Effects of nitrite inhibition on anaerobic ammonium oxidation

Abstract

In order to assess the stability of nitrogen removal systems utilizing anaerobic ammonium oxidation (anammox), it is necessary to study the toxic effects of nitrite on these biochemical reactions. In this study, the effects of nitrite on anammox bacteria entrapped in gel carriers were investigated using batch and continuous feeding tests. The results showed that the nitrite concentration in a reactor must be less than 274-mg N/L in order to prevent a decrease in the anammox activity, which occurred when the gel carriers were soaked in nitrite solutions with concentrations greater than 274-mg N/L in a batch test. In a continuous feeding test, nitrite inhibition was not observed at low concentrations of nitrite. However, the anammox activity decreased to 10% when the nitrite concentration increased to 750-mg N/L over a 7-day period in the reactor. In addition, it was shown that the effects of nitrogen on the anammox reaction were reversible because the anammox activity completely recovered within 3 days when the influent nitrite concentration was decreased to less than 274-mg N/L.

Reject water treatment by improvement of whole cell anammox entrapment using polyvinyl alcohol/alginate gel

“…Some previous researchers reported that the anammox activity decrease by a half when influent NO 2 --N concentration was above 350 mg-N l -1 (Dapena et al 2007) or 37% under influent NO 2 --N concentration of 430 mg-N l -1 (Kimura et al 2010). The results achieved from our study were different from their results.…”

Influence of substrates on nitrogen removal performance and microbiology of anaerobic ammonium oxidation by operating two UASB reactors fed with different substrate levels

“…However, both substrates act as potential inhibitors to the growth and metabolism of Anammox bacteria when their concentrations exceed the threshold inhibitory values [5,[12][13][14][15][16][17][18]. So, the substrate inhibition must be avoided during the operation of Anammox bioreactors.…”

Research advances and challenges in anammox immobilization for autotrophic nitrogen removal

“…confirmed that nitrite concentration less than 280 mg L −1 was suitable for anammox reaction. Kimura et al . concluded that anammox activity loss of 35% was observed only at concentrations higher than 274 mg L −1 in PEG immobilized gels during batch tests.…”

“…Isaka et al 122 confirmed that nitrite concentration less than 280 mg L −1 was suitable for anammox reaction. Kimura et al 88 concluded that anammox activity loss of 35% was observed only at concentrations higher than 274 mg L −1 in PEG immobilized gels during batch tests. The same was again confirmed in PVA cryogels by Magrí et al 44 During continuous operation, nitrite concentration up to 400 mg L −1 does not inhibit anammox bacteria and 90% anammox activity was decreased at a concentration of 700 mg L −1 .…”

“…The same was again confirmed in PVA cryogels by Magrí et al 44 During continuous operation, nitrite concentration up to 400 mg L −1 does not inhibit anammox bacteria and 90% anammox activity was decreased at a concentration of 700 mg L −1 . 88 Thus nitrite inhibition of the anammox process using immobilized gel carriers is much reduced compared with other forms of anammox application. C/N ratio Anammox bacteria are influenced by both the presence and absence of organic carbon in the process.…”