Environmental Impacts Associated with Current Waste Disposal Practices in a Municipality in Sri Lanka A Case Study

Transcription

1 Workshop on Sustainable Landfill Management 3 5 December, 2003; Chennai, India, pp Environmental Impacts Associated with Current Waste Disposal Practices in a Municipality in Sri Lanka A Case Study Nilanthi J.G.J. Bandara Department of Forestry & Environmental Sciences University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka Patrick J. Hettiarachchi Department of Civil Engineering The University of Calgary, Calgary, Alberta, Canada. T2N 1N4 ABSTRACT Inappropriate solid waste disposal is a major threat to the environments of developing countries since most of the solid waste generated in developing countries end up directly in open dumps which are uncontrolled and overloaded. Air pollution from landfill emissions, ground water pollution from leachates, health problems due to breeding of disease causing pests and social problems such as decreasing land values and aesthetic appeal of an area etc. are some associated problems. This paper presents a case study conducted in Moratuwa, Sri Lanka, a suburb municipality in Sri Lanka. Municipal officials, over 300 householders belonging to different income groups and landfill operators were interviewed to examine current practices and related environmental problems. Ground water samples from the vicinity were analyzed which show levels of certain chemical parameters well above acceptable limits. Landfill gas emissions and possible green house gas contributions were theoretically calculated using Scholl Canyon Model for gas estimations. The overall environmental impacts associated with current practice of waste disposal in Moratuwa are presented in this paper. 1. INTRODUCTION Sri Lanka, a developing country with a per capita GNP of US $ 700 is an island in the Indian Ocean off the southern coast of India, which has a total land area of 65,610 km 2 hosting a population of million (2002). Disposal of solid waste is a major environmental problem in Sri Lanka at present and has become a national issue. The National Action Plan of Sri Lanka ( ) has identified solid waste disposal to be one of the major causes for environmental degradation. None of the Local Authorities (Las), particularly those in urban areas have a proper disposal system in place. The most common way of municipal solid waste (MSW) disposal in the country is open dumping of waste. The issue of MSW is most acute in the Colombo municipal area and in suburbs. MSW disposal in Sri Lanka is primarily a function of the public sector and in most of the urbanized municipalities MSW management is the largest employer of labor and is a very expensive operation. In Sri Lanka major amount of the MSW management cost is allocated for waste collection and transportation rather than for waste disposal and treatment (ERM, 1997). According to the provisions of the Local Government Act, in Sri Lanka, the Local Authorities (LAs) are responsible for collecting and proper disposal of waste generated by the people within its territory. The necessary provisions are given under the sections 129, 130 and 131 of the Municipal Council Ordinance; 19

2 Sustainable Landfill Management the sections 118, 119 and 120 of the Urban Council Ordinance; and sections 93 and 94 of the Pradeshiya Sabha Act. Generally, the public health department of the local authority is responsible for solid waste management in addition to many other sanitation aspects. In Sri Lanka the required basis for integrated solid waste management is provided by the present policies, strategies and the legal provisions. The National Strategy for Solid Waste Management put forth by the Ministry of Forestry and Environment in Year 2002, endorsing the need for integrated solid waste management provides the overall guidance for the management of the country s vision. The National Environmental Act of 1980 which was subsequently amended in 1988 by Act no. 56 provides the necessary legislative framework for environmental protection in the country. Although the MSW management system in the country is rather unsystematic the required legislative framework for an appropriate waste management system is in place in the country. The current practices of MSW disposal have led to numerous environmental and social problems. The main environmental impacts are the emissions of landfill gas and leachate due to a complex sequence of physical changes associated with biological and chemical reactions in the solid waste placed in a landfill. Unless necessary control mechanisms are not taken these release into the environment causing severe problems. The contribution to the green house gases from the methane released into the atmosphere through anaerobic degradation of waste material in open dumps is significant. It is said that in the global scale about 8% of the green house gases to the atmosphere comes from landfills. In addition to green house gases the other gases released in the process of degradation of waste material, such as H 2 S and organic mercaptants create odor problems. Air pollution is also caused due to the volatile organic compounds released into the atmosphere. Pollutants found in leachate include organic contaminants which are soluble refuse components of decomposition products of biodegradable fractions of municipal solid waste and a variety of heavy metals (Reinhart, 1993 & Brown & Donnelly, 1998). The existing waste disposal practice has threatened many ecologically valuable habitats such as the conservation areas of Attidiya and Muthurajawela wetlands which are used as MSW dumping grounds. In addition to these environmental impacts many social impacts such as loss in property values, traffic congestion and health problems are caused by the present practices. Although, a sanitary landfill had been proposed for the Greater Colombo Area, it had not been implemented due to public opposing the siting of the facility. Alternative waste management techniques such as composting and biogas generation though advocated, and practiced at small scale, are not implemented to the extent desired. Although recycling is practiced to a certain extent through informal means, formalized mechanisms of alternative waste management strategies are not available to desirable extent as in developed countries mainly because of lack of education and opportunity. According to a World Bank study the current urban MSW generation in Sri Lanka is 0.8 kg/capita/day (World Bank, 1999). The same study estimates that by the year 2025 the GNP per capita would go up to 1,300 $US, the urban population to 42.6% of the total resulting in an increase of urban municipal solid waste generation to 1.0 kg/capita/day (World Bank, 1999). Further, the need for land in urban areas is rapidly increasing. A large amount of the Tax Payer s money is spent on disposal of garbage, even though it has not been effectively handled. Hence it is inevitable that the issue of solid waste disposal is only going to get worse in the future unless timely action is taken to adhere to an appropriate waste management strategy. 20

