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A cross sectional study was carried out at Kality wastewater stabilization ponds, to evaluate their performance.The plant has two Ponds each containing 1 Faculatative, 1 Maturation and 1 Polishing ponds in series. The collected samples were analyzed based on the standard methods for the examination of water and wastewater. The result showed that the average concentrations of BOD5, COD, TSS and TDS in the influent and final effluent were 290.1, 585.8, 212, 328.3; and 47.5, 131.4, 71.0, 294.7 mg/L respectively. Likewise, the concentrations of NH4+- N, NO3- N, TN, Ortho-P and TP were 30.7, 1.13, 89.8, 11.7 and 14.6 mg/L respectively in the effluent and for the effluent their respective concentrations were found to be 16.2, 0.30, 37.3, 8.4 and 10.2 mg/L. On the other hand, the reduction percentages of TC and FC were 99.40 and 99.76 respectively. Regarding the physico-chemical properties of the sludge, its average pH was 6.58ñ 0.11 and the percentage of TP, TK and NO3--N were 3.66 ñ 0.38 %, 0.70 ñ 0.08% and 0.04ñ 0.01% respectively. It is the author´s bilief that this book is of high value for environmental planners.

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Mengesha Dagne Belachew was borne in Ethiopia, on January 11, 1976. He attended his bachler degree in Jimma University and graduated in Environmental Health Science in 2003. He continued his masters degree in Environmental Science and graduated from Addis Ababa University in 2010. He is now a lecturer in wollo University, Ethiopia.

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