TOXICITY EVALUATION OF THROUGH FISH BIOASSAY RAW BULK DRUG INDUSTRY WASTEWATER AFTER ELECTROCHEMICAL TREATMENT

Considering the high pollution potential that the synthetic Bulk Drug industry Wastewater (BDW) possesses due to the presence of variety of refractory organics, toxicity evaluation is of prime importance in assessing the efficiency of the applied wastewater treatment system and in establishing the discharge standards. Therefore, in this study the toxic effects of high strength bulk drug industry wastewater before and after electrochemical treatment on common fish Lebistes reticulatus-(peter) were studied under laboratory conditions. Results indicated that wastewater being very strong in terms of color, COD and BOD is found to be very toxic to the studied fish. The LC50 values for raw wastewater and after electrochemical treatment with carbon and aluminium electrodes for 24, 48, 72 and 96 hours ranged between, 2.5-3.6%, 6.8-8.0%, 5.0-5.8% respectively. Carbon electrode showed marginally better removals for toxicity than aluminium electrode. It was evident from the studies that electrochemical treatment reduces toxicity in proportion to the removal efficiency shown by both the electrodes. The reduction in toxicity after treatment indicates the intermediates generated are not toxic than the parent compounds. Furthermore, as the electrochemical treatment did not result in achieving disposal standards it could be used only as a pre-treatment and the wastewater needs further secondary treatment before final disposal.