MBR-Fenton For Landfill Leachate Treatment

AbstractiMunicipal landfill leachate is a big treatment question as a complicated wastewater of high ammonia and refractory organics. Organics and ammonia are the main removal pollutants which decide the construction and operation cost. For their removal, the membrane bioreactor (MBR) was studied on the role of powdered activated carbon (PAC) added in MBR. Moreover, the Fenton reagent was used for the removal of refractory organics to treat the effluent from the MBR.The main research achievements are summed up as follows:1. At pH 8.7-9.3 in influent, the MBRs (PAC added or not) still remained on the stage of ammonia oxidation with nitrite accumulation. With pH decreased to 7.6-8.2, the nitrite was completely oxidized to nitrate in the MBRl (PAC added) while the MBR2 (PAC not added) still remained with nitrite accumulation. Though air stripping as pretreatment reduced the nitrification loading, higher concentration of SO42" for pH adjustment resulted in nitrification decrease of MBR2 and MBRl was affected less.2. The MBR can efficiently intercept microorganisms and refractory organics and more than 10% of refractory organics were removed. With PAC added, the refractory organics removal increased about 3% in MBRl, but metabolic products accumulation occurred more.3. Fenton reagent was used to treat the effluent from the MBR. With an H₂O₂ dosage of 150mg/L, an FeSO₄ dosage of 550mg/L, oxidation pH of 3 and coagulation pH of 3.8, more than 78% refractory organics was removed and 98% chroma was done. COD in the effluent from MBR decreased from 800mg/L to lower than 200mg/L, and chroma did from 1500 down to 30. Coagulation was the main role of Fenton reaction and removed the bigger molecular humics efficiently.Focus on the two key treatment difficulties of high ammonia and refractor organics, systematic research was done and a certain creation was obtained. In the future work, a systematic process needs to be combined with both high economy and high efficiency.