FINAL DISPOSAL OF SOLID WASTE AND ALTERNATIVE OPTIONS FOR CHITTAGONG, BANGLADESH

Environmental Pollution

ABSTRACT The research highlighted on final disposal and solid waste management (SWM) system in Chittagong for improving its inhabitant’s environmental health and how peoples perceived on solid waste management activities in their areas. Sanitary land filling was cost very low and it did not require any technology. Chittagong City Corporation was practicing a sanitary land filling of waste disposal at ‘Rowfabad’ under Bayezid Bostami (R) Thana, about 3.5 miles away from Chittagong City. The waste generation rate in Chittagong City was 0.30 kg/capita/day (CCC, 2000). Chittagong City Corporation requires an estimated space of 232272.73 cubic-metres (approximately 188 acre-ft) for disposal of solid waste per year. The population growth rate of Chittagong City Corporation was high about 6% (BBS, 1997) and waste production was increasing with the increase of population annually. More vacant space would be required for the improvement of collected solid waste disposal. Increase in collection coverage will aggravate the disposal problem, if the volume of waste is not reduced. As such, waste reduction methods deserve serious consideration in conjunction with sanitary landfill method. Solid waste comprises of organic matter in Chittagong and those wastes contain high moisture and low phosphorous which meant incineration of solid waste in Chittagong City would not be a viable option because 1) large amount of heat will be required to evaporate the moisture content; 2) plastic and papers which mainly add to the calorific value are in low percentage; 3) The waste of Chittagong has lower calorific value since organic part of Chittagong a self sustained combustion reaction cannot be obtained from these wastes. The high percentage of organic matter in the solid waste shows a good possibility of composting for Chittagong City garbage. Moisture content between 50 and 60 percent and carbon-nitrogen ratios between 35 and 50 are optimum for aerobic composting (Peavy et al, 1985, p. 661). The typical moisture content of solid waste of Chittagong was around 45% that was within the acceptable range. The carbon-nitrogen ration of Chittagong solid waste was 23.5% and 0.40% respectively. Soil fertility in many areas of Bangladesh has decreased due to excessive use of chemical fertilizer and lack of use and availability of organic manure (DoE, 1990, p. 68, and The Bangladesh Observer 1994 c, d). As such, the scope, need and importance of recycling of organic waste into organic manure, viewed from agricultural, environmental and sustainable development aspects, highlight the necessity of undertaking composting projects in Chittagong. Presence of high percentage of organic matter in the solid waste of Chittagong made it favorable for bio-gas production. The solid waste of residential and commercial area of Chittagong contained 70%-80% organic matter. Generally, 8 to 12 cubic foot’s gas can be produced by decomposition of 1 found of organic solid waste of which 60% is methane (Pandey et al., 1992, p. 247). Therefore, bio-gas from organic solid waste has good prospect in future to meet the energy requirements of the Chittagong. However, at present bio-gas may be used in areas where natural gas is not available. So, anaerobic digestion for production of bio-gas would obviously help environmental improvement of Chittagong City.

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