The Anaerobic Ammonium Oxidation Process: Inhibition, Challenges and Opportunities

Abstract

The anaerobic ammonium oxidation (anammox) process has been recognized as an efficient nitrogen removal technology. Anammox processes are gaining attention owing to their advantages over the conventional biological nitrogen removal processes. Anammox bacteria are susceptible to various wastewater pollutants, which limits the extensive application of the anammox process worldwide. In general, low-concentration pollutants lead to the promotion of the anammox activity, while high-concentration pollutants show inhibitory effects. Moreover, mainstream anammox processes face a variety of challenges that limit their stable operation, such as difficulty in the out-selection of nitrite-oxidizing bacteria, high organic carbon to nitrogen (C/N) ratio, retention of anammox bacteria, and the influence of high concentrations of ammonia and nitrite compounds. Efficient strategies are necessary to manage high carbon to nitrogen ratios, improve performance in low-intensity wastewater, and retain anammox bacteria. This chapter systemically summarizes the recent advances in the inhibition, mechanism involved and recovery process of conventional and emerging pollutants in the anammox process, such as organics, metals, antibiotics and nanoparticles. The key elements in the operation, and maintenance of mainstream anammox processes in full-scale wastewater treatment plants have also been demonstrated. Moreover, for improving the process performance, the primary influencing factors affecting the anammox process have been identified and discussed in this chapter. Taken together, this chapter effectively illustrates the critical perspective on the challenges and opportunities associated with mainstream anammox processes, which will provide an in-depth understanding for researchers and engineers working in this field.