Sewage Treatment by Waste Stabilization Pond Systems

Abstract

Sewage generated in Ghana is commonly discharged into the environment without any form of treatment to reduce the degree of contamination and mitigate potential public health and environmental issues. Although some attempts have been made in some parts of Ghana to utilize the waste stabilization pond (WSP) system to treat domestic sewage, the ponds often fail to achieve their purpose due to lack of basic maintenance and supervision. To assess the utility of the WSP system for treating sewage, wastewater samples were collected from the raw sewage, anaerobic, facultative and maturation ponds of WSPs at Obuasi in Ghana, and analyzed for physicochemical and microbiological contaminants. The results show that the final pond effluent meets recommended microbiological and chemical quality guidelines. The waste stabilization pond system demonstrates high removal efficiencies of wastewater contaminants. The biochemical oxygen demand, total suspended solids, nitrate and faecal coliforms reduction efficiencies of 97.3%, 97.6%, 83.3% and 99.94% respectively are highly significant, and compare well with reported removal efficiencies in the literature. Additionally, the ponds have high reduction efficiencies for heavy metals and pathogenic microorganisms. The wastewater treatment system complies with standard wastewater management practices, and provides a useful method for treating and disposing wastewater in Ghana.