Treatment of domestic sewage at Akuse (Ghana)

Waste stabilisation ponds are used to treat sewage from the Akuse township. Akuse is located in the Eastern Region of Ghana with a population of about 3 000 people. The whole township has been sewered and the domestic sewage is treated in a series of four waste stabilisation ponds consisting of facultative and maturation processes. The flow rates of both raw and final sewage effluents are about 570 m(3)/d. The weak raw sewage has a BOD and faecal coliform count per 100 ml of less than 100 mg/l and 5 900 000 counts per 100 mt respectively. The final effluent is discharged into the Lower Volta River. The ponds achieve ROD reduction of about 65% and the faecal coliform removal efficiency is about 99.99%. The reduction in suspended solids by the ponds is about 46%. The ammonia and phosphate concentrations of the raw effluent are reduced by about 92% and 94% respectively by the ponds. Under Ghanaian tropical conditions the waste stabilisation ponds have been found to be more suitable and appropriate compared to conventional treatment systems, i.e. trickling filters and activated sludge, because of the ease of operation and maintenance and the high level of treatment efficiencies they are able to achieve. The trend now is to adopt waste stabilisation ponds to replace conventional treatment facilities especially in localities where the cost of maintenance and operation of the conventional facilities seem to be excessive.