Wastewaters are treated through different processes at municipal wastewater treatment plants. Nevertheless they often contain mutagens especially when the proportion of industrial wastewater in comparison to municipal wastewater is high. Properly designed waste treatment systems can remove or destroy many of the harmful contaminants in industrial wastewaters. Such effluents can then be safely discharged to receiving waters. Monitoring parameters that are used to assess the efficiency of these municipal waste water plants are only physico-chemical such as BOD, COD, pH, TDS and appearance in terms of color. No biological parameters are used to check the efficiency of these plants. From the results obtained in this study, it can be concluded that the treatment procedure carried out at sewage treatment plant, Amer Road is successful in treating the wastewater in terms of physico-chemical parameters but are inefficient in removing genotoxicants. The mutagenic compounds present in the sewage can have a negative effect on aquatic life of natural water bodies, where the treated wastewater is finally discharged.