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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2269

Authors: Malefia, Tadele
Advisors: Hammed Suliman /PhD/AAU/
Mekuria Argaw /PhD/AAU/
Keywords: Lake Ziway,
Floriculture industries,
water quality,
Farm effluent,
Water quality guidelines
waste water management
Copyright: Jun-2009
Date Added: 3-May-2012
Abstract: ABSTRACT Lake Ziway is one of the rift valley fresh water lakes. The Lake have long been used as source of town’s water supply, small scale irrigation, bathing, animal watering, domestic water use, fishery and eco-tourism .There is a lot of deliberation about floriculture industries located at the shore discharging untreated effluent directly in to the lake; as a result excessive fertilizer and pesticide residue from the farm is deteriorating the water quality as well as the aquatic life. Therefore, this study was proposed with the objective of assessing the impact of floriculture industries on the water quality. In order to do this, five sites were chosen on the lake near the outlet of flower farms. The first site which was used as a control was located in the upstream area before the effluent joins the lake water and the other four sites were at the downstream. A total of 60 samples were tested for physicochemical, oxygen demanding, nutrient and micronutrient parameters. The results were analyzed using SAS software to see if there were significant differences between the control and impaired sites. In addition, the results were also compared with water quality guidelines to check if the concentrations of these parameters were within the permissible limits.EC,TDS,DO,BOD,COD,NO3 -,PO43- ,Na,Ca,Mg,k,Fe and Zn showed significant difference (P<0.05) between the control and impaired sites; whereas Cu and Cr were below detection level. The result indicated higher levels of TDS (272±9.38 to 574.5±176.5), EC (0.4164±0.044 to 1.358±6.38), PH (9.05±0.188 to 7.98±0.34), COD (92.75±3.38 to 126.8±5.79) BOD (16.8±1.11 to 22.9±7.42) NO3- (1.68±2.524 to 50.8±18.43) andPO43-(0.5142±0.41 to 6.8±2.8) at the impaired sites where the effluent was directly discharged without treatment. However, the concentrations of physicochemical and micronutrient parameters were relatively low in sampling sites where the effluent is treated by the farm to reduce the environmental impact before released in to the lake. The levels of PH, EC, TDS, NO3-, PO43-, Na, Mg, K, Ca, BOD, COD & DO were beyond WHO, FAO and US-EPA water quality guideline values for use as a raw public water supply, irrigation, maintenance of fisheries and aquatic life respectively. In general, the water quality of Lake Ziway has been threatened and becoming less suitable for the variety of purposes being used. Actions should be taken before the once precious fresh water Lake turn out to be seriously polluted. Environmental audit and waste water management could be possible solutions to minimize the direct discharge of fertilizer rich effluents in to the lake.
URI: http://hdl.handle.net/123456789/2269
Appears in:Thesis - Environmental Sciences

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