[Experiment of simultaneous denitrifying phosphorus accumulation].

ABSTRACT

Denitrifying phosphorus accumulation (DNPA) and the factors affecting it were studied in a SBR with synthetic wastewater. The results showed that the sludge acclimatized under anaerobic/aerobic operation with good phosphorus removal ability, showed DNPA soon when fed nitrate instead of aeration following the anaerobic stage. Anaerobic stage was a vital premise to DNPA. If DNPA sludge was fed with nitrate prior to anaerobic stage, the DNPA would weaken even disappear. When acetate was used as sole carbon resource in the influent and nitrate did not exist in anaerobic, 1 hour of anaerobic time was optimal. NO3- -concentration in the anoxic was one of the factors affecting DNPA. When nitrate concentration was advanced from 5mg/L to 20mg/L, the percentage of DNPA increased from 11.9% to 48.7% under the condition of anaerobic(2h)-anoxic(1h)-aerobic(2h). But when the NO3- -concentration was enhanced upwards of 20mg/L, the efficiency cannot be improved. Induced DNPA did not disappear even though there was aerobic stage following anoxic stage, but the shorter the aerobic stage lasted the higher proportions of phosphorus removal via DNPA to total removal.