Research advances and challenges in anammox immobilization for autotrophic nitrogen removal

Abstract Application of the anaerobic ammonium oxidation (anammox) process using suspended or attached growth technology has limitations of slow growth rate such as biomass washout, and large footprint. This has led to the development of smaller, compact immobilized systems. In recent years, wastewater treatment using anammox immobilized cells has received much attention due to its advantages of high biomass content, retention of biomass by prevention of washout, good solid–liquid separation and lower toxicity to microorganisms. This article critically reviews the existing literature on autotrophic nitrogen removal using anammox bacteria in its immobilized form. Different methods of using immobilized anammox bacteria were identified. Characteristics of various polymeric gels such as solubility, biodegradability, stability, diffusivity and growth of biomass in the polymeric gel were studied. However, there is insufficient study of disposal methods and costs involved in anammox immobilization to guide future implementation of immobilized anammox technologies for autotrophic nitrogen removal. © 2018 Society of Chemical Industry