Application Of Struvite-Biochemistry-Fenton Treatment On Landfill Leachate

Currently, sanitary landfill is the main methods for municipal solide-waste disposal.Leachate is bound to be generated from the waste sanitary landfill. The disposal ofleachate has received high attention due to its high concentration of organic matter,high toxicity, quality and quantity fluctuations. With the promulgation andimplementation of the environmental control regulations "municipal solid wastelandfill pollution control standards"（GBl6889-2008）, the discharge standard oflandfill effluent is increasingly stringent.The controland treatment of landfill leachate pollution has become a seriousenvironmental issue. The water quality of landfill leachate that was generated fromthe Heimifeng landfill in Changsha, Hunan Province is analyzed in this study. TheStruvite-Bio-Fenton method is used to deal with the landfill leachate. The Struvitemethod, which was known as magnesium ammonium phosphate precipitation method,effectively removing NH₄⁺from landfill leachatethrough the reaction of Mg²⁺, PO₄^3-and NH₄⁺to generate the magnesium ammonium phosphate precipitation.Experimental results showed that the optimal reaction conditionfor the pretreatmentof magnesium ammonium phosphate precipitation method was as follows：pH9.0,temperature25°C,[PO₄^3-]/[NH₄⁺]/[PO₄^3-]1:1:1, under which97.1%of NH₄⁺could be removed. The effluent was treated using Fenton method, whichcan degradatethe nonbiodegradable organic matters to easily degradable organics. The results forthe Fenton processwas that the best reaction conditions for the influent pH was4.0,H₂O₂dosage was controlled at0.03mol/L, H₂O₂/Fe²⁺molar ratio was4and thereaction time was2h. Landfill leachate was finally flow into aeration tank aftermagnesium ammonium phosphate precipitation method and Fenton method. In theA/O biofilm process, through using a combination of fillers, setting the reflux ratio as2, controlling the temperature at about30℃, and controlling the concentration ofdissolved oxygen controlled at2.0mg/L, the treatment efficiency could achieve thedesired standardand meet the requirements of “garbage landfill pollution controlstandards”（GBl6889-2008）, According above, the results showed that the combinedprocess of Struvite-Bio-Fenton method is a reasonable, effective and feasible methodto deal with landfill leachate.