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

Nitrogen removal performance and characteristics of gel beads immobilized anammox bacteria under different PVA:SA ratios

“…At PVA/SA ratios of 5%/2% and 8%/2%, the proportions of pore diameter distribution of gel beads were very similar and uniform. However, gel beads with PVA concentrations of 12% and 15% were dominated by macropores (88.1% and 92.4%, respectively), and micropores and mesopores accounted for a very small proportion, making them more suitable as microbial carriers (Manonmani & Joseph, 2018). Because of the large pore structure and good connectivity in these gel beads, solute diffusion and gas release were guaranteed, which was conducive to the improvement of NRRs.…”

“…(Herkommerova et al, 2018;Isaka et al, 2007Isaka et al, , 2013Sun et al, 2017). The polyvinyl alcohol (PVA)/sodium alginate (SA) composite material is a kind of biological carrier commonly used (Manonmani & Joseph, 2018;Zhu et al, 2009). PVA is a polymer obtained from the hydrolysis of polyvinyl acetate.…”

Mass transfer efficiency inside the polyvinyl alcohol‐sodium alginate carriers: kinetic changes of immobilized anammox bacteria

“…observed that the use of glutaraldehyde as crosslinking agent not only enhanced the mechanical strength of the PVA‐SA gel beads but also increased the TN removal efficiency. It is noticeable that these crosslinking techniques could influence the mass transfer to some extent 34 . In addition to the crosslinking, the use of chitosan or chitosan coupling with iron to replace SA could construct an immobilization matrix potentially containing more porous microstructures to facilitate the mass transfer.…”

“…It is noticeable that these crosslinking techniques could influence the mass transfer to some extent. 34 In addition to the crosslinking, the use of chitosan or chitosan coupling with iron to replace SA could construct an immobilization matrix potentially containing more porous microstructures to facilitate the mass transfer. It was observed that the chitosan or chitosan coupling with iron mixed with PVA as immobilization material increased the nitrogen removal rate by 89 to 162%.…”

Enhancing the nitrogen removal from swine wastewater digested liquid in a trickling biofilter with a soil layer

“…This requires the coexistence of nitrite accumulation and an anaerobic environment in a nitrication reactor. 6,[34][35][36] The STF in this study satised this requirement; hence, ANAMMOX may have occurred to a certain extent. Besides, some autotrophic nitrogen removal has been ascertained, for example, earlier research found that some AOBs could oxidize NH 4 + -N to N 2 O in a low DO environment.…”