57-Performance Study of Common Effluent Treatment Plant at Delhi with Reference to Effluent Toxicity Reduction using Daphnia Magna as Test Organism

Abstract

Toxicity evaluation in Common Effluent Treatment Plant (CETP) is very important to study the likely adverse effects of the treated wastewater on the aquatic ecosystem of receiving waters. Out of the various test organisms for measuring toxicity, Daphnia magna straus has been identified as reference test organism, because of its techno-economic merits. The paper presents the use of Daphnia magna straus for assessing the toxicity reduction in a Common Effluent Treatment Plant in Delhi. It is found that almost total reduction of toxicity, 65% of COD and 82% of suspended solids removal could be attained after tertiary treatment involving dual media filters followed by activated carbon filters. Since toxicity values at the end of each treatment level shows the status of input and output qualities, therefore, it will be possible to find toxicity levels in relatively short period with Daphnia magna straus so that operating and maintenance trouble in primary, secondary and tertiary treatment units can be corrected.