Insights into the denitrifying phosphorus removal decay processes by profiling of the response mechanism of denitrifying phosphate-accumulating organisms to starvation stress

Abstract

Starvation conditions were inevitably encountered by biological wastewater treatment systems. Four anaerobic starvation periods (5, 10, 16 and 20 days) were conducted to investigate the response mechanism of denitrifying phosphate-accumulating organisms (DPAOs) in order to dissect denitrifying phosphorus removal (DPR) decay processes. The denitrifying phosphorus removal performance suffered with the decay rate of 0.162 ± 0.022 d−1 during 20-day starved duration. Metabolic activity decay was responsible 93.20 ± 0.11% for the damaged DPR performance, while biomass decay contributed to 6.79 ± 0.68%. The genus Dechloromonas affiliated to DPAOs exerted stronger survival adaptability to starvation with the abundance increasing from 1.98% to 3.15%, depended upon the endogenous consumption of intracellular polymers. In view of PHA-driven DPR mechanism of DPAOs, the metabolic activity was restricted by the depletion of available PHA. These results revealed the poorer stability but preponderant recovery of DPR system encountering with starvation.