Competition between Polyphosphate- and Glycogen-Accumulating Organisms in Enhanced-Biological-Phosphorus-Removal Systems: Effect of Temperature and Sludge Age

摘要

Temperature and sludge age were found to be important factors in determining the outcome of competition between polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating non-polyphosphate organisms (GAOs) and the resultant stability of enhanced-biological-phosphorus removal (EBPR). At 20 deg C and a 10-day sludge age, PAOs were dominant in an anaerobic/aerobic (A/O) sequencing-batch reactor (SBR), as a result of their higher anaerobic-acetate-uptake rate and aerobic-biomass yield than GAOs. However, at 30 deg C and a 10-day sludge age, GAOs were able to outcompete PAOs in the A/O SBR because of their higher anaerobic-acetate-uptake rate than PAOs. At 30 deg C and a 5-day sludge age, GAOs coexisted with PAOs in the A/O SBR, resulting in unstable EBPR performance. At 30 deg C, reducing the sludge age from 5 to 3 days improved the EBPR efficiency drastically, and the EBPR performance was stable. The maximum specific-anaerobic-acetate-uptake rates of GAO-enriched sludge were affected by temperature with the Arrhenius temperature coefficient 0 of 0.042 (deg C~(-1)) between 10 and 30 deg C. The effect of sludge age (5 and 10 days) on the maximum specific-anaerobic-acetate-uptake rates of GAO-enriched activated sludge, however, was not significant. For the PAO-enriched activated sludge, the maximum specific-anaerobic-acetate-uptake rate did not change significantly between 20 and 30 deg C, but significantly increased from 0.38 to 0.52 mmol-C/ mmol-C/h as the sludge age decreased from 10 to 3 days at 30 deg C. Water Environ. Res., 78, 4 (2006).