Research On The Recirculation Technology Of Leachate From Municipal Refuse Landfill

At present,almost 90% of the municipal refuse in our country was treated with the technology of landfill.The principal environmental problem of landfill is leachate of which the water quality is complex,whth high CODcr and high NH3-N concentration as well as high heavy metal ion concentration.The soil and groundwater will be polluted if the leachate entering into environment.So seeking a economical leachate treatment process adapted to China is an impendent problem to promote the development of landfill technology.Considering the reality of our country, recirculation as an effective treatment technology of leachate has a great prospect for development.Under the completely natural condition,the paper adopted the pattern which landfilling,collected the leachate and studied the leachate recirculation method processing effect.The recirculation experiment was mainly anaerobic recirculation, the experiment had two aspects: On the one hand , recirculated the leachate of municipal refuse, according to the results , showed the effect of removal CODcr ,NH3-N, and other indicators in leachate by the recirculation ; on the other hand, studied the impact factor of leachate recirculation by changing pH and hydraulic load and other factors.Through above experimental study,drew following main conclusion:(1)Owing to recirculation,time of the anaerobic metabolism phase can be reduced , and also decomposition of the organic substance can be accelerated .Thus, finally stabilization of the refuse was speed up.(2)In temperature range which carries on in the experiment , landfill body average subsidence speed(y)is linear correlation to the total time of landfill body(x), its relationship is: y = -0.0426x + 1.1204 correlation coefficient R2=0.9994,linear relevance well.(3)When the hydraulic loading is about 5.66ml / l ? d ~ 9.06ml / l ? d, the organic load is about 262.44 mg / l ? d ~ 279.79mg / l ? d, the removal effect of CODcr,NH3-N was better, the most removal effect can achieved to 29.29 %, 20.20 % respectively.(4)pH is an important factor in dealing with NH3-N of leachate recirculation , alkalescent environment is appropriate to nitrifying bacteria and denitrifying bacteria growth and is conducive to the removal of NH3-N.(5) In the extension of experiment, considering the removal rate and the stability of remove,the removal effect of CODcr, NH3-N was best by the solution of the leachate recirculation entirely.