The Study Of Leachate Treatment By Membrane Combine Technology

Leachate, produced in the process of refuse disposal, is one kind of organic wastewater of high concentration and difficult treatment, which is very difficult to treat because of its variable quality and much toxic and harmful ingredient in it. Because it may hazard environment badly, it has been one of the critical problem of pollution in the nowadays and a long time later. The membrane bioreactor (MBR), a combined process of biological treatment with advance membrane separation, is a new technology for wastewater treatment and reuse. MBR has the specified research foreground being used for treating the organic wastewater of high concentration and slow -biodegradable nature. Nanofiltration(NF), as a new physicochemical method, has specified research foreground in wastewater advance treatment.MBR's removal effect of contamination, characteristics of sludge and mechanism of membrane fouling , NF's removal effect of contamination and mechanism of membrane fouling were investigated to treat the leachate from Shanghai Jiangqiao Refuse Incineration Plant.The research experimental of MBR results show: MBR has good effect in contamination removal, when sludge loading rates of COD andNH3-N were between 0.08-0.30kgCOD/kgMLSS.d and 0.07-0.42kgNH3-N/m3.d respectively, the MBR had removal efficiencies of COD and NH3-N ranging above 80% and 95% respectively at HRT between 24-102h;In the experimental research of the characteristic of sludge , sludge concentration in stable stage increased with the enlargement of volumetric loadmg and was above 13.5g/l in process of the experiment;The slow-biodegradable substance such as SMP were accumulated in the MBR with the extension of running time, which caused sludge settleability to become worse > sludge activity to decrease and microbial variation to be bad, as well an contributing to the poor membrane permeability of the mixer liquor;In the experimental research of the decline of membrane flux and mechanism of membrane fouling, HRT had the greater effect to the decline rate of membrane flux in actual running process, the decline rate of membrane flux was the largest when HRT act as 24h;The conclusion was obtained that the membrane fouling resistance was completed of polarization layer resistance and external fouling resistance with the distribution tests of resistance , and the sums of two took over 90% of total fouling resistance.The research experimental of NF results show: NF has good effect in contamination removal, when the operating pressure is 0.6Mpa, the NF had removal efficiencies of COD over 90%. In the experimental research of the decline of membrane flux and mechanism of NF membrane fouling,The conclusion was obtained that running time >> wastewater quality had the greater effect to the decline rate of membrane flux in actual running process. The research experimental of NF recovery and membrane fouling result show: the operating pressure^ wastewater quality had the greater effect in the recovery, macromolecules particle had the greater effect in the membrane fouling. In the research of the membrane washing, the chemical washing is a effective method.JinHui Wang (Environmental Engineering)Supervised by Professor YongHui Wang...