Wastewater Stabilisation Ponds: Removal of Emerging Contaminants
Wastewater stabilisation ponds are the simplest, and most economical and maintainable way of municipal wastewater treatment. The fate of selected emerging contaminants using algal monocultures has been studied. However, in an actual wastewater treatment plant, it is likely to be different. Accordingly, a need was felt to take up this study. A waste stabilisation pond based wastewater treatment plant having five ponds in an area of approximately 14 hectares and working for 30 years was selected. High removal (>75 %) was observed in the case of paracetamol and carbaryl. Moderate removal efficiencies (50-75 %) were found for malathion, erythromycin, clofibric acid and 17beta-estradiol while low (< 50%) removal efficiencies were witnessed in the case of aldrin, endosulfan, dichlorodiphenyltrichloroethane, hexachlorocyclohexane and diclofenac. Results show that most of the removal takes place in initial ponds, with higher efficiencies in summer and lower in winter. Results suggest that waste stabilisation pond based wastewater treatment plant is capable of removing emerging contaminants to some extent.