Microbial quality of compost of municipal solid waste

Abstract

Dhaka is one of the fastest growing mega cities of the world. Generation of large volume of solid waste in urban areas is creating environmental problem in Dhaka city. Dhaka City Corporation (DCC), responsible for management of solid waste of Dhaka, is inefficient and its services are unsatisfactory. Presently, improper dumping of huge amount of urban solid waste causes serious environmental and health hazards. This research is aimed at investigating the generation pattern and characteristic of domestic solid waste and microbial quality of the compost samples collected from the Box-composting pilot plant located at Green Road Staff Quarter and Barrel type composting system in Mirpur slum. The assessment was carried out on microbiological and physico-chemical characteristic of compost at different stages of maturation. The research finding indicates that daily solid waste generation rate per households in Green Road area is higher (about 2.68 kglhousehold ) than solid waste generated from slum household (0.59 kg/household). The physical composition of domestic solid waste reveals that organic part (i.e., food waste) generation is higher for slum people in Mirpur (93%) than that of Green Road dwellers (80%). Laboratory analysis reveals that highest number of total coliform 6.Ox102cfulg is found in raw solid waste sample and their population decreases during maturity process. The number of "faecal streptococci shows a -district decrease from 2.Ox102cfulg to nil during the thermophilic phase (60 to 65°C). Experimental results also indicate that highest Faecal Coliform count in the raw solid waste sample and nil in the finished compost samples. The physico-chemical parameters such as temperature, moisture content, pH, C/N ratio during composting are found similar for both composting systems. Field survey also reveals that there is renewed public interest in composting for safe and easy disposal of waste and attainment of favorable economics by selling the produced compost. Therefore, composting of solid waste brings in environmental and financial benefits and offset the costs of collection and processing and management of solid waste.