Cover

Ex sum

TOC

CHAPTER 1

INTRODUCTION

1.1 Background to the proposed project

Kandy is the hill capital of Sri Lanka, situated 823 meters above sea level. It is also the

capital of the Central Province, the most beautiful cultural city in Sri Lanka, which been

declared a World Heritage City. Since then, the importance of Kandy increased. Many

people, Buddhists and other religionist from all over the country and the world visit the

holy place of Sri Dalada Maligawa (The Temple of the Sacred Tooth Relic of Lord

Buddha) in the city centre, besides there are other historical sites and monuments within

the Heritage city attracting more and more tourist each year.

There are number of temples with historical importance scattered in the small villages

surrounding the city. Some of villages have artisans with great skills producing artefacts of

great value. The traditional Kandyans in these villages live a very healthy life while

producing spices, fruits and vegetables for local and export markets.

Similarly, Kandy city dwellers and travellers too enjoy the cool climate of this beautiful

city surrounded with its hills and valleys, rivers, lakes and cascading waterfalls. This

picturesque city with the importance of being the capital of the Central Province has had a

greater impact on the life of the city for several decades with number of renowned schools

and centres of higher education including the University of Peradeniya, which is located

within the periphery of the city. Therefore, it attracts a large student and professional

population from outside.

The expenses of the Kandy Municipal Council (KMC) to provide adequate services on

health and sanitation among other services are noteworthy. The Central Government

interventions to ameliorate the disposal facilities still would reply on additional expenses

to maintain the improved system of managing the ever increasing generations of

Municipal Solid Waste (MSW). In response to such increases, up to 1960 Gohagoda,

which is 7km away from the city was used as an isolated area for dumping hospital waste,

then as a sewage dumpsite and finally as the place for dumping all the waste generated

from the KMC. In year 2003, the dumpsite was semi engineered with the technical and

financial support of the Japan International Cooperation Agency (JICA) for increasing its

capacity for two years. Nevertheless, still Gohagoda is the final disposal site for solid

waste generated in city of Kandy.

Unfortunately, at present 120 tonnes of MSW per day collected in the city are being

dumped at the Gohagoda dumpsite. It is even worse during the festival season. It is a huge

threat in terms of air pollution due to Green House Gases (GHG) and odorous gas

emissions. In addition, emissions pollute the Mahaweli River, which is the main water

source for entire province. In addition to that, due to highly contaminated through deep

percolation and seepage is polluting the groundwater table. As a result, significant

numbers of communities are facing various diseases and health problems, more frequently.

Therefore, open dumping is no longer acceptable for Kandy city and Central

Environmental Authority (CEA). Alternate technologies and safe disposal facility are

essential to overcome the plight of poor MSW management. In addition, it is essential to

rehabilitate the dumpsite, otherwise it will continue to pollute for a considerable length of

time. Unfortunately, the rehabilitation of dumpsites was not strongly emphasised within

the government policy and thus, not given the priority, until recently in the wake of the

crisis at Bloemandhal, Colombo.

However, open dumping is no longer acceptable for Kandy city, since lack of land and

other negative issues of open dumping. Therefore, ECOTECH LANKA has taken the

initiative and responsibility to apply suitable waste treatment technologies for minimizing

environmental pollution. Waste to Energy (WTE) concept is an ideal option, which not

only considers the environment but also generation of energy from MSW. Thus,

application of WTE concept is more feasible for polythene, plastic, rubber etc. and

recyclable component of mined waste. Based on energy values found for different type of

waste within the Kandy Municipality, it is possible to generate a significant percentage of

energy requirements using the wastes discarded at present. It is proposed to extract

compost and convert it to char from the mined waste for plantations and remaining plastic

and other polyethylene to be converted to Residual Derived Fuel (RDF) while extract the

landfill gas and produce electricity as a prime income source to commence other project

activities. It is obvious that with implementations of these activities, it would be possible

to uplift the living standards of the communities via more income generation and protect

the environment for future generations while mitigating present serious environmental

burdens.

The KMC opted to develop a corporate partnership with the University of Peradeniya,

since the University has developed number technologies that can resolve the present

constraints and also provide low cost technological options to rehabilitate the Gohagoda

dumpsite. There were several promotional events conducted jointly between KMC and the

Postgraduate Institute of Agriculture (PGIA) to formulate the project “Rehabilitation of

Gohagoda Dumpsite and Development of an Integrated Solid Waste Management (ISWM)

System for KMC”.

1.2 Justification of the project

The KMC while approving the project recommended and sanctioned to formulate a

company to undertake the proposed project, since none of the companies tended the

expression of interest (EOI) were willing to rehabilitate the dumpsite and dispose the

wastes without a tipping fee. Therefore, EcoTech Lanka Limited formed to implement the

project with the intention of deriving funds from other sources, so as to convert the wastes

to tangible resources.

The plausible conversion technologies are composting, since the composition analysis of

the wastes indicates that more than 60 % of waste is short-term biodegradable that is ideal

for producing compost. However, the quality of compost is questionable. The better

alternatives are converting the compost to char and to establish landfill bioreactors to

generate gas for power generation. It also blends well with the gas generations from the

dumpsite that can contribute to developing a sustainable system. This was one of the

reasons to continue disposal of wastes at Gohagoda, since the earlier proposal of finding

an alternate site was shelved due to many reasons such as Not In My Back Yard (NIMBY)

syndrome, haulage distance, social and political pressures. Nevertheless, rehabilitation of

the dumpsite is a challenge requiring adequate funding with suitable technologies of

making RDF and char fertilizer. Also additional funding is a necessity for social

adjustments of the rag pickers and farmers rearing animals, thus housing and developing

improved livelihoods.

The gas emissions from the dumpsite can be captured to produce electricity. This will

contribute to the reduction of climate change and global warming. However, emissions

need treatment before allowing it to flow eventually to Mahaweli River. The income from

electricity generation should be more than adequate to override the costs of rehabilitating

the dumpsite. The exploitation of the dumpsite resources can commence with the correct

choice of technology to establish the ISWM system. Unfortunately, most of the available

technologies in developed countries are operated inefficiently, since the management of

facilities depends on high tipping fees. Therefore, optimization and development of

scientific principles are lacking in most of the processes that are installed in most Western

Countries. They are now in the process of developing ISWM systems. Still the waste

management professionals either belong to engineered landfills or incineration systems.

The strides made at the University are to combine the two technologies to make the system

truly integrated. In the process of reaching that target, it has been possible to find inventive

ways of managing sustainable landfills with the landfill bioreactor technology at low costs.

The efficiencies of the existing thermal systems can then be improved with much higher

temperatures of combustion by combining landfill gas with producer gas to meet ambient

air dioxin emission standards. In view of these novel approaches the Company has

decided to initially install a 2.5 MW duel fuel system and finally a 7.5MW thermal power

plant. In addition, other supporting technologies are available to increase profitability and

thus reduce risk.

1.3 Objectives of the project

The impact on environment and thus, the health of the populations are affected due to the

open dumping of wastes at Gohagoda. It is essential to rehabilitate the dumpsite and

develop a sustainable ISWM system for KMC and other neighbouring local authorities

while providing a healthy livelihood for the families who are dependent on the wastes. It is

essential to develop the sustainable system at Gohagoda without causing any hindrance to

other Kandian villagers of cultural and historical values.

1.3.1 Main objective(s) of the project

To implement the 30 year lease agreement given to the company to establish and operate

an ISWM system for the KMC which will be implemented in stages with proven

technologies while the dumpsite is rehabilitated to meet environmental standards of the

CEA.

1.3.2 Specific objectives

i. To remove haphazardly dumped wastes, process the existing materials, treatment

of and extraction of gas in the rehabilitation efforts.

ii. To improve the infrastructure so as to access the dumpsite and operate it until

landfill bioreactors can be constructed and used.

iii. To conduct preliminary works on awareness programmes while the collection

system is improved.

iv. To relocate the occupants to a safe and socially acceptable habitats approved and

given by the KMC

v. To undertake preliminary scientific and technological investigations to develop

detailed designs, construct and operate landfill bioreactors in an integrated

approach

vi. To promote avoidance, reduction, reuse and recycle of materials while assisting the

KMC to improve collection of wastes

vii. To maximise conversion of waste to energy by promoting biochemical (biogas)

and thermal processes (RDF) to generate electricity and other thermal uses

1.3.3 Objectives of the EIA report

It is a necessity under the National Environment Act No 47 of 1980 (NEA) to carry out an

Environmental Impact Assessment (EIA) study considering the fact that the proposed

ISWM system will be receiving more than 100 tonnes of waste per day and a dumpsite

mining and rehabilitation component has been suggested as part the project

Ecotech Lanka Limited, Solid Waste Management Research Unit (SWMRU) of the

University of Peradeniya together with other experienced experts evaluated the present

environmental impacts and possible impacts that could arise through rehabilitating of the

dumpsite and during establishing and operational phases of the ISWM system with special

emphasis on converting waste to energy and then to mitigate them with appropriate

techniques so as to minimize the adverse impacts on the environment. In this respect,

special attention was paid to groundwater, surface water contamination, air quality as a

consequence of generation, landfill gas emission and emissions during RDF processing

and utilization. Further this report attempts to provide a suitable monitoring programme to

ensure the adherence to the proposed mitigation measures.

1.4 Brief outline of the methodologies and technologies adopted in EIA preparation

The scope of this EIA mainly covers the Terms of Reference (Annexure 1) prepared by the

CEA, the Project Approving Agency. The study area in general covers the entire land

allocated for the project. Social study covers 500 m radius outside the proposed area.

Every effort was exercised to capture the likely affected areas.

The study involved the collection of baseline data on the existing environment. In this

respect the University Peradeniya with the collaboration of the Institute of Fundamental

Studies (IFS) carried out physico-chemical and microbiological analysis of surface water,

groundwater and sediment quality in the project area. Soil types and bore-hole analysis

were too carried out. The field observations, field and laboratory analysis conformed to

standard methods. National Building Research Organization (NBRO) was contracted to

measure air quality and noise levels in the project area.

Different surveys were undertaken by the experts in order to collect relevant baseline data

as appropriate as possible. The methodologies adopted for this study are summarized in

Table 1.1. Literature, surveys, questionnaires, field visits, meetings and discussions and

computer modeling work that are usually adopted in EIA studies were used. Impacts were

evaluated using the Leopold Matrix method.

1.5 Compatibility with other projects/programs/plans/developments in the area

The Kandy City development under heritage city indicates positive improvements to

traffic by way of one way, overhead bridges, underpasses and even mono-rail and thus, the

waste transportation system can be improved.

The water intake project is somewhat a problematic or a concerning factor for the

development of the project. The balancing tank in the middle of the waste dump and the

proposed landfill bioreactors was not located appropriately in the design and construction

of it. Although, the present dumpsite is having an impact on water quality before treatment

at the Katugathota water purification plant, the proposed ISWM system will reduce the

impacts, thus ameliorating the conditions for supplying intake water.

The sludge beds to be constructed in the promises of the Gohagoda facility by the Kandy

national water supply and drainage board (NWS&DB) will cause odour problems. But it

can be compatible if the sludge is processed by the proposed ISWM system. It can be

processed to produce good quality fertilizer by charring or sterilization and drying with

steam generated from the power plants.

The Gohagoda temple is very old and has a long heritage. It serves the communities living

around the dumpsite. It is deeply felt that the prosperity of the project is blessed with this

temple located at the edge of the dumpsite. The prelate of the temple has already provided

numerous advises and solutions. Therefore, the company is envisaging greater

involvement of the temple to improve the spiritual and educational levels of these deprived

populations living in the neighbourhood. This small temple requires restoration to become

one of the leading religious locations not only for workers and their families employed by

the company. .

Tourism: The odour nuisance is one of the greatest impacts for hotels located on the other

side of the Mahaweli River and in some places quite far from the dumpsite. The challenge

is then to ensure odour free facility enhancing the environment to increase the tourism

industry largely dependent on the Mahaweli River.

1.6 Policy, legal and administrative framework with reference to the project

In Sri Lanka, the basic legal framework required for solid waste management is provided

under an umbrella of Government, Provincial Council and LA regulations and legislations.

The 13th

Amendment to the constitution (1987) and the Provincial Councils Act No. 42 of

1987, the sections 129, 130 and 131 of the Municipal Councils Ordinance (1980), Sections

118, 119 and 120 of the Urban Councils Ordinance, No. 61 of 1989, Sections 41 and 93 to

95 of the PS Act, No. 15 of 1987 and National Environmental Act (NEA) are the key

pieces of legislations governing solid waste management. According to the MC

Ordinance, the urban council (UC) Ordinance and the pradeshiya sabha (PS) Act, all

MSW generated within the boundary of local authorities (LAs) is their property, and they

are mandated to remove and dispose of such waste materials without causing any nuisance

to the public (Vidanaarachchi et al., 2005). These government enactments provided the

provisions and regulation for selecting a suitable lands for the project and help to do the

development within the frame of law and regulations. One of the very important acts

relevant to above mention project is national environmental act. The provision of the act

vindicate and explain how to launch the project without damage to the environment. Other

acts, Ordinance, regulations applicable to the project are provincial council ordinance,

Electricity act and regulations impose by the ministry under the national environmental

act. etc. the Sri Lanka labor law applicable to laborers/ Workers/ Employers and others

who are relevant to that field.

As a response to the growing problem, the Ministry of Environment and Natural

Resources has planned an implementing programme, called “Pilisaru” to coordinate the

efforts of all stakeholders, including the urban planners. One of the aspects of the

programme was to develop appropriate policies for developing sustainable systems. It has

been gazetted and enforced. A strategy based on the policy framework is also

implemented to encourage solid waste management practices through waste avoidance,

reduction, re-use, recycling, treatment and final disposal. Further, the strategy

recommends that all LAs provide proper landfills for final disposal. Also it emphasizes the

importance of these developed policies in order to support existing and developing

economic, industrial and urban planning policies.

1.7 Approvals needed for the project from other state agencies and any conditions

laid down by Government agencies for implementation of the project

It has been envisaged that approvals are necessary from key institutions in charge of

different subjects during rehabilitation of Gohagoda dumpsite and development of an

ISWM System. They are as follows;

- Harispathuwa Pradeshiya Sabha

- Mahaweli Authority

- Central Provincial Council

- Ministry of Environment and Natural Resources

- Ministry of Local Government and Provincial Council

- Urban Development Authority

- Ministry of Power and Energy

- Central Environmental Authority

The conditional approvals except from CEA have been already received and are given in

Annexure 2.1.

- Commitments from the local authorities to supply garbage for the project

- Letter of intent (LOI) from the CEB for purchase of electricity

- Provincial approval from the SEA

CHAPTER 2

DESCRIPTION OF THE PROJECT REASONABLE ALTERNATIVES

2.1 Description of the Project

2.1.1 Project site

The proposed project site is the present final disposal site of the KMC, which is 30 years

old unmanaged open dumpsite known as Gohagoda Dumpsite. It is located in

Thekkawatte, Gohagoda, at about 1.5 kilometers from Katugasthota town on Sri

Rathanapala Mawatha (B365), well known as Katugasthota-Peradeniya road, 200 meters

off the left side at Gohagoda junction. The location belongs to Polwatte Grama Niladhari

division in Harispattuwa Divisional Secretariat Division and Harispattuwa Pradeshiya

Sabha in Kandy District of Central Province of Sri Lanka.

The extent of the proposed project site is around 16 acres on the left bank of the River

Mahaweli. The land is owned by the KMC and leased to Ecotech Lanka Limited for 30

years. A copy of the Lease Agreement is annexed in this report (Annexure 2.2). Figure 2.1

is a map of the proposed location and Figure 2.2 is an aerial view indicating accessibility

to the site, surrounding developments and infrastructure.

Figure: 2.1 Map view of the proposed project site

Proposed Project

Site at Gohagoda

Figure: 2.2 Aerial view of the proposed project site

2.1.2 Nature of the project

a. Waste Collection System

i. Sources and amount of waste to be collected

Residential, commercial, street sweepings and the industrial waste other than sewage

sludge are the main sources of MSW. At present, the waste generation within the Kandy

city is around 215 tones/day and according to the loading survey conducted at the disposal

site, 110.12 tones/day is collected by the KMC and disposed at the Gohagoda dumpsite.

This includes market waste from Kandy central market, Manikkumbura public market,

temple of Tooth Relic, Kandy general hospital, Peradeniya general hospital, and other

institutional waste including schools, banks, private and public offices. Besides, waste

generated at the University of Peradeniya, Mahaweli reach hotel, industries (Ceylon

Tobacco Company, distilleries), Infectious Disease Prevention (IDP) unit and

Harispaththuwa Pradeshiya Sabha collection and disposal by themselves. Amount of

Proposed Project Site

at Gohagoda

Katugastota - Peradeniya

Road

Dumpsite

Site Access Road

NWS&DB Water Intake

Proposed Site for

Kandy Sewerage

Treatment Plant

Sludge Processing

Unit by NWS&DB

Mahaweli River

waste collected from different sectors is given in Table 2.1 and details of the loading

survey are given in Annexure 2.3.1 and Anex. 2.3.2

Table 2.1: Amount of waste collection from different sectors

Source of Waste

Generation

Amount of waste Collection

tonnes / day

Households and

Commercials 79.60

Kandy Central Market 08.27

Manikkumbura Public

Market 04.67

University of Peradeniya 01.50

Hospitals 04.72

Mahaweli Reach Hotel 00.68

Ceylon Tobacco Company 00.15

Distilleries 01.92

IDP Unit 08.61

Total 110.12

ii. Nature of waste

MSW composition could vary from place to place according to the location, population

density, income level and social background (Wang and Nie, 2001). As reported by

Manikpura et al., 2007 the composition of waste collected by Kandy Municipality

averaged as shown in Figure 2.3.

Figure 2.3: Composition variation of MSW in Kandy Municipality

It shows that readily biodegradable is the highest fraction which is about 59.2% and long

term biodegradable portion is about 29.27%. The market waste has higher organic

fraction. University and hospital waste could contain hazardous waste, obviously.

iii. Waste collection process

The KMC is the responsible authority to manage waste within the Kandy Municipality. The present vehicle fleet for MSW collection consists of compactor trucks, open tractors

and handcarts. Compactor trucks and tractors are used to collect the waste from main

roads while push carts are used for narrow roads and lanes, which are then transferred to

the tractors or compactor trucks. Frequency of collection varies from place to place

ranging from three times per week to once a week. KMC area is divided in to 5 zones

according to the collection of SW as given in Table 2.2.

Table 2.2: Zonal waste management process

Zone Sub

Zones Area Wards Responsibility

Zone 1 1 A Central City Kotugodella, Yatinuwara,

Wewelpitiya Carekleen(Pvt)Ltd.

1 B Deiyanewela Ampitiya, Malwatta,

Deiyannewela KMC

Zone 2 Mahaiyawa

Bahirawakanda, Nuweea,

Dodanwela, Asgiriya,

Mahaiyawa KMC

Zone 3 Peradeniya

Peradeniya, Mulgampola,

Katukele, Suduhumpola,

Siyambalapitiya, Bowala KMC

Zone 4 Katugastota Mapanawathura, Katugastota,

Mawilmada, Kahala KMC

Zone 5 Arruppola Watapuluwa, Lewella,

Buwelikada KMC

Annexure 2.3.3. illustrates the management structure of waste collection process in KMC

including labour forces. Proposed project expects to continue with this management

structure while resolving the existing problems and providing adequate resources. Tools

such as mamoties, shovels, pickaxe, rakes, forks and knifes are used to collect the waste.

But in some zones tools are not enough, because lacking of replacements, when need arise.

Handcarts are used in primary collection for discharging their loads of garbage to

community collection points (open, closed, non-permanent concrete bins), from where the

waste is picked up again by tractor/compactor labors and loads in to the respective

collection vehicles. In some places in Arruppola zone, collection crew is directly

collecting the waste from the sources (houses, shops) without transferring to primary

collection points.

At present all five zones are collecting mixed waste without any separation. In future, the

source separation and bell collection system will be introduced. Most likely it will be

commence from the Aruppola zone.

iv. Haulage system to transfer waste from the primary collection areas to the

proposed site including transfer / collection stations

Concrete bins and barrels are used as primary waste collection points. However, most of

the concrete bins are not in proper conditions due to animal interferences, insufficient

roofing, loading problems and not located at suitable locations. Further, there are

temporary locations which are used to dump waste directly on the road sides without any

cover. Those places will be replaced with a well planned waste collection system after

conducting a survey on those areas.

