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Pak. J. Bot., 48(1): 377-385, 2016.

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ALGAL GROWTH AND WASTE STABILIZATION PONDS PERFORMANCE EFFICIENCY IN A SUB-TROPICAL CLIMATE

AAMIR ALAMGIR, MOAZZAM ALI KHAN^* AND S. SHAHID SHAUKAT

Abstract: Both irrigation and potable water are in diminutive supply in most of the developing countries particularly those situated in tropical and subtropical regions where, often untreated wastewater is utilized for the purpose of irrigation. Treated wastewater has proved to be a potential asset serving as an alternate source for the expansion of irrigated agriculture. Waste stabilization ponds (WSP) are considered as less costly and effective substitute for the wastewater water treatment in tropics. The principle of wastewater treatment in waste stabilization pond is based on the symbiotic relationship between bacteria and various algal species. In this study, an attempt was made to relate algal growth and different extrinsic factors using multiple regression models. The predominant algal species found in WSP systems were Chlorella, Euglena, Oscillatoria and Scenedesmus. The growth of individual algal species and overall algal growth was principally governed by temperature, total sunshine hours and Total Kjeldhal Nitrogen (TKN). The study suggested that algal bacterial symbiotic relationship works well and the dissolved oxygen production through algal photosynthesis was optimum to decompose heavy organic load resulting in oxygen-rich effluent (liquid fertilizer) which could be successfully exploited for unrestricted irrigation.

Key words: Waste stabilization ponds, Algae, Wastewater, Effluent, Symbiosis.

Institute of Environmental Studies, University of Karachi, Karachi-75270, Pakistan

*Corresponding author’s e-mail: sherwanis@hotmail.com