Compliance of the effluents from wastewater treatment plants (WWTPs) to the regulatory standards, which mostly entail the removal/reduction of organic waste and deactivation of the potential microbial pathogens is of great importance. The detection of indicator parameters can be used to determine the effectiveness of a WWTP and the level of compliance with the South African regulatory standards. The performance of the WWTP was assessed by biological, physical and chemical measures in wastewater final effluent. The Escherichia coli ranged from 0 and 2420 count/100 mL in the final effluent. The recorded values for the physicochemical parameters were within the following ranges: pH (7.03-8.49), electrical conductivity (81.63-126.5 mS/m), suspended solids (0.40-20.4 mg/L), ammonia (0-22.15 mg/L), Chemical Oxygen Demand (COD) (1-73 mg/L), nitrate (0-16.1 mg/L), ortho-phosphate (0-8.58 mg/L) and free chlorine (0-3.21 mg/L). Furthermore, the concentration of toxic heavy metals was recorded to be between 1-10 ug/L for arsenic, cadmium, lead and mercury. In conclusion, all the parameters that were evaluated in this study indicate that the studied WWTP is performing in accordance with the prescribed general limits.
Keywords: E. coli; effluent; general limits; green drop; heavy metals; influent; physicochemical; special limits; wastewater.