Characterization of bio-degradable municipal solid waste (MSW) for WTE technologies for Sri Lanka

Abstract

Currently the mixed municipal waste as well as the source segregated household and commercial waste from eight local authorities is disposed at the Karadiyana waste-processing site. A small fraction of the source-segregated waste is processed as compost. All of the mixed waste is land filled. While the landfill is a managed landfill it does not meet the modem standards for a landfill by any measure. The environmental externalities due to open dumping caused by the site are palpable. The main objective of the present study is 'Selection of the waste to energy (WTE) conversion options based on composition of short-term bio-degradable portion of Municipal Solid Waste (MSW) available at dump sites under Municipal Councils of Sri Lanka'. Data collection survey has been conducted at dump sites in, Kurunegala and Kandy Municipal Councils to find out the condition of Municipal Solid Waste, especially bio-degradable portion, dump data and waste data to propose suitable WTE conversion technology for each dump site. An analysis was conducted using Case Studies on physical and chemical composition of MSW in Sri Lanka and the results are presented in the report. Karadiyana W2E Project was considered as a case study to get real time data. It is observed that the mixed waste collected in shopping (polythene) bags is causing many issues in both sites such as methane formation in bags, odour, leachate, landslides in the dump site. Composting of old dumps at the sites is practiced as a solution for waste reduction. Cleaning and sorting is done manually creating a lot of problems. Gohagoda dump site is well managed separating plastics and polythene for recycling and bio-degradable for composting. Due to natural wind circulating through the dump odour is considerably reduced compared to Sundarapola site. In contrast to this, Sundarapola dump site shows negative operating conditions with insufficient and disorganized waste management practices. The result revealed that the feasibility of the WTE conversion technology, in the form of a community owned power generation plant, bio-gas generating facility or composting facility operated on thermo-chemical and biochemical energy conversion of MSW. But it is an attractive option for Municipal Councik to reduce its long term stagnation of MSW at dump sites. In other words, if Municipal Councils implement this project, it would be an ideal solution where both the Municipal Council and the related community are benefited. Sorting of waste at the source need to be established and collected separately. Waste Management Authority (WMA) needs monitoring all the dump sites in the country and regulates their operation. Waste auditing scheme is recommended for Waste Management Centers (WMC) while awarding 'Star' ratings for best waste sorting practices at the source.