Sustainable nitrogen removal by denitrifying anammox applied for anaerobic pre-treated potato wastewater

The feasibility of sustainable nitrogen removal was investigated in a two stage biofilm configuration consisting of a MBBR (Moving Bed Biofilm Reactor) and a Deamox reactor (Biobed-EGSB). The MBBR is used for nitrification and the denitrifying ammonium oxidation (Deamox) is aimed at a nitrogen removal process in which part of the required nitrite for the typical anammox reaction originated from nitrate. Anaerobic pre-treated potato wastewater was supplied to a MBBR and Deamox reactor operated in series with a bypass flow of 30%. The MBBR showed stable nitrite production at ammonium-loading rates of 0.9-1.0 kg NH4-N/m(3) d with ammonium conversion rates of 0.80-0.85 kg NH4-N/m(3) d. The nitrogen-loading rate and conversion rate of the Deamox reactor were 1.6-1.8 and 1.6 kg N/m(3) d. The maximum ammonium removal capacity in the Deamox reactor was 0.6 kg NH4-N/m(3) d. The removal efficiency of soluble total nitrogen reached 90%. The Deamox process performance was found to be negatively affected during decline of the operating temperature from 33 to 22 degrees C and by organic loading rates with a chemical oxygen demand (COD)/NO2-N ratio >1.