Continuous Biological Phosphorus Removal in a Biofilm Reactor

Mechanisms for biological phosphorus removal from wastewaters in an upflow granular aerated filter are evaluated. The feasibility of excess phosphorus uptake on fixed bacteria is demonstrated on pilot scale and the limiting parameters are established. The influence of the duration of anaerobic and aerobic states and of substrate loadings on phosphorus removal is verified, as well as the impact of alternating aeration on nitrification. Because bacteria are attached, hydraulic retention time of biomass and water can be separated and the exposure of bacteria to anaerobic or aerated conditions can be optimised.