A study has been conducted to evaluate the performance of an aerated oxidation pond system in a village in Egypt. It comprises an anaerobic pond (AP), an aerated facultative pond (AeP) and a maturation pond (MP). The assessment involved an intensive programme of sampling and analysis of raw wastewater, unit process contents and unit process effluents.
Field studies indicated a wide fluctuation in the BOD5 load applied to the STP. It ranged from 64 to 290 g BOD5/m3.d, with an average value of 146 g BOD5/m3.d. This, however, did not affect physico-chemical characteristics of the final effluent. Residual COD, BOD & SS were around 99 mg/l, 32 mg/l & 66 mg/l, respectively. Although faecal coliform removal was around 98.9%, yet residual count was still high. Also, significant decline in both parasitic eggs and protozoal stages has been recorded.