Research on phosphorus accumulating organisms metabolism characteristics by different ratios of propionic to acetic acid

The effect of different ratios of propionic to acetic acid on the efficiency of enhanced biological phosphorus removal (EBPR) was investigated. Five anaerobic -aerobic sequencing batch reactors(1#-5#)were operated with Synthetic wastewater of acetic acid, different propionate/acetate C-mol ratios of 0.5, 2, 10 and propionic acid to cultivate and enrich phosphorus accumulating organisms (PAOs). It was found that as a sole carbon source, Sodium acetate induced the largest anaerobic phosphorus release rate, so as to the largest aerobic phosphorus uptake rate. With the increase of propionic/acetic acid ratio, the soluble orthophosphate (SOP) release and uptake decreased, the same as PHB synthesize and glycogen degradation; However, the SOP removal efficiency increased by 7%. Apparently, higher ratio of propionic/acetic acid led to superior EBPR. There exist a positive correlation between anaerobic phosphorus release and poly-β-hydroxybutyrate (PHB) synthesis to a certain extent in the five SBR reactors.