Generation, Composition and Characteristics of Municipal Solid Wastes in Some Major Cities of Bangladesh

Abstract

Huge amount of Municipal Solid Waste (MSW) generation and its mismanagement has become one of the major concerned social and environmental issues in urban areas. Characteristics of MSW are important for evaluating infrastructure, technology and equipment needs, management programme and planning, especially with respect to the implementation of disposal as well as resource and energy recovery options, This study identifies the generation rate and total generation amount, composition, physical and chemical characteristics of MSW in four major cities of Bangladesh, namely, Dhaka, Khulna, Raj shahi and Barisal. The MSW generation rates in residential, commercial and institutional areas are determined in each study city. The amount of MSW generations are 5340, 520, 170 and 130 tons/dayfor Dhaka, Khulna, Rajshahi and Barisal city, respectively and the percapita waste generation rates are varied from 0.325 to 0.485 kg/day for four major cities of Bangladesh. Food and vegetable waste is the predominant component in each sampling sources of residential areas due to the habit of food consumption and other inherent socio-economic aspects of the cities of Bangladesh. In MSW stream, food and vegetable waste range from 68.3 to 81.1 %, while papers and plastics range from 7.2 to 10.7% and 3.1 to 4.3%, respectively. The remaining portions are rubber, cloth, metal, tin, glass, dust and others. The important physical characteristics such as pH, moisture content, volatile solid content, bulk density and particle size are determined. It is observed that pH value varies from 7.70 to 8.69, while moisture and volatile solid content vary from 56 to 70% and 43 to 71 %, respectively. The bulk. density in loose state varies from 566 to 621 kg/m3, while in medium and compact state, the bulk density varies from 764 to 951 kg/m3 and 875 to 1127 kg/m3, respectively. The important chemical characteristics are carbon, nitrogen, phosphorous, potassium and calorific value are also determined. The concentration of carbon ranges from 6.53 to 24.93%, while nitrogen, potassium and phosphorous vary from 0.56 to 1.62%, 0.38 to 1.37% and 0.31 to 0.41%, respectively. The highest and lowest calorific values are obtained as 20,467 kJ/kg for rubber and 5,907 kJ/kg for food wastes, respectively. In the context of Bangladesh, MSW are suitable for composting since good concentration of carbon, nitrogen, phosphorous and potassium, while incompatible for incineration due to high moisture and organic contents.