Study On Upgrading Of Sewage Treatment Plant Based On MUCT-MBR Process

With the continuous improvement of environmental protection requirements,most sewage treatment plants have been unable to meet the existing water supply standards,so the upgrading of sewage treatment plants has become an inevitable requirement.The A~2/O process accounts for a large proportion in the existing sewage treatment plant,and the transformation of it into MUCT-MBR process is relatively simple,after the transformation,the original implementation of the first-level A emission standards can be raised to a higher water discharge standard.This paper through a small test of the MUCT-MBR process to examine the operating conditions that meet the requirements of sewage plant marking transformation.In the experiment,the simulated domestic sewage was treated with MUCT-MBR process.The main reseach contents are:(1)Judging the health of the system during the reactor start-up and commissioning by determining the relevant parameters of sludge and the water quality indicators of inandance and outlet,as well as microscope observation of sludge;(2)The effect of MUCT-MBR process on the treatment of pollutants under different operating conditions was studied;(3)The effect of enhanced chemical phosphorus removal on the effect of MUCT-MBR process treatment under the most suitable working conditions was studied;(4)The contamination of membrane components under different operating conditions and the effect of membrane cleaning on membrane components were studied;(5)The 16S rRNA gene of microorganisms was measured by high-throughput sequencing techniques to investigate the diversity of the microbiome in anaerobic pools,hypoxia pools I,hypoxia pools II,and aerobic membrane pools.The following research results were obtained through the experiment:(1)The 1st to 17 d is the start-up and commissioning period of the reactor,and the sludge settling performance is good.Late-born bacteria gum group has good adsorption and sedimentation performance,and the mirror detected bellworms,rotatoes,reactive situworms and other micro-organisms representing good water quality.After the system stabilized,the water quality index was measured for 5 days,and the average removal rate of COD,TN,TP and ammonia nitrogen was 90.75%,70.46%,20.46%and 99.75%.(2)The results of the single-factor test show that the best operating conditions of the MUCT-MBR process are:HRT is 8 h,nitrification reflux ratio is 200%,under which condition the removal rate of COD,TN,TP and ammonia nitrogen is 92.46%and 80.51%,54.14%,99.08%,water out concentrations are 14.57 mg/L,6.912 mg/L,1.82 mg/L,0.354mg/L.(3)By comparing 28%PAFC,anion 18 million molecular PAM,28%PAC cast and addition to TP removal results,the results show that 28%PAFC cast and addition is 120 mg/L,the best effect of chemical phosphorus removal.The results of the test for enhanced chemical dephosphorus control showed that the use of synchronous chemical phosphorus removal and PAFC in the most appropriate operating conditions did little affect the removal effect of COD,TN and ammonia nitrogen,while the average removal rate of TP increased from 54.14%to95.90%and the average concentration of water-out TP decreased from 1.82 mg/L to 0.164mg/L.(4)Combined with TMP and EPS analysis of membrane contamination,the results show that prolonging HRT and increasing the return ratio of nitrification fluid lead to increased membrane contamination and increased EPS and protein content in mixtures.The results of TMP and EPS of the pre-and post-pupaphophobic PAFC systems show that PAFC's injection will speed up the membrane contamination rate.The scanning electron mirror analysis of the membrane filaments of three different states can be seen from the SEM diagram:chemical cleaning can reduce the particulate contaminants in the membrane hole,and thus effectively reduce the membrane pollution.(5)The results of microbial community diversity analysis show that the richness of sludge species is from large to small:aerobic membrane pool,hypoxic pool I,hypoxia pool II,anaerobic pool.The difference with the types and distribution levels of sludge in the four environments is small,and the dominant bacteria are both those of the deformed bacteria Proteobacteria,Bacteroidetes and Planctomycetes,which contain the main phosphorus removal function.At the genus level,?-Proteobacteria Thauera,a typical denitrifying bacteria,is contained in all four kinds of sludge,which transforms nitrate nitrogen into nitrogen when participating in denitrification reaction,so as to achieve denitrification effect.The research results show that the MUCT-MBR process has a good treatment effect on simulated domestic sewage,and the treatment of water can reach the"Water pollutant emission standards in the Minjiang and Tuojiang river basins of Sichuan Province",also the water quality is good and stable,which provides a certain theoretical basis for the upgrading of sewage treatment plants.