Landfill Leachate Concentration Treatment By Multiple Micro-electrolysis

Landfill Leachate Concentration is produced by reverse osmosis membrane treatment of leachate. Compared with the garbage leachate, organic matter, ammonia nitrogen and total phosphorus Concentration of LLC is higher, but B/C is lower. Therefore, it is more difficult to treat. At present, the mainly method is backflow to regulating reservoir, which leads to accumulate heavy metal and refractory organics. Thus, it is very important to develop cost and effective treatment technology to resolve LLC pollution. Landfill Leachate Concentration taken from a household garbage disposal center is studied by Fe-C micro-electrolysis system, Fe-Al-C and Fe-Cu-C system. The effect of packing ratio, initial pH, reaction time on COD and TP removal rate in the landfill leachate has been researched by single factor experiment and optimized by the orthogonal experiment. The main research contents and conclusions are as follows:1) In Fe-C system, the optimum parameters for COD removal are initial pH= 3, the reaction time of 3 h, Fe/C (m)= 8:l,respectively,the optimum process parameters for TP removal:pH= 3, Fe/C= 8:1, the reaction time was 4 h.By the orthogonal experiment analysis, the influence of various factors on COD removal in order were:pH> Fe/C> reaction time,and the optimum parameters was pH=3, time=3h, Fe/C (m)= 8:1,the removal of COD.TP.NH3-N and TN were 62%.59%,11.8% and 14.7%, respectively. The impact of them on TP removal in order were:pH> Fe/C> reaction time.The best condions were pH=3, Fe/C= 8:1 and time=4h.2) In Fe-Al-C system, in acid (pH= 3) and strong alkali (pH= 9) conditions, the COD and TP removal was better, and in neutral (pH= 7), the treatment effect was the worse. pH, reaction time and Fe/Al/C dosing ratio were optimized by the orthogonal test. The three factors influencing COD removal in the Fe-Al-C micro electrolysis system in order were:initial pH> reaction time>Fe/Al/C. The best parameters for COD removal were:Fe/Al/C= 6:2:1, reaction time= 2 h, initial pH= 9, the removal of COD. TP. NH3-N and TN were 61.3%.49%.24.9% and 36% under this conditon. And the influence of various factors on TP removal in order were:reaction time> Fe/Al/C> pH. The best parameters for TP removal were:Fe/Al/C= 2:6:1, reaction time= 1 h initial pH＝9.3) In Fe-Cu-C system, the effect of initial pH, Fe/Cu/C and reaction time on COD and TP removal has been studied. Under acid condition, COD removal rate increased with the increase of pH, when the pH arrived at 7, COD was removed most, COD removal for each dosing ratio were:57.7%,63.8% and 67.3% respectively; In alkaline conditions, with the increase of pH, COD removal rate decreased. By optimizing the conditions with the orthogonal experiment, the three factors influencing the removal rate of COD in the primary and secondary order:Fe/Cu/C> reaction time> pH, the optimal combination:pH= 7, reaction time=3 h, Fe/Cu/C= 4:4:1.The removal of COD、TP、 NH3-N and TN were 68.1%、51.1%、33.3% and 46.2%.And the influence of various factors on the removal rate of TP in order:Fe/Cu/C> reaction time> pH. The optimal Fe/Cu/C was 6:2:1, initial pH value was 3, the reaction time was 3 h.