Study On Fe(?)/PMS-ultrafiltration System For Secondary Effluent And Membrane Pollution Control In Wwtp

Nowadays,the utilization of water resources is widely concerned.As an important part of the urban water cycle,sewage treatment is also gaining more and more attention,and the standards are becoming stricter.At the same time,water reuse has also come into public view because of its cost.The primary standard is similar to the water reuse standard.Therefore,the secondary effluent of the sewage plant is gradually considered as one of the sources of water reuse.However,the secondary effluent of the wastewater plant still has a high residual concentration of organic pollutants,and it is difficult to save trace organic matter,microorganisms removal and other problems.So direct reuse may increase the safety risk.It is necessary to carry out in-depth treatment of the secondary effluent of the sewage plant to expand the increasingly strict water treatment standards and improve the quality of reused water.As one of the more widely used advanced treatment technologies,ultrafiltration is limited due to membrane fouling problems,and coagulation and oxidation are also widely studied as pre-membrane pretreatment methods to reduce membrane fouling.This article takes the secondary wastewater of the sewage treatment plant as the treatment object.In the experiment,peroxymonosulfate(PMS)was used as the oxidant,and Fe(?)was used to activate PMS.Fe(?)coagulation alone,different molar ratios of Fe(?)/PMS and combined with ultrafiltration treatment of secondary effluent in sewage plants were investigated.The effects and characteristics of TOC,protein,polysaccharide,EEM,ammonia nitrogen and other indicators on pollutant removal were investigated.Assessment.The pretreatment effect of Fe(?)/PMS was studied.In the experiment,by analyzing the membrane flux control trend and membrane antifouling distribution,the antifouling effect of the membrane was studied and evaluated.On this basis,the mechanism of membrane fouling and the causes of film formation were discussed,and the concentration range of the experiment was determined according to the experiment results.The optimal molar ratio of Fe(?)/PMS.The addition of Fe(?)coagulation helps to reduce TOC,UV254 and TP,remove protein,polysaccharides,fluorescent components and other pollutants,reduce membrane pore blockage,reduce reversible and irreversible resistance during filtration,and effectively alleviate membrane pollution.And the removal effect of organic matter and membrane pollution is proportional to the concentration.When the Fe(?)concentration is 120 ?mol / L,the removal rates of TOC,UV254,protein,and polysaccharide can reach 58.3%,24.5%,24.2%,and 33.8%,respectively.By comparing the water purification effects of different molar ratios of Fe(?)/ PMS,it can be found that when the Fe(?)/ PMS concentration is 60/60 ?M / ?M,while molar ratio is 1: 1,the organic matter removal and membrane pollution mitigation effect is optimal,and the TOC decreased from 9.06 mg/L,in the 0/60 ?M/?M group,to 6.86 mg/L,and the removal rate reached 24.3%.Both Fe(?)and excessive PMS will increase membrane fouling and filtration resistance.The addition of Fe(?)/ PMS helps to remove organic matter and alleviate membrane pollution.The removal of organic matter depends on the double superposition of coagulation and oxidation.The effect is Fe(?)/ PMS> Fe(?)> unactivated PMS.Compared with untreated raw water,the TOC removal rate of 60/60 ?M/?M Fe(?)/PMS was 31.3%,while the TOC removal rates of 60 ?mol/L PMS and 60 ?mol/L Fe(?)were 18.9% and 22.5%.The high concentration of Fe(?)/PMS may have a synergistic effect when mitigating membrane fouling,which is superior to the superposition of the two.At the end of the ultrafiltration operating cycle,the specific fluxes of 60/60 ?M ?M Fe(?)/PMS were 0.30,while the specific fluxes of 60 ?mol/L PMS and 60 ?mol/L Fe(?)were 0.24 and 0.20.In this paper,coagulation,oxidation and Fe(?)/PMS oxidation were used to systematically study the mechanism of water purification and membrane fouling during Fe(?)/PMS oxidation,as well as the effects of different molar ratios.Provide advanced sewage treatment technology and secondary effluent reuse ideas.