The Study On Treatment Of Coking Wastewater By Microbial Fuel Cell

In the process of coke oven gas primary cooling and coking production,a large amount of coking wastewater will be produced.The removal of coking wastewater is desired,not only for aesthetic reasons,but also because coking wastewater and its breakdown products are toxic to aquatic life and mutagenic to humans.Different physical,chemical and biological techniques can be applied to deal with the coking wastewater.Each technique has its technical and economical limitations.Most physicochemical coking wastewater removal methods have drawbacks because they are expensive,have limited versatility,are greatly interfered by other wastewater constituents,and/or generate waste products that must be handled.Alternatively,biological treatment may present a relatively inexpensive and environment-friendly way for degradation of coking wastewater.In the process of biological treatment,the anaerobic treatment of anaerobic bacteria removed most of the organic compounds in the coking wastewater.Microbial fuel cell(MFC)is a promising environmental technology for simultaneous wastewater treatment and energy recovery in 21 st century.The anaerobic anode chamber of the MFC could be employed for high rate of degradation of coking wastewater.MFCs may offer a new technique in enhancing degradation of coking wastewater while simultaneously recovering electricity in practical applications.In this study,the secondary treated wastewater of coking wastewater treatment plant was used as the anode substrate,and the microbial fuel cell was used to realize electricity production and organic pollutants.A two-chamber bio-cathode Microbial Fuel Cell was successfully domesticated,and it was proved that the coking wastewater can be used as the anode substrate to produce electricity;The advantages and disadvantages of the two methods were compared in the following aspects: the removal rate of COD,coulombic efficiency and the electrochemical performance(output voltage?current density?power density);The topographic of anodic biofilm was observed in this study;Furthermore,the effects of external factors(temperature,cathodal pH,agitation,external resistance)on the performance of microbial fuel cells were investigated,Optimized removal rate of coking wastewater and power generation.The major conclusions are given below:The bio-cathode microbial fuel cell based on the coking wastewater as the substrate could utilize the waste water to produce electricity,the power density of the battery is 42.9mV/m2,and the removal rate of COD is 83%.The MFC's maximum power output under direct domestication 45.1mW/m2 was higher than that of gradient domestication 42.9mW/m2;The apparent internal resistance of the two type of MFC had little difference,that under direct domestication being 814? and that under gradient domestication being 811?;the COD's removing rate of MFC under direct domestication was 91%,that under gradient domestication was 83%,thus a little bit lower than the direct domestication's result.By changing the working condition(temperature,cathodal pH,agitation,external resistance),the battery performance and the removal rate of COD were significantly changed,The output power of the MFC and the removal rate of COD reached the maximum when the external resistance is 1000,the anode is agitated,the temperature is 30 DEG C,and the cathode pH is 6.The analysis of economic benefits of MFC shows that MFC is more economical in treating coking wastewater than traditional treatment methods.This study provides a reliable theoretical and experimental support for the treatment of coking wastewater by microbial fuel cell,It is helpful to realize the application value of this technology in the treatment of coking wastewater.