The Research Of Treating Landfill Leachate By Combined Electro-Coagulation And UASCB Technology

The landfill leachate's,which quality is complex and organic substance content is high,other than treating efficiently the methods using to treat it nowadays are immature. Therefore the landfill leachate pollutes our environment seriously. This paper puts forward the combined electro-coagulation and UASCB process together to treating landfill leachate, in order to study new method and new perspective in treating landfill leachate. The experiments have studied the factors affecting electro-coagulation reactor system on the effectiveness,including retention time(reaction time),electric current,polar plate spacing,concentration of Cl-and organic substance content in the influent etc. Similarly,the experiments studied and analyzed the influence of factors of UASCB reactor system on treating effects of landfill leachate in detail. The factors includes temperature,rising velocity of flour ,hydraulic retention time,organic substance and organic loading content in influent. According to the experiments it can be seen that combined electro-coagulation and UASCB process is very effective on BOD removal and it can get amount of methane to maintain the temperature of reactor as the fuel,as the complex components exiting in the waste water,the biochemical method has litter effect on treating the organics that are hard to degrade. Only adopting electro-coagulation process to treat landfill leachate,keeping the hydraulic retention time(HRT) as 40 minutes,the electric current density as 10.88A/dm2,the polar plate spacing as 20mm and the concentration of Cl-as 4000mg/L,when COD in the input water is 9399.3mg/L,the COD of output water will be 7434.8mg/L,the removal efficiency is just 20.9%. In addition ,when NH4+-N in the input water is 612.4mg/L ,the NH4+-N of output water will be 256.2mg/L,the removal efficiency is about 58.2%. While using upflow anaerobic sludge blanket to treat landfill leachate ,the HRT is just 15h and the organic load rate is more than 26kgCOD/(m3·d),the removal efficiency of COD can be above 80%.But it seems as this process is helpless in removing NH4+-N. Combining electro-coagulation and UASCB together as one process,keeping the reaction in the best running condition,the concentration of COD can reduce from 11573.8mg/L to 2407.4mg/L and the gas production rate is 562mL/gCOD removal at the same time the concentration of drops to 256mg/L from 578mg/L. It is evident that the removal efficiency of COD and NH4+-N have enhanced to 79.2% and 45%. Concluded from the experiments,combining electro-coagulation and UASCB as one process is a better way to treat landfill leachate as the combined process possesses its unique advantage.