Short-Cut Nitrification Of Landfill Leachate Using Aerobic Moving-Bed Boifilm Reactor

Landfill leachate from municipal solid wastes is a kind of organic wastewater with complicated ingredients, high concentrations of pollutants. Especialy the high concentration of ammonium, which increases with the running time of landfill leachate, makes the landfill leachate extremely challenging to reach the discharge standard. Therefore, the ammonia removal from landfill lachate has attracted more and more attention of society.Short-cut nitrification process was studied to remove the ammonia nitrogen from the anaerobically pretreated leachate using aerobic moving-bed biofilm reactor (MBBR) at ambient temperature. The reactor was inoculated with municipal digested sludge. The aerobic reactor was started at ambient temperature (25±1oC). After the normal running of aerobic reactor, the biomass concentration reached 4.196gMLVSS/L There were plenty of protonema ,protozoan and metazoan on the aerobic biological biofilm. MPN experiment results showed that the quantity of Nitrobacter was 4.5×106 cfu per carrier. The specific oxygen utilazation rate of Nitrobacter was 0.1028 mgO2/ (gVSS·min). Batch experiments showed that, aerobic MBBR could effectively remove ammonia nitrogen from leachate and easily realize a stable nitrite accumulation rate due to the selective immobilization and accumulation of ammonia oxidizing bacteria on the bio-carrier.The effect of HRT, DO concentration, pH value, C/N ratio and ammonia loding rate on the ammonium removal efficiency and nitrite accumulation rate was investigated respectively. Experimental results showed that, ammonia removal efficiency higher than 70 % and nitrite accumulation ratio of about 90 % could be achieved when the reaction conditions were controlled as follows: HRT at 24 h, DO concentration at 2 mg/L, pH value at 8 and C/N ratio less than 3 and ammnia loding rate 400 mg/L.In this dissertation, the toxity effect of ammonium under different pH value on the methanogenic activity of anaerobic sludge and memrane was investigated. Experiments showed that, ammonium played a muiti-ply role on methanogenic production. It enhanced methanogenic activity at low concentration, while...