Anammox-zeolite system acting as buffer to achieve stable effluent nitrogen values.
For a successful nitrogen removal, Anammox process needs to be established in line with a stable partial nitritation pretreatment unit since wastewater influent is mostly unsuitable for direct treatment by Anammox. Partial nitritation is, however, a critical bottleneck for the nitrogen removal since it is often difficult to maintain the right proportions of NO2-N and NH4-N during long periods of time for Anammox process. This study investigated the potential of Anammox-zeolite biofilter to buffer inequalities in nitrite and ammonium nitrogen in the influent feed. Anammox-zeolite biofilter combines the ion-exchange property of zeolite with the biological removal by Anammox process. Continuous-flow biofilter was operated for 570 days to test the response of Anammox-zeolite system for irregular ammonium and nitrite nitrogen entries. The reactor demonstrated stable and high nitrogen removal efficiencies (approximately 95 %) even when the influent NO2-N to NH4-N ratios were far from the stoichiometric ratio for Anammox reaction (i.e. NO2-N to NH4-N ranging from 0 to infinity). This is achieved by the sorption of surplus NH4-N by zeolite particles in case ammonium rich influent came in excess with respect to Anammox stoichiometry. Similarly, when ammonium-poor influent is fed to the reactor, ammonium desorption took place due to shifts in ion-exchange equilibrium and deficient amount were supplied by previously sorbed NH4-N. Here, zeolite acted as a preserving reservoir of ammonium where both sorption and desorption took place when needed and this caused the Anammox-zeolite system to act as a buffer system to generate a stable effluent.
Department of Environmental Engineering, Faculty of Engineering, Marmara University, Goztepe, 34722, Istanbul, Turkey. kyapsakli@marmara.edu.tr.
Kozet
0000-0001-6239-6272
K
Yapsakli
Department of Environmental Engineering, Faculty of Engineering, Marmara University, Goztepe, 34722, Istanbul, Turkey.
Cigdem Kalkan
CK
Aktan
Department of Bioengineering, Marmara University, Goztepe, 34722, Istanbul, Turkey.
Bulent
B
Mertoglu
D000327:Adsorption; D064751:Ammonium Compounds / Q000737:chemistry; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002021:Buffers; D009573:Nitrites / Q000737:chemistry; D009584:Nitrogen / Q000302:isolation & purification*; D062065:Wastewater / Q000032:analysis; D017641:Zeolites / Q000737:chemistry*
D064751:Ammonium Compounds; D002021:Buffers; D009573:Nitrites; D009584:Nitrogen; D062065:Wastewater; D017641:Zeolites
Ammonium removal; Anammox; Biodegradation; Ion-exchange; Zeolite