Study On Combined White-rot-fungi-based Process For Dye Wastewater Treatment

Efficient treatment of dye wastewater with white-rot-fungi-based systmes has been reported widely from shake flask experiment to reactor research. However, most studies are limited to treatment of simulated dye wastewater or research of single reactor. This paper investigated the performance of combined biological contact oxidation process that consisted of white rot fungi-combined packing unit, white rot fungi-bagasse unit and activated sludge unit for the treatment of the actual dye wastewater from the eighth dye chemical factory in Shanghai by monitoring dynamic variation of water quality, enzyme activity and biotoxicity in process of dye wastewater treatment. Additionally, the operational mechanisms of the combined process for treating dye wastewater were discussed. This research aimed to provide scientific basis for the optimized manipulation and the actual engineering application of the white-rot-fungi process performance for the treatment of wastewater.Three major operational parameters,i.e., hydraulic retention time, proportion of dye wastewater and culture medium and initial concentration of dye wastewater were optimized at ambient temperature. The results showed that treatment performances of colority, CODCr, BOD5, NH4+ -N and biotoxicity were the best under the conditions of hydraulic remaining time of 24 h, proportion of dye wastewater of 4:1 and initial concentration of dye wastewater. Average removal rates of every water-quality indexes were 99.56%(colority),86.86%(CODCr),88.89%(BOD5),44.98%(NH4+-N) respectively. The average EC50 and reduction times of effluent were 29.30% and 24.39 respectively. Lignin degradative enzyme activities of two white rot fungi reactor were the highest. The average activities of LiP were 22.61 U/L (white rot fungi-combined packing reactor) and 16.75 U/L(white rot fungi-bagasse reactor),respectively. The average activities of MnP were 51.02 U/L(white rot fungi-combined packing reactor) and 28.78 U/L(white rot fungi-bagasse reactor). Activities variation and treatment effects of colority, CODCr, BOD5, NH4+ -N and biotoxicity were significantly correlated in white rot fungi-combined packing reactor.At low temperature, dynamic variation of water quality, enzyme activity and biotoxicity in process of dye wastewater treatment were monitoring and analyzed under the above-mentioned best operational conditions at normal temperature. Compared with the treatment performance at normal temperature, the removal efficiencies of colority, CODCr, BOD5, NH4+ -N and biotoxicity at low temperature were worse. The enzyme activities were lower. The average removal efficiencies of colority, CODCr, BOD5 were 81.88%,56.05% and 60.71% respectively. The average EC50 and reduction times of effluent were 3.67% and 2.98, respectively. The NH4+ -N removal was also very poor. Activities variation range of LiP and MnP were 8.00～30.00U/L and 6.00～30.00 U/L, respectively. Therefore, it was considered that the treating capability of dye wastewater was influence notably by temperature.Theoretical exploration and applied research of the combined technology of white rot fungi widen the research field of dye wastewater treatment with white rot fungi, and make up the disadvantages of the traditional reactor for treating dye wastewater. This work was of important significance to technical maturation, practical application and marketable industrialization of white-rot-fungi-based process.