - 7.48 7066 7.902. BOD (mg/l) 150-
250<30 68 - 19 All Results
3. COD (mg/l) 200-500
- 219 112 70 Observed
4. TSS(mg/l) 300-600
<50 175 - 14 Within
5. Sulphide - <2.0 3.7 - Nil Permissible6. D.O(mg/l) - - Nil - Nil Limit.
7. VFA(mg/l) - - 0.48 0.39 Nil
8. Alkalinity (mg/l)
- - 9.0 8.9 -
29
PLANT LAYOUT
The 42mld STP is divided into 3 identical sections, namely
1. STREAM -A
(a)Stream - A1
(b)Stream - A2
2. STREAM -B
(a)Stream - B1
(b)Stream- B2
3. STREAM -C
(a) stream- C1
(b) stream- C2
All these three sections have same functions and treatment process. Each section is provided with the following units.
1. One screen chamber with 2 mechanical screener and 1 manual screener.
2. One grit chamber with 2 mechanical griter and 1 manual griter.
3. One discharge measuring device.
4. Four numbers of 2A in which water/sewage comes from partial flumes.
5. Twenty numbers of 2B in which sewage comes from 2A and disposed/distributed to the feed boxes provided in the UASB.
6. Two number of UASB. Each UASB is divided into 5 reactors.
7. 16 numbers of feed boxes in each reactor.
8. One number of pre-aeration tank with one floating aerator.
9. One number of gas holder.
10. One number of polishing pond compartment-1.
11. One number of polishing pond compartment-2.
12. One number of sump house.
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The plant is also provided with the following facilities:
1. Administrative Block,
2. Laboratory for testing the treated waste water,
3. Staff quarter,
4. Stores,
5. Chlorine house etc.
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TREATMENT TECHOLOGY (Anaerobic process followed by aerobic post)
Treatment. (UASB) reactors +polishing pond).
S.No Units No. Size1. Inlet chamber 1 No. 20mx9mx4.0m SWD2. No. of stream proposed 3 Nos 115 mld capacity each3. Distribution chamber 3 Nos 8.8 mx7.5 m x 2.0 m SWD4. Screen (mechanical) 6 working +
3 stand bye2 Nos. for each stream + 1 standby6 m x 1.8m x 1.0 m SWD
(Manual standby) 3 Nos 1 No. for each stream 6 m x 1.8m x 1.0 m SWD
5. Grit chamber (mechanical) 6 Nos. 2 Nos. working for each stream 9.50mx9.5mx1.0 m SWD
(Manual standby 50%) 3 Nos 1 No. for each stream divided in two channels of 9.5 m x 4.6 m x 0.70 m SWD
6. Parshall flume 3 Nos. 1 No. for each stream 10.0m x 1.5m x 1.5 m SWD
7. Division Box 3 Nos. 12.8 x2.5mx2.25 SWD8. Division Box 2A 3 Nos. 4 Nos. for each stream
6.85m x 2.0m x 2.25m SWDDivision Box 2B 60 Nos. 20 Nos. for each stream
3.6m x 1.5m x 1.0m SWD9. No. of UASB reactors 11.50 mld
capacity each30 nos 32m x 28.0m x 4.60m SWD (2
seats of 5 reactor in each stream)
10. Feed pipes ( 75 mm dia ) HDPE 6720 pipes 224 Nos. pipe per reactor (4 Sqm.per pipe)
11. HRT at average flow 8.5 Hrs12 HRT at peak flow 5.6 Hrs13 SRT 35 days14 Gas holder 3 Nos. 17.5m SWD & 3.50 m SWD15A Pre aeration Tank 3 Nos. 29.6 m x 13.5m x 3.0 SWD15B Surface aerators in pre aeration tank 6 Nos. 2 Nos. of 30 HP for each
stream (fixed type)16A Polishing pond compartment No. 1 3 No. 1 No. for each stream 140m x
140m x 3m SWD16B Floating aerator for compartment No 1. 18 Nos. 6 Nos. Surface aerator of 50
HP for each stream.17 Polishing pond compartment No.2 3 Nos 550m x 140 mx1.5m SWD18 Chlorine Contact tank 3 Nos 60mx20mx2m SWD19 Chlorination 3 Nos 50kg/hr Booster pump 20m3/hr
@ 6 kg/cm2
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20 Sludge concentration 65 kg/m3
21 Total sludge generation (wet) 1812 m3/day22 Total sludge generation (dry) 100 tons/day23 Sludge pump 3 Nos 1 No. for each stream
9.85m x 6.80m x 1.0m SWD24 Sludge pump 18 Nos
(9W+9S)6 Nos. in each stream of 68 m3/hr at 35 m head
25 Sludge drying beds 106 Nos 27.0mx27.0m26 Sludge cycle 10 days27 Filtrate water sump 2 Nos. 10mx7.5mx1.0m SWD28 Filtrate water pump 4 Nos 40 m3/hr. 18 m head29 Total power requirement of STP 1500KVA30 Effluent pipe 1500M 2400mm dia RCC pipe31 Dual fuel engine for bio gas utilization 2 Nos 850 KVA each32 Gas flaring system 2 Nos Aspiration type pre mixing
burner 6.00 m above GL
1. BIOGAS:- The biogas contain high quantity of methane of about 74% and 10% to 20% of carbon dioxide and about 1% of H2s.About 400m3 Biogas will produced per hour which can be used for CNG and electric generation.
