An autotrophic nitrogen removal process: Short-cut nitrification combined with ANAMMOX for treating diluted e uent from an UASB reactor fed by landfill leachate
An autotrophic nitrogen removal process：Short-cut nitrification combined with ANAMMOX for treating diluted effluent from an UASB reactor fed by landfill leachate

A combined process consisting of a short-cut nitrification (SN) reactor and an anaerobic ammonium oxidation upflow anaerobic sludge bed (ANAMMOX) reactor was developed to treat the diluted e uent from an upflow anaerobic sludge bed (UASB) reactor treating high ammonium municipal landfill leachate. The SN process was performed in an aerated upflow sludge bed (AUSB) reactor (working volume 3.05 L), treating about 50% of the diluted raw wastewater. The ammonium removal e ciency and the ratio of NO2??- N to NOx??-N in the e uent were both higher than 80%, at a maximum nitrogen loading rate of 1.47 kg/(m3 day). The ANAMMOX process was performed in an UASB reactor (working volume 8.5 L), using the mix of SN reactor e uent and diluted raw wastewater at a ratio of 1:1. The ammonium and nitrite removal e ciency reached over 93% and 95%, respectively, after 70-day continuous operation, at a maximum total nitrogen loading rate of 0.91 kg/(m3 day), suggesting a successful operation of the combined process. The average nitrogen loading rate of the combined system was 0.56 kg/(m3 day), with an average total inorganic nitrogen removal e ciency 87%. The nitrogen in the e uent was mostly nitrate. The results provided important evidence for the possibility of applying SN-ANAMMOX after UASB reactor to treat municipal landfill leachate.