Impact of Ecological Factors on Anaerobic Ammonia-Oxidizing Bacteria Enrichments

Abstract

Anaerobic ammonia-oxidizing bacteria (AnAOB) have remarkably strong ability of coupling ammonia and nitrite into nitrogen gas and have been regarded as one of the most promising techniques for wastewater nitrogen removal. However, these anaerobic autotrophs are vulnerable to some environmental factors such as dissolved oxygen (DO), organic carbon, or antibiotics, which are inevitable in actual sewage or industrial wastewater. From an ecological perspective, the factors may not directly inhibit AnAOB but stimulate side populations. In this sense, it is necessary to understand the specific responses of AnAOB competitors to certain ecological factors (EFs). To date, most studies have only focused on direct effects of EFs to AnAOB but have not considered side populations. In this study, the impact of five EFs (DO, carbon, metal ion, antibiotics, and temperature) on AnAOB enrichments was assessed in a mixed-culture anammox reactor, which contained AnAOB, aerobic ammonia-oxidizing bacteria (AeAOB), nitrite-oxidizing bacteria (NOB), and denitrifying bacteria. Batch test results showed that oxygen did not inhibit AnAOB due to the protection of AeAOB and NOB, and both inorganic and organic carbon (acetate) enhanced AnAOB activity. Low concentration (0.04 mM) of iron was beneficial to AnAOB and AeAOB, but AnAOB were inhibited by a high concentration (0.26 mM) of iron. The tolerance of AnAOB enrichments to chloramphenicol was much stronger than that to amoxicillin and oxytetracycline. Temperature is a critical EF to AnAOB enrichments.

Batch enrichment of anammox bacteria and study of the underlying microbial community dynamics

“…Many studies have shown that successful cultivation of anammox bacteria from conventional sludge takes long time; i.e., generally from 4 months to 1 year [24]. Such time will be influenced by factors like (i) the ecological characteristics of the seeding sludge including initial concentration and relative abundance of anammox bacteria [24], (ii) effective biomass retention inside the reactor [25], and (iii) the environmental conditions applied: temperature, pH, and concentration of NH 4 + , NO 2 -, dissolved oxygen (DO), organic carbon, sulphide and other inhibitors like metals and antibiotics [26][27][28].…”

Physiological stabilization, community characterization, and nitrogen degradation dynamics in an anammox consortium from estuarine sediments

“…The enrichment process often takes a long time, months or even years, to succeed (Sun et al, 2011). Enrichment time can be influenced by several factors, including ecological characteristics of the seeding sludge (Tao et al, 2013), biomass retention inside the reactor (Fux & Siegrist, 2004), and the environmental conditions applied, such as: temperature, pH, and concentrations of , , dissolved oxygen (DO), organic carbon, sulfide, and other inhibitors (Carvajal‐Arroyo et al, 2013; Jin et al, 2012; Tao & Gao, 2012).…”

Sewage treatment by an UAFB–EGSB biosystem with energy recovery and autotrophic nitrogen removal under different temperatures

“…However, such one-stage system is not stable because of many reasons such as variations in DO, temperature or the inhibitors from the influents (Tao and Gao, 2012) and amongst them, the temperature is an important factor . Besides of the impact on AOB-AnAOB biofilms/granules, temperature can also affect an AD process.…”