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Distillery wastewater refers to the effluent generated during alcohol production and pollution caused by it is one of the most critical environmental issue. Existing methods of effluent treatment use more quantity of water and they are either pollutant specific, less efficient and more expensive than simple discharge without any effluent treatment.
Present work focused on isolating strains of microorganisms from effluent contaminated sites capable of decolorizing the distillery effluent. Characterization of suitable isolates was done. The effect of pH, temperature and effluent concentration on growth of the selected fungal isolates was investigated. Besides, efforts were made to enhance the enzymatic activity of selected fungal isolates by choosing different growth substrates. An attempt was made to reduce the high nitrogen content in the distillery wastewater, which was identified as a deterrent in the growth of fungi at higher concentration of the effluent using a novel hydroponic treatment step before its treatment by immobilized fungi. The real industrial wastewater was treated employing the microbial consortia developed in this study to confirm its efficacy in decolorization of these recalcitrant wastewaters. Finally an attempt was made towards mass production of these isolates for further application in consortium mode in an improvised biological contactor.
A total of twenty-one different fungal strains were obtained from soil and effluent samples. Using morphologic and genetic characterization, the selected isolates were identified as Penicillium pinophilum TERIDB1, Alternaria gaisen TERIDB6, Aspergillus flavus TERIDB9, Fusarium verticillioides TERIDB16, Aspergillus niger TERIDB18 and Aspergillus niger TERIDB20. The optimum temperature ranged from 25 °C to 37 °C and the optimum pH ranged from 4.0 to 10.0. High nitrogen reduction in the effluent was obtained using two plant species, Phragmites kharka and Vetivereia zizanoides. When this hydroponically treated effluent at 50% dilution was subjected to immobilized fungal biomass, decolorization up to 86.33% by Pleurotus florida EM1303 was achieved. Immobilization of the fungi on the solid substrate was found to be effective in enhancing the ligninolytic activity of the fungi. Agriculture residues such as wheat straw and corncob powder were used as a support material. Using scanning electron microscopy, the degradation of wheat straw while fungal growth was observed. Enzymes extracted from solid state fermentation were concentrated using a 10 KDa filter and further used for effluent decolorization. Bench-scale effluent treatment employing the six fungal isolates was attempted in an improvised bioreactor and substantial decolorization and COD removal could be observed even on absolutely undiluted effluent.
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