Abstract

Concentrated wastewaters produced in many agricultural and food industries are treated by anaerobic digestion nowadays. However, ammonium ion is not removed in the digestion process, thereby yielding an effluent containing a high concentration of ammonia and low biodegradable COD. This ammonium-rich effluent is usually treated by another wastewater treatment plant, but it is costly and troublesome. Recently, a novel process named Anammox (anaerobic ammonium oxidation) was discovered in which ammonium ion could be converted to nitrogen gas under anoxic conditions with nitrite as the electron acceptor. This innovative Anammox process, as a result, has made the nitrogen removal treatment more sustainable. Current modeling research with the combination of partial nitrification (Sharon) and Anammox reactors has been examined for the removal of ammonia from concentrated wastewater. It was evaluated that about 50% of ammonium ion was oxidized to nitrite in the Sharon process and more than 80% of the ammonia was converted into nitrogen gas in an Anammox reactor. This study aims at demonstrating the feasibility of ammonia removal by providing nitrite directly to the Anammox process without the preceding nitrification step. Results showed that approximately 60% of ammonium removal efficiency and 80% nitrite removal efficiency were achieved in a batch sequencing reactor. Additionally, more than 50% of COD removal was obtained, hence, successfully proving the potential of this method.