Partial Nitritation/anammox and Canon – Nitrogen Removal Systems Followed by Conductivity Measurements

The deammonification process is a new biological promising method for a separate treatment of ammonium-rich digester supernatant. Its application can significantly reduce the nitrogen load in Wastewater Treatment Plants (WWTPs). The method is a two-step process and it can be accomplished in two separate stages (partial nitritation and Anammox) or in a singe one (CANON). Both these systems were tested at pilot plants: the CANON process in a laboratory-scale plant while partial nitritation/Anammox in a technical-scale one. The pilot plants were filled with Kaldnes rings as biofilm carriers and supplied with supernatant, coming from digested sludge dewatering at the Bromma and Himmerfjärden WWTPs, Stockholm, Sweden. The supernatant main ions ammonium and hydrogen carbonate were converted during the processes to carbon dioxide and nitrogen gas molecules and therefore the process performance could be followed by conductivity measurements. The experiments proved that conductivity was an easy and simple method to monitor the nitrogen removal processes. Moreover, the data from on-line conductivity instruments, installed in the Anammox reactor of the technical-scale pilot plant, showed great similarity with the manual measurements.