Improving mass balance of municipal solid waste through waste reduction by informal sectors

A study on the mass flow of municipal solid waste in a mediumsize-city was conducted to analyze the potential waste reduction through the informal sector. The city was opted since the local government targets to improve the informal sector’s role to reduce the waste, which is relatively reasonable to implement the informal sector involvement rather than high technology in waste management requiring high investment, which can be challenging for the local government. Waste Bank and scavengers are informal sectors mainly involved in waste reduction in the area of study. Their capacity to reduce domestic waste was evaluated using a mass balance method. The recovery factor of each waste type was also calculated to determine the average reduction rate. The result showed that scavengers and cleaning staff working in temporary waste disposal sites (TWDSs) could reduce the waste collected daily up to 70%, 61%, 48%, 50%, 3% for paper, plastic, glass, metal, and organic waste respectively. Calculation using mass balance showed that 17 TWDS reduce a total of 8% waste per year, while 13 waste banks reduce 2% waste per year. It indicated that waste reduction in the city was only 10%. The reduction rate is far below the target of the government, which is 20% by 2020. Therefore, the study proposes improving the mass balance by increasing the waste treatment capacity in TWDSs and waste banks. By adding the shredder and composting heaps in some TWDSs and the number of active members in waste banks, the waste reduction may increases from 10% to 24%