| Summary: | Wastewater treatment facilities have been identified as potential source of surface water pollution worldwide. In this study, the physicochemical qualities and heavy metal (including Zinc, Cadmium, Iron, Lead and Copper) concentrations in the final effluents, as well as the reduction efficiencies of three municipal wastewater plants in the Eastern Cape, South Africa were evaluated from September 2015 to February 2016 using standard methods. Wastewater effluent and sludge samples were collected from the selected plants on monthly basis over a period of six months from September 2015 to February 2016. Standard analytical method (Atomic absorption spectroscopy [AAS]) was used to assess the concentration levels of heavy metals. The physicochemical parameters assessed include pH, Temperature, Total Dissolved Solid, Turbidity, Biochemical Oxygen Demand, Chemical Oxygen Demand, Alkalinity, Dissolved Oxygen, Free chlorine, Chloride, Sulphate, Phosphate, Ammonium and Electrical Conductivity. The results of the evaluation showed that temperature ranges from 19 to 36 °C, Electrical Conductivity from 60-1095 mS/m, Alkalinity from 2.6-20.9 mg/L, Nitrate from 0.24-26.5 mg/L, Nitrite from 0.01-90 mg/L, Phosphate from 0.02-5.12 mg/L, Ammonium from 0.06-112 mg/L, Sulphate from 3-72 mg/L, Chloride from 3.25-224 mg/L, Chemical Oxygen Demand from 17-394 mg/L and Turbidity from 1.96-715 NTU. Free chlorine concentrations and dissolved oxygen were within the recommended limits for most part of the sampling period and ranged between 0.17-0.48 mg/L and 0.19-21.9 mg/L respectively. The pH, Phosphate, Sulphate and Free chlorine were within acceptable limits while Electrical Conductivity, Temperature, Total Dissolved Solid, Turbidity, Chemical Oxygen Demand, Chloride, Ammonium, Nitrate and Nitrite were not within specified limits. The reduction efficiencies observed generally ranged between 43.9 and 100 percent at all sampling points while zinc and lead were not detected throughout the sampling period. Cadmium showed low reduction rate ranging from 0 to 11.7 percent, while the rate of Copper reduction ranged from 0 to25 percent in January and February 2016. Zinc, lead and cadmium were generally not detected in the sludge samples except in January and February which could be due to the prevailing atmospheric conditions during the sampling period. Cu and Fe were detected through the sampling months of the study. We conclude that these municipal sewage plants are sources of pollution to their receiving watersheds and threats to public and environmental health.
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