Mainstream nitrogen removal from low temperature and low ammonium strength municipal wastewater using hydrogel-encapsulated comammox and anammox

How to Provide Nitrite Robustly for Anaerobic Ammonium Oxidation in Mainstream Nitrogen Removal

“…PN means half of the influent ammonium is oxidized to nitrite, and the stable anammox relies on the coupling to PN . It is also the preferred route to supply nitrite for anammox reactions due to its oxygen and carbon savings. ,,, Typically, the distinct niche of ammonia-oxidizing bacteria (AOB) and NOB, such as activity, growth rate, biomass decay rate, and activity recovery rate, as well as their differential tolerance to specific inhibitors, are the foundation of effective controlling strategies for achieving mainstream PN. Previous studies have proven that an unstable nitrite supply is the primary hurdle hindering the widespread adoption of mainstream anammox .…”

“…Since 2007, the co-occurrence of novel AOMs and AnAOB have been discovered in natural and engineered systems, such as the Black Sea and WWTPs. ,, Then, the coupling of novel AOMs and AnAOB for mainstream treatment has been attempted since the 2010s. ,, AOA and comammox bacteria have a great potential in mainstream PN, owing to their higher affinity of ammonia and oxygen than that of AOB. ,, Also, AOA and comammox bacteria have closer interactions with AnAOB under low substance and oxygen-limited conditions, where NOB could be suppressed. , Under the ammonium limitation condition created by AnAOB, the enrichment of higher affinity AOA and comammox bacteria would be more active than AOB; , moreover, AOA and comammox bacteria may rather cooperate with AnAOB than compete with them for the substrates. , Some experimental results have shown that AOA and comammox bacteria hold promise when it comes to producing nitrite and creating an anoxic microenvironment, ,,, and these microbes could potentially be more effective partners for AnAOB than AOB for realizing mainstream anammox. ,,, …”

“…In a PN/A system (4.5 L) running for more than 1000 days, comammox Nitrospira dominated nitrite supply for AnAOB (accounting for 89.2 ± 7.9% of the total prokaryotic amoA copies) with a low ammonium loading (35.2 mg N/L/d) and oxygen-limited (0.05–0.3 mg/L) aeration, achieving an nitrogen removal of 70.1 ± 2.7% . By establishing synthetic communities in hydrogel granules, , comammox bacteria ( Ca . Nitrospira inopinata) grew in the aerobic outer layer of hydrogel granules and provided AnAOB ( Ca .…”

“…59,158 Under the ammonium limitation condition created by AnAOB, the enrichment of higher affinity AOA and comammox bacteria would be more active than AOB; 118,119 moreover, AOA and comammox bacteria may rather cooperate with AnAOB than compete with them for the substrates. 135,158 Some experimental results have shown that AOA and comammox bacteria hold promise when it comes to producing nitrite and creating an anoxic microenvironment, 66,119,145,158 and these microbes could potentially be more effective partners for AnAOB than AOB for realizing mainstream anammox. 59,60,124,126 To date, the collaboration of these novel AOMs with AnAOB for treating mainstream wastewater has been achieved in lab-scale reactors and artificial symbiotic systems (Figure 5e).…”

Analyzing the nitrogen removal performance and cold adaptation mechanism of immobilized cold‐acclimation ANAMMOX granules at low temperatures

“…However, the stability of ANAMMOX processes depends on the environmental temperature (Li et al, 2019(Li et al, , 2023Zuo et al, 2023). Temperature significantly effects microbial growth and metabolic activity.…”