Study On Performance Of Combined Membrane Technology Used In Treatment Of Leachate From Incineration Plant Of Municipal Waste

The leachate from incineration power plant of municipal waste is a high-concentrated organic wastewater in which complex components are contained. It produces in the process of transportation and stacking. The leachate has the characteristics of high-content organic pollutant, capacity, ammonia and heavy metals etc. If it discharged to environment without any treatment, surroundings will be polluted severely. In the thesis, the author used the combined membrane technology composed of membrane biological reactor (MBR) and disc tube reverse osmosis (DTRO) to treat the leachate from the retention basin of Yu-qiao municipal solid waste incineration power plant, Shanghai.The operating parameters are optimized. The best operating parameters are found: HRT is 6 d, the DO value controls 3-4mg/ L, the pH keeps at 7-8.5, the operating pressure of membrane is about 4.2 bars. The variety circumstance on dirty mire density MLSS, MLVSS and MLVSS/ MLSS in bioreactor has been analysed. The best reverse washing cycle is 12h through ultra filtration washing experiment and did a research of the membrane washing online.The main factors effecting on performance of DTRO reactors about the removal of organic substance were investigated, such as the flux of membrane, the rate of taking off salt, pressure and the recovery rate etc. The forming mechanism of calcium carbonate, sulphate sediment, silicon sediment, microorganism and organic matters about the pollution of membrane are analysed, and it established the basis theory for judging the type of membrane pollution and optimizing the washing method about membrane pollution. The rationality of startup time of the washing method, acid washing and alkali washing has been validated by the washing method of DTRO.Combined membrane technology (MBR+DTRO) was used to treat the leachate from the retention basin of Yu-qiao municipal solid waste incineration power plant in the steady circulation. The effluent can accord with the third discharge limit of sewage discharging in Shanghai (DB31/199-1997) (COD_cr≤300mg/L; BOD₅≤150mg/L; SS≤350mg/L; NH₃-N≤25mg/L).