Therefore, conditions of the collection points will be improved by changing the structure

to unload waste directly to the compactor or tractor and it will facilitate the collection of

source separated waste. Details of the primary waste collection points given in Table 2.3.

Table 2.3. Details of primary waste collection points

Most of the places do not require a transfer station, except at the IDP section. Since, it

necessitate locating a transfer station to collect waste into 2 tractors and 2 compactor

trucks within the Kandy city limit especially during the festival season like Asela

Perahara.

The expected haulage road net work for the waste collection and transport has explained in

Annexure 2.3.4 for each zone with the time schedule. Frequency of collection varies from

place to place but most places daily collection is practiced.

v. Method of transportation and type of vehicles used

Waste is transported using tractors and compactor trucks (see Plate 2.1) as mentioned in

above sections. Handcarts are used in transporting waste to the primary waste collection

points and tractors are used to transport waste from primary waste collection points to the

Gohagoda dumpsite.

Plate 2.1 Type of waste transport vehicles

Hand Cart Tractor Compacter Truck

Zone Permanent concrete bins

Barrels Non permanent places Total Closed Opened

1 A 48

1 B 24 8 3 6 52

2 8 12 6 21 41

3 9 22 4 1 31

4 5 8 0 10 23

5 20 0 5 0 20

A summary of details available vehicles and frequency of waste collection and

transportation expected from each zone are given in Table 2.4

Table 2.4: Waste collection vehicles and frequency of waste collection

In order to ensure the anticipated quantities of solid waste receiving at the site during the

operational period, and KMC is collecting the total quantities at present, a questionnaire

survey was conducted to assess the present conditions of vehicles (see Plate 2.2).

According to that, the variation of the transport capacity of vehicles is given in Table 2.5.

Table 2.5. Transport capacity of vehicles

According to the survey

results, there are several problems and shortcomings associated with waste transportation

vehicles such as falling of waste from vehicles (63% of vehicles are opened and 37% are

closed), leakages of oil, not enough labors (37% of vehicles have 4 labors and others have

less than four), leakage of water from the radiator, missing body parts (lights,

speedometer, seat belts, safety guards, fuel gauge, air pressure gauge, etc.) and problems

in hydraulic system. These limitations will be resolved to give efficient waste transport

Waste

Collectio

n Zone

Waste Collection Area Details Compactor

trucks Tractors

Hand

Carts

Zone 1

1 A Number of vehicles 4 0 48

Central City Number of trips 12,13 0

1 B Number of vehicles 1 1 17

Deyyannewela Number of trips 2 5 per week

Zone 2 Mahaiyawa Number of vehicles 1 1 10

Number of trips 2 3

Zone 3 Peradeniya Number of vehicles 1 2 13

Number of trips 4 2

Zone 4

Katugastota Number of vehicles 1 2 20

Number of trips 3 8

Manikkumbura market Number of vehicles 0 1 3

Number of trips 0 1

Zone 5 Arruppola Number of vehicles 0 2 7

Number of trips 0 5

Transport

capacity Number of vehicles Percentage

< 1500kg 3 13.04

1501 – 3000kg 16 69.56

>3000 kg 4 17.40

Total 23 100

system for the proposed project. Details of assessed vehicle conditions are given Annexure

2.3.5 ...

Plate 2.2 Vehicle conditions assessment

Nevertheless, almost all the vehicles have proper documentations like insurance, revenue

licenses, copy of the certificate of registration and maintenance reports. Maintenance of

70.4% of vehicles (KMC vehicles) is done in the municipal workshop at Katukele. Others

are maintaining them by their own places.

vi. Principal haulage routes and traffic management plan

vii. If hazardous waste is collected, the collection and haulage system

Hazardous waste could be collect separately in parallel to the source separation.

Especially, hospital wastes except the hazardous waste other types of waste will be

collected. Hazardous waste will not be accepted by the proposed project.

viii. Alternative roads for waste transportation

There are no alternative roads to transport waste.

b. Waste pre-processing

i. Method of pre-processing

In the initial stages of the project, pre-processing activities will be minimal. The existing

warehouses will be renovated and use for this purpose and to store electronic wastes (e-

wastes). Then a Materials Recovery Facility (MRF) will be constructed to promote 3R

(Reduce, Reuse, Recycle) system. The facility will be fully functional when the point

source separation programmes are successful, such that prior sorted wastes will then be

separated and graded to different categories of wastes. The vehicles that are transporting

non-biodegradable or long term biodegradable will enter the facility that has the storage

section. The biodegradable wastes will be sent directly to the landfill bioreactor cells or

transferred to awaiting haulage trucks. Then, the haulage trucks are the only trucks that

will take biodegradable and mixed wastes to the landfill bioreactor cells.

ii. Equipment to be used

Conveyor belts, lifts, extruders, pumps, exhaust fans, firewood splitter and fans will be

used for different activities. One of the precision extraction works for e-wastes will have

air conditioned (AC) facility. An electrically driven forklift is essential for lifting pallets

with relatively high loads.

iii. Requirement of power for pre-processing activities

The power requirement for pre-processing activities is given in Table 2.6.

Table 2.6 Requirement of power for pre-processing activities

Item Description Qty Power consumption (kW)

1.0 Conveyor belts 2 8

2.0 Lift 2 7

3.0 Extruder 1 8

4.0 Pumps 2 7.5

5.0 Exhaust fans 5 4

6.0 Fans 10 15

7.0 Firewood splitter 1 3

8.0 Power saw 2 2

9.0 Precision extractors 6 12

10.0 Air conditioners 5 15

11.0 Forklift 1 13

c. Rehabilitation of the existing dumpsite

i. Details of clearing, levelling & embankment construction

The dumpsite was not accessible due to poor management of the dumpsite by the

Municipality. The end result was dumping of wastes in three of the convenient locations

causing tremendous hardships to the people living near by these disposals. It was also

directly polluting the River. These dumps were cleared using 240 hours of excavator and

two dump trucks. The cost of the entire operation was Rs1,890,000.

The road network was developed to work under all weather conditions and followed by

hauling the sprawling wastes over the embankment and embankments were levelled with

the wastes and compacted to form stable sides. The composite liner system of clay and

waste polyethylene was applied on the compacted first terrace on the bench level of 476

from mean sea level. The next embankment will be constructed and again the composite

base cover will be applied to minimise gas emissions. On top of this layer, a soil layer

applied to turf the entire surfaces of sides and embankments. The top of the dumpsite is to

be levelled to have a 2% gradient on both sides towards the lower part of the dumpsite.

ii. Installation of vertical barriers (if any)]

The hydrogeological study found that there is a confined rock outcrop and stable soil

supporting surcharge loads of the dumped wastes. It seems that there is hardly any

seeping through the parent materials that is supporting the wastes. Instead, it is evident

that is weeping from the embankment. Nevertheless, provisions are made to construct a

vertical barrier near to the natural drain.

iii. Details of capping of the dumpsite

In order to ensure sanitary conditions, it is proposed to apply a daily cover of compost

extracted from old wastes dumped on oldest disposals around the main dumpsite or soil.

The dumpsite will be completely covered with composite cover, soil and turf. This finial

cover will be applied at the finish level of 479. The completion of cover will be after

installing the gas extraction system to a depth of 6 m and it will depend on the

establishment of landfill bioreactor in Phase II constructions.

iv. Availability of cover material

The estimated quantity of compost cover materials is approximately 1430 tonnes. It is

more than sufficient to use as daily cover materials. However, the availability of clay is

restricted to the river banks and it may cause environmental problems. Alternatively, the

available clayey soil from a borrow pits at Aladeniya, Muruthalawa and Nanuoya could be

used with increased thickness and additional quantity of polythene wastes. Also there are

considerable quantities of clayey soils illegally disposed along roadsides that can be

recovered. Some of them are mixed with construction and demolition (C&D) wastes. It is

proposed to extract clay from these soils, so that made up clay can be a useful substitute

for the cover and liner systems.

v. Gas extraction and storage system including anticipated quantity and quality

of gas to be extracted

Similar to the liner, the capping of the dumpsite is constructed to maintain a live biocap.

The waste polythene sandwiched between clay allows water to enter but prevents escape

of gases, as long as the live biocap remains above field capacity. When the capping is

undertaken, gas wells are installed and they will be installed at different depths to

compensate the level differences between terraces, such that deeper wells will be installed

8m and shallower at 6m. The radius of influence is 12m for all of the wells. In addition, it

is envisaged to install some of the wells on the embankments to capture maximum gas.

The safe extraction level is 12.3m3/min and the expected quality is given in table 2.7. A

5kW blower or a vacuum pump is needed to main a minimum vacuum of 14.2kPa in the

well head. After number of tests, it was found that the intrinsic permeability of the wastes

was found to be 3.2x10-11

cm2. Thus, it will create a total vacuum of 18.15 kPa at the inlet

of blower as shown in the calculation given in Annexure2.5

vi. Gas flaring system

The following figure 2.4 shows the landfill gas flaring system.

Figure 2.4 Gas flaring system

Table 2.7 Gas quality

vii. collection and treatment system

generation and collection

The generation and quality is described in detail in section 3.3. It is necessary to construct

subsurface drains up to the embankment level of the rehabilitation done in 2003 and drains

cut in the embankment to lead the flows to the toe of the embankment. However, without

weakening the toe, thus considerable quantity of backfilling required.

Therefore, it was decided to lay perforated pipes with aggregate backfill of sizes from 25

mm and 40 mm at the top of the cut drain as shown in Annexure2.6 An additional

subsurface drain of the same specification was installed on the North East end of the

embankment, since s were oozing out due to the natural slope. Draining the and collection

not only lessen the environmental impacts but also reduce the pore water pressure exerted

on the waste embankments with soil on the outer surface built in 2003 and now in 2010.

The subsurface drains were specifically designed to cater the rate of permeating from the

sides of embankments.

Therefore, the pipes were perforated with 2mm slots and 25mm long and depending on the

permeability results the slots were made 33%, 66% or 100% of the circumference with

spacing between slots, see Annexure... It is very important to make slots to ensure

Flame Arrester

Flare Stack

Condensate

Knockout

Gas Pressure

and Flow

Measurement

Gas Blower

continuous flows without blockages, rather than circular perforations that were made in

the pipes installed in 2003 of the JICA rehabilitation efforts.

Treatment

Manikpura et al., 2008 did estimate generations using the HELP model to be as much as

30,304m3/year. Notably with additional waste disposals, the recent study reveals a higher

figure of 30, 810m3/year. The average BOD and COD values were 7,500 mg/l and 30,000

mg/l. Therefore, the treatment system should be robust and capable of reducing the value

to 30mg/l to discharge the treated . The present systems cannot achieve such low values

without having to rely on chemical treatment. Instead, biochemical means are being

researched with very marginal advantages. Nevertheless, bioreactor technology with the

liner system and recycling of can reduce it to manageable values of 500 mg/l to 1500 mg/l

in less than 90 days. The Figure 2.5 illustrates the performance of the landfill bioreactor

„test cell‟ with fresh wastes. A similar concept can be used for treating the s generated

from the dumpsite.

500

10500

20500

30500

40500

50500

60500

70500

80500

90500

0 50 100 150 200 250 300 350 400

Time (days)

(mg

/l)

BOD COD

Figure 2.5 The performance of the landfill bioreactor ‘test cell’ with fresh wastes

Therefore, a bioreactor can be designed to have an estimated hydraulic retention time

(HRT) of one day and solid retention time (SRT) of 14 days under anaerobic conditions. It

will be sufficient to reduce high BOD and COD values to low values that could approach

less than 500 mg/l of BOD. In order to reduce overloading at high values and to ensure a

SRT of 14 days, there should be two reactors. Each one operated alternatively between

active and passive modes. In the active mode both influent „‟ flow and effluent flow takes

place with recirculation of , whereas in passive mode, recirculation of the stored takes

place with few discharges depending on the rainfall and irrigation. In this manner, solid

build up is restricted to 14 days. The seven day cycles reported in many of the publications

(ref………..) points towards a natural cycle of 28 days. Thus the SRT can be increased

from 14 to 28 days, depending on the required quality of the effluent.

The discharged effluent having strengths of less than 500 mg/l BOD from the bioreactor

will be pumped to the existing two Activated Sludge Process reactors measuring 287 m3

and 261 m3 constructed in 2003 for treating sewerage gully discharges. The design of the

ASP is different because the aeration is with 4 numbers of air guns providing sufficient

oxygen for physiochemical process by adding alum for flocculating the . The expected

duration of treatment is six hours. In fact, the design criteria were based on the laboratory

experimentation done to reduce the BOD to meet CEA standards. The criteria are given in

Figure 2.6 and Figure 2.7 for settling the flocculated mass in the second reactor. The

settlement time is 3 hours.

Figure 2.6 Design criteria for treatment bioreactor

Figure 2.7 Design criteria for settling tank for flocculated mass

After settlement, the effluent is discharged into the Constructed Wetland and then finally

to the watercourse. The sludge is removed and dried for subsequent thermal treatment to

oxidise further the ion compounds. The sludge can be used as filler materials for making

cement blocks, refer section k.

viii. Permanent and temporary structures

The treatment plants of bioreactor, sludge drying sheds and activated sludge process

(ASP) reactors are permanent structures. The bioreactors will be rehabilitated once in

three to five years. There will be movable temporary sheds for mining the dumpsite during

rainy weather conditions. The newly constructed site office is temporary, until the

administrative complex will be established; see layout plans given in Figure 2.31 and

Annexure….

ix. Fire protection system (if any)

There will be irrigation system established to douse fires in the dumpsite and landfill

bioreactors. Furthermore, stocks of clay will be available to douse any fires, so as to

prevent cavities within the dumpsite or landfill body. It will be a filler material and an

effective sealant. Furthermore flame arresters will be installed at landfill gas flare station

to protect the system from backfire; refer Figure 2.4.

x. Off site disposal of waste material (if any)

The dumpsite may have materials that cannot be recycled. It will be recovered and stored

for subsequent disposal in the inert landfill built in the last stage of development. Until

then, these materials, like e-wastes will be stored in the existing warehouse and in the

demarcated lands for final disposal marked in the layout plan, see Figure 2.31 and

Annexure….

d. semi-engineered landfill

i. Extent of the site

It is proposed to extend the dumpsite, in the event that the dumpsite is inaccessible. The

location as given in Figure 2.8 and Annexure is in between the dumpsite and the road

leading to the treatment plants.

Soil embankmentand the culvert

ExistingDump

Surface water drain

Subsurfaceleachate pipe Proposed extention

to the dump site

LBR-2

LBR-1

Subsurfaceleachate pipe

Surface waterdrain

Figure 2.8 Proposed location for semi-engineered landfill

ii. Process description

A soil embankment will be constructed in between the two embankments to retain the

wastes. Before constructing the embankment, a culvert will be constructed as shown in

Figures 2.9 and 2.10. It will be underneath the embankment. This earth embankment, the

embankment of the dumpsite and the firm ground on the side of the road will be lined with

the composite clay-waste polythene liner. The surface drain will be covered with

reinforced concrete half circular covers to withstand point and surcharge loads. They will

be placed with 25mm gaps between the covers. A layer of 40 mm and 25 mm sized

aggregates will be used as backfill and a soil layer will be placed above the backfill. The

composite liner constructed above it, thus allowing purified water to percolate down to the

drain. Above the composite liner, another 10 to 25mm sized aggregate layer will be

placed with a central pipe, having an envelope of these aggregates rapped with a „geonet‟.

The pipe will be connected to a stilling well. The base constructions including

establishment of gas wells, will ensure direct disposal of wastes without allowing any

heavy vehicles moving over the wastes.

10.0m

Soil embankmentWaste filling

0.6 dia Hume pipe culvert

Half circular r/c cover on the concrete drain

Concrete drain connect to hume pipe culvert100mm thickRCC base

Liner system

3.0m

Figure 2.9 The culvert through the bund of semi-engineered landfill

Compacted MSW

Liner system

RCC drain

Half circular r/c cover onthe concrete drain with 25mmgaps between the covers

100mm thick soil layer

25mm Aggregate backfill

100mm dia perforated PVCpipe with a gravel pack

Figure 2.10 A cross section through the culvert

The raw wastes will be disposed commencing from the side of the soil embankment. The

waste loads from the vehicles will be tipped onto the engineered landfill. It will be filled

up to the road embankment level. The bulldozer can be used to level and compact the

wastes up to 800kg/m3 after allowing settlement for 10 days. However, a daily cover of

compost will be used to ensure sanitary conditions. Once the total inclined heights

between the embankments 469 m 476 m are achieved, re-circulation pipes will be laid and

a cover made similar to the dumpsite and finally turf established. It will be an ongoing

process until the engineered landfill is completed. The recycling regime based on the

permeating rate will be used to control the head of above the liner. Whenever there is

excess , the valve in the leading pipe connected to main conveyance pipe system will be

opened. It is expected to have low BOD values, after three months of operation. In this

instance, the will be directed through the second valve to the ASP reactor. The

recirculation of enhances methane productions and the pipes will be interconnected to the

gas extraction system network of the dumpsite.

iii. Capacity and life span of the landfill site

The capacity of the landfill is 100 days, filling at the rate of 120 tonnes/day. The total

amount of filling is estimated at 12,000 tonnes.

iv. Equipment and structures to be used

collection pipes, stilling well made from reinforced concrete cylinders, recirculation

pump and bulldozer or waste handler.

v. Initial soil requirement –source

The soil for the embankment, liner and cover will be from the site and clay deposits that

are available at the site. The total quantities are given in Table 2.8.

Table 2.8 Initial soil requirement

Soil Requirement Quantity (m3)

Bund Construction 120

Capping 390

Total 510

vi. Post closure procedure

The gas extractions will last three years and it will be aerated and mined as explained in

landfill bioreactor operations given in section (e) below.

e. landfill bioreactors (LBRs)

i. Introduction

The classical landfill is an engineered land method to curtail and encase the solids wastes

disposed in a manner that protects the environment. Within the landfill body, biological,

chemical and physical processes occur that promotes biodegradation of wastes. Polluting

emissions of and gases needs careful design of landfills with the required barriers and

treatment facilities. Inclusion of environmental barriers such as landfill liners and caps

frequently excludes moisture that is essential to waste degradation. Consequently, wastes

are contained and entombed in modern landfills and remains practically intact for long

periods of time, possible in excess of the life of barriers (Reinhart et al., 2002).

The waste degradation can be enhanced and accelerated within the life of barriers if the

landfill is designed and operated as a bioreactor landfill. The bioreactor landfill provides

control and process optimization, primarily through the addition of or other liquid

amendments, if necessary. Thus, the bioreactor landfill attempts to control, monitor, and

optimize the waste stabilization process rather than contain the wastes as prescribed by

most regulations. It necessitated defining bioreactor landfills by a Solid Waste Association

of North America working group as “a sanitary landfill operated for the purpose of

transforming and stabilizing the readily and moderately decomposable organic wastes

constituents within five to ten years following closure by purposeful control to enhance

Microbiological processes. The bioreactor landfill significantly increases the extent of

waste decomposition, conversion rates and process effectiveness over what would

otherwise occur in a landfill”.

Reinhart et al., 2002 states that there are four reasons generally cited as justification for

bioreactor technology: (1) to increase the potential for waste to energy, (2) to store and to

treat , (3) to recover air space, and (4) to ensure sustainability. The latter although not very

well defined, points towards sustainable landfills with considerable cost benefits in

reducing long term monitoring and maintenance and delayed sitting of new landfills. As

long as outputs are controlled and acceptable way to prevent pollution, including residues

left should not pose unacceptable environmental risks, thus the need for post closure care

need not be passed on to the next generation and the future use of groundwater and other

resources are not compromised.

In order to make it more sustainable by reducing the time for biodegradation, Hettiarchchi

et al., 2007, introduced the concept of biocells within the landfill bioreactor. In combining

yet another concept of landfill mining or mechanical and biological treatment (MBT), the

pretreated materials can be processed to produce RDF. Naturally, almost all of the wastes

can be used to produce energy and power generation is a feasible option. In view of

introducing such a technological approach, it was necessary to evaluate the problems

encountered in developing landfill bioreactor with number of biocells for optimum

conversion of wastes to landfill gas.

ii. Technological brief

The research conducted at the University of Peradeniya entailed many aspects of MSW

management. However, the focus was on developing sustainable landfills. Therefore,

landfill simulations of lysimeter studies on open dumping, sanitary landfills, pretreated

wastes on engineered landfills and landfill bioreactors were undertaken. There were

number of landfill bioreactor lysimeter simulations. In each design, there were number of

intervention to understand the processes taking place in landfills and landfill bioreactors. It

was found that there were four major problems encountered in landfills and landfill

bioreactors. They are;

1. Ammonia toxicity due to increasing in concentration with time when

decomposition of organic materials takes place under anaerobic conditions.

