Phosphate Removal in a Biofilm Reactor

Abstract

Biological phosphate removal was achieved in a laboratory scale fixed bed biofilm reactor. To create the conditions required to enrich for phosphate accumulating bacteria, the reactor was periodically filled and drained, and the aerator periodically turned on and off (Sequencing Batch Reactor strategy). The reactor performed very effectively, but it took several weeks to reach steady-state. The highest phosphate uptake rates were observed when sequestration of the organic substrates was accomplished at an early stage of the anaerobic process phase, and release of phosphate at the expense of sequestered or stored substrates (endogenous phosphate release) was encouraged. In the range between 15°C to 25°C, the temperature had only minor effects. The biofilm dry weight contained about 5 per cent phosphate.