Abstract
Using a nonwoven material for biofilm attachment in a continuous flow reactor, conversions of nitrogenous compounds closely following the stoichiometry of the recently discovered anaerobic ammonium oxidation (anammox) process were developed and maintained for over one year of operation. Removal rates of ammonium (NH4+) and total nitrogen as high as 31 and 63 mg N/ (l⋅h), respectively, were demonstrated over several weeks of operation and removals of approximately 24 and 47 mg N/ (l⋅h), respectively, were maintained over most of the study, which are in a suitable range for industrial applications. With a HRT of 8.5 hours, influent NH4+ and nitrite (NO2-) concentrations of over 300 mg N/l, each, were successfully treated with removal efficiencies of approximately 70%. However, very little benefit could be attributed to the use of recycle in attempts to work with higher influent concentrations where NO2- toxicity would be of concern.
