Microbial decolorization of distillery effluent for its application in wasteland reclamation

Abstract

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.