Modeling versatile and dynamic anaerobic metabolism for PAOs/GAOs competition using agent-based model and verification via single cell Raman Micro-spectroscopy

Guangyu Li; Nicholas B Tooker; Dongqi Wang; Varun Srinivasan; James L Barnard; Andrew Russell; Beverley Stinson; Jim McQuarrie; Peter Schauer; Adrienne Menniti; Erika Varga; Hélène Hauduc; Imre Takács; Charles Bott; Paul Dobrowski; Annalisa Onnis-Hayden; April Z Gu

doi:10.1016/j.watres.2023.120540

Modeling versatile and dynamic anaerobic metabolism for PAOs/GAOs competition using agent-based model and verification via single cell Raman Micro-spectroscopy

Water Res. 2023 Oct 15:245:120540. doi: 10.1016/j.watres.2023.120540. Epub 2023 Aug 29.

Authors

Guangyu Li¹, Nicholas B Tooker², Dongqi Wang³, Varun Srinivasan⁴, James L Barnard⁵, Andrew Russell⁶, Beverley Stinson⁷, Jim McQuarrie⁸, Peter Schauer⁹, Adrienne Menniti⁹, Erika Varga¹⁰, Hélène Hauduc¹¹, Imre Takács¹¹, Charles Bott¹², Paul Dobrowski¹³, Annalisa Onnis-Hayden², April Z Gu¹⁴

Affiliations

¹ Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States; School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, United States.
² Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States.
³ Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States; Department of Municipal and Environmental Engineering, Xi'an University of Technology, Xi'an, Shaanxi, China.
⁴ Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States; Brown and Caldwell, One Tech Drive, Andover, MA, United States.
⁵ Black & Veatch, Kansas City, MO, United States.
⁶ South Cary Water Reclamation Facility, Apex, NC, United States.
⁷ AECOM, Kelowna, BC, Canada.
⁸ Tetra Tech, Denver, CO, United States.
⁹ Clean Water Services, Tigard, OR, United States.
¹⁰ LISBP, INSA Toulouse, Toulouse, France; Dynamita, Nyons, France.
¹¹ Dynamita, Nyons, France.
¹² Hampton Roads Sanitation District, Virginia Beach, VA, United States.
¹³ Woodard & Curran, Inc., CT, United States.
¹⁴ Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States; School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, United States. Electronic address: aprilgu@cornell.edu.

PMID: 37688851
DOI: 10.1016/j.watres.2023.120540

Abstract

Side-stream enhanced biological phosphorus removal process (S2EBPR) has been demonstrated to improve performance stability and offers a suite of advantages compared to conventional EBPR design. Design and optimization of S2EBPR require modification of the current EBPR models that were not able to fully reflect the metabolic functions of and competition between the polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) under extended anaerobic conditions as in the S2EBPR conditions. In this study, we proposed and validated an improved model (iEBPR) for simulating PAO and GAO competition that incorporated heterogeneity and versatility in PAO sequential polymer usage, staged maintenance-decay, and glycolysis-TCA pathway shifts. The iEBPR model was first calibrated against bulk batch testing experiment data and proved to perform better than the previous EBPR model for predicting the soluble orthoP, ammonia, biomass glycogen, and PHA temporal profiles in a starvation batch testing under prolonged anaerobic conditions. We further validated the model with another independent set of anaerobic testing data that included high-resolution single-cell and specific population level intracellular polymer measurements acquired with single-cell Raman micro-spectroscopy technique. The model accurately predicted the temporal changes in the intracellular polymers at cellular and population levels within PAOs and GAOs, and further confirmed the proposed mechanism of sequential polymer utilization, and polymer availability-dependent and staged maintenance-decay in PAOs. These results indicate that under extended anaerobic phases as in S2EBPR, the PAOs may gain competitive advantages over GAOs due to the possession of multiple intracellular polymers and the adaptive switching of the anaerobic metabolic pathways that consequently lead to the later and slower decay in PAOs than GAOs. The iEBPR model can be applied to facilitate and optimize the design and operations of S2EBPR for more reliable nutrient removal and recovery from wastewater.

Keywords: Agent-based modeling; EBPR ananerobic metabolism; EBPR modeling; Glycolysis-TCA pathway switch; PAOs and GAOs competition; S2EBPR.