To develop an effective waste management strategy for a given region, it is important to know the amount of waste generated and the composition of the waste stream. Past research has shown that the amount of waste generated is proportional to the population and the average mean living standards or the average income of the people. In addition, other factors may affect the amount and composition of waste. These are climate, living habits, level of education, religious and cultural beliefs, and social and public attitudes. This paper presents the findings of a study carried out in a suburban municipal area in Sri Lanka to determine the solid waste generation rate and waste composition based on field surveys and to determine the related socio-economic factors. A database was developed that included information on the quantity and composition of waste generated in a sample of households in the study area over a time period. The collected data was analysed to relate waste generation and composition data to various socio-economic factors. Over 400 sample households were selected for the study using a stratified random sampling methodology based on municipal wards and property values. A technique that considers both the number of households in a particular income group (property value range) and the standard deviation of property values within a given income group was used to determine the appropriate sample size for each municipal ward. Through category and regression analyses, the quantities of waste and waste composition were related to several socio-economic factors. The paper describes the basis for the sample selection, the methodology adopted for data collection, the socio-economic parameters used for the analysis, and the relationships developed from the analysis.

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The methane oxidizing capacity of landfill cover soils was investigated through column and batch experiments by simulating conditions that are usually encountered in tropical climates. The rate of oxidation was monitored at different temperatures and moisture contents. It was observed that a low moisture content of 6% produced negligible oxidation, whereas oxidation rates were at a maximum at moisture contents between 15 and 20%. Temperature was found to be a dominant parameter which controlled the oxidation rates. The optimum temperature was between 30 and 36°C. In the column tests, the temperature influenced the methane oxidation capacity indirectly by causing the topsoil surface to become totally dry, resulting in almost zero oxidation in spite of aerobic conditions. Although some increase in oxidation rate was observed, a higher concentration of methane could not produce a corresponding increase in oxidation rates, indicating the limiting capacity of the soil to oxidize methane. A depth profile of the gas in the column system indicated that the depth of maximum oxidation was around 15 to 40 cm under normal test conditions. Experimental results indicated that the topsoil, if maintained at an optimum moisture content, could also produce a higher oxidation capacity. The results of this experimental program indicate the possibility of maximum methane oxidation in a tropical climate if the correct moisture content is maintained at the top surface.

Current concern over the potentially negative impacts of climate change has brought attention to anthropogenic sources of methane, a primary greenhouse gas. Two such emission sources are methane leakage at heavy oil wells and sanitary landfills. At both of these sources, substantial quantities of methane could potentially be oxidised by methanotrophic microbes living in soils. Optimisation of this phenomenon may serve as an inexpensive technique for reducing methane emissions. Soil column and batch incubation experiments were performed on a landfill loam, an agricultural loam and a sedge peat to gain a better quantitative understanding of the biological and physical processes limiting CH4 oxidation in soils that undergo the freeze-thaw cycles associated with northern climates. Moisture content emerged as a critical variable that can limit a soil's CH4 oxidation potential. For example, the oxidation rate of the agricultural soil was seen to increase by an order of magnitude after increasing its moisture content from 6% to 10% of its dry weight.