Research On Small Water Treatment Technology Based On The A/O Biological Contact Oxidation-ultrafiltration Membrane

With China’s rapid social and economic development,environmental issues becomeincreasingly prominent,especially in the deterioration of water environment exacerbatedthe shortage of water resources.To develop the integrated residential water reuseequipment can not only solve the problem of water pollutiom,but also reduce theresidencial waterusing cost，which has some environmental and economic benefits.The test upgraded and transformed the bio-contact oxidation nitrogen andphosphorus removal process, by adding hypoxia area which used to form biofilmformation system before the process worked, and adding UF membrane cisterna tofiltrate the outlet. To obtain the effects of efficiency and low consumption, lowinvestment, easy management and the nitrogen and phosphorus removal, an integratedsystem combined with A/O bio-contact oxidation and UF membrane formed throughPLC automatic control technology.The biofilm formed after17days later using the method of combined with artificialinoculation and natural enrichment hanging membrane biofilm, which showing blackink on hypoxia area fillers and drab on aerobic zone. Moreover, the removal rate ofCODcr was more than75%. In order to determine the optimum operating condition ofthe system, an orthogonal test with influencing factors of biofilm HRT, gas and watermixture ratio and reflux ratio was conducted. Efficiency of system operation impactedby those factors has also been investigated using the single variables method. Theresults showed that average removal rates of CODcr、NH4+-N、TN and TP met92.4%、94.07%、81.03%and78.99%when the system under the optimum operating condition.Effluent water quality can meet the demands of the water,and the concentration ofCODcr、NH4+-N and TN reached "Urban sewage treatment plant pollutant dischargestandard"（GB18918-2002）.Secondly, the UF membrane fouling during the system operation and the variationof TMP after hydraulic blush were investigated. The results showed that TMP decreasedsignificantly by blushing UF membrane cisterna and UF membrane.Finally, enlarged design has been launched aiming at the domestic wastewatertreatment. Meanwhile, economic analysis and cost estimation have been studied. Theprocess of A/O bio-contact oxidation-UF membrane is economically feasible with considering factors of investment costs, operating costs and effluent quality.Furthermore, reclaimed water reuse technology characterized by this process has moreprominent advantages in a long term.