Study On The Effect And Microflora Characteristics Of MBR Process For Wastewater Treatment In An Industrial Park

Membrane bioreactor(MBR)is a kind of efficient wastewater treatment technology which combines activated sludge process and Membrane filtration technology,eliminates the need of secondary sedimentation tank and improves the effect of solid-liquid separation.In recent years,it has been widely applied in engineering in China.MBR process was used in sewage treatment plant of an industrial park in Xinjiang.In this paper,the treatment effect of the plant was studied,and 16S r RNA gene sequencing and acer sequencing technology were used to study the characteristics of bacteria in the plant MBR process system and antibiotic resistance genes carried by the bacteria.The main research results are as follows:(1)During the study period,the average BOD₅/COD of influent water in sewage treatment plant was only 0.05,and the biodegradability of influent water was very poor.A hydrolytic acidification tank is designed in front of the biodegradability tank to improve the biodegradability of influent water.BOD₅:TN:TP=2.56:11.52:1,indicating that the ratio of carbon,nitrogen and phosphorus in the influent was seriously unbalanced.BOD₅/TKN=0.79 and BOD₅/P=2.56 in the influent water,the biological nitrogen and phosphorus removal carbon source was insufficient,and methanol was added in the front of the biochemical tank to fill the carbon source to meet the demands of microbial growth and biological nitrogen and phosphorus removal carbon source.The average influent concentrations of COD and BOD₅ are 308mg/L and 15mg/L,respectively,and the average influent concentrations of TN and TP were 66.4mg/L and 5.8mg/L,respectively.After the MBR process,the effluent reaches the design discharge standard.(2)After sequencing the diversity of MBR wastewater treatment system,a total of34 bacterial phyla and 401 bacterial genera were detected.Proteobacteria and Bacteroidetes are the dominant bacteria in the MBR wastewater treatment system,accounting for 58.51-79.69%and 11.57-19.62%of the total bacteria,respectively.(3)Thioclava,Acinetobacter and Gemmobacter were the dominant bacteria in the water,accounting for 19.83%,15.81%and 10.28%of the total bacterial abundance,respectively.Norank?c??skagenf62 and Hyphomicrobium are the dominant bacterial genera in oxidation ditch sludge and MBR membrane tank sludge,and their relative abundance was 31.16-32.70%and 27.79-28.32%,respectively.Acinetobacter,Hyphomicrobium and Norank?f??saprospiraceae were the dominant bacteria genus in the effluent,accounting for 18.69%,16.81%and 13.35%,respectively.(4)The microbial community in the oxidation ditch sludge was different from that in the influent mainly because the addition of methanol changes the microbial community structure.Microbial community structure in MBR membrane tank sludge and oxidation ditch sludge is similar.The change of microbial community structure in effluent was mainly related to Na Cl O disinfection.(5)Multiple resistance,polypeptide and fluoroquinolones were the main types of resistance in MBR wastewater treatment system,with the relative abundance of 26.47-29.35%,17.97-12.95%and 10.40-11.72%,respectively.mac B,evg S and mfd were the ARGs subtypes with the highest relative abundance in the system,with the relative abundance of 3.85-4.35%,2.62-3.75%and 3.02-3.04%,respectively.In the MBR treatment system,the ARGs subtype firstly increased and then decreased,and the absolute abundance of ARGs in the activated sludge was the highest,which was significantly higher than that in the influent and effluent.There was no significant removal of ARGs in sewage treatment plants.