Study Mechanism Of Perchlorate Bio-degradation With Redox Mediators And Characteristics Of Reactor Operation

With the rapid development of national economy,more and more perchlorate was released into the water,and at the same time,perchlorate wastewater discharge standards and pollution treatment effluent water quality standard is also increasing day by day.Therefore,it is imminently to explore an efficient perchlorate reduction technology.Heterotrophic microbial perchlorate reduction technology is low cost,no secondary pollution,but the redution speed is slower and the reduction mechanism is not clear.The topic of this study is using the redox mediator to accelerate the perchlorate reduction by the strain GWF,studying the perchlorate reduction electron transport and perchlorate reduction mechanism.Two different ways were used to domesticate the perchlorate granular sludge by the UASB reactor.The conclusion is as follows:1)the perchlorate reduction rate by intracellular,extracellular and membrane enzyme were 33.7%,63.4% and 65.3% respectively.The optimum time was 32 h.For the intracellular enzyme,only 2,7-AQDS had improved the perchlorate reduction rate.The perchlorate reduction rate was nearly 100%.For the extracellular enzyme,only α-AQS had improved the perchlorate reduction rate.For the membrane enzyme,α-AQS and AQDS had improved the perchlorate reduction rate.2)Five kinds of Redox mediators could accelerate perchlorate reduction by the strain WGF.Nine kinds of different concentrations of α-AQS could accelerate the perchlorate reduction and the optimal concentration was 0.24 mmol/L.The perchlorate reduction rate of the strain GWF was enhanced 1.3-fold using 0.24 mM α-AQS.The accelerating sites ofα-AQS were at NADH dehydrogenase,complex IV,quinone loop and ATPase.α-AQS has an important catalytic role as a carrier and bridge in the perchlorate reduction.3)At the start-up phase,the sludge was flocculent and the perchlorate removal rate was not high.As sludge granular,the physical and chemical properties of the perchlorate granular sludge was stable gradually.The perchlorate reduction rate of the perchlorate granular sludge was heighten subsequently.According to the kinetics model analysis,the modified S-K substrate removal kinetics model could accurately reflect the perchlorate reduction by the perchlorate granular sludge.