COMBINED TREATMENT OF DOMESTIC AND INDUSTRIAL WASTE-WATER IN WASTE STABILIZATION POND SYSTEMS IN KENYA

Waste stabilisation pond systems have traditionally been used for treating domestic wastewater, although they may also be suitable for treatment of high-strength industrial wastes. The long retention times and high buffering capacity of such systems enables them to cope more rapidly with widely fluctuating organic loads and biologically toxic compounds. Data are presented from two waste stabilisation pond systems in Kenya, both of which treat sewage containing a high proportion of mixed industrial effluent, e.g. tannery and textile wastes. Data from both sites indicated that anaerobic ponds are of primary importance in the treatment of industrial wastewaters. Not only did they significantly reduce the organic carbon content of the wastewaters, but they effectively buffered the sensitive algal populations in the secondary facultative ponds from shock loads of highly toxic chemicals and wastes of widely varying pH. This enabled an overall higher loading to be applied to the aerobic system.