3 Environmental Impacts Associated with Current Waste Disposal Practices This paper discusses findings from a study to assess environmental and social costs associated with MSW disposal in a suburban municipality in Sri Lanka. Moratuwa, a suburban municipality in Sri Lanka, with an area of 21.6 km 2, a population of , households and located 18.5 km from the Colombo city center was selected to conduct the case study as a good representation of a fast growing, densely populated suburb centre in the developing world. The municipality is divided into 16 wards. 2. METHODOLOGY Information on the municipality and present MSW management system was gathered through interviews with municipal officials and community, field observations and literature search. To estimate the total waste generation and the waste composition in the municipality and to assess waste disposal methods and satisfaction with municipal services a household waste generation and composition study was done on 325 households which is about 10% of the number of households in the Moratuwa Municipality. The households were selected, based on stratified random sampling technique. The samples were stratified according to wards first so that all areas of the municipality are represented in the study and then were stratified according to property values which were categorized as low income, lower-middle income, upper-middle income and high income groups to get representation from people of all living standards. The number of samples from each ward was taken proportionately to the number of households in each ward. The waste generated by these households were studied over a period of one week to gauge the average waste generation per day per capita and per household. The householders were requested to separately store their waste as organic waste, which includes bio-degradable kitchen and yard waste, paper, plastic, glass, metal and other. The organic waste was weighed once in two days whereas the rest were weighed at the end of the week. The same households were interviewed as to their waste disposal practices and satisfaction with municipal services. Social impacts and perceived environmental impacts from the waste disposal practices were assessed based on a questionnaire survey conducted on 200 residents randomly selected from close to a landfill which has ceased to operate about a year back and the present landfill in operation. Ground water contamination was estimated through analysis of well water samples taken from wells around the old landfill site. Landfill gas productions were theoretically estimated using the waste generation estimates and Scholl Canyon Model for landfill gas generation. 3. RESULTS AND DISCUSSION 3.1. Household Waste Composition and Waste Generation Rates The average residential per-capita waste generation, average household waste generation and average composition of waste generated taking the total sample population was derived by analysing descriptive statistics and is given in Table 1. 21

4 Sustainable Landfill Management Table 1: Waste Generation From Households In The Moratuwa Municipality Waste Type Household Waste Composition % Mean Generation kg per day Per capita Per household Organic E Paper E E-02 Plastic E E-02 Glass E E-02 Metal E E-02 Total 4.217E From the above results the total household waste generation for the Moratuwa municipality is estimated to be 80 tons per day. The total MSW content disposed from the municipality per day has been estimated by the municipality as approximately 135 tons per day (Ministry of Forest & Environment, 1999). Since the MSW other than that collected from households is mainly market waste and from light commercial establishments the waste composition is not expected to differ much from household waste composition which consists primarily of organic waste Current Practices of MSW Management Solid waste collection and disposal in the municipality is handled by the health division of the municipality. Only household waste, light commercial waste and street sweepings are collected as municipal solid waste (MSW). In the past solid waste disposal had not been considered as a main concern due to availability of freely available degraded land. However, land scarcity is now a main problem faced by the municipality. The collection and disposal of MSW is supervised by a group of Public Health Inspectors (PHI). Overseers are employed to assign duties to a collection crew which includes sweepers and a vehicle crew. The number of staff employed solely for solid waste management includes 350 workers with 14 overseers. Most of the staff employed is on casual basis. Since many of these workers lack the basic educational qualifications for permanency they work for several years on temporary basis and are not dedicated to the work (Pathinather, 1995). The workers are not given a training programme on solid waste management aspects (Pathinather, 1995). This crew is supervised by 1 Chief PHI and 6 PHIs. The financial resources for the solid waste management aspects come from the health vote of the municipality. Solid waste collection is done daily. Working hours for the collection crew is from 6.00 am till 2.00 pm. For the entire municipality 35 push carts and 11 trailers pulled by tractors are used daily (Ministry of Forest Resources & Environment,1999). Usually, trailer-tractors are operated by a driver and 3 workmen. These have a capacity of about 5.66 m 3 (2 cubes) when full (Pathinather, 1995). The main functions of the trailer tractors are to collect the waste heaped on temporary dump sites along the road sides and transport to the final disposal sites. The average trips for the tractor-trailers are 4 trips per day. In large market areas a trailer is parked for market waste and it is transported to the disposal site once full. 22

