Egyptian Effluent Standards for Treated Sewage: Evaluation and Recommendations

The characteristics of sewage discharged from four Egyptian villages and four Egyptian cities were determined. The results showed that the sewage of the Egyptian villages is a concentrated wastewater with chemical oxygen demand (COD) as high as 1100 mg/L. Moreover, the experiments indicated that the filtered COD after aerobic biodegradability ranged between 50 and 70 mg/L for the sewage of villages and 40 and 60 mg/L for the sewage of the cities. Therefore, it is difficult to achieve the Egyptian effluent standards (EES) for COD (80 mg/L), especially for the sewage of the villages. Accordingly, the EES of the treated sewage are evaluated. Moreover, applicable recommendations for the EES and recommended treatment systems are presented. For the sewage of Egyptian cities, stringent effluent standards (class 1) should be applied, as compared to that of the rural areas and small communities (classes 2, 3 and 4). The EES is proposed to be in classes and phases to guarantee achieving the required effluent standards in short and long term. The required time for reaching the target effluent standards (in the last phase) should be selected based on the development in Egypt.