Diurnal and Seasonal Variations in Carbon Dioxide Emissions in a Solid Waste Management Facility, Akure, Nigeria

O.O Elemile, M.K.C Sridhar, A.O Coker

Municipal solid waste (MSW) is a significant contributor to greenhouse gas emissions through decomposition and waste life-cycle processes. The available literature is scanty on fluctuations of carbon dioxide (CO2) emissions from MSW facilities especially in tropical developing countries like Nigeria. This study monitored seasonal variations in the CO2 levels emitted at an open dump in the solid wastes management facility, Akure. For a year, wastes brought to the MSW facility from three major sources, viz: markets, residences and other non-specific sources dumped on roadside were assessed for their physical composition and the amount of waste generated. Air CO2 levels were monitored at seven critical locations Laboratory (L), Organic Fertilizer (OF), Plastic Recycling (PR), Overhead Tank (OT), Sorting Area (SA), Gatehouse (GH) and Outside(O) every day for a week at 9.00am, 12.00 noon and 2.00pm , during the dry and rainy seasons using a P-Sense Plus CO2 meter AZ-7755 (USA) and computed. Results indicate that the total wastes generated (paper) from all the sources were 5,834,005.0+ 5,079633.8 (wet season) and 4,266,871.0+3,745,337.8 kg (dry season), respectively. There were no significant differences in the carbon dioxide levels in the morning: 506.9 + 71.1 and 537.0 + 91.8 ppm; 450.6 + 28.4 and 456.0 + 10.8 ppm; 442.6+ 19.4 and 448.0 + 10.4ppm for the L, SA and GH; in the noon: 415.0 + 15.9 and 458.5 + 44.1ppm; 427.3 + 20.5 and 443.5 + 10.4 ppm and 425.6 + 14.3 and 438.0 + 0.12 ppm for PR, OT and GH and the afternoon: 434.3 + 45.3 and 438.0 + 7.2 ppm for GH only in the wet and dry seasons respectively. The atmospheric CO2 data in the study area showed clear seasonal and diurnal variations as evident in values of 438.00 to 630.0 ppm in the dry season and 407.3 and 506.9 ppm for wet season. These values were above the regulatory limit of 400.00 ppm specified by the National guideline values. The study suggested periodic monitoring of air carbon dioxide levels keeping in mind the seasonal variations.