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Li G, Tooker NB, Wang D, Srinivasan V, Barnard JL, Russell A, Stinson B, McQuarrie J, Schauer P, Menniti A, Varga E, Hauduc H, Takács I, Bott C, Dobrowski P, Onnis-Hayden A, Gu AZ. Modeling versatile and dynamic anaerobic metabolism for PAOs/GAOs competition using agent-based model and verification via single cell Raman Micro-spectroscopy. WATER RESEARCH 2023; 245:120540. [PMID: 37688851 DOI: 10.1016/j.watres.2023.120540] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/25/2023] [Accepted: 08/27/2023] [Indexed: 09/11/2023]
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.
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Affiliation(s)
- Guangyu Li
- Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States; School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, United States
| | - Nicholas B Tooker
- Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States
| | - Dongqi Wang
- 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
| | - Varun Srinivasan
- Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States; Brown and Caldwell, One Tech Drive, Andover, MA, United States
| | | | - Andrew Russell
- South Cary Water Reclamation Facility, Apex, NC, United States
| | | | | | | | | | - Erika Varga
- LISBP, INSA Toulouse, Toulouse, France; Dynamita, Nyons, France
| | | | | | - Charles Bott
- Hampton Roads Sanitation District, Virginia Beach, VA, United States
| | | | - Annalisa Onnis-Hayden
- Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States
| | - April Z Gu
- Department of Civil & Environmental Engineering, Northeastern University, Boston, MA, United States; School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, United States.
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Sabba F, Farmer M, Jia Z, Di Capua F, Dunlap P, Barnard J, Qin CD, Kozak JA, Wells G, Downing L. Impact of operational strategies on a sidestream enhanced biological phosphorus removal (S2EBPR) reactor in a carbon limited wastewater plant. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159280. [PMID: 36216061 DOI: 10.1016/j.scitotenv.2022.159280] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/23/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
Water resource recovery facilities are faced with stringent effluent phosphorus limits to reduce nutrient pollution. Enhanced biological phosphorus removal (EBPR) is the most common biological route to remove phosphorus; however, many facilities struggle to achieve consistent performance due to limited carbon availability in the influent wastewater. A promising process to improve carbon availability is through return activated sludge (RAS) fermentation via sidestream EBPR (S2EBPR). In this study, a full-scale S2EBPR pilot was operated with a sidestream plus carbon configuration (SSRC) at a carbon-limited facility. A model based on the pilot test was developed and calibrated in the SUMO platform and used to explore routes for improving orthophosphate (OP) effluent compliance. Modeling results showed that RAS diversion by itself was not sufficient to drive OP removal to permit limits of 1 mg L-1, therefore, other strategies were evaluated. Supplemental carbon addition of MicroC® at 1.90 L min-1 and controlling the phosphorus concentration below 3.5 mgP L-1 in the primary effluent (PE) proved to be valid supplemental strategies to achieve OP removal below 1 mg L-1 most of the time. In particular, the proposed supplemental carbon flow rate would result in an improvement of the rbCOD:P ratio from 17:1 to 26:1. The synergistic approach of RAS diversion and supplemental carbon addition increased the polyphosphate accumulating organisms (PAO) population while minimizing the supplemental carbon needed to achieve consistent phosphorus removal. Overall, this pilot and modeling study shows that joint strategies, including RAS diversion, carbon addition and PE control, can be effective to achieve optimal control of OP effluent.
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Affiliation(s)
| | - McKenna Farmer
- Northwestern University, Dept of Civil and Environmental Engineering, Evanston, IL, USA
| | - Zhen Jia
- Northwestern University, Dept of Civil and Environmental Engineering, Evanston, IL, USA
| | | | | | | | - Cindy Dongqi Qin
- Metropolitan Water Reclamation District of Greater Chicago, IL, USA
| | - Joseph A Kozak
- Metropolitan Water Reclamation District of Greater Chicago, IL, USA
| | - George Wells
- Northwestern University, Dept of Civil and Environmental Engineering, Evanston, IL, USA
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