Competition between polyphosphate- and glycogen-accumulating organisms in biological phosphorus removal systems – effect of temperature

This study demonstrated that temperature is an important factor in determining the outcome of competition between polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating non-poly-P organisms (GAOs) and the resultant stability of enhanced biological phosphorus removal (EBPR) systems. At 20°C and a 10-day sludge age, PAOs were dominant in the anaerobic/aerobic (A/O) SBR, however, at 30°C and a 10-day sludge age, GAOs were dominant in the A/O SBR. For kinetic batch studies, the anaerobic specific acetate uptake rate of GAO-dominated sludge (1.34 × 10⁻³ mg C/mg VSS·minute) was higher than the rate of PAO-dominated sludge (0.89 × 10⁻³ mg C/mg VSS·minute) at 30°C, leading to the eventual failure of EBPR processes at high temperatures.