2. Increasing in ion concentration due to decomposition of organic wastes leading to

inhibition of reactions and eventually toxic conditions.

3. Breaching of high density polyethylene (HDPE) liners due to shear forces acting

on the liner, particularly with cracks forming in clay cushion layers underneath the

HDPE liner. It takes place with dehydration underneath the HDPE. High

concentration of ion compounds, including heavy metals bound with organic

substances is corrosive and thus, damages the liner systems. In the case of clay

liners, they undergo rapid dispersions when the concentrations are high.

4. Inadequate good quality water (not direct recirculation of ) for anaerobic digestion

to produce methane. Inability to breakdown coarse fibres due to lack of fresh

water.

In order to overcome these constraints in converting sanitary landfills to landfill

bioreactors, external treatment is coupled to recirculation of high strength . It enables

reduction of high ammonia and ion concentrations. The cost of treating the is one of the

drawbacks in landfill bioreactors. The United States (US) environmental protection agency

(EPA) prohibits use of external water supply, compelling recycling water for enhancing

methane production, thus diluting the strength of the in the landfill body. Reinhart et al.,

2002 in reporting the status and future gives the following summaries of expected

performance of bioreactor landfills and lessons learnt from field scale bioreactor

operations in Table 2.9 and 2.10below.

Table 2.9 Objectives of field scale bioreactor operations

Table 2.10 Lessons learned from field-scale bioreactor operations

N

o

Objectives

1 Demonstrate accelerated landfill gas generation and biological stabilization while

maximizing landfill gas capture

2 Monitor biological conditions to optimize bioreactor process

3 Landfill life extension through accelerated waste degradation

4 Inform regulatory agencies

5 Better understand movement of moisture

6 Evaluate performance of shredded tires in LFG collection

7 Achieve a 50% waste diversion goal

8 Reduce usable gas extraction period to three years

9 Reduce 6+ management costs

10 Shorten time period required to put the site to a beneficial end use

11 Evaluate performance of recirculation techniques

12 Investigate the use of bioreactor to treat mechanically separated organic residue

13 Investigate the use of air injection to increase waste biodegradation rate

No Lessons learned

1 Sealed system can result in plastic surface liners ballooning and tearing

2 Rapid surface settlement can result in ponding

3 Short circuiting occurs during recirculation, preventing achievement of field

capacity for much of the landfill

4 Continuous pumping of at two to three times the generation rate is necessary to

avoid head on the liner build up

5 A more permeable intermediate cover may be more efficient in rapidly reaching field

capacity than recirculation

6 Low permeability intermediate cover and heterogeneity of the waste leads to side

seeps

7 Accelerated gas production may lead to odors if not accommodated by aggressive

LFG collection

8 infiltration and collection piping are vulnerable to irregular settling and clogging

9 Waste is less permeable than anticipated

10 Increased condensate production led to short circuiting of moisture into landfill gas

collection pipes

11 Storage must be provided to manage during wet weather periods

12 Conversely, may not be sufficient in volume to completely wet waste, particularly

for aerobic bioreactors

13

Increased internal pore pressure due to high moisture content may lead to reduced

factor of saf ety against slope stability and must be considered during the design

process

14

Channeling leads to immediate production, however long term recirculation

increases uniform wetting and declining generation as the waste moisture content

approaches field capacity

Eventually, a composite clay-waste polythene and clay liner and cover was conceived to

function effectively and efficiently, a tropical landfill bioreactor with optimum anaerobic

conditions for rapid methane production.

iii. The process

Phase of anaerobic digestion and permeability

The lysimeter studies that led to the landfill bioreactor were important in identifying

different physical and biochemical processes undergoing anaerobic decompositions. It was

found that there are distinct reaction zones appearing inside the reactor. There exists

moisture saturation layer below the surface and above the base of the landfill, dividing the

reaction zones. These reactions zones promote different phases of anaerobic digestion

processes, where the upper zone is hydrolysis and acidogenesis and acedogenesis and

methanogenesis thriving in the lower zone. These zones get mixed with increased

recirculation, causing toxic conditions, although the intention of recycling is to increase

moisture contents in the upper layers of the landfill. At the same time recirculation create

favourable pH for methanogenesis by buffering of excessive acidity in acidogenesis.

Evidently, the needs treatment or dilution for upper zone reactions.

The success of the technology is due to the live biofilter liner system developed to make

the system biologically stable, providing optimum conditions for anaerobic digestion. The

construction of the clay polythene clay (CPC) liner system is with waste polyethylene

sandwiched between clay soil layers. The bottom layer is first compacted and then a

mixture of clay and waste polyethylene applied and again compacted. The top layer too is

applied on the compacted waste polyethylene to a very high density. Once the composite

liner system is constructed on the base and sides of the embankments, hydraulic

conductivity of the liner is measured with a standing water head of at least one meter. The

results of the Samanthurai experimentation on a test cell are shown in Figure 2.11. Both

Peradeniya and Samanthurai landfill bioreactor test cells gave permeability values much

less than internationally accepted standard of 1x10-7

cm/s and, making it a higher level of

containment (Gunarathna et al., 2007 and Thivyatharsan et al., 2009). However, it is best

to avoid total containment, since biological systems do require nutrient balancing. The use

of HDPE liner causes desiccation of soil underneath and large cracks formed throughout

the soil profile that leads to failure of most sanitary landfills. It is then necessary to impose

the regulations and norms of keeping a safe distance of 500m from a water source, since it

is a point source pollution from where HDPE liner breach. There will then be natural

attenuation of the through the groundwater over 500m. However, the breaching needs to

be attended to before saturation conditions develops, since there will be preferential paths

leading to the nearest water source. These preferential paths exceed permeability limits as

stated above.

Figure 2.11 Permeability of the field scale liner at hydraulic head of 86.2cm in

saturated and unsaturated conditions

In the case of a live composite biofilter liner, it is not a point source discharge and the rate

of percolation is less than the scientifically justifiable limit, and thus, natural attenuation is

attained at steady state flow. In fact, in a live biofilter, the biochemical reactions reach

equilibrium within the composite liner due to dissimilar materials of waste polyethylene

and clay (Pathirana, 2008). Biochemical transformations of the take place in the liner to

form water. Unlike HDPE or clay liners restricted to 300 mm of head for safety, the

composite liner can withstand higher pressures, thus providing adequate storage of for

anaerobic digestion.

Inhibitions and toxicity

The sanitary landfill suffers from inherent inhibitory reactions due to high concentrations

of ion compounds as reported by many authors. The action of recirculation causes these

ion compounds to occupy active sites making the conditions toxic. The nitrogen initially

taken up for cellular growth is released when these cells undergo premature death. The

decaying cells and the biomass increases the concentration of ammonia, which eventually

makes the anaerobic process toxic, through these inhibitory reactions. A number of

supporting literature is available on ammonia toxicities in anaerobic digestion (Li et al.,

1999).

In the landfill bioreactor, the excess free ammonia gas is utilized in the live filter cover

made from the same composite materials. It is kept above water saturation making the

conditions ideal for replacing evaporating water with ammonia, which then are converted

to ammonium cations or transformed to nitrite and nitrate. All of these nitrogen

compounds constitute an excellent nitrogen source for the grass cover above the live

biofilter cover. In most instances, the nitrite and nitrate leach down with rainfall and

irrigation, whereas ammonia gets absorbed to soil particles. The availability of anommox

bacterium even in small numbers can convert ammonia and nitrite to nitrogen, stated as,

OHNNONH 2224 2

The excess nitrate nitrogen washed down from the cover and solid wastes goes through the

liner at a concentration of 30.1 ±1.9 mg/l. The nitrate leaves the biofilter after mineralizing

the organic materials in terms of biomass and residual cellular materials. The mineralized

compounds formed within the narrow passages and above the liner as solid phase

reactions. These findings were from a leaching column study simulating the biofilter

composite liner system (Pathirana, 2008). The mineralized depositions were examined

and it was found to be similar in nature to fine clay deposits found in low lying lands, just

at the interface between peat and peaty soil. In the lower profiles these clayey fractions

“Kirimatta” crystallizes to form fine white sand. These were the observations that led to

developing the liner system.

emissions

In an earlier study, it was pointed out that there are distinct phases and zones of reactions

in landfills and dumpsites (Basnayake, 2008). At the beginning of the reactions,

hydrolysis and acidogenesis occur in the upper zone and the products enter the zone below

the saturation zone, separating the two major phases of reactions, causing those products

as substrate to undergo acedogenesis and finally methanogenesis. The well stratified

landfill body reduces the pollutant loads.

Both the BOD and COD reduce rapidly with increase in rainwater entering the Cell, see

Figure 2.6. The gradual reduction of these two parameters with precise recycling along

with Total solids (TS), volatile solids(VS), total suspended solids (TSS), volatile

suspended solids (VSS) and total dissolved solids (TDS) indicated as illustrated in Figures

2.12 to 2.14 that non-inhibiting conditions seemed to have influenced the stability of the

saturation zone. The dilutions were considerable since the water balance study indicated

that rainfall contributions were 65% in supplying the upper zone with fresh water. The

higher the moisture contents in this zone, the greater the production of substrate

influencing the lower zone. The influence of the lower zone on the upper was discussed in

terms of ammonia migration and leaching of nitrate to the lower zone.

0

10

20

30

40

50

60

70

0 100 200 300 400

Time (days)

Co

nce

ntr

atio

n (

g/l)

TS

VS

Figure 2.12 Variation of TS and VS with time

0

5

10

15

20

25

30

35

0 100 200 300 400

Time (days)

Conce

ntr

atio

n (

g/l) TSS

VSS

Figure 2.13 Variation of TSS and VSS with time

0

2000

4000

6000

8000

10000

12000

14000

16000

0 100 200 300 400

Time (days)

Co

nce

ntr

atio

n (

mg

/l) TDS

Figure 2.14 Variation of TDS with time

Gas generations

The top cover too certainly has had an effect on gas productions. Although, it allowed

water to enter the cell, it also prevented gas from escaping since the cover was saturated in

most instances with heavy rainfall experienced throughout the experimentation. It also

prevented the cracking of the surface. With this passive sealing, the gas extractions were

2.8 l/min and it was augmented to 4.2 l/min with increase in suction pressure. The gas

productions began very much earlier than reported (Alvarez, 2003), perhaps it is the fastest

rate so far for landfill bioreactors/biocells.

The methane gas generated from the Biocell can be used for secondary combustion to

reduce and eliminate dioxins in the combusted fumes. This is a novel technique and it has

been endorsed as the primary method to reduce filtration requirements to meet air quality

standards (Basnayake, 2006). In the initial stages, the gas will be torched to satisfy the

Cleaner Development Mechanism (CDM) project.

Liner and cover integrity

A 150 mm thick clay layer is unable to withstand high point loads, overburden and

shearing forces that exceeds 10 kN/m2/m high (Qian et.al., 2002). Therefore, one meter

thick clay is prescribed as the standard not only for ensuring natural attenuation of

permeating through the clay but also to overcome surcharge loads. The shear forces of the

composite liner system can bear over ten times the loads compared to pure clay soils of

equal thickness. The bearing capacity is much higher exhibiting greater plasticity due to

enmeshed pieces of polythene. It is recommended to avoid point loads, thus travelling on

the liner system is prohibitive. Therefore, disposal of one meter thick raw waste layer prior

to travel is required to prevent point loads as expected from the wheels of compactor

trucks. Also crawler tractors can rip the composite liner and should not be allowed without

prior disposal of raw wastes above the liner system.

Under very dry conditions clay cracks and it is a problem when dries up. In the case of

liner left for long periods awaiting disposal of wastes, cracks and thus, allows wastes to

fill up the cracks. The advantage of the composite liner system is that only the top clay

layer allows fragmented and small particles to enter small cracks, since the enmeshed

polyethylene layers prevents further movements of such materials. Also the cracks are

very much smaller since the depths of the cracks are restricted and constrained with

polyethylene sheets.

Under waterlogged conditions, the consistency of clay reach liquid limits and beyond it

dispersion takes place, but with polyethylene sheets they are held together, even at very

high moisture contents without being dispersed. It is evident from the results shown by

Terzaghi and Peck, (1967) given in Figure 2.15 that moisture contents within the

composite liner remains less than 89% moisture content and thus, exhibits cohesive and

adhesive strengths. The adhesive strengths are much higher than soils with high clay

contents. However, the strength of the composite liner is low relative to low moisture

consistency states, see Figure 2.15. Therefore, initial loading should be done under dry

conditions. When the water table rises, the water pressure on the liner is compensated with

an equal and opposite force from the . It is very apparent that the damage to the liner can

be prevented and could be used under both wet and dry conditions. In fact, it is the

minimum risk in comparison to HDPE or only clay liners. Similarly the composite cover

with a final soil layer makes the system more natural with high content of water absorbed

from rainfall or irrigation. As long as the surface is wet, it is gas tight and the composite

cover and soil layer will not crack. The comparisons of liner systems and landfill types,

namely between conventional landfill gas (LFG) and LBR are given in Tables 2.11 and

2.12.

Figure 2.15 Rupture lines for undrained test on a lean clay, in terms of total stresses,

at various initial degrees of saturation.

Table 2.11 The strength and weakness analysis of liner systems

No Reported problems HDPE Clay Composite

1 Ballooning and tearing Frequent none none

2 Rapid surface settlement can result in

ponding Frequent Likely Less likely

3

Short circuiting of leachate

recirculation, preventing FC

achievement of field capacity for

much of the landfill

Limited

quantity

Limited

quantity

Unlimited

quantity

4

Continuous pumping of leachate at

two to three times the generation rate

is necessary to avoid head on the

liner build up

Limited

quantity

Limited

quantity

Unlimited

quantity

5

A more permeable intermediate

cover may be more efficient in

rapidly reaching field capacity than

leachate recirculation

Compost Compost Compost

6

Low permeability intermediate cover

and heterogeneity of the waste leads

to side seeps

Less More More

7

Accelerated gas production may lead

to odors if not accommodated by

aggressive LFG collection

Less More Much more

8

Leachate infiltration and collection

piping are vulnerable to irregular

settling and clogging

Very

vulnerable

Very

vulnerable

Less

vulnerable

9 Waste is less permeable than

anticipated

Less, low

degradation

Less, Low

degradation

More, High

degradation

10

Increased condensate production led

to short circuiting of moisture into

landfill gas collection pipes

Less Less More

11 Storage must be provided to manage

leachate during wet weather periods Yes Yes No

12

Conversely, leachate may not be

sufficient in volume to completely

wet waste, particularly for aerobic

bioreactors

Inadequate Inadequate Adequate

13

Increased internal pore pressure due

to high moisture content may lead to

reduced factor of safety against slope

stability and must be considered

during the design process

Unsafe Unsafe Safe

Table 2.12 The strength and weakness analysis of conventional LFG and LBR

Sustainable landfills

The estimated gas generations are three years and after the gas ceases, the biocell is

aerated to oxidize and remove odorous compounds. The pipes are used to aerate the body

of cells. The excavation is done by slicing through the profile as shown in Plate 2.3. It is

important to carefully remove the cover consisting of grass and composite liner. These two

components should be removed separately, so that they could be reutilized. The remaining

materials are excavated, and heaped up in rows for ten days and at least one turning of the

piles is required to dry and completely digest rapid biodegradable wastes. The material is

then scooped and raked to remove large particles. The small particles and waste

polyethylene is sent through a screening machine to separate polyethylene and digested

biodegradable matter. The latter is sold as grade II compost and the wasted polyethylene

made into pellets and sold as RDF to envisaged power plants in the future. Since the

power plant is in close proximity to the power plant within the disposal facility, the dried

excavated wastes need not be further processed before feeding the gasifier. It is reported

that RDF manufacture is costly, if the raw wastes are processed to produce RDF as

reported by UNEP, 2010 Instead the RDF manufactured from residual wastes derived

No Measurable output Conventional LFG LBR

1.0 Life of landfill Long duration Very short duration

2.0 Onset of gas productions Long Very short

3.0 Gas generation rate Low High

4.0 Gas fluctuations and ceasing High Low/controlled

5.0 head Low High/composite liner

6.0 Average strength High Low

7.0 Regular Maintenance Low High

8.0 Duration of Maintenance High Low

9.0 Sustainability (landfill footprint) Large Small

from excavated wastes by mining landfills is cost effective and technically feasible, since

the calorific value is even higher than coal (Ecotech Lanka, 2010). There are many

publications Prechthai et al., 2006; SmellWell, 2010 to justify the use of RDF produced

from mined wastes

Plate 2.3 Slicing through the landfill bioreactor profile

The dual fuel system as against direct use of LFG in internal combustion (IC) engines is

better for the following reasons.

a. The gas need not be very clean, since combustors can burn mixture of gases,

unlike IC engines.

b. The efficiencies of steam turbine systems are much higher than IC engines.

c. In the event of reduction in gas productions, RDF component can be increased,

thus consistent production of energy.

d. The reliability of producing power is higher with a dual fuel system with less

maintenance

e. There will be less dioxin productions with dual fuel.

f. The polyethylene component can be combusted safely

There are many RDF plants, not necessarily made for mined wastes that can be used with

dual fuel system, thus making the system more robust and risk aversive. The average

capital costs are within US$ 1.5 to 1.7 for generating 1MW (Ref. curtailed for

confidentiality).The unusable material is disposed of in a residual landfill having the same

composite liner. The next important operation is to rehabilitate the cleared biocell,

preparing for disposing once again of raw wastes.

iv. Capacity and life span of the landfill bioreactors (number, capacity, & lifespan of

each bioreactor

The Landfill Bioreactor (LBR-1) as shown in Figure 2.16 and Annexure will have a

capacity of 64800 tonnes. It will be 2 meters below ground and 8 meters above. It will

have a life span of 1.5 years. The LBR-2 will be constructed, once the squatters are

relocated. It should be constructed and operational before post closure of LBR-1. The

expected life of LBR-2 is two years. In both of the LBRs, the embankments will be

constructed to take the total load with 1.5 meter head. In each of the LBRs, number of

biocells will be constructed. Each biocell is filled for a period of three months, since gas

generations are much quicker than conventional LBRs.

2.5 m

2.0 m

6.0 m

Leachate stilling well

RBR-1

SECTION X -X

P L AN

Gas extraction well

Compacted earthembankment

Gas extraction well

Compacted earthembankmentLeachate recirculation system

Leachate recirculationpipe network

Leachate collection welland gravel filled trench pipe

X X

Compacted MSW(800 kg/m³ )

Gas collection pipe

GL

Figure 2.16 Landfill bioreactor (LBR-I)

v. Equipments and structures to be used

The construction details of the landfill bioreactor are given in Annexure……The

equipments used for construction are;

Excavator,

Dozer,

Hand held plate or roller vibrator compactor

Pumps

Redevelopment of roads

Fencing, gates and retaining walls

Liner and capping systems

wells, collection pipes and recirculation system

vi Details of all inputs, outputs of the process and by products including material

and energy balance sheets

The composition of the wastes disposed in the LFB will differ and depends on the amount

of wastes being recycled. Although recycling is encouraged, LCA points towards limited

recycle use of plastics and the maximum number of recycling events is one, since the

quality becomes very poor if the number of events increases. However, there will be a

progressive increase in recycling plastics. The pie charts (Figures 2.3 and 2.17) illustrate

the average composition of wastes collected in Kandy and mined from the Gohagoda

dumpsite. The flow diagram (Figure 2.18) shows the inputs and outputs of the integrated

system.

Figure 2.17 Average composition of mined waste from gohagoda dumpsite

Landfill bioreactor

Mine & Sorter Raw Wastes

120 TPD

RDF processing Plant MRF

WTE Plant

Electricity to

National grid

10 MW

Block Manufacture C&D Wastes

Dumpsite

Recyclables

CH4

Ash

Figure 2.18 Inputs and outputs of the integrated solid waste management system

The mass and energy balances of the LBR Test Cell are given in Annexure…… The mass

balance is also summarized in the Tables 2.13 and 2.14 for one tonne of wastes. The ratio

of ash content was used to deduce the total decomposition, since the initial quantum

remains the same. Thus the ratio gives the actual amount decomposed. The volatile

content of samples before after loading and mining the test cell were experimentally

obtained. The amount of carbon were determined based on C content = VS/1.8. Therefore,

the actual losses of dry materials, volatile solids and carbon were 36%, 48% and 51%

respectively. Also the mass balance calculations were based on the captured gas of

methane and carbon dioxide given in Table 2.14. The total gas generations were 22% of

the raw wastes on dry basis. The and permeate are accounted in the losses and notably

very small, given in Tables2.15, 2.16 In fact, the recycling of reduced the quantity to be

discharged. Nevertheless, almost 13kg of carbon, notably 5.25% cannot be accounted. It

could very well be retaining in the mined wastes, since there could be considerable error in

the determining volatile content in wastes and the error could be as much as 12%.

