| The utilization of reclaimed water is an important way to alleviate the shortage of water resources.However,the traditional regenerative water treatment technology has some limitations.In this paper,the secondary effluent from a sewage treatment plant in foshan was used as the raw water of the reclaimed water,and O3-BAC was combined with gravity-driven plate ultrafiltration membrane to study the efficiency of unit process and combination process in the treatment of secondary effluent.The efficiency of treating secondary effluent by O3-BAC+modified membrane combination process(modified membrane combination process)was studied,the effect and operation characteristics of the secondary effluent treated by modified membrane process were analyzed,and the anti-pollution and photocatalytic properties of modified membrane were explored.The main research results are as follows:(1)On the basis of static test,the optimal operating conditions of o3-bac process were determined:the ozone dosage was 18mg/L,the optimal bed residence time(EBCT)was 25min,and the optimal depth of carbon layer was 100cm.The maturity time of hanging film in BAC process is about 30d.O3-BAC process had good removal effects on CODcr and ammonia nitrogen,with removal rates of 55.3%and 51.89%,respectively,and poor removal effects on TN and TP,with only 4.85%and 5.68%respectively.(2)When the modified membrane process runs alone,the stable flux of the modified membrane is 4.72L/(m2·h).Since the anti-pollution capacity of the modified membrane is higher than that of the original membrane,the flux attenuation is 74.2%of that of the original membrane.O3-BAC process,as the pretreatment process of modified film,can improve the stable flux of modified film to 4.93L/(m2·h),reduce the film attenuation rate and slow down the film pollution.(3)The modified film surface has good interception ability and photocatalytic performance,which can enhance the removal effect of pollutants.The stable removal rates of CODcr,UV254 and DOC were 27.1%,24.16%and 25.32%,respectively.The removal efficiency of nitrogen and phosphorus pollutants was slightly higher than that of the original film,but the removal rate was lower.(4)The removal effect of modified membrane composite process is higher than that of unit process.The removal efficiency of CODcr,UV254,DOC and ammonia nitrogen by modified membrane combination process was better,and the removal rates were 59.26%,42.35%,50.52%and 61%,respectively,which were 2.6 times,2.3 times,2.4 times and 3.3 times of the corresponding pollutant removal rates when the modified membrane process was running alone.The removal rates of total nitrogen and total phosphorus were lower,17.13%and 18.52%respectively,which were 2.5 times and 2 times of the corresponding removal rates when the modified film process was running alone.The effluent quality of the modified membrane and the original membrane in the combined process all meet the standards of urban landscape water and urban life miscellaneous water reuse(5)The modified membrane can trap and remove the organic pollutants such as tryptophan protein,microbial metabolites,and fulminic acid.The membrane pollutants are mainly reversible pollution caused by tryptophan proteins and microbial metabolites.Under light conditions,the modified membrane can degrade membrane pollutants by photocatalysis. |
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