Study Of Perchlorate Reduction Regulated By Redox Mediators Using Biological Heterotrophy Bacterials

Perchlorate contamination has been recognized as a major environmental issue.Various technologies exist to remove perchlorate from water,but it is important to develop an economic,applicable and effective method.Biological reduction of perchlorate is a well established process for perchlorate removal,and it costs low.So the biological degradation of perchlorate has important research significance.REDOX mediators can accelerate the transfering rate of the electron,and increase the degradation rate.Therefore using REDOX mediators has a theoretical guidance meaning to the the regulating biological reduction of perchlorate,and improves technical support for the biological degradation of perchlorate.The anaerobic digested sludge treating perchlorate was acclimatized in anaerobic reactor.CH3COONa was used as the carbon source.Several parameters affecting perchlorate removal were examined through batch experiments,these include pH?the concentration of carbon source and NO3-.The results suggested that the optimal condition of reducing perchlorate was 30?,pH=8.5,acetate concentrations=2.4 g/L.In addition,REDOX mediators accelerate the electron transfer by continuous self oxidation and reduction.REDOX mediators were introduced in biological degradation process,which can reduce the difficulty of transfer between electron donor and electron acceptor.Screen water-soluble and water-insoluble quinone compounds as REDOX mediators.Five water-soluble quinoid compounds were used to study its accelerating effect on the perchlorate reductiong,which had similar chemical structure.The acceleration effects of five similar water-soluble were compared and AQDS was the best one.Several parameters affecting perchlorate removal were examined through batch experiments with AQDS,these include pH?the concentration of carbon source and NO3-.The acceleration effects of six water-insoluble quinone compounds were compared and 1,5-dichloroanthraquinone was the best one.High concentrations of ClO4-has no restrictions on the ability of degrading perchlorate for bacteria.Low concentration of NO3-can accelerate in biological degradation process,while high concentration of NO3-first inhibit and then accelerate in biological degradation process.Quinone compounds as REDOX mediators can accelerate the degradation of perchlorate,which richs domestic and foreign application of environmental pollutants degradation accelerated by REDOX mediators.Meanwhile this provides a new way of thinking for the biological removal of perchlorate,expand the connotation of biological anaerobic treatment technology and enhance ability of pollution control.