Potential and constraints of composting domestic solid waste in developing countries: findings from a pilot study in Dar es Salaam, Tanzania

摘要

The most promising strategies for improving management of solid waste have been identified as minimisation of the amount of the solid wastes generated and maximisation of waste recycling as well as resource recovery. The latter strategy includes composting. A composting research and pilot scale demonstration project was implemented in Dar es Salaam City. It was meant to try out the applicability of composting as one of the strategies for minimising waste and recovering resources from household waste. Among other things, the project set out to quantify compostable waste and establish as well as test-run a pilot scale composting plant. Field operations and pilot scale experimental work were carried out along with pertinent laboratory analyses. The carbon-nitrogen (C/N) ratio of raw organic waste, which accounts for over 78% of all household waste 37-43. The C/N ratio of the final compost was between 6 and 21. Composting achieved a waste volume reduction of 49-70%. Thus the net reduction in volume of all the household waste was 38-55%. Field trials of the compost project improved yields of vegetable crops by more than 35% and extended their production period by more than a month. Also, the temperature developed during the waste composting process was high enough to kill pathogens, making the solid waste safer for soil application and disposal.