http://repository.hoarec.org:80/home/handle/123456789/163 2026-05-28T05:17:09Z http://repository.hoarec.org:80/home/handle/123456789/165 Title: ASSESSSMENT OF DOWNSTREAM POLLUTION PROFILE OF HAWASSA CITY MUNICIPAL WASTEWATER AND ITS INFLUENCE ON LAKE HAWASSA Authors: TAREKEGN, TEMESGEN Abstract: Lake Hawassa is used for a variety of purposes like fishing, recreation, swimming, drinking water supply by the communities surrounding it and cultivation of vegetables. However, it is exposed to wastewater discharge from the city and polluting the aquatic ecosystem. The objective of this study was characterization of municipal wastewater of Hawassa city and its impact on the receiving lake water quality. Five sites were selected from Wastewater channel and on the lake. A total of 20 grab samples were collected on two week basis for physio-chemical analysis. Samples were examined using standard procedure over the duration of May 2013 to July 2013. The significant pollution parameters for these effluents include a COD mean concentration ranged from (13.28±2.00mg/l -75.48±3.48), BOD5 concentration of (6.03±1.74 mg/l -26.97±3.56mg/l). Chloride and total hardness concentrations with mean values ranged from (12.44±4.14-18.58±14.88) and (292.75±438.21mg/l- 49.50±14.46) respectively. Ammonia and total nitrogen concentrations were with mean values of ranged (0.52±0.25mg/l -4.39±0.99 mg/l) and (10.00±1.63-32.75±2.75mg/l) respectively. The mean phosphorus, nitrate and nitrite content of the effluent were also found to be 0.34±0.06mg/l -4.20±0.14, 0.41±0.25mg/l 3.77±0.34 and 0.11±0.15mg/l- 0.27±0.17 mg/l respectively. The concentration of nitrite was negligible when the value compared with other parameters investigated. The pH values were 7.36±0.52-8.31±0.28 indicating alkalinity of the wastewater. Total Dissolved solids, electrical conductivity and Total Suspended Solids of the effluent wastewaters were (513.00±45.77-755.25±162.70) mg/l, (865.00±66.73-1287.75±297.23) (μS/cm) and (21.75±23.89 - 276.75±109.76) mg/l, respectively. The investigation of temperature and turbidity ranged from 21.50±2.69 - 23.00 +2.7 OC. and 23.28±21.10NTU -226.00±35.56 NTU respectively. The values of most parameters were significantly different among sites, at 0.05 significant level of post Hoc ANOVA. 2015-03-01T00:00:00Z http://repository.hoarec.org:80/home/handle/123456789/164 Title: Potential of Floriculture Residue For Biogas Production Authors: Asnake, Tamrat Abstract: Production of methane reach biogas through anaerobic digestion of organic material provides versatile carrier of renewable energy, as methane can be used in replacement for fossil fuels. Thus contributing to cutting down the emission of green house gasses and slowing down the climate change. This calls for widening the scope of the technology by tapping organic material like plant waste, industrial waste, and floriculture residues. Floriculture farms produce huge amount of residues and this can be used as feedstock for biogas production. In this study floriculture residue were characterized for their physical properties such as total solid, volatile solid, heavy metal concentration and the biogas potential was assessed in six different treatments with a cow dung The heavy metal concentration in the floriculture residue is below the standard for biogas and it can be used as a feedstock for biogas production. On the batch experiments of eight week digestion, the combination of floriculture residue and cow dung in the ratio 2:1 produced the maximum biogas of 14,127±155 ml in 52 days, followed by floriculture residue and cow dung in the ratio 1:1 11,776 ±164 ml in 51 days, the combination floriculture residue and cow dung in the ratio 3:1 as 8,461 ± 129ml 53 days, and the least with cow dung as 4,428 ± 57 ml in 43 days. The floriculture residue (flower only) produced the least amount of biogas 345 ± 8.36 ml for 19 days. 2008-11-01T00:00:00Z