| A combined system consisting of Anoxic-Aerobic membrane bioreactor(A/O-MBR) and reverse osmosis(RO) were used for treatment of high concentration nitrogen and carbon.and landfill leachate.First,experiments of treating synthetic wastewater of high-carbon and nitrogen were carded out.to investigate NH4+-N and COD removal effect.and the pathway of removal of nitrogen in different ratio of COD/N in the system of A/O-MBR.Secondly, experiments of treating practical landfill leachate were carded out.to investigate NH4+-N and COD removal effect.Meanwhile reverse osmosis of treating wastewater from MBR effluent and membrane fouling was investigated.The results are as follows:(1) Most organic was removed in the A/O-MBR and the average removal efficiency was 95.6%.The average removal efficiency of organic was almost unaffected by COD/N。But the process of TN removal was affected by COD/N.TN removal was primarily based on simultaneous nitrification and denitrification(SND) process occurred in the aerobic zone and the average removal efficiency of TN was 89.4%with average COD/N of 10.2.Both aerobic SND and conventional biological nitrification/denitrification contributed to nitrogen removal, the average removal efficiency of TN was 72%,74%with average COD/N of 7.1 and 5.6.(2) When membrane bioreactor(A/O-MBR) system treating terminal Landfill leachate, the average removal efficiency of organic was low at 33.5%because of low ratio BOD/COD(0.15).Running for some time,by adding some sugar to maintain basic biodegradability,now the ratio of COD/N was 3.5.The average removal efficiency of organic 79.6%,87.5%,81.42%respectively in different dilution Times of 4,2,1.The average removal efficiency of TN was 23%,39%,51.3%respectively and the average removal efficiency of nirogen was 97.6%,95.8%,89%respectively in this three phases.MLSS in Anoxic-Aerobic Zone was mixed well,difference of nitrite nitrate and nitrogen was lower(3) The water quality of RO effluent treating synthetical wastewater could meet the water quality requirements for the town wastewater reuse.The operation of system was stability.It shows that RO system for TOC rejection,TN and conductivities rejection were 93.2%,89%,92.9%respectively even if it was operation at the condation of low temperature(13-14℃) and high ion concentration(4000 us/cm).RO ystem for TOC rejection,TN rejection was 96.3%,90%when RO system was used for treating Landfill leachate at the operation pressure of 0.45MPa.(4) The membrane fouling of RO treating synthetic wastewater is characterized by scanning electric microscopy and Fourier transform infrared spectroscopy technique The fouling cake layer formed on the RO membrane surface was observed by scanning electric microscopy.The membrane fouling was characterized by Fourier transform infrared spectroscopy technique which showed that the major components of the foulants were soluble microbe products.The membrane fouling of RO treating landfill leachate was characterized by(dissolved organic matter) DOM.The result shows that HiA has a strong permeability and HoN has a strong retention for RO.Meanwhile it implying a portion of HoN is high MW (molecular weight) substances like proteins. |
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