5 Environmental Impacts Associated with Current Waste Disposal Practices Generally, for each push cart three sweepers are assigned other than along the Galle road, which is the main arterial which runs through the municipality, where four are assigned. Waste along the roads are cleaned by the sweepers operating push carts who clean the roads, collect waste and keep them in small heaps in temporary transfer sites. There are no permanent transfer stations prepared for this purpose but public areas close to bus stands, temples etc. which are accessible by the trailers are used for this purpose. Household waste collection varies from ward to ward. In poor communities with temporary dwellings where accessibility is limited, waste collection is rather neglected. Often these householders dump their waste onto roadsides, neighborhood bare lands or even open drainage canals. In certain other areas push carts are employed to collect the waste whereas households along main roads are served by trailer tractors. The waste collection period also varies. Whereas in some household areas waste is collected every other day in certain other areas waste is collected only about twice a week. However, waste along the Galle Road and market areas are usually collected daily. According to the household survey conducted municipal waste collection is done in 56% of the households only. 20% of the households dump their waste on the road side and 8% dump the waste into pits in their own back yards. In addition very few numbers use alternative waste management techniques. 7% compost their waste whereas 7% give their recyclable waste for recycling. It was also revealed that whereas a higher percentage of households from the high income and upper-middle income groups enjoy municipal waste collection services a lower percentage from the low income groups do so. It was also revealed that a higher percentage of low-income and lower-middle income group households dispose their waste onto roadsides. When asked about the services provided on MSW collection only 0.3% has said it is very good, 3.7% has said it is good, 65% has said it is satisfactory and 30% have said it is poor Waste Disposal In the past till the year 1995 the municipality used to operate several small temporary open dump sites spread throughout the municipal area. From the year 1995 till 2001 waste was dumped at two large dump at Moratuwa which are privately owned low land areas. Since their closure after filling in mid 2002 MSW was again disposed at about seven temporary locations in the municipal area including the airport grounds. These entire dump sites were temporary open dumps with no control measures. Since the February 2003 till now all of the MSW of the Moratuwa municipality is disposed at Karadiyanawatta, which is located in the border of Moratuwa municipality and the neighboring local authority (LA) area, Kesbawa. In addition to the MSW from the Moratuwa municipality the MSW from Kesbawa is also disposed at the site. The Moratuwa municipality pays Rs 14,000/- per day to the land owner for disposing the waste at the site. In addition to the payment the owner gets the advantage of getting the land filled at no additional cost, which is the reason why many land owners let municipalities dispose wastes on their sites. This disposal site is also a temporary un-engineered open dump which is an abandoned paddy field. Since it is bordering the Bolgoda lake it has served as a flood plain. The site extends to about 4 acres and consists of red-yellow podzolic soils with soft and hard laterite, and bog and half bog soils. The vegetation is marsh land vegetation. The site is located at the end of a populated byroad. In the dump site itself there is a temporary dwelling and permanent residences are located from within 50 m of the site. 23

6 Sustainable Landfill Management 3.4. Impacts from MSW Disposal Environmental Impacts Five ground water samples from the vicinity of the former landfill site at Dandeniyawatte were analysed in 2002 just after the site was closed down to gauge the quality of ground water and to assess whether the ground water quality had been affected by the landfill operation. The results show that the water is unacceptably acidic and that in all the samples the COD level far exceed tolerance limit. Of even more significance is the unacceptable levels of Cd present in almost all the samples. The Cd levels range from µg/l in the five samples which far exceed the tolerance limit of 5 µg/l given by the Sri Lanka Standards Institute for potable water. The BOD level is rather low indicating that the well water at that time has not been contaminated with fresh leachate. The high COD values may be explained by the leachate maturing process. The Cd content can be only explained by presence of hazardous industrial waste in the open dump in addition to MSW. From the survey of those living near landfill sites it was revealed that 67.7% of the surveyed households use well water out of which 86% use it for drinking and cooking purposes, 98% for bathing and washing of clothes and vehicles and 99% use it for gardening purposes. However, the % of households using well water is significantly low (only 7%) in residences very close to the landfill (< 100m). The % using well water increases with the distance to the landfill. It is an indication that although wells are present in households close to landfill areas residents are reluctant to use them. However, since most of the householders use well water in the area ground water pollution is a serious concern. Using the results of the waste generation study on the Scholl Canyon Model it is estimated that the annual landfill gas generation during the first year of operation from the household waste alone is 72,276.7 m 3 while from the total MSW in the open dump the amount of landfill gas generation is 122,823 m 3. The gas generation will increase with time with the cumulative gas production in the second year of operation been 216,906 m for household waste alone and 368,598 m for total waste. For the estimation the ultimate methane generation potential for the waste was taken as 251 m 3 / tonne and the gas generation rate constant was taken as 0.01 yr Social Impacts The respondents were asked to list down up to seven problems associated with present day practices of waste disposal as perceived by them. A weightage was then assigned to each response based on the order of priority. Thus adjusted, the main problems identified in order of priority are: 1. Unpleasant odor when garbage is transported. 2. Breeding of mosquito and flies due to landfill site and garbage on either side of the main road fallen from the garbage trucks 3. Loss in property value 4. Unpleasant odor due to landfill site 5. Traffic congestion due to garbage trucks and tractors 6. Falling of garbage bags from garbage trucks on either side of the main road 7. Arising of dust when garbage vehicles are going. 8. Deterioration of road conditions. 9. Increase in floods during the rainy season. 24

