Study On The Efficiency Of Membrane Bioreactor For Pollutant Treatment

In this study,a sequential batch membrane bioreactor(SMBR)was used to treat artificial sewage by artificial water distribution.Through experiments,three environmental influence factors(temperature,p H,dissolved oxygen)and two nutrient influence factors(C/N ratio,C/P ratio)and the efficiency of SMBR reactor to deal with pollutants.At the same time,the high-throughput sequencing technology in metagenomics was used to investigate the bacterial flora in the SMBR reactor under various conditions and levels.Changes in microbial community structure and exploration of dominant microorganisms.Lay a theoretical foundation for the design of the SMBR process and provide scientific guidance,and provide useful information for a comprehensive understanding of the microbial diversity and degradation mechanism in the SMBR process.The main research results are:(1)The high temperature environment is not conducive to the metabolism of microorganisms.As the temperature increases,the nitrogen and phosphorus removal capacity of the system is significantly reduced,and the phosphorus release and absorption are slowed.As the temperature increases,the average concentration of the COD supernatant decreases.At a temperature of 30°C,the removal rate is only84.42%.The removal rate of effluent from the COD membrane remained above95%,indicating that the system has a strong ability to adapt to changes in temperature;as the temperature increased,the species richness of the flora increased first and then decreased,while the community diversity decreased.It shows a trend of decreasing first and then increasing.Although the temperature is 20°C,it is beneficial to the large number of microorganisms,but the diversity of microorganisms is not abundant.(2)If the p H value is too high or too low,it will affect the removal ability of the organic matter.When the p H value is 6.5,the removal rate of COD is the lowest.With the increase of p H value,the removal rates of nitrogen,phosphorus and CODboth increase.The COD removal rate of the system remained above 95% at various p H values,indicating that the membrane can largely compensate for the stability of the system and ensure the quality of the effluent water;as the p H value increased,the species richness and community diversity of the flora decreased.At 8 o’clock the number of OTU dropped to 1709.(3)When the DO concentration is increased from 0.5mg/L to 3mg/L,the system’s pollutant removal rate is improved,and the sludge sedimentation is improved.When it is increased from 3mg/L to 5mg/L,the improvement effect is no longer obvious.;With the increase of dissolved oxygen concentration,the species richness and community diversity of the flora increased,but when the dissolved oxygen concentration increased from 3mg/L to 5mg/L,the increase was not obvious.(4)Under different carbon-nitrogen ratio conditions,the biological removal rate of COD is more than 90%,and the biological removal rate of COD is the highest when the carbon-nitrogen ratio is 100:8;as the nitrogen concentration in the feed water increases,the reactor is removed Phosphorus capacity rapidly deteriorates,with the decrease of the carbon-nitrogen ratio,the species abundance of the bacterial flora decreases,and the diversity of the community increases slightly,indicating that the nitrogen content in the system increases,which inhibits the proliferation of microorganisms and increases diversity Is more abundant.(5)When the ratio of carbon to phosphorus is increased from 100:2.0 to 100:1.0,the dephosphorization efficiency is significantly improved,but when the carbon and nitrogen ratio of the inflow water is reduced to 100:0.5,the effluent phosphorus content is below 0.5mg/L However,the system cannot further strengthen the removal of phosphorus,so that the removal rate of phosphorus is not high.This system reaches a certain limit of phosphorus removal;as the carbon-nitrogen ratio decreases,the species richness of the flora first increases and then decreases,and the community diversity also appears.In the same trend,the number of microorganisms was the largest and the diversity was the most when the carbon-phosphorus ratio was 100:1.5.