Research On Concentrated Landfill Leachate Treatment By Concentration-Precipitation-Recirculation

Recently,new membrane separation techniques has been widely used in the treatment of landfill leachate in China,because the standards of pollutants in municipal solid waste landfill have been raised.The concentrated liquor that comes from the membrane treatment o f landfill leachate has its own features such as complex components,high concentration,varied quality and quantity.There is still no mature and common technique to deal with these concentrated leachate.In this thesis,combined process is used in purifi cation of landfill concentrated leachate.Firstly,the concentrated liquor is need to be highly concentrated by using new membrane techniques.Secondly,we add some agentia to m ake pollutants assembled.Thirdly,the remaining liquid is recharged to the landfill which contains thousands of bacterium.With all these process,salinity and organic substance that in the concentrated leachate can be removed from it and be adsorbed by bacteriums or soil.The concentrated leachate that is need to be cleaned is come from the landfill leachate treatment plan in Guangdong.We determined the component and analyzed the characteristics of it.Then,we analyzed the influence factor and result of using high pressure DTRO technique in concentration of these liquid.We also chose some kinds of agentia to gather the pollutant and explored the best combination and process conditions.Last,we recharge the remaining liquid to the special apparatus which is filled with solid wastes.The experiment results show that these combination process can be used in engineering.With a membrane flux of 20 to 30L/h·m²,concentration times of 2 to 4and a cleaning cycle of 8 to 12 hours,the high pressure DTRO technique can be more effective.PFS is chose as best coagulant in these conditions.When p H is 7.6with a dosage of 9g/L of it,PFS is in suitable flocculating conditions.The best p H of MAP is 9 with a mixing time of 10min when[Mg²⁺:NH₄⁺:PO₄^3-]=1.1:1:1.Compared to the recharge of landfill concentrated leachate directly,the recharge of remaining liquid has better treatment effect.