Experimental Study On Landfill Leachate By Aged-Refuse-Based Bioreactor

The semi-aerobic ARBB (Aged-Refuse-Based Biorecators) is formed based on the structrure improvement of anaeroic ARBB. The COD_Cr and NH₃-N removal rate of semi-aerobic ARBB were investigated with the study on start-up acclimation and operating parameters. The comparisons to the result of COD_Cr and NH3-N removal were taked to with the anaerobic ARBB.Acclimation experimental study indicated that, the change of hydraulic load and the length of acclimation time have obvious impact on the multiplication of heterotrophic bacteria. The extremely big change of hydraulic load easily lead to the effluent of microorganism in the bed , the longer the adaptation time of heterotrophic bacteria to a certain density ,the more obvious multiplication tend to be, the adaptation time should not less than 4d.The nitrifying bacteria be influenced maninly by oxygen concentration when influent concentration was lower than 12000mg/L.The adding of sanitary sewage caused the high microorganism density, which enhanced the acclimaiization remarkably.The operating parameters experimental study indicated that, just enhance the hydraulic load ,influent frequency and influent concentration under the other factor fixed would lead to the removal rate of NH3-N and the COD_Cr reducuction. When the influent frequency is 2d^-1 or 2.5d^-1, the suitable hydraulic load is 0.026 L/(kgonce) and the influent density should be controlled not more than 12000mg/L. Also the pH change of effluent shows that that the ARBB has a good alkalinity buffer capacity, the higher the pH value of effluent, the higher removal rate of NH₃-N.Contrast experiment shows that compared with anaerobic ARBB, semi-aerobic ARBB has better removal ability to COD_Cr and NH₃-N, especially to NH₃-N .The removal rate of semi-aerobic ARBB to NH₃-N were less than 90%,whicn were higher 47% averagely than anaerobic ARBB when hydraulic load,influent frequency and influent concentration were confirmed 0.026 L/(kgonce), 2d^-1 and 12000mg/L separately.The two-cluster ARBB experiment study indicated that in the condition of certain hydraulic load ,influent frequency and influent concentration ,the COD_Cr and NH₃-N concentrations in effluent are less than 150mg/L and 2mg/L respectively, which can meet Level II discharging requirements stipulated by GB16889-1997.This paper provide a new way for the onsite treatment of landfill leachate,it has a positive significance to the control of the landfill lechate pollution.