Research On The Pre-treatment Of Domestic Landfill Leachate By Modified Bentonite

Bnetonite is a clay mineral with expandable layer structure that primary constituent ofmonntlorillonite. It has higher adsorption and excellent ion exchange property.Simplemodification of natural bentonite can significantly improve the characteristics, such as layerspacing, specific surface area, adsorption properties, etc. Therefore it has received widespreadattention in the field of wastewater treatment.In this research， the hexadecyl trimethyl ammonium bromide (CTMAB) and aluminumsulfate (Al2(SO4)3) was used to modify the purified bentonite respectively. The modifiedbentonite was used for pretreatment municipal solid leachate. The removal effect of Xi’anJiangcun Ducth landfill leachate pollutants by modified bentonite was studied and got theoptimum adsorption conditions, with the main index of CODCr, ammonia nitrogen, nitratenitrogen and total phosphorus.The results of Static adsorption experiments were just as the follows. For theCTMAB-bentonite as absorbent, optimum adsorption conditions were additive amount of40g/L, the pH of about8, adsorption time for40min, and settling time for15min. In this time,CODCr, ammonia nitrogen, nitrate nitrogen and total phosphorus were removed about65.5%,23.4%,35.9%and65.5%, and CTMAB-bentonite adsorption was165.3mg,14.1mg/g and0.36mg/g/g and0.23mg/g respectively; For Al2(SO4)3-bentonite as adsorbent, the bestadsorption conditions were dosing quantity of40g/L, adsorption time for40min, the settlingtime of15min, the pH of8~9. The CODCr, ammonia nitrogen, nitrate nitrogen and totalphosphorus removal were removed about53.2%,43.9%,33.0%and69.9%, andAl2(SO4)3-bentonite adsorption was134.3mg,26.5mg/g and0.34mg/g/g and0.28mg/grespectively.Under the optimum experimental conditions, it was shown that the effect of adsorbingpollutants from landfill leathate with modified bentonite was obviously compared to bentonite.The removal rate of CODCr, ammonia nitrogen, nitrate nitrogen and total phosphorus wasincreased by50.5%,10.3%,10.3%and50.5%through CTMAB-bentonite adsorption， respectively. The removal rate of CODCr, ammonia nitrogen, nitrate nitrogen and totalphosphorus was increased by38.2%,30.8%,30.8%and38.2%through Al2(SO4)3-bentoniteadsorption，respectively. Based on experiment, A disposal process of pretreatment (modifiedbentonite adsorption), biochemical treatment and membrane process is proposed in the lightof the features of a leachate from urban landfill. Meanwhile based on the researchachievements of the research group members, the adsorption saturation bentonite could bedisposed through composting method.