Physicochemical characterization of municipal solid waste in Sawla town, Gofa Zone, Ethiopia

Abstract

To design and develop integrated waste management systems, it is necessary to have information about the physical and chemical characteristics of the household's municipal solid waste (MSW). The study aims to characterize the physicochemical composition of MSW in Sawla town, Ethiopia using structured questionnaire and field observation to obtain data on the socio-economic condition and current MSW management practices of the residents. The data showed that, the town has no sanitary landfill. The per capita daily SW generation for HH range 0.21- 1.02 kg/capita/day with mean value of 0.51 kg/capita/day. Regarding its chemical characteristics, the HHMSW was composed of main food and organic waste (34.81%) and ash- dust (49.45%). The remaining 6.08% of plastic, 3.87% glass, 3.51% of paper and 2.28% of metal waste. The mean percentage moisture content, volatile matter content, ash content and fixed carbon content of the MSW were 25.57%, 28.09%, 32.03%, and 14.32% respectively. The mean density, pH and fusing point of ash for the MSW were 613.22 kg/m³, 10.657 and 965 °C respectively. Using AAS, the concentration of heavy metals Cu, Pb, Zn, Co, Cd, and Cr were determined and the result was 2.59, 7.12, 293.39 and 0.125 mg/kg for Cu, Pb, Zn, and Co respectively. The concentration of Cd and Cr was not detected. In conclusion, the best ways to tackle the problems related to MSWM practices of residents are: improving the institutional structure and budget allocation of the SBD, the involvement of stakeholders in SWM practices, implementation of sustainable SWM practices through awareness creation and training and implementation of rules and regulations. The result of this study suggests that biodegradable SW constituted a lion share of the SW generated in the town. Thus, the municipality can recover this organic fraction by introducing integrated urban agriculture that might convert this waste to organic fertilizer through composting.

Keywords: Solid waste, waste characterization, proximate analysis, heavy metal