Abstract:
Solid waste, which is a consequence of day-to-day activity of human kind, needs to be managed
properly. Jimma, like other towns in the country, faces problems associated with poorly
managed solid waste operation. This poor solid waste management and urban growth are posing
a threat on sustainable development, which results in human health problem and environmental
pollution. This study deals with evaluating the quantity, composition, energy potential and
nutrient value. A cross-sectional study design was used to assess the composition as well as the
physical and chemical properties of the residential solid waste. The daily solid waste generation
and composition of household solid wastes were determined following standard protocols.
Estimates of the energy content were made results using bomb calorimeter and models
developed on physical composition and proximate analysis. Physical characterization showed
that food, yard, textile, leather, rubber, wood, yard, metal, plastic and paper waste were
the constituents of all collected waste samples in the study area, but in varying proportions.
Proximate analysis showed household solid waste characteristics as: moisture, volatile matter,
fixed carbon, and ash content, being 49.38, 41.21, 6.10, and 3.31%, respectively. The total solid
waste generated daily from Jimma town household was estimated to be 77,364.46 kg, and the
average per capita generation rate was 0.50 ± 0.08 kg/capita/day. The energy content of
household solid waste was estimated to be 17.50 MJ/kg for gross heating value (HHV), and
9.54 MJ/kg for net heating value (LHV). Such difference between HHV and LHV is due to high
portion of water content of solid waste. Results from selected models showed higher heating
values, but still equivalent with the experimental value of 17.5 MJ/kg and fit the minimum level
of 7 MJ/Kg net heating value required for incineration projects. Further analysis showed that
biodegradable organic waste constituted 62.75% by weight with an average moisture content of
49.38% and good nutrient contents suggest the applicability of household solid waste stream for
implementing composting operations. In conclusion we suggest that the residential solid waste
can be used as a valuable resource for recycling in the form of organic fertilizer and energy
recovery. As such, an economic benefit can be obtained from this waste while avoiding the cost
of treatments and disposal. Further study is required with detail analysis of solid waste to
optimize its use for both nutrient and energy recovery