2. SLUDGE: - The dry sludge cakes of about 100 tonne per day will produced which can be used as a fertilizer and for filling the low rising areas.
3. IRRIGATION PURPOSE: - If the parameter of treated water is found within the permissible limit then these treated water can be used for irrigation purpose.
4. FISHING PURPOSE: - If the treated water is improved and made infection less with sufficient quantity of oxygen, treated water in polishing ponds can be used for fishing.
33
34
PRODUCTS & DESIGN
The most important feature is the modular approach adopted for the design of the STP. The
major treatments units, which includes UASB reactors and final polishing unit (EPU) has been
provided in modules of same capacity. Each reactor operation is independent of each other and
during trouble shooting in one reactor the flow can be suspended and diverted to the other
reactors for its maintenance without disturbing the operation of criteria derived over the years
experience that have been adopted in most of the UASB reactors in India are presented in table 2.
The design of UASB reactors for domestic wastewater is mainly based on hydraulic
principal and the incoming wastewater composition. A top view and sectional views of UASB
reactor are shown in figure3.
DESIGN PARAMETERS
1. Design average flow 345 million liter per day (mld)
2. Peak factor 1.50
S.NO Parameter Influent Effluent
1. Total suspended solids mg/I 300-600 < 50
2. BOD5 (mg/I) 150250 mg/I < 30
3. PH 7-8 7- 8
4. MPN per 100ml 106 - 109 < 104
5. Sulphide (mg/I) < 2
Table 2: Basic Assumptions and Design Criteria adopted for UASB Reactor
Parameter Value/Range Unit
Ambient Temperature 18-42 0C
Temperature of Sewage 20-25 0C
35
Bacterial yield coefficient 0.06-0.08 kg VSS/kg COD
Sludge Retention Time (SRT) 32-38 Days
VSS Destruction in Reactor 50 %
Maximum Sludge Bed Height 80-85 % of height to gas
collector
Sludge Bed Concentration 65-70 Kg TSS/m3
Upflow Velocity at average
flow
0.52-0.58 m/h
Maximum Biogas Loading
HRT(Hydraulic Retention
Time)
1.0 M3.m-2.h-1
Maximum Aperture Velocity 8-12 Hours
Volumetric Loading Rate 5 m/h
Biogas Production 1.15-1.25 Kg COD/m3/day
Methane Content in Biogas 0.08-0.11 m3.kg-1 COD rem.d-
1
Gas Hood Width 0.44-0.50 %
Settling Zone Surface 75 Degree
Angle of Glass Collector 50 Degree
Angle of Deflector 45 m2
Feed Inlet Density 0.25 M
36
Overlap of Gas collector over
deflector beam
0.15-0.20 M
Centre to centre distance
between gas domes
4.0 M
Clear Distance between gas
domes
3.0 m/s
Feed pipe velocity 1.0 %
COD removal efficiency 75-80 %
BOD removal efficiency 65-70 %
TSS removal efficiency 75-80 %
37
MATERIAL OF CONSTRUCTION OF UASB REACTORS
From the time of introduction UASB concept in India in late 1980s and till date there have been
significant modifications in the material of construction of UASB reactors, which has
significantly resulted in lowering capital costs. The modifications incorporated in the 14 MLD
UASB plant at Mirzapur constructed in 1989 over that of 5 MLD UASB plant at Kanpur under
GAP were in the selection & introduction of fiber reinforced plastic(FRP) (bisphonol resin) to
rectify corrosion problems and resulting in longer durability. Simpler wastewater feed inlet
system in the UASB reactors is adopted to take care of choking, operation and maintenance
problems surfaced at 5 MLD plant. But, in the ten UASB STPs designed for Yap in Haryana and
recently in other UASBs, further necessary improvements were incorporated, such as,
improvement in fixing of FRP feed inlet boxes, gas liquid solids separator (GLSS), change in
design of deflector beam, selection of most appropriate material with respect to durability and
costs etc.
In the present scenario, the main structure of UASB reactor being constructed at various places
in India is with RCC (Reinforced Cement concrete) since concrete is easily available and has
been used in most of the developing countries for construction work. The inside surface was
coated with epoxy paint as a protective layer to avoid corrosion due to formation of H2S and
co2.FRP of isothelic resin class gas hoods and domes have been provided in the GLSS (gas-
liquid-solid separation). The purpose of us of FRP was because of easy construction, high
weight, anti-corrosion and simple maintenance. The feeding boxes, effluent gutters, baffle plants
and gas collection pipes are also constructed with FRP material. For feeding pipes, HDPE (high
density polyethylene) pipes are being used to distribute the wastewater uniformly over the
surface of the reactor. For sludge discharge, CI (Cast Iron) pipe is being generally used.
