Removal Of Organics And Heavy Metals From Landfill Leachate By Fenton

Landfill leachate composition is very complex and contains a variety of toxic andhazardous refractory organics and heavy metals, if not handled properly will causegreat pollution of the surrounding environment. In this paper, Fenton oxidation andcoagulation was used to treatment landfill leachate containing heavy metals, thecharacteristics of landfill leachate was studied, the removal effect of organic matterand heavy metals removed by Fenton was investigated, and compared iron seriescoagulant with Fenton, also analyzed the Fenton removal mechanism of the organicand heavy metals in landfill leachate.Analysis of characteristics of landfill leachate found that it had lowbiodegradability and in order to improve the biodegradability need to removal ofrefractory organics and heavy metals. What is more, dissolved heavy metals accountfor most and very stable. It needs high pH to precipitation, so precipitation methodshould not be used to remove heavy metals in landfill leachate.The experiment of Fenton treatment of organics in landfill leachate concludedthat the order of the influence factors on the influence of organic matter in wasteleachate treatment was initial pH﹥H2O2/Fe2+mole ratio﹥coagulation pH﹥H2O2dosage﹥reaction time. Among them, the factors afected the removal of heavy metalswas initial pH and H2O2/Fe2+mole ratio and coagulation pH. Fenton reagent caneffectively remove the organic matter in landfill leachate, especially for refractoryorganics removal is better. COD removal rate reached72.1%and UV254removal ratereached88.9%. GC-MS experiment detected in10kinds of organic matter, but only3new kinds of organic matter were checked out after Fenton treatment. And throughGC-MS experimental analysis found that Fenton can oxidation of complex organiccompounds, efficient removal of refractory organics, and reduce the toxicity oflandfill leachate.The experiment of Fenton treatment of heavy metals in landfill leachate provedthat heavy metals can be removed efficiently under its best conditions, but it affectedthe treatment of Organics, so Fenton reagent was not recommended for removal ofheavy metals simply. Considering the removal of organics and heavy metalssimultaneously, Fenton can efficient removal of organic matter and heavy metalsunder appropriate condition. So Fenton was suitable for treating organic and coordination treatment of heavy metal.Fenton reagent compared with iron coagulants containing the same amount ofiron ions, the comparison results showed that iron coagulants for the removal of heavymetals had good results. Iron series coagulant and Fenton reagent with same ironcontent to treatment landfill leachate was showed that in addition to the ferrous sulfateremoval efficiency of Cr was slightly better than Fenton reagent, and the coagulationability of iron ion in Fenton reagent to remocal of Cd, Zn, Mn, Pb was better thanferric chloride, ferrous sulfate and ferric sulfate. In addition, the mechanism analysisconcluded that Fenton able to degrade most of the organic matter under oxidation,and can make the heavy metals and organic matter to take off the stability andseparation. The intermediate of Fenton coagulation under alkaline conditions, and itcan remove a large amount of heavy metals and organic matter. So the concentrationof organic matter and heavy metals had fallen sharply.