The Deep Denitrification And Phosphorus Removal And Microbial Community Of 3DBER-S

With the increasingly severe water resources situation in China,the serious shortage of water resources and the serious situation of water pollution such as rivers and lakes are being taken seriously.To alleviate the difficulties faced by water resources in our country at present,mAny researchers have proposed all sorts of sewage treatment technology.But the water after treatment by most of these process still contains a certain concentration of nitrate nitrogen and phosphorus pollution.The existence of these substances is a potential hazard to the life of humans and animals and plants,and it is difficult to continue to be removed.In this paper,the three dimensional electrode biofilm method(3DBER)and sulfur autotrophic denitrification were combined to solve the difficult problem of depth nitrogen removal and phosphorus removal of low C/N water such as effluent from sewage treatment plant.The effects of deep denitrification and phosphorus removal under different conditions were investigated and optimized..In this paper,the effects of current,HRT,C/N on the removal of nitrogen and phosphorus in 3DBER system were analyzed by single factor experiment.The results showed that when HRT=8 h,I=20 mA,and C/N=2,the maximum removal rate of the 3 DBER system for NO3--N and P removal rate was 99%and 94%respectively.In addition,when the current increases,the HRT and C/N decreases,the concentration of NO2--N in effluent water increases significantly.Then this paper focuses on optimizing the denitrification effect of 3DBER system by adding sulfur autotrophic denitrification.The effect of S/N on the denitrification of 3DBER-S system was studied.The results showed that,when S/N increased from 0.5 to 2,the removal rate of NO3--N was increased from 86%to 97%,and the concentration of NO2--N was reduced to 0 mg/L.According to the orthogonal test,the optimal operating conditions of 3DBER-S were obtained,which is HRT=8h,I=100 mA,S/N=2.Under this condition,the removal rate of NO3--N reached 100%,the concentration of nitrous nitrogen in effluent was 0.02 mg/L,and the concentration of ammonia nitrogen was about 0.01 mg/L.According to the analysis of influence of each factor,S/N has the greatest influence on system denitrification.Next,the 3DBER-S process was used to treat high concentration of nitrogen-nitrogen wastewater.The effect was optimized by C1-.It is concluded that the addition of Cl-has greatly reduced the concentration of NO2--N and NH4+-N in water.When C1-is 600 mg/L,the current was increased,after 5h reaction,the removal rate of NO3--N was 92.45%,and the concentration of NO2--N in effluent was 1.45 mg/L,and no ammonia nitrogen was produced.Finally,the microbial community characteristics of 3DBER-S system were analyzed by MiSeq sequencing technology.According to the analysis of diversity index,the OUT number,Ace index and Chao index of anode samples were the biggest.In addition,Proteobacteria in each sample were the largest bacteria gate with the highest abundance of 82.6%.The most abundant class in Proteobacteria was the ?-proteobacteria,with the maximum abundance of 84%.Thiobacillus was the largest genus in all samples,and with a maximum abundance of 50.04%.Thiobacillus,Rhodocyclaceae,Thauera,all of the three bacteria were far more abundant in the cathode samples than in the anode samples.In addition,The abundance of most other bacteria were higher in the anode than the cathode.