Two-chamber Microbial Fuel Cell And Its Application In Groundwater Nitrate Pollution Remediation

According to the introduction of the current technology on remediation of nitrate ingroundwater and its disadvantage, in this paper, microbial fuel cells(MFC) isproposed as a method to restore the nitrate pollution in groundwater. Introduced theprinciple of microbial fuel cells, its classification and application progress inwastewater. On this basis, using glucose as the organic substrates in anode chamberand use nitrate in simulated groundwater as the sole electron acceptor to construct thesmall test and pilot equipment of two-chambered MFC. Analyze the electricalproperties of the two chambers MFC, impact on groundwater nitrate removal. Usingthe experimental data to establish a prediction model of output voltage based on SVM.Through the identification of the dominant strain, determine the dominant bacteriathat can produce electricity. The results show that:(1) Respect of electrical properties:The stable voltage of MFC is170-210mV, settling time appears in13-27days, itsmaximum output voltage of is210mV at19days, internal resistance is1332. Whenthe external resistance is1000, the maximum output power density oftwo-chambered MFC is44.235m W/m2, current density is0.1698m A/m2.COD inanodes can be better removed, and the COD concentration reduce from initial value550.36mg/L to120.24mg/L after30days, the removal rate reaches to78.15%.(2)Small scale and pilot experiments:In the small scale test, the degradation rate of nitrate if add microorganism intocathode chamber is15%better than the natural. According to preliminary analysis bysmall scale test, the best initial concentration of nitrate is300mg/L, the removal rateis63%.In the pilot test, when the number of salt bridge is three, the maximum degradationrate is69.42%. The degradation rate of nitrate can be increased through extendingHRT. When the HRT is30d, nitrate concentration reduce from272mg/L to99.12mg/L, the degradation rate is64%, when the HRT is60d, nitrate concentrationreduce from280.56mg/L to72.12mg/L, the degradation rate is75%.(3) Output voltage prediction:Nitrate removal rate reaches11mg·L-1·d-1， When the highest voltagereaches210Mv.Nitrate removal and cumulative electric quantity shows positive linear relationship.It shows that nitrate is reduced to nitrogen gas through acceptingelectronic transmission over the anode chamber. Nitrate removal of the cathodechamber can be calculated by cumulative electric quantity. The MAPE of SVMprediction model of the output voltage is3.0653%, the MAPE of power density is4.6852%. MAPE below10%illustrates the SVM model has good predictive results.(4) Identification of bacterial aspects:There are7order13class microorganisms in the anode chamber. Bacilli (24%),α-proteobacteria (20%), actinomycetes (10%) are the dominant bacteria in the MFCanode chamber system，for more than10%of the total number of bacteria.