Nutrient removal from mainstream anaerobic processes using a membrane biofilm reactor and a granular sludge sequencing batch reactor
Mainstream anaerobic treatment provides low-energy wastewater treatment; however, for wide-scale adoption, nitrogen removal must be considered. Anaerobic effluents contain ammonia, volatile organics, methane, and sulfide which could be used to support nitrogen removal. Our objective was to evaluate low-energy nitrogen removal from anaerobic effluents using two technologies: a membrane biofilm reactor (MBfR) and a granular sludge sequencing batch reactor (GSR). One strategy for achieving low-energy nitrogen removal is reducing oxygen demands through nitritation (oxidation of ammonia to nitrite, without further oxidation to nitrate). Currently operating at bench-scale, the ammonia in the MBfR is being fully oxidized to nitrate. Transient anoxia through the lumen of the membrane is being tested to support nitrite oxidizing bacteria out-selection. For the GSR, sustained nitritation has been achieved, with limited denitritation to date. Ultimately, our goal is to understand how the unique characteristics of anaerobic effluents impact the nitrogen removal capabilities of these technologies.
