EVALUATING ANOXIC-OXIC REACTOR PERFORMANCE FOR SYNTHETIC TEXTILE WASTEWATER TREATMENT AND ITS EFFLUENT APPLICATION FOR IRRIGATION PURPOSES

Abstract

The aim of the study was to evaluate the anoxic-oxic reactor performance in synthetic textile wastewater treatment and its effluents application for irrigation purposes. The anoxic-oxic reactors were inoculated with 10% microbial consortium and raw simulated textile wastewater was allowed to flow under controlled conditions. When the OLR, dye concentration and HRTs were 0.7 Kg/m3 d, 200 mg/L and 48 h, respectively the system performed maximum removal of 98.83% dye, 97.42 % BOD, 96.30% COD, 77.51% TN and 76.19% TPO4. At the higher OLR (0.7 kg/m3 d) and HRT (48 h) conditions, maximum RR dye removal efficiency of 81.16% was achieved by anoxic than oxic (8.99%) reactor which might be due to the biomass adaptations to use the cleaved dye bonds as an electron acceptor. The lower oxic performance was resulted from the higher DO (average 3.70 mg/L) in the reactor in which the biomass utilizes more organic matter rather the dye molecules. Unlike dye removal, the removal efficiencies of COD and BOD in the oxic reactor are higher (83.16 and 88.54%, respectively) than anoxic (78.10 and 77.46%) since the microbes use the available DO as a final electron acceptor in degrading the organic waste. An attempt was made to isolate and characterize the anoxic-oxic activated sludge and the result revealed that the type and number of biodegrading organisms were higher in anoxic than oxic reactor. In the present study, the effluent was evaluated for their relative toxicity by irrigating commercially edible crops. Both influent and effluent irrigation significantly affected the germination rate of evaluated crop seeds. Furthermore, the effluent irrigation has showed alterations in morphological and biochemical characteristics of experimental crops. Finally, it was depicted that a system was found to be valuable to scale up at pilot level.