The energy balance study shows a loss of 32% from experimental values obtained from

Manitkpura et al, 2010 and Nimalan 2010 as given in Table 2.17. Almost one third of the

energy content is lost to the atmosphere and small quantity as . Methane emissions from

the test cell were calculated based on the extraction rate of 4.2l/min for the 52 tonnes

disposed, refer to Table 2.18. The energy content per tonne of wastes in Table 2.19 is

slightly above than reported value of Manikpura et al., 2010.

Table 2.13 Mass Balance for one tonne of wastes before and after mining of Test Cell

Note: Carbon content calculated VS/1.8 = C, 203.67/18=113.15, thus unaccountable 12.81 kg

losses include small quantities of leachate and permeate as tables 2.15 and 2.16

Type of material wb db VS Ash C content

1 Combustible raw Wastes 961.33 468.96 423.23 45.73 244.14

2 Non Combustible 38.67 8.43

Total 1000.00 477.39

3 Combustible mined wastes 949.86 574.29 364.08 210.21

4 Non Combustibles 50.14 7.37

Total 1000.00 581.66

Average Ratio 0.22

5 Deduced Qty of mined 192.76 114.04 63.35

6 Gas 105.52 105.52 54.83

7 Losses 170.67 203.67 125.95

Mass balance 5+6+7 468.96 423.23 45.73 244.14

% loss 36.39 48.12 51.59

Table 2.14 Mass balance of methane extraction from Test cell

Description CH4 CO2 unit

Volume % 60 40

mol. wt 16 44

Density 0.71 1.96 kg/m3

Mass 42.86 78.57 kg

% mass 0.35 0.65 1

Extraction rate 4.20 2.52 1.68 l/min

6048 3629 2419 l/day

2,207,520 1,324,512 883,008 l/year

2,208 1,325 883 m3/year

6,623 3,974 2,649 m3

Mass of extraction for 52 T 5,487 2,838 2,649 kg

5.49 2.84 2.65 tonnes

0.1055 0.0546 0.0509 kg/tonnes

Mass of extraction for 1 tonne 105.52 54.58 50.94 kg

Carbon extracted for 50 T 2.85 2.13 0.72 tonnes

0.05 0.04 0.01 kg/tonne

Carbon extracted for I tonne 54.83 40.94 13.89 kg

Table 2.15: Mass of materials removed with

Description TS VS Ash unit

Average concentration of removed 25.10 14.42 12.24 g/l

Quantity of removed 4,736 4,736 4,736 l

Mass of 118,890 68,273 57,974 g

118.89 68.27 57.97 kg

2.29 1.31 1.11 kg/tonne

Table 2.16 Mass of materials permeated

Description unit

Liner permeability 1.00E-07 cm/s

Total surface area 35 m2

Rate of permeation 3.50E-08 m3/s

Time duration for 3 years 9.46E+07 s

Total volume permeate 3.31128 m3

Average total solids 12.24 g/l

Total solids removed for 52 tonnes 40.53 kg

Unit of solids removed 0.78 kg/tonne

Table 2.17 Energy balance per tonne of wastes in kJ for Test Cell

Category Experimental Modified Shafizadeh % of Raw waste

Raw waste 9,585,164

Mined waste 3,460,514 3,870,456 36.10

Gas 3,030,128 31.61

Loss 3,094,522 2,684,580 32.28

Table 2.18 The HHV of the methane gas extracted from one tonne of wastes

Description Value Units

Calorific value 212.5 kcal/mole

13.28 kcal/g

55,515.63 kJ/kg

CH4 for 52 T 2.84 Tonnes per 3 years

Total energy generated 157,566,668 kJ per 3 years

CH4 for one tonne 3,030,128 kJ per 3 years

Table 2.19 Predicted Energy balance per tonne of wastes in kJ

Category Experimental Predicted

Raw 9,585,164 9,585,164

Mined 3,460,514 3,460,514

Gas 3,030,128 4,328,755

Loss 3,094,522 1,795,896

% loss 32 19

f. landfill gas extraction from LBRs and power generation from extracted gas

i. Gas extraction system including anticipated quantity and quality

The expected quantity of gas extraction is given in Table 2.20 and mass balance of

methane extractions given in Table 2.21. It is very likely in large scale applications to

increase the extractions which will reduce the losses to 19% from 32% as stated in Table

2.19. A network of staggered arrangement of extraction wells will be installed as shown in

Figure 2.19 and a single well shown in Figure 2.20.

Table 2.20 Predictions of HHV of the methane gas extraction in the proposed system

Description Value Units

Calorific value 212.5 kcal/mole

13.28 kcal/g

55,515.63 kJ/kg

CH4 for 52 T 4.05 tonnes per 3 years

Total energy generated 225,095,239 kJ per 3 years

CH4 for one tonne 4,328,755 kJ per 3 years

Gas extraction wells

Main gas deliverypipe

Gas header pipe

Well connection

8 mGW 9

GW 16

Gas header pipe

LBR-1

8m

Power Plant

MRF

Service roads

8 m

8 m

6 m

8 m

8 m

8 m

8 m

8 m 8 m

8 m

8 m 8 m

6 m

6 m

6 m

6 m 6 m

6 m 6 m

6 m

6 m

6 m

6 m

6 m

6 mGW 1

GW 2

GW 3

GW 4

GW 11GW 12

GW 5

GW 10GW 6

GW 13GW 7

GW 8GW 14

GW 15

GW 17

GW 18

GW 23

GW 22

GW 24 GW 27

GW 25

GW 26

GW 21

GW 20

GW 19

Figure 2.19 A network of staggered arrangement of extraction wells.

150mm dia PVC header pipe

50 mm dia Flexibleconnecting pipe

Control valveRemovable pressure gaugewith 12" valve

Sampling port

Wellhead

1.25m

50mm dia perforated PVC pipewith a gravel pack (75-100mm)

compacted soil layer toa radious of 0.5m.

1.0m

Geonet around gravel pack

vary(6m-8m)

Waste Fill

100mm thick top soil layer

150mm liner system

150mm thicl compactedsoil layer

Figure 2.20 A gas extraction well

Table 2.21 Mass balance of predicted methane extraction from LFBs and dumpsite

Description CH4 CO2 unit

Volume % 60 40 percent by vol.

mol. wt 16 44

Density 0.71 1.96 kg/m3

Mass 42.86 78.57

% mass 0.35 0.65 1

Extraction rate 6.00 3.60 2.40 l/min

8640 5184 3456 l/day

3,153,600 1,892,160 1,261,440 l/year

3154 1892 1261 m3/year

9461 5676 3784 m3

Mass of extraction for 52 T 7839 4055 3784 kg

7.84 4.05 3.78 tonnes

0.1507 0.0780 0.0728 kg/tonnes

Mass of extraction for I MT 150.75 77.97 72.78 kg

Carbon extracted for 50 T 4.07 3.04 1.03 tonnes

0.08 0.06 0.02 kg/tonne

Carbon extracted for 1 MT 78.33 58.48 19.85 kg

ii. Gas cleaning system

The landfill gas cleaning system will have a combination of filtering systems as shown in

following figure 2.21.

Figure 2.21 Gas cleaning system for power plant

iii. Installation of power plant and power generation equipments and process

In the initial stages a test generator system will be operated and then to supply the gas for

the dual fuel RDF thermal power plants.

g. Installation of RDF plant and mining of dumpsite

i. Mining of dumpsite and RDF manufacturing procedure

Once the first LBR is constructed, the dumpsite will be capped and then gas extracted and

flared. The torch to flare the LFG is shown in Figure 2.22. It will be flared or a small

generator will be operated until the thermal power is commissioned. On the Southern

side, a three month mining capacity will be demarcated with drains cut such that is

drained or pumped to ensure dry conditions in the isolated cell for mining. These cells will

be constructed and mined progressively working inwards of the dumpsite while gas is

extracted from the other parts of the dump. The working face of the dump will be aerated

and odour filter installed and operated with temporary shelter for both the filter and

working face. The shelter will house the sorting and separation machinery for screening

and manufacture of RDF.

Controlpanel

Propane

Blower

Stack

Control valve

SparkarrestorConcrete base

Air inlet

Gas from

Landfill

Flame detector

Self-actuatingvalve

GAS FLARE SYSTEM

Figure 2.22 The torch to flare the LFG

ii. expected calorific value of RDF

The Table 2.22 gives the experimental calorific values of the RDF expected from the

dumpsite. They are highly degraded samples and could be considered as the worse

scenario. In contrast, Table 2.22 gives values for the LBR in the future LBR.

Table 2.22: Experimental and predicted energy values for the mined wastes from Gohagoda dumpsite (samples from surface)

Category

Gohagoda Mined Waste Mined Waste

kg in

wb

kg in

db

VS

kg

C in

kg C%

Exp

HHV

(kJ/kg)

Mod.Sha

(kJ/kg)

Energy

Cont. (kJ)

Mod.Sha

(kJ)

Coconut husk 3.77 1.10 0.61 0.341 31.111 17200.000 15560.033 15093.133 17067.562

Coconut shells 3.19 2.06 1.92 1.065 51.667 17200.000 19617.700 28359.001 40431.568

Paper 2.23 0.71 0.62 0.345 48.889 27470.000 19069.367 15501.774 13451.448

Biodegradable 0.39 0.19 0.06 0.031 16.667 24563.585 12708.700 3695.965 2390.272

Wood 1.70 0.69 0.56 0.312 45.000 16400.000 18301.700 9090.733 12681.087

Leather 0.81 0.40 0.32 0.180 44.444 14000.000 18192.033 4532.233 7361.655

Textile 2.14 1.07 1.01 0.563 52.778 11531.019 11531.019 9847.450 12309.313

Plastics 9.81 7.73 7.63 4.238 54.833 45000.000 45000.000 278245.922 347807.402

Polythene 22.36 5.19 1.19 0.663 12.778 33300.000 33300.000 138323.265 172904.081

Rubber 1.02 0.83 0.81 0.449 54.472 25500.000 25500.000 16831.603 21039.503

Mixed Materials 35.12 15.78 4.70 2.611 16.549 22578.090 22578.090 285018.792 356273.490

Health hazard materials 2.19 1.77

Sub total 84.72 37.52 19.44 10.80 804539.8708 1003717.381

Scrap metal 0.77 0.50 18.08

Batteries & electronic

parts 0.28 0.28

Construction

demolitions 6.66 6.30

Glass 4.78 4.58

Ceramic 2.79 2.21

Sub total 15.28 13.86

Total 100.00 51.38

iii. Equipment and structures to be used

The envisaged system will require the following equipment and structures.

1. Excavator

2. Moveable shelter for RDF manufacturing.

3. Sorting and screening machines and equipment (convey belts etc.)

4. Shredder

5. Mixer

6. Gas storage tank.

iv. initial power requirement – source and capacity

The LFG will be stored in tanks and used for initial start-up.

v. Power generation using RDF

There are number of different power plants in the world. Most of them are incinerators

rather than power generation systems. Although they produce electricity, the primary task

is to incinerate as much as possible large quantities of wastes generated in highly

urbanized cities. All of them are dependent on the tipping fee (disposal fee) for generating

profits and tariff for electricity productions are so low that it is not economically feasible

to make business sense in generating power. Therefore, the systems efficiencies are

within the range of 15 to 25%. However, RDF plants, particularly in Germany and France

reach 40%. In this study, it was finally decided to be very conservative and calculate on

the basis of 33%, although gas is also available for secondary combustion, thus

augmenting thermal conversion efficiency of the boiler to generate super steam. In this

instance, the thermal conversion efficiency will increase to 40% or more. It is proposed to

in the first instance to install and operate a 5MW plant and then install another 5MW or

less if other sources of energy are available on contract. The plausible sources are MSW

from other local authorities, saw dust and plastics that cannot be recycled. The quantity to

be sourced will depend on the thermal conversion efficiencies of the first 5MW plant and

the quantity of wastes available in the dumpsite. It is estimated to be 196,309 tonnes, see

Table 2.23. The Figure 2.23 below show the duration of mining depending on the rate of

excavation and Table X10 gives the options and transition between dumpsite mining and

LBR mining for 5MW and 10MW.

There are number of power plants being examined. They are;

1. stoker grate,

2. rotary kiln and

3. pyrolyser/gasifier

Table 2.23 the estimation of available quantity of MSW in the dumpsite

Year Tonnes/day Disposal

Tonnes

Residual

Fraction

Predicted

Total Tonnes

1970 55

1980 67 200,750 0.12214 24519.66

1990 82 244,713 0.149182 36506.91

2000 100 298,304 0.182212 54354.52

2010 121 363,631 0.222554 80927.53

2020 148 443,264

2030 180 540336

2040 200 657000

Total 196,309

y = 364.16e-0.235x

R2 = 0.9827

0

50

100

150

200

250

0 2 4 6 8

years

Min

nig

rate

TP

D

Series1

Expon. (Series1)

Figure 2.23 Mining rate as a function of required duration of dumpsite life

Electrical System

In theoretical terms, the electric power system at Gohagoda will comprise of four main

components. These are as follows:

1. Electric power generating plant (10-MW)

2. Switchyard inclusive of power conditioners, SCADA, safety devises and step-up

transformer

3. Transmission line from power plant to the Grid Interconnection Point

4. Grid Interconnection Point and Existing (National) Transmission Line

The design and installation of components itemized 1 – 3 above are under the direct

purview of the promoter company Ecotech Lanka Limited while the intake of power from

the site into the national grid – itemized 4 above - falls under the purview of the national

power utility, the Ceylon Electricity Board (CEB). Considering the nature and its

importance to the proposed 10 MW Power plant, this chapter will be dedicated to

describing design details of components 1–3. Component 4 merits some mention as it

forms the link between the project and the national electric grid. The main characteristics

of the proposal are summarised in Table 2.24 below.

Table 2.24 Main characteristics of the proposed power project

General

Life of project Approximately 25 years

Generation capacity Approximately 10 megawatts

Vegetation clearing

for power plant

Not more than 4 acres for proposal site, easement for power line

and easement for water pipeline.

Water requirement Not more than 10 mega liters per year

Fuel

Fuel quantity Not more than 40,000 tonnes per annum

Fuel type Methane from Land-fill Bio Reactor, Gas and RDF from Dump

Site

Fuel storage Plant is located within the Dump Site Boundary.

Main plant equipment

Combustion system Fluidized bed combustion boiler with flue gas recirculation and

over fire air systems

Particulate emission

control system

baghouses fitted with fabric bags

Stack height Not more than 30 meters

Cooling system Air-cooled condenser

Misc

Ash storage Maximum of 100 tonnes on site stored in enclosed containers.

Other arrangements made to store excess ash.

Electric Power Generating Plant

There will be a 10 megawatt (10-MWe) electrical power system installed at the dumpsite

utilizing waste material to generate electricity to be delivered to the national electrical grid

of the Ceylon Electricity Board (CEB). The proposed method is based on a dual-fuel

system, which is a gasifier technology coupled to a steam turbine. Methane produced

from the dump through the bio-reactors will be burnt under controlled conditions to

produce producer gas which is sent to a furnace that also takes in solid fuel (RDF); the

multi-fuel burning process produces heat sufficient to generate super-heated steam that is

in turn utilized to operate a condensing (steam) turbine based on a Rankine cycle.

There have been many advances made in the gasification area globally, in which state of

the art gasifiers, aided by recent developments in fluidised bed technologies – are making

a come back in power generating scenarios when the single operation of a Rankine type

power plant is itself not feasible or would only yield lower energy conversion percentages.

A gasification technology coupled to a conventional Rankine cycle power plant would

allow electricity generation at an enhanced rate. This typically brings in a high efficiency

of energy conversion. Under this system (also known as the so-called BIG/GT

technologies – Biomass Integrated Gasification and Turbines), a condensing steam turbine

will be used with a fluidized bed or other gasifier in a typical MSW application for power

generation. Gasification (initially) to capture a fluidized fuel state for both solid and near-

solid fuel has been successfully demonstrated in related biomass industries such as in

bagasse based power generation. The lower use of steam as opposed to primary cycle,

steam based power generation is a noteworthy and desirable feature in the use of a

gasifier.

Figure 2.24 shows a simplified, generic layout of a BIG/GT system that is also proposed

for the Gohagoda MSW Project. This system includes a fluidized gasifier, equipment that

transforms methane gas from bio-reactors in the dump site and solid fuel (RDF) into a low

calorific value gas through a high temperature conversion process. Fuel gas from the dump

site contains particulates, tar, alkaline metals and other compounds that could affect the

steam turbine operation. Thus, before introducing the fuel gas into the turbine combustion

chamber, it needs to pass through a cleaning filter.

Figure 2.24 Simplified scheme of a BIG/GT system

For descriptive purposes, a steam turbine is a thermodynamic device that converts the

energy in high-pressure, high-temperature steam into shaft power that can in turn be used

to turn a generator and produce electric power. A steam turbine requires a separate heat

source and does not directly convert fuel to electric energy. The energy is transferred

from the boiler to the turbine through high-pressure steam, which in turn powers the

turbine and generator. This separation of functions enables steam turbines to operate with

an enormous variety of fuels, from natural gas to solid waste, including coal, wood, wood

waste, agricultural byproducts and even with municipality solid waste.

In the thermodynamic cycle illustrated in Figure shown below, called the Rankine cycle,

liquid water is converted to high-pressure steam in the boiler and fed into the steam

turbine. The steam causes the turbine blades to rotate, creating power that is turned into

electricity with a generator. A condenser and pump are used to collect the steam exiting

Steam turbine

Compressor

Filter for gas cleaning

Condensator

Recuperative boiler

Turbine inlet

Combustion chamber

BRAYTON

CYCLE

Biomass

Gasifier

RANKINE

CYCLE

I

I

I

Technological

process

the turbine, feeding it into the boiler and completing the cycle. There are several different

types of steam turbines: 1) A condensing steam turbine as shown in the Figure 2.25 is for

power-only applications and expands the pressurized steam to low pressure at which point

a steam/liquid water mixture is exhausted to a condenser at vacuum conditions.

Figure 2.25 A condensing steam turbine

The turbine exhaust gases have a temperature of approximately 500°C and they still can

constitute a source of heat for steam generation in a recuperative boiler, and that could be

used in a cycle with steam turbines. Typically in the steam combined cycle there is a

topping section with a Brayton cycle (I), and a bottoming section, that uses the heat

rejected by the Brayton cycle as its source, constituted by a Rankine cycle with a steam

turbine (II). This “in cascade” use (conversion) of the heat makes the efficiency of this

combined cycle higher than that of pure and conventional steam cycles.

In essence, gasification provides a means to convert methane and other gases generated

under controlled conditions into fuel gas through its partial oxidation at high temperatures.

This gas, also known as producer gas, is an intermediate fuel, and it will be able to be

further employed on another conversion process – aided by the RDF (residue derived

fuel), gotten from the dumpsite - in order to generate heat or mechanical power, fitting

itself to systems where solid waste material alone cannot be used. Basically, the average

content of the combustible components in the gas resulting from biomass is: CO between

10 and 15%, H2 between 15 and 20% and CH4 between 3 and 5%.

The main project facilities comprise multi-fuel fired two 5-MW steam turbine based

power modules, a power house and auxiliary facilities that include a switch yard, raw

water reservoir, water pre-treatment system, de-mineralization plant, cooling water pump

house, fuel handling system, ash handling and disposal system, and a residential facility

for the power plant staff. The break-up of the power plant into other different

configurations, such as initially a 2.5-MW module to be supplemented by a 7.5-MW

module or, the installation of a complete 10-MW power plant in the first instance is a

possibility but this will not affect the generic description here involving the upper limit of

the power capacity for the site, that is, 10-MW.

