Comparison between acetate and propionate as carbon sources for phosphorus removal in the aerobic/extended-idle regime

Lately, we have proved that biological phosphorus (P) removal can be achieved in the aerobic/extended-idle (AEI) regime using glucose as the sole carbon source, which might develop a potential simple strategy for simultaneous removal of P and organic substrates from wastewater. Since acetate and propionate are the two most common substrates present in real domestic wastewater, this paper further assesses the P removal performances in the AEI process using acetate and propionate as the sole carbon source. The results showed that 3.91 and 3.64 mg of P/g of total suspended solids were, respectively, removed in the acetate-reactor and propionate-reactor after 50 days, respectively. After 90 days P removal in the propionate-reactor increased to 4.91 mg P/g of total suspended solids whereas that in the acetate-reactor kept in the same level (3.98 mg/g). Though both acetate and propionate could be used as carbon sources for P removal in such a novel system, the latter was more effective after long-term operation. Further investigations showed that, after 90 days’ acclimatization, sludge poly-P content in the propionate-system was more than that in the acetate-system, which was the primarily reason for the propionate-system showing higher P removal.