Pushing the limits of solids retention time for enhanced biological phosphorus removal: Process characteristics and Accumulibacter population structure

Paul Roots, Alex Rosenthal, Yubo Wang, Fabrizio Sabba, Zhen Jia, Fenghua Yang, Heng Zhang, Joseph Kozak, George Wells*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Reducing the solids retention time (SRT) of the enhanced biological phosphorus removal (EBPR) process can increase organic carbon diversion to the sidestream for energy recovery, thereby realizing some of the benefits of the high rate activated sludge (HRAS) process. Determining the washout (i.e. minimum) SRT of polyphosphate accumulating organisms (PAOs), therefore, allows for simultaneous phosphorus and carbon diversion for energy recovery from EBPR systems. However, few studies have investigated the washout SRT of PAOs in real wastewater, and little is known of the diversity of PAOs in high rate EBPR systems. Here we demonstrate efficient phosphorus removal (83% orthophosphate removal) in a high rate EBPR sequencing batch reactor fed real primary effluent and operated at 20 °C. Stable operation was achieved at a total SRT of 1.8±0.2 days and hydraulic retention time of 3.7-4.8 hours. 16S rRNA gene sequencing data demonstrated that Accumulibacter were the dominant PAO throughout the study, with a washout aerobic SRT between 0.8 and 1.4 days. qPCR targeting the polyphosphate kinase gene revealed that Accumulibacter clades IIA, IIB and IID dominated the PAO community at low SRT operation, while clade IA was washed out at the lowest SRT values.

Original languageEnglish (US)
Pages (from-to)1614-1627
Number of pages14
JournalWater Science and Technology
Volume82
Issue number8
DOIs
StatePublished - Oct 15 2020

Keywords

  • A-stage
  • Candidatus Accumulibacter phosphatis
  • Enhanced biological phosphorus removal (EBPR)
  • High rate activated sludge (HRAS)
  • Polyphosphate accumulating organisms (PAO)
  • Wastewater treatment

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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