Research on In Situ Ammonium Removal in Leachate Recirculation

摘要

The goal of this experiment was to investigate and identify the feasibilityof in situ ammonium removal with landfill leachate recirculation. Aeration was used toprovide aerobic environment and wood chips were added on the top of the municipalsolid waste as aeration media for better air distribution. With top aeration, anaerobicleachate recirculation system was changed into a system which included aerobic, anoxicand anaerobic environments. When leachate recirculated to the top, aerobic environmentimproved ammonium transformed into nitrate by biological nitrification. Later leachateentered into anoxic environment where nitrate transformed into nitrogen gas by biologicaldenitrification. Lastly, leachate passed through anaerobic environment, ammoniumgenerated from the degradation of the nitrous organic pollutants dissolved into theleachate and came into the next biological nitrification-denitrification. The experimentalresults indicated that top aeration avoided ammonium accumulation with removal ratiosof ammonium and total nitrogen as 77.83% and 77.24% respectively. To enhance treatmentefficiency of leachate recirculation with top aeration system, activate sludge wasadded into wood chips layer to increase microorganism population. It was demonstratedthat activated sludge accelerated attenuation of ammonium and other pollutants, and removalratios of ammonium, total nitrogen and COD were all over 80%.