Each of the power modules will have a fluidized bed gasifier, high pressure steam boiler,

turbine and generator, and a condensate recovery system along with auxiliary parts. The

steam that passes through each turbine is partly condensed into water that allows the steam

to expand so that the turbine can extract most of the energy from the steam. This allows

the steam to expand more and helps the turbine extract the maximum energy from it,

making the electricity generating process much more efficient. Each boiler unit will have

a multi-fuel furnace, regenerative type air heater, forced draft (FD) fan, and induced draft

(ID) fan. Each will have steam conditions of about 25 mega-pascals (MPa)/571 °C for

main steam and 569 °C for re-heated steam. Low oxides of nitrogen (NOx) burners will be

used. The main plant comprises of three inter-connected structures: (i) Boiler Structures

(ii) Turbine Building (iii) An integrated Control and Operational Building.

The following are some other salient features of the power plant:

Electrostatic precipitators: Each steam generating unit will be fitted with an electrostatic

precipitator (ESP) with parallel exhaust gas paths. Each path will consist of a number of

fields or the collection of fly ash. The ESP‟s will have a dust collection efficiency of not

less than 99% while firing with solid fuel (RDF) with the highest ash content (estimated at

about 34%).

Flue Gas De-sulfurization units: Each generating unit will have one limestone based de-

sulfurization unit, including a booster fan, de-aerating fans, two to three slurry de-

circulation pumps, one-absorber tower, one emergency slurry tank (for both units), and

two air-compressors (for both units).

Fuel Handling System: The Fuel handling system, (FHS) will comprise of two fuel

streams into each power plant, and in the case of RDF, one operating conveyer and one

standby conveyer. The complete FHS will be designed for the simultaneous entry of both

fuels, namely producer gas and RDF.

Cooling Water System: The power plant will have a closed-circuit cooling water system

using water from the Mahaweli River. The project‟s total cooling water system is

estimated at about 150 cubic meters per day. The make-up water requirement is estimated

to be 25 cubic meters per day.

Water Treatment System: Water to be used in power plant operations will be filtered and

de-mineralized before use.

vi. offsite disposal of RDF

In the event of sourcing funds for a power plant or there is excess of RDF, it is possible to

sell it at the same price as coal for Norochcholai coal power plant, since the GCV/HHV of

RDF found in the dumpsite and predicted RDF from LFB is more than coal. Also some of

the organic residual materials like coconut shells, husk and the like can be sold to tea

estates or converted to biochar for marketing the product as fertilizer.

h. Power transmission system

i. Transmission system, switch yard connections

The Switchyard will form an integral part the 10-MW MSW (Biomass) power plant. The

main integral controls for the key equipment, namely, the Boiler, Turbine and generator as

well as the SCADA system shall constitute the switchyard and control system. True

unification will be achieved by incorporating or integrating switchyard controls (SCADA).

The Supervisory control and data acquisition system (SCADA) of switchyard consists of

Operator Stations, Engineer's Observation Station, Historical Data Logger, Computers and

associated peripherals and the switchyard bay control systems interconnected through a

high speed network . The system constitutes several operator work stations and engineer's

work station with a high resolution Color display monitor.

The switchyard shall comprise of air-insulated aluminous bus type suitable for medium

scale current uptakes. Each circuit breaker shall comprise of a no-load breaker, air-

insulated, disconnect switch on each side. An isolating switch is connected to each

generator transformer connection to the main bus. Current and Voltage transformers are

located at points within the switchyard to provide for metering and relaying. Control,

protection and monitoring for the switchyard will be located in the switchyard relay room

of the electrical building.

All protection and circuit breaker controls will be powered from the station battery-backed

220V DC system. A grounding grid is provided to control step and touch potentials.

Lightning protection will be provided by shield wires for overhead lines through

appropriately sized Lightning arrestors. The communication between the facility

switchyard and the control building will be facilitated through an internal

telecommunications system.

Revenue metering is provided on the outgoing lines, recording net power from the

switchyard.

Upgrading transformer will be installed before the metering side. The standard upgrade

conversion of 440-volts to 33-kV transformer will be available at the point of installation.

The following specifications for the step-up transformer are currently available: 3 phase,

50-60 Hz, 33kV high voltage winding and 440V low voltage winding. The transformer

will be sourced locally or otherwise, depending on price and availability, and conformity

with specifications.

The switchyard and the transformation system will be certified by either a CEB-supervised

independent verification process, carried out by a chartered engineer.

ii. grid substations

The Grid substation as proposed by the CEB is at Kiribathkumbura. Folowing figure 2.26

shows the proposal issued with the Letter of Intent (LOI) by the CEB.

Figure 2.26 Grid substation as proposed by CEB

iii. details of power distribution

Transmission line from power plant to the Grid Interconnection Point

The following description is based on the CEB‟s distribution condition as of January 2011.

Power Line: Approximately 10-km long SC-LYNX Tower 33 kV line will be constructed

at the expense of the project to the nearest interconnection point. The interconnection

point is identified as Kiribathkumbura GSS (Grid Sub-Station).

Load Breaker Switch (LBS): One number of SF6 LBS –with remote control capability -

will be installed at the power plant before the energy meters and the 33-kV tower line will

be directly connected to the DSS through a separate 33-kV Distribution Bay.

Metering Equipment: AS noted above, metering equipment will be installed within power

house premises.

The layout diagram below Figure 2.27 (courtesy: the CEB) illustrates the grid-

interconnection transmission line from the Gohagoda Site to the Kiribathkumbura DSS

while the single line diagram further below illustrates the entire power plant and the DSS

connection point in more detail along with other electrical structures and networks within

the boundary of the power plant.

Figure 2.27 Layout of Transmission line from power plant to the Grid

Interconnection Point

iv. safety devices

i. collection and treatment system

i. generation points, collection and treatment methods

The EIA team spent considerable time and effort in finding the surface and subsurface

flow of . In order quantify number of rainfall storm events have been recorded at site and

also physically observed the transportation and the noted number of points the oozing out

from embankments. The pipes that had been laid in 2005 were intact, but had not

functioned as intended. The network of new pipes and the drainage system is given in

Figure 2.28. The wells that were examined for water quality has been marked on the

Figure 3.13 in section 3.35. In most deep percolations of subsurface flows, in most parts

of the dump, there seems to be natural attenuation. However, an interceptor drain around

the dump has been installed to capture all of subsurface flows in the upper strata that

normally discharge into surface flow streams at different points in the dumpsite. On the far

North East side of the dump, it is best to pump the excess into the nearest pipe network

points. It is strongly recommended to relocate the piggeries to prevent additional pollution

loads on the surface streams leading to the river.

The Hydrological Evaluation of Landfill Performance (HELP) model was used in

estimating the total discharges as reported by Manikpura et al., 2008. In addition, the

discharges were measured during low and heavy rainfall events. According to Manikpura

et al., 2008 the total estimated discharge is 30,304 m3/year. The contribution to

formation is 24% of the total rainfall on average received per year. The highest storage

requirement can be calculated based on a peak rainfall event of 400 mm at Gohagoda. The

primary treatment is in an anaerobic Treatment Bioreactor (LTB) and the design criteria

and deductions are given in Table 2.25. It has been shown that old LBR perform extremely

well in breaking down high strength , thus reducing to less than 500 mg/l or even less

values to 250 mg/l. In the process of mineralization in the liner system, the COD is

reduced to 1500 mg/l and as the required solid retention time (SRT) is achieved, it can

even reach 800 mg/l.

Figure 2.28 The network of new pipes and the drainage system

Table X11 2.25 Treatment Bioreactor (LTB) and the design criteria and deductions

Once the is removed from an anaerobic environment, considerable odour nuisance is

created. In order to lessen this effect, an aerobic biofilter system will be used. If the need

arise to incorporate a gas cleaning system, the wet and dry media biofilter developed by

Ariyawansha et al., 2009 can be incorporated to negate odour emissions. In the next stage

of treatment, an activated Sludge Process (ASP) will be installed and operated with

chemical treatment for settlement in the clarifying tank. The entire process flow diagram

is given in Figure 2.29.

Figure 2.29 The entire process flow diagram

ii. Treated effluent disposal systems

Finally the treated water will be sent trough the constructed wetland and then discharged

into the main water course. The cross section of the constructed wetland and the layout

design is given in Annexure…..or figure 2.30

Figure 2.30 The cross section of the constructed wetland and the layout design

j. cooling water treatment process

There are two options for condensing the steam for a closed loop system with 10 to 15%

losses. The latest being fin type air condensers and the other water condensers and water

towers for cooling the water to ambient temperatures. The advantage of using air as the

media has both the effects of condensing the water while providing directly the hot air for

reducing the moisture content of the RDF. Otherwise a closed loop system of water is

required for the condenser too with an additional heat exchanger with air to make use of

hot air for drying RDF to very low moisture contents.

There is yet another option of using ground source cooling of slightly above ambient water

coming out of the initial cooling to reduce the temperature to 20oC. The use of heat

pumps is another option rather than increasing the water temperature of the river. The river

water can be used but it should be the last option.

The water looses can be as much as 100 to 150 m3/day if the system has problems of

condensing. Therefore, a water treatment plant is required to ensure Si content to be less

than 5 microgram/L and hardness zero.

k. inert material disposal system

It is envisaged to produce textile fibre C&D waste cement blocks with SLS standards

building material, stemming from a recent study by Jayasinghe et al., 2009. Materials like

PVC, inert in nature at ambient temperatures will be used for making these building

blocks. The large PVC pieces will be size reduced to small aggregate sizes. Furthermore,

ceramic and glass either could be used in these cement blocks or used for paving in roads.

There is a very high demand for scrap metal, even rusted and they can be sold to the

informal sector or directly sold to steal manufactures. Estimated quantity of inert materials

in the dumpsite is given in Table 2.26.

Table 2.26 Estimated quantity of inert materials in the dumpsite based on a fraction

of different materials

Year TPD Disposal (wb) Disposal (Db) Scrap metal C&D Glass Ceramic

55 0.005 0.063 0.046 0.022

1980 67 200,750.00 100,375.00 497 6,324 23 140

1990 82 244,713.13 122,356.56 606 7,709 28 170

2000 100 298,303.94 149,151.97 739 9,397 34 208

2010 121 363,630.84 181,815.42 901 11,455 41 253

Total 2,743 34,886 126 771

l. Air emission control system

The quality of exhaust fumes is detected for dioxins in order to increase the secondary

combustion temperature and also to increase the temperature at primary combustion, so as

to reduce the dioxin concentration to the required standards. High temperature gasification

is the proposed system, while maintaining high temperature at the secondary combustion

with LFG. The advantage of the LFG is to ensure a stratified flame that can reduce the

NOx levels, thus requiring less catalytic conversions. The amount of LFG at the secondary

combustion can be varied to ensure high temperature at low NOx emissions. However,

fuel NO formations are likely and selective catalytic reduction is a must. Instead of flue

gas recirculation, which is another technique to reduce NOx formations, the presence of

CO2 in LFG will prevent excessive prompt and thermal NO formations, since carbon

monoxide radicals are formed which then combust once again in the stratified flame. For

the removal of sulfur dioxide, flue gas desulfurization is done. The particulate is removed

with electrostatic precipitators and semi-dry absorber with bag hose filters. The maximum

expected emission levels which will be monitored continuously along with the flow rate

are: NO, SO2, CO and Particulate Matter in 2.14 g/s, 0.66 g/s, 0.23 g/s and 0.166 g/s mass

flow rates, respectively, at an average flue gas flow rate of 24000m3/hr.

m. Buffer zone

The boundaries have not been demarcated, since there are additional number of houses to

be relocated and the reallocation of lands was done only recently between the two

organizations; National Water Supply & Drainage Board and the Company.

n. noise and vibration control strategies

i. noise/vibration generation points

The details have yet to be received from the manufacturer.

ii. control strategies.

The details have yet to be received from the manufacturer.

o. infrastructure facilities required /provided

i. operating room (control panel etc.)

There will be two operating rooms for power plant and landfill bioreactor. Main gate

security room will have the Weighing bridge scale recording and monitoring of incoming

vehicles and vehicle washing unit. Power plant will have a one centralized operating room

with all the facilities for remote monitoring. The details of the control room have yet to be

received from the manufacturer.

ii. Vehicle cleaning and parking facilities

There will be one vehicle washing plant with tyre wash bay and high pressure guns for

body wash. Every waste transporting vehicle will be washed each time before leaving the

site. Waste handling machines will be cleaned at the same facility every day.

There will not be any parking facility for waste collection and transport vehicles, but waste

handling machinery will have a parking shed facility of 110 m2 with maintenance facility.

Main administrative complex will have the main vehicle parking facility of 120 m2 and

Power plant area will also have a vehicle parking facility that can accommodate long

vehicles.

iii. Safety devices /fire protection facilities/lightening protection facilities

The details have yet to be received from the manufacturer.

iv. Construction of new roads and /or improvements of access roads (if any)

A 6 m wide new access road will be constructed from the South Western side of the

proposed site. See Figure 2.31 Project layout.

v. Storage facilities, warehousing etc.

Existing warehouses near to the temple at North Western side of the site will be

rehabilitated and used as warehouses and storage in the initial phase. After constructing

MRF facility, there will be separate storage facility.

p. any other components (if any)

2.1.3. Project layout

LeachateTreatmentBioreactor

Landfill Bioreactor-1

(18 months capasity)

Landfill Bioreactor-2

(24 months capasity)

Constructed Wetland

Storage Facility

Power Plant

Buffer Zone

Buffer Zone

Buffer zone

Material Recovery

Facility (MRF) M A H A

W E L

I R I

IV E R

Administrative Complex

Security Room

Leachate treatment tanks

Existing balancing tank

Landfill Bioreactor

(20 months capasity)

Gas extraction system

at dump

Machinery parking,

repair and maintenance

Access road Service roads

Road to water Intake

To main road(Peradeniya -Katugastota)

Tyre wash pit & weighbridge

Temporary Site Office

& vehicle Parking Area

To main road(Peradeniya -Katugastota) Area for the proposed

inert landfill

Figure 2.31 Project Layout

existing surface water bodies within the site should be provided of appropriate scale, order

to get a clear picture of the project.

2.1.4 Implementation schedule

The implementation schedule is given in table 2.29 below.

2.1.5 Operational activities

i. Details of operation and maintenance activities, schedule of collection and disposal

Operational plan

ii. Water requirements (sources and quantities)

The water requirements in project operation are as following table 2.27.

Table 2.27 Water requirements

Water Use Amount

(m3/day)

Source

Drinking & Sanitary

Water

9.4 National Water supply and Drainage

Board

Vehicle Washing Plant 8 Abundant Large Well at the Site

Irrigation 715 Abundant Large Well at the Site

Power Plant 150 Abundant Large Well at the Site

2.1.6 Relocation of settlers

No of families to be relocated

Places to be relocated

Permanent and temporary structures

Facilities to be provided

2.1.7 Work force

i. Labour requirements (during construction and operation)

The labour requirements in project constructional and operational phases are as following

table 2.28

Table 2.28 Labour Requirement

Type of labour required Constructional Operational

Supervisors 4 3

Skilled Labour 6 6

Labour 20 12

Total 30 21

Table 2.29 Implementation Schedule

1 EIA approvals

2 Leachate Treatment

3 Construction of Administrative Complex

4 Vehicle wash and other facilities

5 Access Road to Dumpsite

6 Relocation of First Two Houses

7 Construction of MRF and Operation

8 Dumpsite grading and leveling

9 Removal of Small Dumpsite

9.1 Construction of Landfill Bioreactor

9.2 Stage I

10 Stage II

11 Installation of gas wells, pipes and turf

12 Flairing of Landfill Gas

13 Operation of Landfill Bioreactor

14 Relocation of rest of the settlers

15 Fencing around the site

16 Power Plant

16.1 Finalysing Power Plant

16.2 Signing of Contract and 1st Payment

16.3 Training

16.4 Power Plant construction

16.5 Commissioning of power plant

M 15

Year 1 Year 2

M 11 M 12 M 13 M 14M 7 M 8 M 9 M 10M 5 M 6M 1 M 2 M 4No Activity M 3

ii. Employment of local people during preconstruction, construction and operation

Local people residing within the proposed site that are working in the dumpsite as

scavengers will be given the priority when selecting the labour force. Two skilled labours

trained at the University of Peradeniya will work as supervisors in landfill bioreactor and

material recovery facility operation and construction. During the power plant construction

there will be a specialized work force working with the recommendation of the power

plant manufacturer. During its operation there will be a trained supervisor and skilled

labours working under the management staff.

iii. Availability of skilled labour

There are few skilled labours locally available within the site for operation of excavator,

bulldozer and tractors and for rough masonry work.

iv. Occupational health and safety provided

All the staff will be covered under a health and accidental insurance cover. Activated

carbon masks, gloves, boots, head gears and overall will be provided and the project

management will be strict on wearing safety gears at work. During rainy season rain coats

will be provided for all of the worker.

Every measure will be taken in MRF and Power Plant to protect the labour from accidents.

Frequent monitoring and repairing of machinery will help in reducing labour injuries. First

aid kits will be available in administrative complex, MRF and power plant. Sanitary

facilities and disinfection allowances will be provided for the work force.

v. Facilities required or provided

Two workers rest facilities will be provided for women and men and each will have a

separate changing room facility, sanitary facility, drinking water, first aid facility, and

store facility for boots, gloves and other safety gears. A common and good quality

restaurant facility will be provided for all.

vi. Scavengers (permitted or not) if yes plan for incorporating them in to operations,

age limits

No scavenging activity will be allowed within the project premises.

2.1.8 Any offsite infrastructure facilities envisaged

2.2 Analyses of Alternatives

The following alternatives could be described

2.2.1 “no action’’ alternative

The dumpsite cannot be used and it needs rehabilitation. The CEA has taken legal action

against the KMC, thus no action alternative cannot be considered.

2.2.2 Alternative sites

At the beginning of developing the project, a site was selected in ……and there were

protests against establishing any type of disposal facility, including waste to energy plant

and the cost of transportation the wastes was a negative factor, thus compelled to withdraw

the idea. The decision was made by the then Chairman CEA. The recent cite that was

selected by the CEA was examined. The main reason for not considering the site is the

reduction of Kandian cultural values, while creating undue pressures on the people living

in the villages.

2.2.3 Alternative scales of the project

The project cannot be scaled down by not mining the dumpsite. However, the pollution

will continue for a very long time to come.

2.2.4 Alternative designs, construction techniques, operation and maintenance

procedures

The composting of MSW is an alternative, but the quality of the compost is questionable.

Furthermore, low temperatures and high rainfall in Kandy is not conducive to composting.

Nevertheless, it is an alternative technology in the Policy document of managing MSW.

2.2.5. Alternative ways of dealing with environmental impacts

CHAPTER 3

DESCRIPTION OF THE ENVIRONMENT

3.1 Physical Environment

Selected site is situated adjacent to the north western boundary of Kandy city and 3km

away from the city of Kandy. Its location coordinates are 7° 18‟ to 45.89” N and 80°

37‟to 19.87” E which lies at an altitude of 461 m above mean sea level.

The site is located in a valley surrounded by mountain ridges from all sides.

Wattaramthanna range with a peak of 510m is located towards east in about 0.5 km

distance to the site. Highly ecologically valuable two mountain ranges like Hantana and

Udawattakelle are located towards the south east of the area making the situation more

critical. To the south and south west of the site lies the Gannoruwa mountain range with a

peak of 570m. Mahathanna Watta mountains with its highest peak of 725m are situated

towards western side of the area at a distance of about 4km. Entire surrounding area is

with hilly undulating terrain with vital eco systems, which makes it imperative that a

proper attention is paid on the possible effects of emissions from the power plant.

The location map of the surrounding area is given in Figure ….. The contour plan of the

site is also given in Annexure 6.1

3.1.2 Geology and soil

3.1.2.1 General geology of the area

3.1.2.2. Soil type distribution

a. Soil characteristics

According to the FT-IR analysis it can be observed that the soils in the downstream of

Gohagoda dump site shows kaolin type clay structure and clay is lack of organic matter.

Analysis of soils contaminated by

i. Total metal concentration

The sample locations were selected in order to determine the physical environmental

characteristics of the study area such as: topography, surface water drainage pattern and

quality, flow regimes and streams draining the area. For the purpose to ensure

representative and same condition in all samples, soil samples were collected from auger

at 0.5 m above to the bed rock and closer to the bed rock as shown in Figure 3.1.

