The Pretreatment Of Landfill Leachateby MAP Methods Combined Process Of Coagulation

Landfill leachate--byproduct generated by landfill，is highly polluted organicwastewater containing complex components， high ammonia concentration，biodegradable and organic matters and heavy metals. How to treat effectively landfillleachate has been a difficult and hotspot issue of wastewater treatment areas in recentyears.Biological treatment is conventional treatment process for landfill leachate，but it is susceptible to external environmental impacts and adaptable poorly on waterquality and quantity. With the promulgation and implementation of new standards forlandfill leachate，biological treatment alone is not effective enough to t achieveeffluent discharge requirements.In this study， landfill leachate of a certain Landfill in Shanxi City wasexperiment object， using combined technology as coagulation-MAP method topretreat it， which is aimed to removal high ammonia and refractory high organicconcentration of landfill leachate.The influence of dosage of PFS，pH value，reaction time and dosage of PAMon the treatment effect of landfill leachate was discussed during single factor andorthogonal experiment. The optimal reaction conditions which were determined bythe orthogonal experiment were that under the room temperature condition， firststirs30s by the200r/min mixing speed， then responds25min by the100r/min mixing speed， PFS dosage was420mg/L， PAM dosage was3.5mg/L，pH was5.5and reaction time was35min.When coagulation was used to treat the landfill leachate， the removal rate ofCODcr was61.43%， ammonia nitrogen was only4%to5%.The study was investigated the influence factors on the landfill leachatetreatment effect by single factor experiment， such as pH， the reagent mooredosing ratio， reaction time and precipitation time. The best experiment conditionsof coagulation-MAP method was determined by the orthogonal experiment. Under theroom temperature conditions: The pH was8.5， the reagent moore dosing ratio ofMg2+:NH4+: PO43-was1:1:1.15， the stirring speed was100r/min， the reactiontime was35min， and the precipitation time was35min.The coagulation-MAP method is effective to treat the landfill leachate， CODcrremoval rate is up to65.43%， NH3-N removal ratesis up to87.61%， The methodhas laid a good foundation for follow-up biological treatment. Besides， MAPprecipitation has good market value as a slow-release fertilizer， which increases theeconomic efficiency of the combined pretreatment process.