Attached
Environmental and social problems caused from improper solid waste
disposal are some of the biggest environmental threats Sri Lanka faces at present.
Most of the waste generated in Sri Lanka ends up directly in open disposal sites on
land. These disposal sites are overloaded and uncontrolled. Often the sites selected are
marshy areas on lowland. These open dumps have posed serious environmental and
social threats. 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
of these problems. Currently about 60 temporary open dumpsites are in operation
within the Colombo Metropolitan Region (CMR) alone. All of them can be said to be
temporary because they are small in size, unplanned and unengineered. As in most
other low and middle income countries Sri Lanka has a high percentage of organic
content in their waste. Due to this high percentage of organic waste (80-90) high
amounts of Carbon dioxide and Methane are released in to the atmosphere from
anaerobic degradation under low oxygen conditions prevalent in uncontrolled
landfills. Thus in addition to many other social and environmental problems, Green
house gas contribution is another major concern arising from the current waste
disposal practices in Sri Lanka. It has been estimated that through out the world about
8% of methane that is released in to the atmosphere comes from landfills.
This study intends to estimate the amount of greenhouse gases that is Carbon dioxide
and Methane that is released into the atmosphere annually from the landfills under
study operating in the Colombo Metropolitan Region. Most of the landfills are open
dumpsites. Colombo, Gampaha and Kaluthara districts are located in the CMR in
which 45 local authorities are included. All the relevant data was collected from each
local authority in CMR by using questionnaires, primary interviews, field
observations and past data. Scholl Canyon gas generation model was used to estimate
greenhouse gas emissions from the municipal solid waste degradation in the dumps in
the CMR.
As model inputs the amount of waste dumped annually, the age of the waste and the
gas generation potential of the waste was used. Gas generation potential was
calculated on the basis of the composition 'of waste. It was found that methane gas
emission is 1507.681 x 10
3
m
3
and CO2 gas emission is 9474.516 x 103
m
3
in CMR in
the year 2003.
