RELEASE OF METHANE AND CARBON DIOXIDE GASSES FROM MUNICIPAL SOLID WASTE LAND FILLS IN THE COLOMBO METROPOLITAN REGION.

Abstract

Environmental and social problems caused from improper solid waste disposal are some •of the biggest environmental threats Sri Lanka face at present. Most of the wastegenerated in Sri Lanka ends up directly on open disposal sites on land. These disposalsites are overloaded and uncontrolled. Often the sites selected are marshy areas onlowland. These open dumps have posed serious environmental and social threats. Airpollution from landfill emissions ground water pollution from leachates health problemsdue to breeding disease causing pests and social problems such as decreasing land valuesand aesthetic appeal of an area etc. are some of these problems

Currently about 60 temporary open dumpsites are in operation within the ColomboMetropolitan Region (CMR) alone. All of them can be said to be temporary because theyare small in size, unplanned and unengineered. As in most other low and middle incomecountries Sri Lanka has a high percentage of organic content in their waste due to thishigh percentage of organic waste (80-90) high amounts of Carbon Dioxide and Methaneare released in to the atmosphere from anaerobic degradation under low oxygenconditions prevalent in uncontrolled landfills. Thus in addition to many other social andenvironmental problems, Green bouse gas contribution is another major concern arisingfrom the current waste disposal practices in Sri Lanka. It has been estimated thatthroughout the world about 8% of methane that is released in to the atmosphere comesfrom landfills

It is the intention of this study to estimate theoretically the amount of Green House Gasesthat is Carbon dioxide and Methane that is released into the atmosphere annually fromthe land fills operating in the Colombo Metropolitan Region. Most of the landfills areopen dumpsites. Colombo, Gampaha and Kaluthara districts are located this region and45 local authorities are included. All the relevant data was collected from each localauthority in CMR by using questionnaire, primary interviews, and field observations andpast data. Scholl canyon model was used to estimate Green House Gas emissions fromthe municipal solid waste

As model inputs the amount of waste dumped annually, the age of the land filled gasgeneration potential was used. Gas generational potential was calculated on the basis ofthe composition of waste. It is found that a substantial amount of green house gasesMethane and Carbon Dioxide are released annually from the municipal solid wastedumps operating in the Colombo Metropolitan region