Development of a biotechnological Anammox process for the removal of nitrogen from aqueous effluents

The industrialized world is generating a global climate change, which is causing severe impacts on both environment and socioeconomic systems. Therefore, it is important to study and find a sustainable development worldwide. Nitrogen contamination, due to anthropogenic activities, represents a critical environmental problem. The discovery of ANaerobic AMMonium OXidation (anammox) bacteria allow to improve the conventional nitrogen removal from wastewater. In fact, the anammox process oxidize the ammonium, present in the contaminated water, to dinitrogen gas, reducing nitrites that are produced by the partial nitrification, the preliminary step needed by anammox in wastewater treatment plants. Considering the lower production of the excess sludge, the lower aeration demand, the lower CO2 emissions and the autotrophic nature of bacteria, the partial nitrification-anammox process has been considered a sustainable alternative to the conventional nitrification-denitrification. However, the full-scale application of this technology is limited because of the operational control difficulties and the anammox activity problems are limiting factors, therefore it is important to continue to investigate their causes, and also troubleshooting to ensure the stability at full-scale facilities. This study focuses on the selection of the anammox biomass from a mixed culture and on the evaluation of the anammox activity in sequential batch and then in fed batch reactor at lab-scale; and a further study investigates the possibility to perform the partial nitrification starting from mixed cultures. It was also discussed the possible causes of inhibition observed during the experiments.