Figure 3.1: Sample locations and depth of samples

The total quantity of metals extracted from 0.5 m above from the bed rock polluted soils

were recorded as Zn>Cu>Pb> Cr > Ni >Cd concentrations and had a significant increasing

pattern from the river towards the dumpsite direction (Figure 3.2). Accordingly, the

highest total concentration of heavy metal recorded was Zn (318.45 mg/kg) and Cu, Pb,

Cr, Ni and Cd; 124.1, 98.45, 69.85, 70.15 3.45 mg/kg respectively. A scattered metal

behavior was recorded closer to bed rock as shown in Figure 3.3. According to observed

data all binding sites in soil particles may have been occupied by metals in the upper layer.

Thereafter can be facilitated to move towards down wards and the deeper soil layer may

adsorb toxic metals. That may be the reason for the unique pattern observed at 0.5 m

above layer from the bed rock.

Figure 3.2 Total metal concentrations of soil – 0.5m above from bed rock

Figure 3.3 Total metal concentrations of bottom layer

ii. Exchangeable metal fraction

The heavy metals in the exchangeable fraction can be released rapidly to the environment.

According to the exchangeable metal fraction results as shown in Figure 3.4, the

predominant heavy metal recorded is Zn (59.4 mg/kg) and it may cause a threat to the

surrounding environment since the concentrations are high. Further, Pb, Ni, Cu were

recorded as 10.05, 7.35, 5.05 mg/kg respectively and Cr was not recorded as exchangeable

although a significant amount was detected in total metal content. This may be a reason

due to the representation of negatively charged complexes of soil in fewer amounts.

Comparable less values for recorded cation exchange capacity (49.09 meq/100g) and

specific surface area (9.25 m2/g) determinations reveals enough evidences to confirm that

the analyzed soil has low ability to absorb in to it‟s outer-sphere.

Figure 3.4 Exchangeable metal fraction of bottom layer

iii. Bioavailable fraction

The heavy metal elements can be transferred from abiotic (soil) to biotic environments and

further facilitated to enter to the food chains by bioaccumulation. According to the results

upper layer soil samples had high concentration of heavy metal such as Pb, Zn, Cu, Ni,

Cd; 38.25, 10.45, 8.85, 3.60, 2.65 mg/kg, respectively (Figure 3.5). Low metal

concentrations at the bottom layer was recorded as Zn, Pb, Cd; 4.55, 3.20, 1.65 mg/kg

respectively and Cu, Ni and Cr were not in measurable amount as shown in Fig. 6. This

result can be arisen due to many factors associated with soil; desorption and solubilization

of mineral phases etc. Furthermore, these metal leaching patterns are similar to the total

concentration variation at the bottom and upper layers soil sample leaching patterns.

Figure 3.5 Bioavailable metal fraction of soil – 0.5m above from bed rock

Figure 3.6 Bioavailable metal fraction of bottom layer

The presence of high concentration of heavy metal in soil is considerably high in

Gohagoda open landfill area compared to the regulatory limits of other countries. High

toxic metal concentrations in exchangeable and bioavailable fractions express the risk on

local living being as well as the open water bodies such as rivers and groundwater sources.

It is important to evaluate the potential risk to environment, and can be concluded that the

soils play a major role as a natural attenuator for toxic metals however the release of these

metals into the water bodies and plants especially after exceeding the capacity of binding

may create problems in the future.

3.1.2.3. Height of ground water table

3.1.2.4. Ground stratification and permeability

3.1.2.4. Land use capabilities

3.2 Meteorology

The project area is located within the Wet zone mid country, which experiences a rainy,

humid and mild climate.

3.2.1 Temperature

Long-term records of temperature are not available in the project area. However, it is

anticipated that the temperature patterns occurring in the project area are comparable to

the temperature variations occurring in the Gannoruwa area. For the period of 2001-2010,

the mean annual temperature was 25.5oC with mean maximum and minimum temperatures

of 29.9oC and 21.0

oC, respectively. Table 3.1 presents the average monthly temperature in

the Gannoruwa area during the period of 2001- 2010. The warmest months are April, May

and March while the coldest months are December and January.

Table 3.1: Average monthly temperature for years 2001-2010

Month Temperature oC

January 24.3

February 25.1

March 26.3

April 26.5

May 26.3

June 25.8

July 25.3

August 25.4

September 25.4

October 25.4

November 25.1

December 24.5

3.2.2 Wind patterns

No long-term records of wind patterns are available in the project area. However, it is

anticipated that the wind patterns occurring in the project area are also similar to the wind

patterns occurring in the Gannoruwa area. Table 3.2 presents the monthly maximum wind

speed experienced in the period of 2001 to 2010.The maximum wind speed was reported

in February, 2002.

Table 3.2: Monthly maximum wind speed of Gannoruwa from year 2001-2010

Note: *** Not observed

3.2.3 Relative humidity

Recent data pertaining to the relative humidity are not available in the project area.

However, the project area experiences a humid climate and according to the data reported

in the period of 2001-2010, the maximum daily pan evaporation was reported in February

2010 amounting to 10 mm, while minimum was 0.1mm in December, 2006.

Tables 3.3 -3.5 show the average monthly evaporation and humidity data collected from

the Gannoruwa area and it is anticipated that the data presented in Tables 3.3 -3.5 are also

similar to the average monthly evaporation and humidity patterns occurring in the project

area. The mean humidity throughout the year is around 70 % in evenings and 81 % in

mornings and the average annual evaporation is about 1123 mm.

Table 3.3: Average monthly pan evaporation in the Gannoruwa area for the period of

2001-2010

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Evaporation (mm) 107 124 124 90 96 90 81 90 91 76 67 88

Table 3.4: Mean daily pan evaporation of Gannoruwa for the period of 2001-2010

Month Date

Wind speed

(km/h)

Direction

Morning Evening

January 7-Jan-2002 11.19 E E

February 23-Feb-2002 14.66 E E

March 9-Mar-2002 9.42 E E

April 5-Apr-2007 6.45 E ESE

May 17-May-2002 5.45 NW ***

June 23-Jun-2002 6.88 *** ***

July 7-Jul-2001 7.30 SW SW

August 2-Aug-2001 6.19 W SSW

September 30-Sep-2001 8.1 W SW

October 6-Oct-2001 4.81 SW S

November 29-Nov-2007 11.10 E E

December 29-Dec-2003 14.21 E E

Month Mean Daily

Evaporation (mm)

January 3.5

February 4.4

March 4.1

April 3.0

May 3.1

June 3.0

July 2.6

August 2.9

September 2.8

October 2.4

November 2.2

December 3.0

Table 3.5: Mean humidity for the period of 2001-2010

Month Morning (%) Evening (%)

January 80 65

February 77 56

March 79 60

April 84 73

May 80 73

June 81 74

July 83 75

August 81 72

September 79 72

October 82 76

November 84 77

December 82 72

3.2.4 Rainfall

Tables 3.6 shows the average monthly rainfall data reported at the Meteorological

Department at Gannoruwa. According to that the average annual rainfall is 1973.9mm.

Figure 3.6 illustrates the cumulative rainfall variation from 2001 to 2010.

Table 3.6: Mean Rainfall for the period of 2001-2010

Month Average monthly

RF (mm)

Daily average

RF (mm)

Jan 76.2 2.5

Feb 42.3 1.5

Mar 163.1 5.3

Apr 298.2 9.9

May 128.7 4.2

Jun 150.2 5.0

Jul 152.0 4.9

Aug 108.3 3.5

Sep 136.9 4.6

Oct 254.5 8.2

Nov 282.7 9.4

Dec 180.7 5.8

0

500

1000

1500

2000

2500

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Month

Cu

mila

tiv

e ra

infa

ll (

mm

)

cum 2001

cum 2002

cum 2003

cum 2004

cum 2005

cum 2006

cum 2007

cum 2008

cum 2009

cum 2010

Figure 3.6: Cumulative rainfall variation during year 2001 to 2010 in Ganoruwa

3.3 Hydrology

3.3.1. Surface water drainage pattern

The study area have three small watersheds as shown in Figure .. The dumpsite is located

in the largest one, having an area of 184,765 m2 of which approximate 40% of the land is

used for the dump. The hydrological characteristics are very much influenced by the

dump. Unlike any other watershed, the wastes have greatly influenced the water

absorption capacity, permeating rate and therefore the release is partially governed by the

soil permeability. Although, the stream of the sub-watershed was a dry one during non

rainy seasons, now has considerable base flow, nearly 1 m3/h. The measurements were

made with V-Notch weirs that were installed to obtain the flow rates from the three sub-

catchments. Also the three flows that joined the main stream were measured.

Unfortunately, all of them got washed away with the storm that occurred. However, the

random measurements of flow during the storms and accurate base flow readings,

permitted to develop a simple model. It is based on the concept of releasing subsurface

flows that eventually discharge as base flow, since shallow confining layers exists in the

location where the waste is dumped.

3.3.2 Flow regime of the streams draining the area

The rainfall data, ET and the observations permitted to develop a hydrograph based on this

model considering the water balance of the dump for the sub-watershed. The equilibrium

water balance model is based on methods proposed by Budyko (1958) and Fu (1981) and

further developed by Milly (1994) and Zhang et al., (2001, 2004). In determining the

water balance the index of dryness defined as the ratio of potential evapo-transpiration to

precipitation was found to be a dominant factor (Zhang et al., xx) It would be apt to

include another term “baseflow” to the dryness index and thus, term as “storage deletion”,

SD index. Therefore, the absorption capacity will depend on the maximum SD value for

the duration considered.

RF

BETSD

f

Higher the SD value, runoff will be lower. Also there are number of equations developed

to determine accurately the baseflow. The baseflow component of streams represents the

withdrawal of groundwater from storage. As the stream drains water from the groundwater

reservoir, the water table falls, and the baseflow to the stream decreases. Baseflow

recession can be expressed by the following equation:

kt

ob eQQ

Where Q is the discharge at some time after the initiation of recession, Qo is the discharge

at the start of the recession, t is the time since the recession began, and k is a constant for

the basin. A plot of lnQ versus t therefore gives the value of k from the slope of the line. In

this watershed the minimum flow measured were very constant, indicating that there is

large reservoir within the watershed. The above equation can also be written as;

t

ob KQQ . Where, t can be either +ve or negative –ve, depending on the recession limb,

turning point or rising within the period of recession as illustrated in Figure 3.7.

0

5

10

15

20

25

30

5 7 9 11 13 15

Time in days

Flo

w Q

in

mm

/day .

Baseflow

Recession

Threshold

Total flow

Figure 3.7: Illustration of baseflow variations with time for calculating recession

flow

The storage of water within the watershed can be written for a rainfall event as;

ETQRORFS bd

Where, ∆S= change in storage capacity in mm for a unit area. It could either be above or

below the maximum storage Sm for a unit area and over a period of time, it will approach;

Sm = ∑Qb+ ∑ET,

RF = Rainfall in mm,

ROd= Direct runoff of a storm in mm defined as (1-SD)

Qb = Measured base flow for a unit area of the dump in mm

ET= Pan evaporation in mm

The condition where ∆Sf = ∆Si -Qb –ET, ∆Sf < ∆Si, since i = initial and f = final

Q = Qb+ ROd + ∆S, for the condition, when change in storage capacity ∆S is above the

maximum storage Sm and when ∆S is below Sm;

Q = Qb+ ROd and in the absence of rainfall, Q = Qb

The Figure 3.8 was developed from the following data;

Qb = 0.000274 m3/s

Ad = 30,500 m2, the area of sub-watershed of the dump

Turning point

d

bbu

A

QQ

, mm/s = Qb per unit area

RF = in mm/hr measured over a period of one month and converted to mm/day

ROd= 0.2 of RF, since SD =0.8 for the dry period examined for each storm event on the

same day. The maximum period of direct runoff is one day, therefore in the recession

curve, K value can be obtained, assuming that Qb is 0.1 at the minimum turning point and

the Qo is maximum flow of total RF of one day, then K=0.1, since t=1 from turning point.

It can be considered as lag flow. When there are several rainfall incidences, the

computation should be the same.

0

100

200

300

400

500

600

700

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

Time in days

Q d

isch

ag

e m

m/d

ay

Rainfall

Discharge

Figure 3.8: Generated discharges Q in mm/day for a unit area from the prediction

model vs time for the highest rainfall and highest rainfall intensity recorded at the

Gohagoda Dumpsite

The Figure 3.8 shows the generated discharges for the period 1st to 31

st December 2010. In

applying the same model on the entire watershed, it indicates the difference of resistance

to flow. The base flow rates were governed by the groundwater permeability, see Table

3.7. As expected, the lowest permeability was for the dump, next lowest the entire

watershed and highest the area without the dump. The comparative cumulative discharges

illustrated in Figure 3.9 manifest these differences.

Table 3.7: The relationship of baseflow from groundwater and permeability of

watershed

Category Extent m2 Base flow

Mm/m2/month

Base flow

m3/month

Gross Permeability

cm/s

Sub-watershed Dump 30,500 24.06 734 8.98E-07

Sub-watershed without dump 144,500 52.61 7,602 1.96E-06

Total watershed 175,000 47.63 8,335 1.78E-06

The average flow can be considered as the baseflow from the dump. It can account for

approximately 9,000 m3

and the remaining 21,000 m3 for the year is washed out for every

rainfall event. The retention time is very low and the pollution loads are considerable. It is

important to continue this study so that management should be automated to cope with

the large variations of day and night discharges as shown in Figure 3.10 In comparison,

the sub-watershed without the dump manifests an interesting pattern showing the influence

of ET on reduction of and the dew contribution in the night as illustrated in Figure 3.11

These influences perhaps are more pronounced in a river basin. It is a good example of

dew contribution as precipitation.

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

0 5 10 15 20 25 30 35

Time in days

Cu

mu

lati

ve Q

in

m3

Total WS Dumpsite WS WS without Dump

Figure 3.9: A comparison of the cumulative discharges of the entire watershed (WS)

and sub-watershed without dump and the dumpsite

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

12:00 AM 12:00 PM 12:00 AM 12:00 PM 12:00 AM

Q l

/s

Figure 3.10: Stream flow (baseflow) measurements in the dry season of the dumpsite

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

12:00 AM 12:00 PM 12:00 AM 12:00 PM 12:00 AM

Q l

/s

Figure 3.11: Stream flow (baseflow) measurements in the dry season of the sub-

watershed excluding dumpsite

3.3.3 Occurrence of floods

Ten year flood flow data of the Mahaweli River was analyzed according to the flood

hazard analysis (statistical methods). The study took into account nature of the flood

hydrograph, peak flow vs. shape/volume. The probability analysis required data selection

and processing. The log values of the flows were obtained and then ranked them from low

to highest. The selection was made according to number of occurrences, such that the

Figure 3.12 can give the relationship between the maximum discharges for difference

recurrence intervals. Although, 10 year flood flow data was used, it is very much

applicable since the Kotmale Dam reduces risk of flooding. The maximum rise in the

water level will inundate the paddy fields of the low lying lands of the main watershed.

y = 64.701x + 125.44

R2 = 0.9606

0

100

200

300

400

500

600

700

800

900

0.00 2.00 4.00 6.00 8.00 10.00 12.00

REOCCURANCE INTERVAL Years

AN

NU

AL

MA

X.D

ISC

HA

RG

E m

3/s

Figure 3.12: Annual maximum discharges and its recurrence intervals based on

records of ten years

3.3.4 Surface water quality

The sampling points were located and positioned in order to represent the entire area of

Gohagoda dumpsite. S1 was on the main dumpsite and S2, S3, S4, S5, S6 were around the

boundaries of main dumping area. D1 and D2 were taken from old dump and new burned

dump area respectively. Then C1 was located on main canal which drain directly to the

Mahaweli river, while R2 was located on discharge point to the river. And R1, R3 were

located on upstream and down steam of the river respectively. The locations of the

sampling points are shown in the Plate 3.1.

Plate 3.11: Locations of sampling points

The collected samples were analyzed for the parameters of pH, electrical conductivity

(EC), Salinity, total dissolved solid (TDS), total solid (TS), volatile solid (VS), total

suspended solid (TSS), volatile suspended solid (VSS), biochemical oxygen demand

(BOD), Nitrate, Phosphate, using standard methods.

In summarizing the study done by Widanagamege, 2010 the EC measurements were

within the range of 1.12 to 9.32 mS and it is typical of a MSW dumpsite (Pathirana, 2006).

The salinity levels were very low in upstream samples of river at the beginning and then

increased significantly. All other samples showed higher variations of salinity values

within the range of 0-0.8%. The contribution of salinity to the river can be clearly seen in

Annexure 2. . In evaluating the data, influencing the river flow, the pH had decreased,

although upstream and incoming effluent pH levels were higher. TDS were within 500-

6000 mg/l range. In general, TS fluctuations were high since decomposition and burning

create high content of TS and VS. Very low values of TS and VS were recorded in the

stream flow.

There were low nitrate nitrogen and after a dry spell, the nitrate nitrogen values in the river

were higher than downstream and at the discharge point, but the process reversed after

sometime. The phosphate levels varied considerably. The quality and quantity generated

from dumpsite was strongly influenced by the hydrological conditions. In an earlier study,

the BOD value reported was 7500 mg/l (Manikpura et al., 2008). In this study the BOD

and COD values puddles on top of the dumpsite were 4800 and 32000, respectively.

Sometimes due to toxicity and other complications a lower BOD values are recorded. The

results of upstream (R1) in comparison to downstream after river water mixing with (R2)

clearly show the level of pollution. The total loads could be considerable considering the

washouts from the top of the dumpsite, let alone the baseflow. Additional burden is the

effluent discharges from the piggery as shown in S6 values. The pollution level of river

increases with the additions from Gohagoda stream flow. The quality parameters of

discharge flow were very much higher than standard values.

3.3.5 Groundwater levels

Figure 3.13: Bore hole locations

Table 3.8: Borehole details

Bore

hole

No

Total

Depth (m)

Permeability (m3/s)

X 10-10 Remarks

P1 0.46 gray soil, could not observe

P2 0.54 0.182 First 30 cm depth was a soil layer, thereafter decomposed

waste layer could be observed

P3 0.41 7.350 First 30 cm depth was a soil layer, thereafter decomposed

waste layer could be observed

P4 1.03 0.186 First 35 cm depth was a soil layer, thereafter decomposed

waste layer could be observed

P5 0.73 2.820 First 30 cm depth was a soil layer, thereafter decomposed

waste layer and flowing on the surface could be observed

P6 0.64 1.410 First 45 cm depth was a soil layer, thereafter decomposed

waste layer and flowing on the surface could be observed

P7 0.48 Could not dig further due to aggregates and beneath, could

not observed

P8 0.61 no / quarry dust in the bottom layer

P9 0.54 8.030 Could not observe a soil cover

P10 0.76 62.500 Could not observe a soil cover

P11 0.58 Could not dig further due to waste material, stagnating on

the surface was observed and there was not underneath

P12 0.28 Could not dig further due to … stagnating on the surface

was observed and there was not underneath

P13 0.52

Could not dig further due to gravel waste material,

stagnating on the surface was observed and there was not

underneath

P14 0.63 Could not dig further due to gravel, stagnating on the

surface was observed and there was not underneath

P15 0.82 4.630 First 20 cm depth was a soil layer, and flowing on the

surface could be observed, underneath there was

P16 0.47 7.540 First 30 cm depth was a soil layer, thereafter decomposed

waste layer

P17 0.82 There was not measurable quantity of

P18 0.33 2.800 First 30 cm depth was a soil layer, thereafter decomposed

waste layer

P19 0.48 1.090 First 35 cm depth was a soil layer, thereafter decomposed

waste layer

P20 1 It was only a soil layer, could not observe

P21 0.86 could not observe waste layer or , wastewater from a

nearby piggery was flowing on the surface

Ground water quality

Surface water uses including water intake points

Ground water uses

3.4 Land use

The existing land use pattern within 500m radius of the project site is given in Table 3.9.

Table 3.9 :Land use pattern within 500 m radius of the project site

Description Area (m2) Percentage

Waste dump 51,735 6.59

Abundant paddy fields 19,400 2.47

Cultivated paddy fields 57,165 7.28

Commercial 9,518 1.21

Mahaweli river 88,122 11.22

Roads 27,645 3.51

Home gardens 531,813 67.71

Total 785,398 100

3.5 Air quality

Inventory of existing emission sources and ambient air quality measurements

3.6 Noise

Inventory of existing noise sources and ambient noise levels

3.7 Ecological Resources

The site is located in Wet zone mid country within WM3b agro climate zone

(Harispattuwa DSD) where mean annual rainfall exceed 2500mm. WM3b climate zone is

characterized by presence of well developed Kandyan home gardens (Punyawardena,

2008). Geomorphologically, the site is part of rolling and hilly landscape of the area.

