Research On Low Temperature Of Nitrate Pollution In Groundwater By Microbial Fuel Cell

Now widespread nitrate contamination of groundwater has been serious harm to normal human life. In this paper, the use of microbial fuel cell method situ treatment of groundwater nitrate contamination in the course of the study, found that at low temperatures, microbial fuel cell performance drops significantly, adding betaine selected for this method to improve the low-temperature environment microbial fuel cell efficiency to reduce the phenomenon, specific conclusions are as follows:(1) At a low temperature environment, the microbial fuel cell efficiency decreased significantly, in which case the dosage of betaine, hypothermia can alleviate the inhibition of microbial activity, to improve the reactor’s electricity production capacity and degradation of nitrates purpose for processing at low temperatures MFC on groundwater nitrate pollution problem of poor performance provides a viable solution;(2) When the experimental study in a closed two-chamber MFC when the reactor is in a low temperature environment at 5-10 ℃, influent COD of 1000 mg/L, NO3- concentration of 100 mg/L, the betaine optimum dosage is 0.7 mmol/L, this time COD degradation rate and degradation rate of NO3-w as 54.5% and 96.5%, respectively, compared to not adding betaine, COD removal efficiency increased by 18.1% NO3- on the degradation rate increased 41.2%;(3) On the basis of dual-chamber reactor, the amplification of microbial fuel cell reactor, build a single-chamber bulky MFC, simulated groundwater environment, research on the MFC nitrate degradation;(4) Results obtained in the study of the optimum parameters for the microbial fuel cell operation is COD concentration of 1000 mg/L, nitrate concentration was 100 mg/L. Under these conditions, the microbial fuel cell decontamination electricity production capacity:the final tank overflow outlet COD concentration of only 157.5 mg/L, COD removal efficiency reached 84.3%, COD removal effect is good; NO3- concentration of outlet of 5.3 mg/L, the outlet NO2- and NH4+ concentrations were 0.69 mg/L and 2.96 mg/L, the removal of nitrate is very good, nitrite and ammonia did not produce a certain accumulation of nitrogen and the whole system good results; in reactor operation period produced good electrical properties, the maximum power density of 43.74 mW/m2, corresponding to a current density of 135.47 mA/m2, indicating that the reactor in the production of nitrogen and electrical properties have achieved better effect;(5) For low-temperature environment microbial fuel cell performance is not good, the selection adding betaine to improve this phenomenon. The results show that:the influent dosing of 0.1 mmol/L when betaine, COD removal rate was 75.13%, NO3- removal rate was 86.53%, MFC effluent NO2- concentration of 1.27 mg/L, NH4+ concentration of 3.88 mg/L; influent dosing of 1.0 mmol/L when betaine, COD removal rate was 72.38%, NO3-removal rate was 82.05%, MFC effluent NO2- concentration of 0.88 mg/L, NH4+ concentration of 4.78 mg/L, visible after adding a certain concentration of betaine, the ability to remove contaminants MFC were to a certain extent. On this basis, determine the best dosage of betaine is between 0.1 mmol/L to 1.0 mmol/L, the experimental results show that:the optimum dosage of betaine was 0.60 mmol/L.