| With the development of livestock husbandry,a large amount of livestock wastewater is produced.Due to its complexity,it is hard to be treated to reach the national standard.Therefore,livestock wastewater has become the major environmental issues.According to the actual situation,it is necessary to find a reasonable,economic,technically feasible and widely adaptable treatment.The microbial enhanced technology has been coming the center of attention as its high removal efficiency.Although the microbial enhanced technology has the advantages of low impact from the external environment and no secondary pollution,it has not been widely used in the treatment of high concentration livestock wastewater.There are many kinds of microbial agents with different effects,the purpose of this study is to screen out the microbial complex agent with better effect on livestock wastewater and combined with SBR treatment.The effluent index of combined SBR is analyzed for the enhanced effects.At the same time,high-throughput sequencing technology is used to analyze the microbial community of the sludge in microbial enhanced SBR reactor.To study on the main function related bacteria in treatment process,we also analyze the correlation between the microbial community and the change of wastewater index.The results are as follows:1、The removal efficiency of COD,ammonia nitrogen and total phosphorus in livestock water with three kinds of complex microbial agents varied with time,and there were significant differences among the three microbial agents（P<0.05）.after 48h of treatment,FHJ1and FHJ2 agents reached the highest removal rates of COD,ammonia nitrogen and total phosphorus.Respectively,the COD removal rate ware68.19%±1.87%and76.33%±1.83%;the ammonia nitrogen removal rate ware 98.9%±0.70%and 96.31%±2.82%;the total phosphorus removal rate ware 77.89%±1.16%and 82.84%±3.96%.It was significantly higher than other treatment time（P<0.05）.The highest removal rate of COD with FHJ3 agent which was 66.38%±2.76%at 72h;the highest removal rate of ammonia nitrogen was 92.94%±1.46%at 96h;and the highest removal rate of total phosphorus was 58.71%±0.68%.Therefore,FHJ2microbial agent showed the best effect on the treatment of livestock wastewater.2、FHJ2 agent was added into SBR reactor,and after 5d running,the removal rate of COD increased from 52.96%±1.57%on the first day to 64.35%±1.41%on the fifth day.However,there was no significant improvement compared with SBR control group.The removal rates of ammonia nitrogen and total phosphorus were significantly increased,reaching 97.21%±1.31%and 84.52%±2.18%respectively,which were high than 95.28%±0.41%and 77.48%±1.74%of the control group.Through the electron microscope scanning and biological phase observation,it was found that FHJ2agent increased the number of microorganisms and improved the sludge structure to enhance the efficiency of SBR system.3、The dominant phyla in all samples ware Proteobacteria and Bacteroidetes,secondary are Verrucomicrobia and Gemmatimonadetes.The dominante genera ware Saprospiraceae＿unclassified、Gemmatimonadaceae unclassified、Pseudomonas、NS9marinegroup unclassified、Dechloromonas unclassified.The COD was negatively correlated with the relative abundance of Gemmatimonadaceae＿unclassified、Flavobacterium and Acidovorax（P<0.05）.The NH4+-N was negatively correlated with the relative abundance of Gemmatimonadaceae＿unclassified and NS9 marine groupunclassified（P<0.05）,and positively correlated with Pseudomonas、Dechloromonas（P<0.05）.The combination of microbial agent and SBR can enhance the effect of SBR on the treatment of livestock wastewater.It is a microbial reference for the treatment of high concentration livestock wastewater.Therefore,it provides theoretical basis and reference for farms to carry out sewage treatment reasonably and also to improve the efficiency of the treatment technology. |