However, further R&D shows that the reactors can be constructed fully in FRP using lsothelic
resin instead of RCC for small flows provided modular approach is adopted.
38
OPERATION AND MAINTENANCE (O&M) AND
PERFORMANCE OF UASB REACTORS UNDER YAP
The O&M responsibility of UASB created under YAP is not uniform. In the state of Uttar
Pradesh, the O&M of STPs comes under UPJN ( Uttar Pradesh Jal Nigam) while in the state of
Haryana where 10 UASB STPs were constructed responsibility lies with PHED (public
engineering department) however in Delhi, it is up to (DJB) Delhi Jal Board which looks after
O&M.
This major operational activity associated with UASB plants is monitoring of sludge and its
profile inside the reactor. There has to be balance in sludge ash content, VFA to alkalinity ratio
and routine sludge discharge. Maintenance include cleaning of screen chambers grit chambers,
checking of valves weirs the effluent gutters, gas collectors feeding boxes de-choking of feeding
pipes and time-to-time checking of pumps and electrical items. The cost involved in the
operation and maintenance of UASB plants is less than 1% of capital cost per year. It has also
been estimated that the annual operation and maintenance cost of the UASB plant approximately
30% of the ASP base plants.
The performance results of 5 plants, i.e. Faridabad (45 MLD & 50 MLD), Gurgaon (30 MLD),
Ghaziabad Trans Hindon (56MLD) and Ghaziabad cis Hindon (70 MLD) are presented with
respect to the removal of BOD, COD, and TSS in table 3. all the plant have a typical flow
scheme comprising screens, grit chambers, UASB reactors, ponds as polishing unit (ponds) ,
sludge drying beds, gas holder and duel fuel generators. The UASB section of the plant
comprises modular reactors, which typically have capacity varying in between 5 to 15 MLD.
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EVALUATION OF LIFE CYCLE COST
A good number of sewage treatment plants under various river action plans have been created
over the past two decades. Number technologies like activated sludge process, trickling filter,
waste stabilization ponds, UASB and other new technologies have been applied. Based on the
reliable source of data available and experience of authors, and attempt has been made to
evaluate the life cycle cost (LCC) of different sewage treatment technologies operated in India
with an objective to compare and forecast the future prospects of UASB the LCC can be used as
a reference for selecting an appropriate technology for future STP projects in India and other
countries having similar economies. UASB with final polishing unit (FPU), and extend aeration
system (EAS) and other common technologies being used in India batch reactor (SBR), moving
bed bioreactor (MBBR) and membrane bioreactor (MBR) have been considered for LCC.
Data on capital costs, O&M costs, land price etc. were collected from various reliable sources.
The total annual cost was calculated by suing standard equation, TAC= CR F x IC+OMC, where
TAC is the total annual cost, CRF the capital recovery factor, IC the initial cost (e.g. for capital,
land), OMC the operation and maintenance cost (e.g. manpower, power, repair, replacement of
E&M items, Chemicals).the economic life of STP and annual rate of interest have been
considered as 30 years and 12% respectively. The base year is taken as 2010 and the land cost is
assumed for the ultimate demand up to 2040. the cost is given in Indian (1 US $ = RS. 40) table
4 present the life cycle cost evaluation and net worth investment costs for different technologies
on per MLD basis. On the basis of figures given in table 4, net worth investment cost has been
evaluated for different technologies assuming a flow of 50 MLD as a case study. The land cost
has been and it is assumed as Rs. 200 lacs per hectare, which may be the prevailing rate in many
cities and towns of India having population more then million such as Agra where YAP is being
implemented. It can be seen from tables 4 that the net present worth of investment for WSP is
lowest followed by UASB with FPU. Although WSP option is lowest but it cannot be considered
due to large area requirement for places where large vacant land may not be available. It can be
applied where land is cheap and easily available which could be possible for small flows in
other. After WSP, UASB in combination with FPU gives better proposition in terms of
40
investments as compared to other technologies experience of trickling filters has not been very
good in India and therefore it is not recommended anymore.
CONCLUSION
After the commissioning of DLW at Varanasi it is hoped that the Ganga river will get rid of
pollution of waste water of nalas and the health of Ganga river will improve with the increase of
dissolved Oxygen in the river and not only the life of Varanasiities will improve but the aquatic
life will revive in Ganga the life line of Varanasi.
41
SUGGESTIONS
The quality of treated water should improve in that limit so that it may be us for irrigation and
fishery purpose and for drinking in future. The sewage through pipe line coming from main
pumping station and intermediate pumping station to 42 MLD STP must check properly.
All the tanks and all other units such as Screen, Grit Chamber, UASB Reactor, Pre Aeration
Tank, Polishing Pond, Chlorine Contact Tank, Bye pass Arrangement ,Gas Domes, Feed Box,
Connecting pipes etc. should be check time to time to prevent the leakage & chocking of pipes
and tank.
Treated water must be check before disposing it to the Ganga River. The Hydraulic parameter of
treated water must be within limit so as to suite the aquatic life and avoid soil pollution. Officers
must be punctual with his work. Security must be very accurate because nobody can damage
goods, and any other units of plant.
42