| Mature landfill leachate has the characteristics of high ammonia nitrogen content,complex organic pollutants,poor biodegradability and so on.If not treated or directly discharged,it may cause serious contamination to environment.Aiming at this category of mature landfill leachte,the paper takes The landfill leachte of Fuxin city as the subject of investigation,and probe in the high efficient and low cost approach to treat mature landfill leachate.Based on the improvement of biodegradability and cost reduction,MAP chemical precipitation method was conducted as pretreatment technics in this study.The effect of stirring intensity,stirring time,initial PH and reagent ratio on the MAP was studied by single factor experiments,on this basis,The optimal operating conditions of MAP for the improvement of biodegradability were studied by response surface method-ology(RSM).The biochemical properties of the pretreated leachate were obviously improved,but it was still not in accordance with the standard of landfill pollutioncontrol standard?GB16889-2008?.And then the adsorption biological membrane as the mainbiological treatment process.Taking the dominant microorganism which adapted mature leachate after pretreatment and activated carbon fiber with adsorption culture adsorption biological membrane.The effects of organic loading,initial PH and dissolved oxygen content on thetreatment of mature leachate by the adsorption biological membrane were studied by static experiments,on this basis,The effect of hydraulic retention time and influent C/N on the treatment of mature leachate by the adsorption biological membrane was studied by dynamic experiments.Based on the fore-mentioned research contents,the conclusions were listed as follow:(1)The optimal experimental conditions for the treatment of high ammonia landfill leachate by the combination of MgO+NaH2PO4·2H2O were 200r/min of stirring intensity,120min of stirring,and the initial PH was 9,the proportion of medicament n(Mg2+):n(N):n(P)=2.12:1:1.20,which were determined by single factor and the response surface experiments.Experiments show that under this experimental conditions,COD of leachate after treatment was 468mg/L,NH3-N was 118.35mg/L,TP was 9.16mg/L,and pH was 8.67,the removal rate of COD is 22%,the removal rate of NH3-N was 90.3%,the residual phosphorus content is 9.16mg/L.(2)The adsorptive biological membrane can withstand the organic load of 96kgCOD/(m3·d).The optimal pH value of the adsorptive biological membrane is 8.When the organic load was 96kgCOD/(m3 · d)and pH value was 8,the removal rate of COD,NH3-N and TP increased with the increase of oscillation frequency.To ensure a better TP removal effect,the experimental study should be required to control the oscillation frequency greater than 100r/min.(3)In experimental device for hydraulic retention time of 12h,the removal effect of COD and NH3-N is best.In experimental device for hydraulic retention time of 4h,the removal effect of TP is best,Optimum removal rate is98.75%,100%,44.59%,respectively;In experimental device for influent C/N ratio of l,the removal effect of COD and TP is best,In experimental device for influent C/N ratio of 5,the removal effect of COD and NH3-N is best,Optimum removal rate is100%,100%,67.18%,respectively;In 1#experimental device which hydraulic retention time was 8h and influent C/N ratio was 1,Effluent quality were COD concentration of Omg/L,NH3-N concentration of 24.75mg/L,TP concentration of 2.09mg/L.It accords with discharge standard of landfill leachate.To sum up,MAP chemical precipitation and adsorptive biological membrane can effective treat the old landfill leachate.under certain reaction conditions,the concentration of organic pollutants can reach the landfill pollution control standard?GB16889-2008?. |
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