Experimental Research Of Combined Technology For Treating Landfill Leachate

Landfill leachate with the characteristics of Complex components, highconcentration of organic pollutants and ammonia nitrogen and the proportion of thenutrition were imbalanced, especially the “late” leachate the biodegradability ofwhich was poor, was difficult to deal with. In this paper, take Hefei Longquanmountain landfill leachate as an example, through the experiment, designed theeconomic and reasonable combined technology for landfill leachate treatment tomeet the emission standard.（1）Using coagulation+magnesium ammonium phosphate （MAP） precipitationmethod as pretreatment method.①Coagulation pretreatment:Using FeCl3as thecoagulant, the removal rate of COD can reach55.5%when pH was5.0, ferricchloride dosage was840mg/L, precipitation time was30min, coagulant dosage ofPAM was16mg/L.②MAP precipitation pretreatment: The removal rate of ammonianitrogen can reach85%under the condition of pH was10.0, n（N）： n（Mg）：n（P）=1:1.2:1.2and the reaction time was20min.（2）The coagulation+MAP precipitation+biochemical treatment methodcombined technology had good treatment effect on the landfill leachate. Theremoval rate of COD, ammonia nitrogen and total nitrogen of the final effluentwere80%,98%and90%under the condition of the temperature was33℃,pH was7.0⁷.5,the drainage ratio was10%and reaction period was12h, and the content ofammonia nitrogen and total nitrogen meet the national emission standard, but theconcentration of TOC was between172mg/L²73mg/L, indicating that there was aconsiderable part of organic matter was not removed, the water needed foradvanced treatment.（3）Effluent further treatment adopted Fenton oxidation and aerobic process.The removal rate of COD in Fenton oxidation effluent can reach57.5%under thecondition of pH=3.0, the dosage of H₂O2and FeSO₄·7H₂O were0.15mol/L and8.15g/L, reaction time was90min, while the biodegradability of wastewater wasimproved. Fenton oxidation effluent entered the aerobic reactor for furthertreatment, and the concentration of COD in the final effluent was less than100mg/L, meet the national emission standard.