According to local informants, the site was part of Gohagoda village system with luxuriant

home gardens until some 30 years back. Mahaweli River makes the eastern boundary of

the land while north and south are bounded by marsh lands which were formerly tracts of

paddy lands. The dumping site is an elevated (10m-15m) land area bounded by marshes

and Mahaweli River in three sides. Except for the centrally located dumping site, the rest

of the project area has good vegetation cover representing various habitats types that have

evolved due to long term human habitation and disturbances. Weedy plants and

agricultural crop plants characteristic of Kandyan home gardens are the leading floristic

elements in the area.

3.7.1 Vegetation types identified

Several vegetation types (9) were identified in the project area and their characteristics are

as follows.

3.7.1.1 Grasslands - away from dumpsite

They occur on peripheral lands of the dumping site where tree cover has destroyed due to

various human activities such as grass cutting, grazing by cattle, fire, removal of timber,

firewood gathering etc. Grasslands have a simple vegetation structure; just the closely grown

grassy cover up to 2m in height. Occasionally, isolated and scattered trees (up to 20m) and

shrub (up to 3m) species can be seen.

3.7.1.2 Home gardens – existing

Home gardens are the vegetation found immediately around homesteads which are results of

long term human manipulations. Occurrence of tree dominated multipurpose vegetation

community arranged similar to a natural forest is one of the main characteristic features of

these home gardens. Best developed multi-storey home gardens can be located in the eastern

part of the site close to Mahaweli River. However, the appearance varies in relation to the

individual farmer practice. Generally, there are several plant layers; canopy 20m, sub canopy

10m and shrub/herb layer 2m could be recognized. Continuous canopy allow very little light

to reach the ground. Often the structure is fast changing in time and space due to weeding,

pruning, fencing, digging etc. More exotic and agricultural crop species are found in this

habitat. Also, home garden is an important faunal habitat providing animals with feeding and

nesting sites. It provides people with fruits, nuts, yams, flowers, vegetables, medicines,

firewood, timber etc. throughout the year.

3.7.1.3 Home gardens - abandoned

Abandoned home gardens also have a fairly similar structure as in managed home gardens.

However, plants of the lower layers i.e. herbs and shrubs, are mostly weedy species

growing abundantly with no management.

3.7.1.4 Marshland - abandoned paddy land

Marshlands have resulted from long term abandonment of terraced paddy lands in low

laying areas of the site. Aquatic or semi-aquatic shrubs and herbs are abundant in this

habitat. Ludwigia shrubs growing up to 2m are the dominant plant in many sites.

Generally, the site is characterized by excessive growth of aquatic weeds.

3.7.1.5. Riverine forests

The riverine forest is found along the banks of Mahaweli river streams. The distribution of

this vegetation type is as narrow as 10m. Vegetation height is about 15m-20m with a partly

closed canopy belt of forests. Sub-canopy (10m) and shrubs/herbs (1m-2m) layers can also

be distinguished. Bamboo is a dominant component in this habitat. Natural rivrine species

such as Kumbuk and Mee are lacking in this strip of vegetation due to long term disturbance.

Riverine forests form the inter phase between stream and other terrestrial habitats. It is the

frontline defense against stream bank erosion due to water currents. Thick root system of

trees and shrubs acts as a protective cushion covering the banks. Well developed riverine

forests provide convenient resting sites for birds, bats, reptiles, amphibians etc.

3.7.1.6 Shrublands - Short

Scrublands - short are characterized by one stratum of shrubs (up to 2 m) with many grass

species grown as a thicket. Grazing by cattle, site disturbance and removal of tree vegetation

has lead to the formation of such shrublands. Most shrublands are distributed around the

dump site. They occur as a patch work over the landscape. Vulnerability to fire is more or

less similar to grasslands. Shrublands are good resting places of insects and some other small

mammals.

3.7.1.7 Shrublands – Tall

The tall version of shrubland has shrubs growing up to above 2m and below 5m and has a

very simple structure; two strata could be recognized. Shrubs, mainly Thelendaru (Ricinus

communis) are scattered over the expanse of grasslands. They do not form a continuous

canopy. An important feature of these shrublands is that they are well adapted to disturbed

and unfavorable site conditions including garbage accumulation. The tall shrubs are an

advanced growth stage of short shrubland in absence of grazing pressure and other

mechanical disturbances.

3.7.1.8 Woodlands

Woodlands also have a similar structure as abandoned home gardens, but the flora (trees,

shrubs and herbs) are the result of growing plants with total absence of human care. They

are found especially on embankments near marshlands or the former terraced paddy lands.

3.7.1.9 Dumping site flora

Surviving flora of the sites with newly accumulated solid and liquid waste was considered as

dumping site flora. The important visible feature of the flora is that most of the trees, which

occupied former orchards/home gardens, are at varying stages of dying or showing

unhealthiness due to impact of garbage accumulation at the ground. However, shrubs and

herbs which are invading the garbage heap are well adapted weedy species for such harsh

conditions.

3.7.2. Flora

A total of 165 species belonging to 47 families were recorded from the site and among

them 15 species are noted invasive species (see Annexure …). No endemic or threatened

plant species were encountered.

3.7.3 Abundance of plant species

The leading plant species reference life form and vegetation type are summarized in Table

1. Different vegetation types were dominated by different plant species as given in

Annexure 2.

3.7.4 Fauna in the project area

Faunal richness is the project site is extremely poor (Table 3.11). This area is

experiencing regular disturbance, such as garbage trucks that bring waste materials to the

site and, caterpillars piling- up and compacting garbage for a long period of time. Even in

the marshland bordering the garbage dumping site is very poor in its faunal composition.

from the dump drain into this marshland (formerly a paddy field) may be toxic to many

ground living. Total list of fauna encountered during sampling is given in Annexure ..

Table 3.10: Major plant species in different habitats

Habitat Life

Form

Plant

Species

Local name Abundance

code vegetation type

1 Grasslands - away

from dump site Herb

Panicum

maximum 27.78

Avg.Cover

per unit area

2 Homegardens -

abandoned Tree

Castilla

elastica

Panama

rubber 81.82

Density per

Ha

2 Homegardens -

abandoned Shrub

Neolitsea

cassia Kududawula 520.00

Density per

Ha

2 Homegardens -

abandoned Herb

Rivina

humilis Divibiju 17.56

Avg.Cover

per unit area

3 Homegardens -

existing Tree

Gliricidia

sepium Wetahira 300.00

Density per

Ha

3 Homegardens -

existing Shrub

Gliricidia

sepium Wetahira 986.67

Density per

Ha

3 Homegardens -

existing Herb

Setaria

barbata 23.89

Avg.Cover

per unit area

4

Marshland -

abandoned paddy

land

Shrub Ludwigia

octovalis 3,714.29

Density per

Ha

4

Marshland -

abandoned paddy

land

Herb Panicum

maximum 23.24

Avg.Cover

per unit area

5 Riverine forests Tree Bambusa

vulgaris Kahauna 1,600.00

Density per

Ha

5 Riverine forests Shrub Tithonia

diversifolia 2,400.00

Density per

Ha

5 Riverine forests Herb Panicum

maximum 100.00

Avg.Cover

per unit area

6 Shrublands –

Short Herb

Panicum

maximum 80.00

Avg.Cover

per unit area

7 Shrublands – Tall Shrub Lantana

camara Hinguru 1,040.00

Density per

Ha

7 Shrublands – Tall Herb Acalypha

indica kuppameniya 70.00

Avg.Cover

per unit area

8 Woodlands Tree Castilla

elastica

Panama

rubber 266.67

Density per

Ha

8 Woodlands Shrub Castilla

elastica

Panama

rubber 400.00

Density per

Ha

8 Woodlands Herb Panicum

maximum 47.86

Avg.Cover

per unit area

9 Dumping site

flora Tree

Cocos

nucifera Pol 80.00

Density per

Ha

9 Dumping site

flora Shrub

Ricinus

communis Edaru 1,300.00

Density per

Ha

9 Dumping site

flora Herb

Panicum

repens Etora 32.50

Avg.Cover

per unit area

Table 3.11: Summary of the fauna recorded from the project area

Faunal

Group

Total

recorded

No. in

Home

Gardens

No. in the

Dumping

Site

Number in the

Marshland

No. of

Endemics

Butterflies 25 25 01 04 00

Amphibians 03 03 00 00 01

Reptiles 05 04 00 01 01

Birds 39 33 04 07 03

Mammals 09 05 03 01 00

3.3 Socio-economic Environment

Location of centers of population and settlements

population characteristics

Existing infrastructure facilities

Housing and sanitation

Principal economic activities

Religious and cultural centers

CHAPTER 4

ASSESSMENT OF ANTICIPATED ENVIRONMENTAL IMPACTS

Evaluation Criteria of Impacts

The Leopold Matrix will be prepared after a brainstorming session.

4.1 Constructional Impacts

The following constructional impacts are identified.

a. In the dry period, considerable dust loads are expected during construction. The fine

clay soil in the site makes it difficult for workers and surrounding habitats. The site

becomes very muddy during heavy rains and the dumpsite is not accessible.

b. The present air pollution is the worse condition, since decomposing wastes are

exposed and the particulate and odor nuisance is considerable. The impact will be less

when controlled mining is undertaken. Nevertheless, it is a concerning problem that

needs scientific and technological solutions that are acceptable. It is important to

completely remove the dumpsite, but in the process of achieving this goal, water

pollution will create adverse conditions.

c. There will be considerable amount of heavy machinery and trucks that will ply through

the site and the exit roads. The noise pollution will be considerable.

4.2 Operational impacts

4.2.1 Air

4.2.1.1 Types of emissions

At the beginning LFG is emitted to the atmosphere. The measured CH4 emissions amounts

to 288 g/m2/day and once it is rehabilitated and torched, flue gases will consists of CO2,

H2O, SOx, NOx and PM. However the concentrations will be very low. Table 4.1 gives

approximate concentrations. The power plant will emit NO, SO2, CO and Particulate

Matter in 2.14 g/s, 0.66 g/s, 0.23 g/s and 0.166 g/s, respectively.

Table 4.1: Landfill gas composition

Description Value Units

Total Combustible Gases 60 - 65 %

Methane 55 - 62 %

Total VOC 4 - 7 ppm

Benzene 1.2 -1.5 ppm

Table 4.2 shows the emission levels specified by the supplier.

Table 4.2: Stack emission levels from the proposed power plant

Parameter Unit Value

Flue gas emission m3/h 6000

NO g/s 2.14

SO2 g/s 0.66

CO g/s 0.23

Particulate Matter g/s 0.166

4.2.1.3 Anticipated rate of discharge

The methane emissions based on point source measures with flux chambers of surface

emissions may not be accurate, because uncontrolled LFG emissions occur on sporadic

manner when gas pressure builds up and release within a short time (Ref

Sardinia/Dileepe). The LFG emissions from the dumpsite are estimated at 4090 kg/day

and it may approach extraction values of the LBR. Therefore, 6822 kg/day is a realistic

value. The extractions will reduce methane losses at low pressures maintained in the

dumpsite. It will replace 24000m3/hr of flue gases from the thermal power plant.

a. Impacts of emission on ambient air quality

There are number of impacts on ambient air quality from the dumpsite with or without

operating it. The methane emissions and other odorous landfill gases are the major

concerns, since there will be an escape of LFGs from the capping and embankments. Not

all of the gasses can be captured for providing gas for the WTE power plant. Although, the

effect of LFGs will be reduced, they will be replaced with flue gas emissions from the

power plant.

b. Impact of odour due to processing of waste and excavation of existing waste

In all of the activities, odour emissions are expected. It is a drawback and a concerning

issue. The excavation of old wastes is a technological challenge and a necessity, since the

ambient air quality will be affected even after closure of dumpsite. The developed

filtration system is the solution to reduce odour nuisance.

4.2.2 Wastewater and other liquid effluent

4.2.2.1 Quality and quantity of effluent to be discharged to the environment

It is expected that the estimated and monitored quantity of that will be treated in an

anaerobic reactor, ASP and finally in a Constructed Wetland will meet the required water

quality standards of the CEA. The quantity as given earlier is 30,000 m3/day.

4.2.2.2 Impacts of effluent disposal on ambient water quality of Mahaweli River

The impact will depend on the effectiveness of LTB and the amount of chemicals applied

to precipitate the organic and inorganic components in the ASP and the final heavy metal

uptake in the Constructed Wetland.

a. Cooling water discharge

There will be utmost efforts made to have closed loop systems. However, if the need arise

in the final selection of machinery the discharge water will have a maximum of 60oC at a

flow rate of 120m3/day. If the hot water is discharged directly to the River it will cause

adverse effects and avoidance is recommended.

b. Surface run offs

The surface drains as shown in Figure 3.8 will be separated from the flows. Unfortunately

there could be contamination from the polluted soil as given in Chapter 3. The

accumulated heavy metals will be washed out.

4.2.3 Solid and hazardous waste

4.2.3.1. Accumulation of residue waste and possible impact

Almost all of the residue wastes will be sorted during the mining operation. Any of the

materials that cannot be recycled or converted to RDF will pose environmental and

management issues in the relocated final disposal.

4.2.3.2. Impacts due to disposal of sewage and sludge waste

The gully sucker wastes can be discharged into the ASP, but it may overload and there

will be additional sludge to be disposed in a secure landfill. The odour emissions as well

as difficulties in handling such wastes are the major impacts. However, mixing certain

quantity of sewage with the will improve the ASP performance as reported by

Thilakerathne, 2010.

4.2.3.3. Accumulation of hazardous waste and possible impacts

The most hazardous wastes found in the dumpsite are e-wastes and sharps.

Approximately, 300g of e-wastes per tonne of wastes was found in the old dumpsites.

They were more of electrical appliances, but now electronic wastes dominate. The latest

finding is 2800g per tonne of wastes. Although, mathematically inaccurate, it is possible

then to fit an exponential function to determine the intermediate values, such that a plot of

e-wastes vs time can be plotted as shown in Figure 4.3. The total wastes disposed overtime

can be multiplied by the predicted amounts to deduce the total e-wastes as given in Table

4.4. It should be noted that most of those wastes have hard plastics, including PVC. The

sludge too is hazardous and needs safe disposal.

Table 4.4: Estimated quantity of e-wastes in the dumpsite

Year Disposed

Tonnes

E-wastes

g/tonne Tonnes

1980 200,750 317 64

1990 244,713 656 160

2000 298,304 1355 404

2010 363,631 2800 1018

Total 1,107,398 1647

y = 1E-60e0.0726x

R2 = 1

0

500

1000

1500

2000

2500

3000

1975 1980 1985 1990 1995 2000 2005 2010 2015

Year

E-w

aste

s g

/to

nn

es

Figure 4.3: Hypothetical increases in e-wastes with time

4.2.4 Noise and vibration

Sources of noise and vibration (including machinery, heavy vehicle movemets etc.)

Predicted noise levels and impacts

Manufacture‟s specifications are not given and expert findings are yet to be reported.

4.2.5 Ecological resources

Since the site is botanically inferior in respect to the occurrence of endemic and threatened

plants, no on-site impacts on flora is expected due to project activities. Not a single species

of endemic or threatened plants have survived in this garbage dump and associated human

modified habitats due to unfavourable ecological conditions. In contrary, a large number

of invasive plants species (15 species – see Appendix II) have found competitive

advantage and established successfully. The occurrence of 15 invasive species in this

single site is a matter of concern. In future, the site has to be managed in a way that it

provides no or minimum opportunities for the breeding and spread of invasive plants for

surrounding areas. In fact, the draining of the land is towards the Mahaweli, therefore,

there are good possibilities of spreading invasive plants to other areas using the river as the

agent of dispersal.

4.2.6 Traffic impacts

In order to investigate the possible impact on traffic due to garbage trucks as a result of

this project, few surveys were carried out. The main attention was paid to the Katugastota

town.

To facilitate the study a traffic count was administered targeting traffic flowing in main

roads in Katugastota town including turning movement information for a period of 12

hours. Level Of Service (LOS) on roads at present and for 15 years was calculated based

on a traffic growth of 4% per annum.

In any of the calculations, there was no any significant effect indicated for the LOS due to

garbage collectors passing through Katugastota town.

A detailed analysis will follow with the next report

4.2.7 Human, economic and socio-economic impacts

Number of families to be affected and to be relocated

Impacts on existing economic activities and income sources

Changes in land use and land use pattern

Impacts on access roads and transportation

Impacts on historical sites/religious places

Positive /negative impacts on health

Positive / negative impacts on tourism

Employment opportunities provided

4.2.8 Impacts on visual environment

Positive and or negative impacts

There will certainly be a positive visual impact because the dumpsite is being rehabilitated

and the shanty dwellings removed and relocated. However, there will be negative impacts

when mining the dumpsite and LBRs.

CHAPTER 5

PROPOSED MITIGATORY MEASURES

5.1 Mitigation Measures During Construction

Dust and waste materials cause considerable problems during constructions and it is

preferred then to undertake relocation of housing activities and be completed before the

construction commences, particularly of the power plant. Although the houses on the

…..will be set back, they will be affected when the first landfill bioreactor is constructed.

Therefore, a barrier fence should be constructed between the housing and the proposed

LBR.

Landfill or dumpsite mining is a new concept to attain complete rehabilitation of existing

dumpsites or sustainable landfills. In this instance, the dumpsite is mined under controlled

conditions with shelter and gas purification system to mitigate pollution loads that will

continue to pollute for a long time. Eventually, the dumpsite will be converted to a

sustainable landfill.

The duration of potential LFG extractions will depend on the feasibility of management

without an income from the dumpsite. Therefore, the mining of the dumpsite becomes

both environmentally and economically beneficial, let alone a progress in social

development. In the case of LFR, it will have a complete solution, since aeration can be

done with the pipes, whereas, effective aeration in dumpsites are questionable and yet to

be perfected, refer to section below.

It is recommended to confine all activities between 5 am and 8 pm. However, in ideal

working conditions, which are becoming rear, in consultation with the immediate

neighboring households, night work can be applied for approval from the Grama Niladari

and Environmental Police. Most of the neighboring communities will agree to allow

constructions, since they are also stakeholders of the project, particularly so when they are

employed in the project. It is expected to employ over hundred workers during the

construction.

5.2. Reductions in Operational Impacts

The methane gas and particulate emissions from the dumpsite will be replaced with

polluting flue gases and escape of LFG. However, good practices of maintaining low

pressure at the headers of the gas extraction wells, depending on the radius of influence,

can reduce escape of LFG. The replacement of landfill gas with flue gases as a polluting

agent from thermal power plants can be overcome with advanced flue gas control

technologies that will be incorporated in proposed power plant. The level of pollution is

less in this well equipped filtration system of NOx, SOx and PM control. In fact the

concept developed by the University of Peradeniya to incorporate the dual fuel system will

reduce both atmospheric pollution and filtration requirement. The replaced filters and

hazardous materials will be disposed in a secure landfill or used for road constructions

(ref…..).

There will be a positive impact on the ambient air, when the landfill bioreactors and

thermal plant will function. The reductions in methane emissions as well as reduced

compounds from the dumpsite will drastically improve the air quality. Therefore, the

ambient air quality will improve with the rehabilitation works, but the thermal power plant

will add pollution loads, but it will be dispersed to meet the required ambient air quality

standards.

5.2.1 Atmospheric Pollution

5.2.1.1 Air pollution control and dispersion modeling

As a primary step of mitigating the environmental damage from emissions, due attention

was paid to the selection of a power plant with proper air pollution controlling units. Table

4.2 in Chapter 4 shows the emission levels specified by the supplier.

A thorough air pollution dispersion modeling was carried out in two steps to establish a

suitable stack height for the power plant that would prevent ambient concentrations of

pollutants exceeding the allowable limits.

In the first step of modeling, the worst case scenario was established as follows

1. Even though only a 2.5 MW power plant would be established initially, the

modeling was done for a power plant of 10 MW taking future expansions into

account.

2. Initial Gaussian dispersion modeling was carried out using a spread sheet

calculation procedure to establish the 24 hour maximum concentrations for the

worst case stability, taking ground reflection into account. This method permitted

the use of local metrological and topological data easily to investigate their effect

on the ground level concentrations. Further, it was assumed that the wind direction

would persist throughout the day towards the point which was under consideration

for modeling, even though this would never happen in practice. The stack height

required to reduce the ground level concentrations to permissible levels were

established using this initial round of calculations.

