[Short-cut nitrification of landfill leachate by aerobic moving-bed biofilm reactor].

Short-cut nitrification process was studied to remove the ammonium nitrogen from the anaerobically pretreated leachate using aerobic moving-bed biofilm reactor (MBBR) at ambient temperature. The effect of DO concentration, pH and C/N ratio on the ammonium removal efficiency and nitrite accumulation rate was investigated, respectively. Experimental results showed that, more than 70% of ammonium removal efficiency and about 90% of nitrite accumulation rate could be achieved when the reaction conditions were controlled as follows: HRT at 24 hours, DO concentration at 2 mg x L(-1), pH at 8 and C/N ratio less than 3. Batch experiments showed that the quantity and activity of ammonia oxidizing bacteria were much higher than those of nitrite oxidizing bacteria. MBBR could effectively remove ammonium nitrogen from leachate and easily obtain a stable nitrite accumulation rate due to the selective immobilization and accumulation of ammonia oxidizing bacteria on the bio-carrier.