Solid Waste Landfills as Carbon Sinks for Sequestration of Greenhouse Gases and Curtailment of Climate Change Phenomenon
Authors: Gloom Sheikh , Alyousfi Basel , Aljenaid Sabah Saleh 
Published: June 2022

This paper concentrates on studying, analyzing and assessing the potential effects of Municipal Solid Waste Management (MSWM) on Climate Change (CC). The study was carried out through conducting a Greenhouse Gas )GHG( inventory, and calculating the past and future Methane Gas (CH4) emissions generated from Askar Landfill in Bahrain. The work was based on a methodology established by the U.S. Environmental Protection Agency )USEPA( as well as an approach adopted by the Intergovernmental Panel on Climate Change )IPCC( to determine the amounts of methane gas that can be generated from MSWM; and therefore to estimate, under different scenarios, the net amounts of methane gas sequestered and emitted from the landfill into the atmosphere. Specifically, the research approach, aimed at quantifying GHG emanating from Askar Landfill )whether released from or stored within the site( during the period 2000-2020. Also it aims at investigating the possibility of converting MSW from being a source of GHG emissions with adverse CC impacts to being a carbon sink to claim emissions reduction credits through proper management of such wastes. The amounts of biochemically biodegradable organic matter contained naturally within MSW were estimated throughout the study period, incorporating available data and future forecasts. The volume of methane gas emanating from Askar Landfill had reached 25 million m3 in 2000 of a total mass estimated at 18 thousand tons or 106 thousand tons MTCE )Metric Tons Carbon Equivalent(, of which 10 thousand tons MTCE were detained within the landfill while about 95 thousand tons MTCE emitted into the atmosphere. Such quantities of generated methane gas have increased in the year 2008 to reach about 98 million m3 in volume and 69 thousand tons in mass )i.e., equivalent to 408 thousand tons MTCE(, of which more than 40 thousand tons MTCE were sequestered within the landfill and 370 thousand tons MTCE discharged up to the outer atmosphere. In the Year 2020 )at the end of the landfill’s design-life(, considering population growth and MSW increase in Bahrain, the cumulative amounts of GHG predicted from Askar Landfill in terms of methane gas generation is anticipated to stretch up to 1975 million m3 in volume and 8.3 million tons MTCE, of which 820 thousand tons MTCE is to be seized within the landfill and about 7.5 million tons MTCE is likely emit into the atmosphere, i.e., this is total over the entire 20 years period of landfill operation. From the above, it is clear that MSW sanitary landfills, though considered as significant sources of GHG emissions )particularly methane( contributing to global warming, are at the same time carbon storage vaults of some fractions of GHG resulting from the decomposing MSW mass as well as of the recalcitrant organic portions. The potential of carbon storage and sequestration at MSW landfills can be estimated at about 10 - 15% of the total quantity of biogas generated. As a result, the well- designed and operated landfills form carbon sinks and natural depots for GHG, positively impacting the climate change phenomenon. They can also be utilized to gain )and trade( credits from carbon emissions reduction in order to secure additional financial resources to help funding integrated wastes management systems.