Initial calculations indicated that a stack height of 150 m is needed to ensure that the

ambient levels would not exceed the permissible concentration levels of individual

pollutants. A sample graph obtained through the calculations is shown in Figure 5.1

where the calculated maximum NO2 concentrations are shown. The highest concentration

predicted was of 96.5 g/m3. Maximum permissible concentration levels and calculated

maximum concentration levels are shown in Table 5.1

Table 5.1: Permissible concentration levels and maximum concentrations predicted

Pollutant Permissible Level

(g/m3)

Maximum Concentration

predicted (g/m3)

Carbon Monoxide 58,000 10.5

Particulate Matter 50 7.5

Nitrogen Dioxide 100 96.5

Sulphur Dioxide 80 29.7

Figure 5.1: Calculated maximum 24 h NO2 concentration profile

3. A thorough modeling was then carried out using the dispersion modeling software

Industrial Source Complex (ISC 3). Source strength, stack height, Meteorological

data from Hanthana and Gannoruwa weather stations, and local topological data

were the input for the model. Worst case stability parameters were again selected

to simulate the maximum possible concentration levels. Figure 5.2 shows a section

of a sample graph obtained from the ISC 3 model where NO concentrations are

depicted. The maximum concentration levels predicted through this model were

much lower than the values given in Table 5.1.

Figure 5.2: Concentration profile of NO2 (g/m3) obtained from ISC 3

Similarly concentration profiles of SO2, CO, particulates matter were developed at a stack

height of 150 m and found that the resulting ambient concentration levels would be lower

than the permissible levels. Consequently, following steps are proposed to mitigate the

environmental impacts from the air pollutant emissions

1. Initial verification of supplier specifications and regular maintenance of pollution

control units to ensure emission levels remains close to specified values.

2. Dispersion of pollutants through a properly designed stack. The height of the stack

should be more than 150 m and should have an internal exit diameter of less than

0.4 m to prevent the downwash of pollutants at high wind speeds. Provision must

be made available to increase the height of the stack further, if monitoring results

indicate the violation of regulatory requirements.

5.2.2 Aeration and management in dumpsite

A careful study of the mining procedure is required at every stage of mining it. It is

important to isolate cells for mining, primarily for aerating, thus adequate surface drains

are required. It is proposed to use the vertical wells installed for gas extractions to aerate

the defined isolated cells, which can be termed in the phase of operation as “Aerating

Cell” (AC) and “Mining Cell” (MC). The drained water should not be connected to

surface drains. They should be at all times connected to the drain pipes or pumped to the

nearest pipe network or better still in some points in the dumpsite to pump the directly to

the treatment plant.

The shelter that has been suggested will reduce both impacts; odour nuisance and . The

shelter will prevent moisture entering the isolated AC and working conditions will become

ideal for mining. It may necessitate the use of polyethylene sheets to direct the odour

gasses for treatment in the proposed wet and dry media biofilter. It will still be

experimental in large scale applications. However, it can reduce at least 80 to 90% of

nitrogenous and sulfurous compounds.

5.2.3 treatment

The LTB is a new development stemmed from the composite liner LBR. The results

indicate that it is an advance system of managing highly polluting . In order to ensure

application of known and best practices, an ASP has been incorporated in the treatment

system. The final treatment in the constructed wetland will ensure discharges that will

comply with CEA water quality standards. The harvesting regime of the cattail (Typha

latifolia) is an important management practice to remove heavy metals (Sasikala

S.etal.,2005). There will always be some traces of accumulated heavy metals as given

Chapter 3, which will be washed out with time.

In order to prevent high temperature water discharges from the closed looped system

directly to the River, it will be mixed in the ASP to improve the process and dilute the

effluents, which will eventually be sent to the Constructed Wetlands. The design capacity

of the wetland has been increased to accommodate increased flows. The efficiency of

heavy metal uptake will increase at high growth rates of cattails.

5.2.4 Safe disposal of sewage and sludge waste

As mentioned in chapter 4, mixing sewage with in the ASP is an efficient management

practice. The disposal of sludge is the main concern of such practices. Therefore, the

additional lands that will be given in the new lease agreement will be used to construct

lined pits with the composite liner system and the sludge buried with a good soil cover.

These pits could be dug in the River reservation where the houses would be vacated. It is

suggested to plant trees to uptake the heavy metals and nutrients from these sludge.

Similar pits have been dug and when examined it was found that the root systems have

invaded the pits and thriving well. Also a study is underway to extract phosphate from

sludge.

5.2.5 Management of residue wastes to prevent possible impacts

The point source separation progamme that will be introduced will drastically eliminate

such wastes being deposed in LFB. The MRF will be functional for sorting and separating

new wastes that are hazardous. A temporary landfill will be constructed as marked in the

layout plan for any of the wastes that will be permanently disposed once the dumpsite is

mined and isolated from the LFB. Double liner system will be used in the temporary and

permanent landfills. The dischages from these landfills will be treated in the ASP and

finally in the Constructed Wetland

5.2.6 Management of hazardous wastes

A management system is required to tackle the problems of hazardous waste arising from

rehabilitation of dumpsite. Also, it is essential to ensure a well developed e-waste

management unit within the MRF. The estimated quantities are considerable, amounting

to 1647 tonnes of wastes from the dump and about 1018 tonnes in 2010. The actual e-

wastes may be 20 to 40 % of the total estimated. It is suggested to store these wastes and

then finally dispose them when the mining operation of the dumpsite is completed. The

best possible option is to concrete these materials covered in polyethylene bags.

The long term solution is to recover the materials from e-wastes and it is a lucrative

solution to the present problems of managing them. The technologies are available, but

they are under patents. The immerging trend of „by back‟ option is the ethical way out,

thus promoting the use of less harmful materials. Nevertheless, these solutions are in the

infant stages or in the incubation period to be materialized in the near future.

There are several categories of waste materials that are hazardous, but they can be

assimilated to provide an ecological solution. Like the sludge, it can be safely disposed in

secure landfill pits which can be isolated from surface and subsurface flow. The evasive

measure is based on the concept of constructing composite liner system which prevents

from excessive permeation of heavy metals. The study conducted on adsorption properties

of the soils indicate greater possibilities of harnessing such mechanisms manifested by the

existing soils for beneficial purposes. The use of plants and trees grown on these pits can

take up the nutrients over number of years. The layout of the system is shown in detail in

Figure…….

5.2.7 Impacts on flora and fauna

The use of waste to produce electricity would result in the reduction of waste accumulated

in the area. The restoration of the site will also help to establish the characteristic faunal

and floral components that could be seen in a Kandyan Home Garden system, which is the

typical vegetation in the area, instead of the invasive plants that dominate because of waste

dumping. Therefore, it is recommended that, opening up of lands for development

activities should be done to the bare required minimum. In future, all lands that are not

used for civil constructions or physical infrastructure need to be rehabilitated to maintain a

good forest cover with native trees or plants that have no adverse impacts on flora - on site

as well as away from the site. It is suggested that the project area needs to be surrounded

by a protective vegetation belt that can prevent noise pollution from the power plant other

machinery, most importantly, discourage spread of invasive species and protect the site

from land degradation. The gardeners will be trained to suppress invasive species and

encourage native habitats to thrive for developing a conducive ecosystem for humans,

fauna and flora.

CHAPTER 6

CONTINGENCY PLAN

The breakdowns of the waste handling bulldozers are frequent operating in most MSW

dumpsites and landfills. The wear and tear is very high with the wastes that have corrosive

action and particles having diverse physical and chemical properties. In order to reduce

breakdowns of vehicles and machinery, a more frequent servicing schedule than

recommended should be adhered to ensure low repair and maintenance costs. A standby

dozer, even an old one, perhaps is best to replace the company owned machine. It could

even be a replacement dozer supplied by the Municipality.

The best practices of daily cleaning and maintenance of the track is vital. Ideally, a waste

handler should be used to prevent frequent breakdowns of the track. Such machines are

bulky for the project in Kandy; instead guards can be fixed to the bulldozer track and a

baton just above and across the track to remove entangling waste materials.

There could be number of breakdowns of the MRF. It is very susceptible to jamming

routine systems operations, so that adequate storage facility should be available to buffer

the shortcomings. The MRF should be designed and operated to clear the accumulating

wastes. A large floor area is required to stock the wastes in containers that can be stacked

one over the other. There should be number of parallel activities so that human and other

available resources can be used effectively.

The power plant will have two 5MW generators, each independent in waste loading,

gasification, boiler, steam turbine and generator. Therefore, frequent maintenance can be

done by shutting down one at a time. Both can be shut down as well when power is in

excess. There are times when the power plant can be operational, but there are problems of

substation, distribution lines etc., thus compelling stoppages of electricity generations.

Under such circumstances, the excess gas is stored and utilized directly in secondary

combustion or flared to meet air emission standards.

The system of disposal will not be hampered since LBR can be operational under most

weather conditions. However, there could be occasions when the weather conditions are

adverse for disposing the wastes. Therefore, it is best to have a moveable covered structure

like in…. and even have a conveyor to lift and place the wastes in the required cell, so as

to reduce the number of roads constructed inside the landfill, thus reduce the use of

bulldozer and the need for collection vehicles hauling the wastes inside the LBR. These

suggestions may sound too advanced, but the company‟s objective is to find novel

approaches to reduce costs in the long term. In fact, it will eliminate the use of soil in the

LBR, since the daily cover will be compost materials, derived from mining. Also it will

make the mining activity easier to produce high quality RDF.

In the event of a fire in the LFB, the irrigation system will activate and if the fire persists,

the clay found in the site can be diluted with water to inject the slurry inside the burning

cavities within the waste, inside the LBR. In order to prevent excessive cracking of the top

cover under dry conditions, again the irrigation system play a major role in the application

of required quantity of water to have gas tight conditions.

There is always safety and fire prevention regulations to be adopted in the power plant.

There are number different units within the power plant to prevent and ensure dousing of

local fires within those units. Naturally, all of the different types of fire extinguishers will

be serviced regularly to comply with the CEA, KMC, Harispathuwa PS and the insurance

company fire drills conducted to ensure safety of personnel and protection of power plant

from any dangers.

It is unlikely to have floods, but in the event that there could be an event, the power plant

will be built above the maximum flood level of………Only the Constructed Wetland will

be affected in unlikely occurrence of a flood.

CHAPTER 7

MONITORING PLAN

7.1 Background

The Project Proponent Eco tech Lanka Limited necessitates to conduct a comprehensive

environmental monitoring programme of the different segments of the environment within

the project site and the vicinity of the project site. This is imperative to assess the

performance or success of the implemented mitigation measures. There are three basic

environmental monitoring tasks to assess the success of mitigation and identifying residual

impacts as follows.

i. Pre-construction monitoring to determine the baseline conditions in detail to identify

impacts and mitigation measures and costs to respond to CEA conditions of approval.

ii. Construction compliance monitoring, and

iii. Post construction monitoring of maintenance and operational project activities

including surface water quality, groundwater quality, air quality and noise level baseline

conditions.

It should be noted that during the construction phase both the contractor and the Project

Proponent will take the major responsibility in undertaking the monitoring aspects with

assistance from SWMRU, Department of Agricultural Engineering, University of

Peradeniya. Further, the SWMRU will undertake environmental management issues,

monitoring aspects and implementation of mitigation measures to prevent environmental

pollution. In addition to that, ISWMS Monitoring Committee will be established for the

following purposes;

i. To ensure the ISWMS operation in compliance with the conditions stipulated

by authorities and the ISWMS‟s operation manual and

ii. To keep the transparency of the ISWMS operation.

The proposed ISWMS monitoring committee will comprise of representatives from

various organizations and individuals as described in Table 7.1. The chairperson of the

monitoring committee should be appointed at the first committee meeting. He/she is

responsible for executing the routine monitoring activities that described in section 7.2 and

should take the responsibility of reporting the status of the ISWMS to the relevant parties.

Table 7.1 Members of the proposed ISWMS Monitoring Committee

Organization Nominee

Eco Tech Lanka ltd The Chairman/Technical Director

Manager

Site Engineer(s)

Site Manager

Environmental Executive

Site Supervisor(s)

SWMRU Research Associate

Research Assistant(s)

CEA Environmental Officers

Central Provincial Council Officer (s)

KMC Commissioner

Chief Engineer

Head, solid waste management division

PHI (s) (public health inspectors)

CEB Electrical Engineer (s)

NWS&DB Engineer (s)

Mahaweli Development Authority Engineer (s)

Divisional Secretariat Office

- Harispaththuwa

Grama Niladari- Project area

Samurdhi Niyamaka- Project area

Environmental Officer

Harispaththuwa Pradeshiya Sabha Environmental Officer

Public Health Inspector

Non Government

Organizations (NGO‟s)

Representatives from local NGO‟s

Community representatives

Clergy of the nearest religious organization

Representative(s) from Community Based

Organizations

A representative from a Women‟s organization in

the neighborhood

Representatives(s) from neighboring villages

Representative (s) from resettlers

7.2 ISWM Monitoring Plan

7.2.1 Quantity and Quality testing of incoming solid waste

Table 7.2 presents the monitoring plan quantity and quality testing of incoming solid

waste.

7.2 Quantity and quality testing of incoming solid waste

Monitoring objective In order to avoid unauthorized waste such as clinical and

hazardous waste entering the facility

Parameters to be

monitored

Weight of the all the incoming waste, fast and slow biodegradable

fraction, moisture content, bulk density, temperature, pH and

volatile solids

Monitoring Locations At the weighbridge area

Frequency Daily

Responsible Agency

For monitoring work

For monitoring work: Site supervisors with the

assistance of SWMRU, University of Peradeniya

For Supervision: Eco tech Lanka Limited, ISWMS

monitoring committee

For Communication: Submission of report by monitoring agency

and reporting the same to CEA and ISWMS monitoring

committee by Eco tech Lanka Limited.

7.2.2 Meteorology

In order to monitor the prevailing climatic conditions of the project site a meteorological

station will be installed at the selected location of the project site (see layout plan Figure

..). The meteorology monitoring plan is given in Table 7.3.

Table 7.3 Meteorology monitoring plan

Monitoring

objective To monitor the prevailing climatic conditions of the project site

Parameters to be

monitored

Precipitation, Maximum and Minimum Temperature, Relative

Humidity, Pan evaporation, wind speed and direction

Monitoring

Locations The location given in Figure …..

Frequency Continuously throughout the each day

Responsible

Agency For

monitoring work

For monitoring work: Site supervisors with the

assistance of SWMRU, University of Peradeniya

For Supervision: Eco tech Lanka Limited, ISWMS monitoring

committee, Meteorological Department, (Katugastota or Ganoruwa)

For Communication: Submission of report by monitoring agency

and reporting the same to CEA and ISWMS monitoring committee

by Eco tech Lanka Limited and Meteorological Department

(Katugastota or Ganoruwa)

7.2.3. Hydrology

The hydrology monitoring plan is given in Table 7.4.

Table 7.4: Hydrology monitoring plan

a. Construction Phase

Monitoring objective

To prevent erosion of the fill material and excess erosion of

slopes and waterways with corresponding silting of the

eroded soil into the low lying marshy area and Mahaweli river

Parameters to be

monitored

Water table, Water levels, flow rate of surrounding streams , pH

value, Sulfate content, Iron Content, Heavy metals Sediment level

and Suspended solids

Monitoring Location The location given in Figure …..

Frequency According to climatic conditions of the area and schedule of

construction.

Responsible Agency

For monitoring work

For monitoring work: SWMRU, University of Peradeniya

For Supervision: Eco tech Lanka Limited, ISWMS monitoring

committee

For Communication: Submission of report by monitoring agency

and reporting the same to CEA and ISWMS monitoring

committee by Eco tech Lanka Limited

b. Operational Phase

Monitoring objective

To prevent erosion of the fill material and excess erosion of

slopes and waterways with corresponding silting of the

eroded soil into the low lying marshy area and Mahaweli river

Parameters to be

monitored

Records of rainfall pattern/seasons, Records of flood levels

stability of vegetation cover after construction. Functions of

constant surveillance programs as part of routine maintenance.

Monitoring

Locations

The embankment surrounding the proposed landfill site. Also

the canals and culverts necessary to be constructed, the

existing water bodies

Frequency Before and during rainy seasons

Responsible Agency

For monitoring work

For monitoring work: SWMRU, University of Peradeniya

For Supervision: Eco tech Lanka Limited, ISWMS monitoring

committee

For Communication: Submission of report by monitoring agency

and reporting the same to CEA and ISWMS monitoring committee

by Eco tech Lanka Limited

7.2.4 Surface water quality monitoring plan

Table 7.5 presents the environmental monitoring plan for surface water quality.

Table7.5: Surface Water Monitoring Plan

Monitoring objective

Pre-construction phase:To determine

baseline (existing) conditions on surface water

quality

Construction phase:To avoid contamination

of water by construction and related activities

Operational phase:To ensure existing water

sources will not be spoilt during the

operational phase

Parameters to be monitored

pH, turbidity, electrical conductivity, total and

faecal coliform levels and

chemical parameters such as TS,VS,TSS,VS

TDS, COD, BOD5, DO, oil & grease,

TN, NH4-N, NO2-, NO3-, TP and various

heavy metals such as Pb, Zn, Cd, Cr, Hg

The results should be assessed with reference

to the CEA stipulated standards.

Monitoring Locations

Surrounding streams, upstream, downstream

and effluent discharge point at the Mahaweli

river, wastewater collecting ponds.

Frequency

Once a month (The monitoring frequency

should be varied and in wet season more

frequent sampling should be undertaken)

Responsible Agency

For monitoring work: SWMRU, University

of Peradeniya

For Supervision: Eco tech Lanka Limited,

ISWMS monitoring committee

For Communication: Submission of report

by monitoring agency and reporting the same

to CEA and ISWMS monitoring committee by

Eco tech Lanka Limited

7.2.5 Ground water quality monitoring plan

Table 7.6 presents the environmental monitoring plan for surface water quality.

Table 7.6: Groundwater monitoring plan

Monitoring objective Pre-construction phase:To determine

baseline (existing) conditions on ground water

quality

Construction phase:To avoid contamination

of water by construction and related activities

Operational phase: To avoid groundwater

quality deterioration arising due to

Parameters to be monitored Depth of groundwater, pH, salinity, electrical

conductivity, turbidity, total and faecal

coliform levels and chemical parameters such

as total hardness, total alkalinity, Fe, Cl-

,SO42-, TSS, TDS, COD, BOD5, DO, oil &

grease, TN, NH4-N,

NO2-, NO3-, TP and a variety of heavy metals

such as Pb, Hg, As, Cd, Cr, Cu, Ni and Zn,

etc.

Monitoring Locations Existing wells which are located adjacent to

the project site, bore holes given in Figure …

Frequency Once a month (The monitoring frequency

should be varied and in wet season more

frequent sampling should be undertaken)

Responsible Agency For monitoring work: SWMRU, University

of Peradeniya

For Supervision: Eco tech Lanka Limited,

ISWMS monitoring committee

For Communication: Submission of report

by monitoring agency and reporting the same

to CEA and ISWMS monitoring committee by

Eco tech Lanka Limited

7.2.6 Sediment quality

In addition to water quality monitoring, the soil and sediment quality of the natural marshy

should also be monitored mainly with reference to heavy metals. The sediment quality

monitoring plan is given in Table 7.7.

Monitoring objective Pre-construction phase: To determine baseline

(existing) conditions on sediment quality

in the existing water bodies

Operational phase: To avoid sediment quality

deterioration arising due to unavoidable

circumstances such as malfunctioning of the

wastewater treatment plant and subsequent

bioaccumulation scenarios

Parameters to be monitored Heavy metals such as As, Zn, Hg, Pb, Cd, Cr and Ni.

pH, CEC

Monitoring Locations Existing wells which are located adjacent to

the project site, bore holes given in Figure …

Frequency Once in 3 months

Responsible Agency For monitoring work: SWMRU, University

of Peradeniya

For Supervision: Eco tech Lanka Limited,

ISWMS monitoring committee

For Communication: Submission of report

by monitoring agency and reporting the same

to CEA and ISWMS monitoring committee by

Eco tech Lanka Limited

7.2.6 Monitoring of treatment

It will include all the measurements and parameters given for surface and groundwater,

such that the performance of individual treatment units and the entire system will be

evaluated and reported.

7.2.7 Monitoring of emissions from the power plant

The monitoring systems and plans are still to be finalized by the manufacturers. However,

NOx, SOx, CO and PM will be monitored before and after controlling flue gas quality and

at the point of emissions.

The company will be responsible to provide all the equipment for monitoring the ambient

air quality in the specified locations derived from the effected areas that will be finalized

after the ambient air quality measurements are completed. It will include locations

stipulated by the CEA.