Comparison Of Key Factors Affecting The Enrichment Culture Of Phosphorus And Glycongen Accumulating Organisms

In the systems enriched with phosphorus accumulating organism (PAOs) and the systems enriched with glycogen accumulating organism (GAOs), the effects of different ratios of propionic to acetic acid, pH and temperature on PAOs and GAOs metabolism were investigated. Control strategies in favor of PAOs growth and metabolism were proposed. At the same time, control strategies that were not in favor of GAOs growth and metabolism were also proposed. It aims to provide regulating possibility for PAOs' competition over GAOs, and to create greater stability of biological phosphorus removal.Five lab-scale anaerobic-aerobic sequencing batch reactors (SBRs) were operated with activated sludge enriched with PAOs (or GAOs) long-term cultivated respectively with an average propionic to acetic acid carbon molar rations of 0.1, 0.5, 1,2,10. The results with sludge acclimation showed that:In the systems enriched with PAOs, biomass cultured with higher ratio of propionic to acetic acid had higher efficiency of biological phosphorus removal than with lower one in long-term culture experiments. Soluble ortho-phosphate (SOP) removal efficiency promoted with increasing ratio of propionic to acetic acid. Considering the propionic acid cost, the optimal ratio of propionic to acetic should be controlled at 2:1, and the SOP removal was 85%. The uptake rate of propionic acid was faster than that of acetic acid.In the systems enriched with GAOs, the uptake rate of propionic acid was lower than that of acetic acid. The quantity of PHA synthesized in anaerobic phase and metabolized in aerobic phase increased with decreasing ratio of propionic to acetic acid. So did the quantity of glycogen metabolized in anaerobic phase and synthesized in aerobic phase.Also, five SBRs were operated with activated sludge enriched with PAOs (or GAOs) long-term cultivated under the condition of an average propionic to acetic acid carbon molar ration of 10 and anaerobic initial pH 6.4, 6.8, 7.2 7.6 8.0. The results with sludge acclimation showed that:In the systems enriched with PAOs, SOP removal efficiency increased with...