Innovative landfill bioreactor systems for municipal solid waste treatment in East Africa aimed at optimal energy recovery and minimal greenhouse gas emissions

Landfilling is currently the dominant disposal method for municipal solid waste (MSW) in developing countries. Approximately 50% of the MSW generated in East Africa is disposed in landfills. Low costs and availability of land have made landfilling the most common waste management option in East Africa. Two main aspects associated with landfills are the landfill gas potential (LFG) and the greenhouse gas emission. A desk study into the development and application of landfill systems for treating MSW have indicated that the operation of landfills as bioreactors is an interesting and viable option for MSW management. The main objective of the thesis was to develop and describe landfill bioreactor (LFB) basedtreatment systems suitable for MSW in East African cities. MSW collected in these cities is characterized dominantly by a high content of organic material and a high moisture content. It is expected that a more sophisticated and modern form of landfill such as a LFB will become important as a treatment system for MSW in East Africa on the short and middle term. For this purpose, four innovative landfill bioreactor system options which are technically feasible and resource-recovery oriented that match the conditions of East African cities have been developed. These innovative system options of landfills operated as bioreactors were identified, elaborated and evaluated based on literature information regarding the construction and performance of landfill bioreactors in highly industrialized western countries and characteristics of MSW in East Africa, experimental research on pilot plant scale and desk studies regarding biological conversion of the waste, and modeling of the biodegradation rates and biogas production of MSW. The four system options were also evaluated by means of a semi-mathematical calculation model regarding their investment and operation costs, land space requirement, leachate treatment costs and savings, LFG generation and LFG collection and utilization costs and benefits, airspace recovery, greenhouse gas accounting and global warming avoidance.The results with respect to the evaluation were compared with a controlled dumpsite for MSW as currently applied in East Africa. All four modifications of the LFB show great advantages with respect to landfill size, amount of biogas collected and reduction of the emission of greenhouse gases.The innovative system options proposed in this thesis are useful and helpful for decision makers in making the choice of MSW disposal suitable for the East-African cities