Study On UF+DTROMembrane Treatment Of Landfill Leachate

It is difficult to treat landfill leachate, the quality and quatity of which are fluctuate with time and also contain a high concentration organic, and it is a pollution source to landfill site chiefly. If is treated inappropriately, leachate will bring out serious 2th pollution.In China, landfill leachate treatment projects began in 1990s, and treatment processes adopted were biological treatment technologies, which result treated was affected sharply by season and landfill operation. As a result, it is of great difficulty to reach design target. Reverse osmosis membrane was regard as the most effective technology to treat landfill leachate, in which disc-tube reverse osmosis (DTRO) membrane technology popularized in landfill leachate treatment field abroad, because of simple pretreatment, not easy membrane fouling, stable performance and so on.Based on overall analysis of LiuFang sanitatary landfill site, WuHan, the paper carried out a technology route to study the leachate that is landfill leachate-Precipitate-Ultrefilter-DTRO. Furthermore, a great deal study in-pilot to research points of do mastic landfill leachate treatment by DTRO. The paper focus on the study of performance and influence factors on DTRO system treating landfill leachate, membrane fouling,cleaning and prevention, effluent quality, systemic stability and its effect factors, and so on. At the same time, the paper brings landfill leachate treatment into landfill management system, and the pilot experiment was carried out to analize the influence of controlled concentration injection on leachate quality and landfill stabilization.After precipitate and Ultrefilter pretreatment, the high performance was achieved that landfil leachate was treated by DTRO. From muddy yellow to limpid, from rancid to inspid, COD, NH₃-N and conductivity decend from 3200mg/L, 1685mg/L, 8500μs/cm to 65mg/L, 140mg/L and 230μs/cm, removal of SS, color and turbidity reached 100%, respectively. Except NH₃-N, the discharged water quality reached not only first-class discharge standard of《Pollution Control of City Landfill Sanitary Site Criterion》(GB16889-1977), but also《Life Mix-used Water Quality Cryterin》 (CJ25.1-89), which can be use to wash car and water landscape.aiming at the high NH₃-N still (140mg/L), author bring up 2th DTRO to treat leachate further.Membrane's withhold law of contamination in leachate is discussed. Ultrefilter membrane can remove the color and turbidity of landfill leachate, more than 99%, which can't be influced by quality of income. Ultrefilter can remove effectively the colloid also, the SDI<5. Ultrefilter membrane with small withhold molecular can remove completely color and turbidity of leachate, but can't withhold validly organic with small molecular and inorganic ion. However, RO membrane can withhold all ion effectively.It is a measure validly to avoid membrane pollution that Periodicity contrary rinse and chemistry wash. The best filter periodicity of ultrefilter membrane is 12 houses, chemical clean periodicity is 15 days. The membrane flux can be recovered more 90% by chemical clean.The effect factors on investment and operation cost include capacity, leachate quality, required effluent quality, control mode and so on. By comparing to other treatment projects, the DTRO technology is acceptable and worth popularizing, in term of investment, operation cost and discharge standard.In term of overall analyis of landfill leachate treatment by DTRO system, the optimal treatment process was brought out: leachate-adjustment basin-precipitate and Ultrefilter treatment-DTRO unit-discharge or reuse.