The Research Of Pollutants Removal Of Old Age Landfill Leachate In The Dual-chamber Microbial Fuel Cell

With the rapid growth of economy, energy crisis and environmental pollution were twoissues which have been particularly focused by current society. Microbial fuel cells (MFCs), anew sewage treatment technology combining traditional biodegradation and electrochemicaltechnology, have developed rapidly in recent years. MFCs employ microorganisms to directlytransform chemical energy stored in biodegradable organic/inorganic matters to electricity,while simultaneously accomplishing wastewater treatment.It has gained increasing attentionsby researchers as a novel notion for environmental pollutants treatment.In order to construct some new technologies for mature landfull leachate treatment, adual-chamber microbial fuel cell (MFCs) system was builted. The treatment efficiencies andelectricity generation properties of MFCs for mature landfill leachate treatment were studied.The results showed that when20%mature landfill leachate was used as fuel, the maximumoutput voltage and maximum output power density of MFCs could achieve660.6mV and2182.0mW/m3under1000Ω, respectively. When the proportion of mature landfill leachatewas increased to100%, the maximum output voltage and maximum output power density ofMFCs were709.4mV and2513.4mW/m3, respectively. As a result, the concentration ofCOD was decreased from8644mg/L to2560mg/L, and the removal rate reached70.4%after28-days running. During the operation of MFCs, some ammonia nitrogen was removed aselectron donor in the anode chamber, and another part of ammonia nitrogen transferred fromthe anode chamber to cathode chamber due to the concentration difference between the twochambers. Totally,43%of ammonium ions were transferred in7days. Meanwhile, theinternal resistance of MFCs was increased from1010Ω to2000Ω, and the anolyteconductivity was decreased from2.09mS/cm to0.915mS/cm. The pH declined from8.37to7.82in anode chamber, and increased from7.96to8.23in the cathode chamber.Ammonia in landfill leachate could transfer from anode chamber to cathode chamberwithin MFCs. Based on this observation, the nitrifying bacteria and aerobic denitrifyingbacteria CY1were inoculated in the aerobic cathode chamber. Under such condition, MFCscould generate electricity with the removal of ammonia nitrogen. The concentration variationof nitrate nitrogen and nitrite nitrogen in the cathode chamber were observed. And the effectsof aeration and nitrification on the transfer of ammonia nitrogen were investigated. Theresults showed that the existence of nitrate nitrogen and nitrite nitrogen in the cathodechamber could enhance the output voltage. Dissolved oxygen was consumed during thenitrification process. The nitrifying bacteria in cathodic biofilm reduced the effective surface area of cathode and the output voltage decreased. When the nitrite nitrogen concentration washigh in the cathode chamber, the nitrification process was inhibited. The transformation andvolatilization of ammonia nitrogen in the cathode chamber was not favorable for the movingof ammonia nitrogen from anode chamber to cathode chamber. More ammonia nitrogenvolatilized into the air by the aeration effect. The ammonia nitrogen transferred could befurther removed,44.2%of by the contribution of microbiological nitrification anddenitrification.This study provided valuable information for the further development of a continuouslyoperating dual-cathode MFCs system for landfill leachate treatment.