ELECTROCHEMICAL TREATABILITY OF REFRACTORY POLLUTANTS IN LANDFILL LEACHATE

Landfill leachate treatment is the most troublesome aspect of the land fill management. Investigation of leachate characteristics at two land fill sites in Taiwan showed that the biological processes were ineffic ient for the treatment of leachate, regardless of whether an anaerobic or aerobic process was used. In addition, conventional flocculation/s edimentation processes were also ineffective for post-treatment of lea chate effluents from biological treatment processes. The discharged le achate still contained lots of refractory pollutants and it failed to meet the effluent quality standards of the R.O.C. (COD < 500 mg/L, NH4 +-N < 20 mg/L). In an attempt to improve leachate effluent quality, in this study, an electrochemical oxidation process was applied to treat the landfill leachate after biodegradation. Results from both batch a nd continuous experiments indicate that over 90% of COD and NH4+-N in the landfill leachate are removed by the electrochemical oxidation pro cess. In addition, the electrochemical oxidation process also demonstr ated a good efficacy for the removal of refractory compounds. After el ectrolysis, the chlorinated organic matters (as TOX) in the landfill l eachate was reduced from 19.4 to less than 2 mg Cl/L and the BOD/COD r atio of the landfill leachate was also improved from 0.05 to 0.71. The se results indicate that the electrochemical oxidation process is a pr omising process for the treatment of landfill leachate.