Low Temperature Biological Phosphorus Removal and Partial Nitrification in a Pilot SBR System

Abstract

Partial nitrification and biological phosphorus removal appear to hold promise of a cost-effective and sustainable biological nutrient removal process. Pilot sequencing batch reactors (SBR) were operated under Anaerobic/aerobic configuration for 8 months. It was found that biological phosphorus removal can be achieved in an SBR system, along with the partial nitrification process. Sufficient volatile fatty acids supply is the key for enhanced biological phosphorus removal. This experiment demonstrated that partial nitrification can be achieved even at low temperature with high dissolved oxygen (>3 mg/L) concentration. Shorter solid retention time (SRT) for nitrite oxidizing bacteria (NOB) than ammonia oxidizing bacteria due to the nitrite substrate limitation at the beginning of aeration cycle was the reason that caused NOB wash-out. Controlling SRT should be the strategy for the SBR operated in cold climate to achieve partial nitrification.