7 Environmental Impacts Associated with Current Waste Disposal Practices 10. Release of smoke and poisonous gases giving rise to safety problems. 11. Children affected by various diseases such as skin diseases in the area 12. Breeding ground for worms and insects These responses can be categorized into three subgroups. The first 4 impacts identified are direct impacts felt by the community arising from garbage. The second 4 impacts are problems related to the transport of garbage. The next 4 problems are those considered as less important or indirect. In addition to these identified problems the survey also revealed that the residents close to the landfill site had suffered significantly more from typhoid and diarrhea than those living further away from the site which may be due to ground water contamination with leachate. In addition, a traffic composition study along the road to the site has revealed that with the landfill there is a significant increase in heavy vehicles due to vehicles transporting MSW. This in turn has caused severe road degradation since the roads in the area are not designed for heavy vehicle transport. As identified by the residents traffic delays have increased due to obstructions caused by heavy vehicles since the roads are very narrow. 4. CONCLUSIONS The above study has very clearly shown that present day waste disposal practices in the municipality has caused severe environmental and social problems. Although fair allocation from resources of the municipality is utilized for the MSW management process the efficiency of its use and distribution is questionable. The emphasis placed on waste disposal as opposed to collection is minimal. The main environmental problems identified in the study are the release of landfill gas and leachate. The significant amount of landfill gas which is generated from the site is released without any constraint to the atmosphere contributing to global warming. Leaching of pollutants into ground water has also been found to be a significant concern due to the high use of ground water for residential purposes and due to the possible illegal disposal of industrial waste along with MSW. From the public perception as worst impacts of present solid waste disposal practices are seen direct social impacts such as odor, breeding of pests and loss in property values. Transport of the collected waste also appears to cause significant impacts due to increased traffic flows and causing odor while transporting the waste. While combating impacts such as pollution from leachate and gas emissions require heavy capital investments some of the other problems can be easily avoided without much of a financial burden. Covering of waste material while being transported, application of a daily cover on the landfilled waste and careful planning of transportation of collected waste are some of these measures which can be considered by the municipality. The continuous practice of haphazard waste disposal which in the short term may appear to give an effortless solution is the main reason for these impacts. In addition to municipal lapses lack of law enforcement is also a culprit for these continuous practices. Responsible agencies such as the CEA should ensure that the laws and regulations are adhered to. Although an overnight change and improvement in the present day waste management practices cannot be expected without more financial commitments the present situation can be improved upon provided there is adequate understanding of the problem and willingness to do so. 25

8 Sustainable Landfill Management REFERENCES 1. Brown, K.W. & Donnelly, K.C. (1998), An estimation of the risk associated with the organic constituents of hazardous and municipal waste landfill leachates, Journal of Hazardous Waste and Hazardous Materials 5(1), ERM (Environmental Resources Management) (1997), Environmental Impact Assessment for a proposed Sanitary Landfill, Alupotaha Division, Salawa Estate. 3. Ministry of Forest Resources & Environment (1999), Data Base on solid waste disposed by Local Authorities in Sri Lanka. Ministry of Forest Resources & Environment, Sri Lanka. 4. Pathinather, S. (1995), Situation Report on Municipal Solid Waste Moratuwa Area. Prepared for Emace Foundation of Sri Lanka, Moratuwa, Sri Lanka. August Reinhart, D.R. (1993), A review of recent studies on the sources of hazardous compounds emitted from solid waste landfills: a U.S. experience. Waste Management Research, vol11, pp World Bank (1999) What a waste: Solid waste management in Asia. Urban Development Sector Unit, East Asia and Pacific Unit, world Bank, Washington, D.C. U 26