Synergistic simultaneous nitrification-endogenous denitrification and EBPR for advanced nitrogen and phosphorus removal in constructed wetlands

Jie Wang, Ling Xia, Jieyu Chen, Xiaoning Wang, Hu Wu, Dapeng Li, George F. Wells, Jun Yang, Jie Hou*, Xugang He

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

This study assessed the feasibility of achieving phosphorus removal through enhanced biological phosphorus removal (EBPR) in an intermittent aeration constructed wetland (CW). The results showed that within just 3 weeks, a polyphosphate-accumulating organisms (PAOs)-enriched biofilm was successfully established in the CW by integrating a pre-anaerobic stage, intermittent aeration and periodic PO43--P release strategies. This strategy enabled a high PO43--P removal efficiency of 92.68% using normal gravel as a substrate. Moreover, simultaneous nitrification-endogenous denitrification (SNED) was found to be the main nitrogen removal pathway in the EBPR-CW without specific control. SNED significantly reduces the demand for oxygen and organic carbon compared with classical nitrification-denitrification, and allowed the system to reach 96.21% total nitrogen (TN) removal even under carbon limiting conditions. With control experiment, EBPR combined with SNED in CWs improved the phosphorus and nitrogen removal by about 73% and 48%, respectively, compared with normal nitrification-denitrification and media storage-based nitrogen and phosphorus removal processes. Based on stoichiometric analysis, 71.25% of PO43--P was removed by aerobic PAOs (APAOs), with 27.50% removed by DPAONi (denitrifying PAOs using nitrite as electron acceptor) and 1.25% removed by DPAONa (denitrifying PAOs using nitrate as electron acceptor). DGAOs were the main organisms providing nitrite to DPAOs. Overall, our results demonstrate a novel approach to combine SNED with EBPR for advanced nitrogen and phosphorus removal in CWs.

Original languageEnglish (US)
Article number127605
JournalChemical Engineering Journal
DOIs
StateAccepted/In press - 2021

Keywords

  • Constructed wetlands
  • EBPR
  • Nitrogen and phosphorus removal
  • Simultaneous nitrification-endogenous denitrification

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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