Steady-state analysis to evaluate the phosphate removal capacity and acetate requirement of biological phosphorus removing mainstream and sidestream process configurations

A stoichiometric analysis for the evaluation of different process configurations for biological phosphorus removal (BPR) is developed. This analysis is a steady-state simplification of the general dynamic model of biological phosphorus removal developed previously. It provides a simple method to compare the phosphate uptake capacity and acetate requirement of different BPR process configurations like the mainstream and sidestream process. Based on the phosphate concentration in the influent and the system configuration, the minimal required concentration of phosphorus removing organisms (polyP-organisms) in the system, and the maximal phosphate/acetate-COD ratio of the influent to obtain full P-removal can be calculated. The phosphate/acetate-COD ratio of the influent can be used as one of the main parameters in the analysis of a process configuration. The acetate requirement for the sidestream process where P-removal in a stripper tank is applied is shown to be much lower than the requirements needed in a mainstream process. The required concentration of polyP-biomass in a sidestream process is 10 times lower.