Determination of Effluent Quality of Two Wastewater Treatment Systems: An Activated Sludge Sewage Treatment Plant and Waste Stabilization Ponds at Juapong

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The study was conducted to determine the effluent quality of the two domestic waste water treatment plants; the Volta Star Textile Limited Activated –Sludge Treatment Plant and the State Insurance Company Lowcost Housing Estates Waste Stabilization Ponds at Juapong. Wastewater samples were obtained monthly from the influent and effluent of the two treatment systems. Temperature, pH, conductivity, turbidity, colour, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), nitrate, nitrite, ammonia, phosphate, and counts of total coliform (TC), and Escherichia coli (E. coli) were analysed over a period of six consecutive months. The waste stabilization ponds (WSP) final effluent values obtained for temperature, pH, conductivity, colour, BOD, COD, TDS, nitrate, and phosphate were in compliance with the Ghana Environmental Protection Agency (EPA) guidelines for discharges into natural receiving water bodies. However, quality parameters such as turbidity, TSS, nitrite and ammonia were unacceptable. The treatment performance of the WSP for conductivity was 49.34%, turbidity 68.78%, colour 21.89%, BOD 80.61%, COD 62.32%, TSS 55.31%, TDS 43.36%, nitrate 16.47%, ammonia 93.43%, and phosphate 92.0%. With the exception of ammonia and nitrite which were unacceptable, all the effluent values obtained for the Activated-sludge treatment plant were in good agreement with EPA of Ghana guidelines. The treatment performance of this plant for conductivity was 25.18%, turbidity 86.29%, colour 65.48%, BOD 74.55%, COD 68.04%, TSS 79.07%, TDS 26.59%, ammonia 60.69%, and phosphate 77.27%. The treatment performances of the two plants for nutrients such as nitrite and nitrate were rather poor. Nitrite exhibited negative values which implied an increase in the effluent compared to the influent. Although reduction of Total coliform and Escherichia coli exceeded 95% indicating high performance of the treatment plants, the final effluent discharged did not satisfy the EPA of Ghana permissible values. Most of the effluent quality parameters of the two systems were found to satisfy the standard set by EPA. One way analysis of variance (Anova) ran indicated that statistically, the final effluent of most quality parameters did not differ significantly between the two wastewater treatment plants. The ability of the wastewater treatment plant to effectively deal with some key parameters suggests that the treatment plants are efficient. It is recommended that the final effluent be disinfected before disposal to improve the wastewater quality. All damaged embankments of the waste stabilization ponds be repaired and the times or duration of aeration of wastewater in the activated- sludge plant be increased to improve the effluent quality.
A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the award of the Degree of Master of Science in Environmental Science,