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Baeten JE, van Dijk EJH, Pronk M, van Loosdrecht MCM, Volcke EIP. Potential of off-gas analyses for sequentially operated reactors demonstrated on full-scale aerobic granular sludge technology. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 787:147651. [PMID: 34000528 DOI: 10.1016/j.scitotenv.2021.147651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/22/2021] [Accepted: 05/05/2021] [Indexed: 06/12/2023]
Abstract
This work shows how more variables can be monitored with a single off-gas sampler on sequentially operated than on continuously fed and aerated reactors and applies the methods to data from a full-scale aerobic granular sludge reactor as a demonstration and to obtain insight in this technology. First, liquid-gas transfer rates were calculated. Oxygen (O2) absorption and carbon dioxide (CO2) emission rates showed comparable cyclic trends due to the coupling of O2 consumption and CO2 production. Methane (CH4) emissions showed a stripping profile and nitrous oxide (N2O) emissions showed two peaks each cycle, which were attributed to different production pathways. Secondly, aeration characteristics were calculated, of which the gradual improvement within cycles was explained by surfactants degradation. Thirdly, liquid phase concentrations were estimated from off-gas measurements via a novel calculation procedure. As such, an average influent CH4 concentration of 0.7 g·m-3 was found. Fourthly, reaction rates could be estimated from off-gas data because no feeding or discharge occurred during reaction phases. The O2 consumption rate increased with increasing dissolved oxygen and decreased once nitrification was complete. Fifthly, greenhouse gas emissions could be derived, indicating a 0.06% N2O emission factor. Sixthly, off-gas gave an indication of influent characteristics. The CO2 emitted per kg COD catabolized corresponded with the TOC/COD ratio of typical wastewater organics in cycles with balanced nitrification and denitrification. High nitrogen removal efficiencies were associated with high catabolized COD/N ratios as estimated from the O2 absorption. Finally, mass balances could be closed using off-gas O2 data. As such, an observed yield of 0.27 g COD/g COD was found. All these variables could be estimated with a single sampler because aeration without feeding creates a more homogeneous off-gas composition and simplifies liquid-phase mass balances. Therefore, off-gas analyzers may have a broader application potential for sequentially operated reactors than currently acknowledged.
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Affiliation(s)
- Janis E Baeten
- BioCo Research Group, Department of Green Chemistry and Technology, Coupure Links 653, 9000 Gent, Ghent University, Belgium.
| | - Edward J H van Dijk
- Environmental Biotechnology, Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands; Royal HaskoningDHV, Laan 1914 35, Amersfoort 3800, AL, the Netherlands.
| | - Mario Pronk
- Environmental Biotechnology, Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands; Royal HaskoningDHV, Laan 1914 35, Amersfoort 3800, AL, the Netherlands.
| | - Mark C M van Loosdrecht
- Environmental Biotechnology, Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands.
| | - Eveline I P Volcke
- BioCo Research Group, Department of Green Chemistry and Technology, Coupure Links 653, 9000 Gent, Ghent University, Belgium.
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Reifsnyder S, Cecconi F, Rosso D. Dynamic load shifting for the abatement of GHG emissions, power demand, energy use, and costs in metropolitan hybrid wastewater treatment systems. WATER RESEARCH 2021; 200:117224. [PMID: 34029871 DOI: 10.1016/j.watres.2021.117224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 06/12/2023]
Abstract
The installation of satellite water resource recovery facilities (WRRFs) has strengthened the ability to provide cheap and reliable recycled water to meet the increasing water demand of expanding cities. As a result, recent studies have attempted to address the problem of how to optimally integrate satellite systems with other sectors of the urban sphere, such as the local economy, the power supply, and the regional carbon footprint. However, such studies are merely based on the spatial domain, thus neglecting potential time-dependent strategies that could further improve the sustainability of metropolitan water systems. Therefore, in this study a new conceptual framework is proposed for the dynamic management of hybrid systems comprised of both centralized and satellite WRRFs. Furthermore, a novel set of integrated real-time control (RTC) strategies are considered to analyze three different scenarios: 1) demand response, 2) flow equalization of the centralized WRRF and 3) reduction of greenhouse gas emissions. Data from a case study in California is used to develop an integrated dynamic model of a system of 8 facilities. Our results show that by dynamically shifting the dry-weather influent wastewater flows between hydraulically connected WRRFs, a reduction in power demand (up to 25%), energy use (4%), operating costs (8.5%) and indirect carbon emissions (4.5%) can be achieved. Therefore, this study suggests that a certain degree of hydraulic interconnection coupled with dynamic load-shifting strategies, can broaden the operational flexibility and overall sustainability of hybrid WRRF systems.
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Affiliation(s)
- Samuel Reifsnyder
- Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Water-Energy Nexus Center, University of California, Irvine, CA 92697-2175, USA
| | - Francesca Cecconi
- Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Water-Energy Nexus Center, University of California, Irvine, CA 92697-2175, USA
| | - Diego Rosso
- Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Water-Energy Nexus Center, University of California, Irvine, CA 92697-2175, USA.
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3
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Borzooei S, Amerlinck Y, Panepinto D, Abolfathi S, Nopens I, Scibilia G, Meucci L, Zanetti MC. Energy optimization of a wastewater treatment plant based on energy audit data: small investment with high return. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:17972-17985. [PMID: 32170609 DOI: 10.1007/s11356-020-08277-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
Ambitious energy targets in the 2020 European climate and energy package have encouraged many stakeholders to explore and implement measures improving the energy efficiency of water and wastewater treatment facilities. Model-based process optimization can improve the energy efficiency of wastewater treatment plants (WWTP) with modest investment and a short payback period. However, such methods are not widely practiced due to the labor-intensive workload required for monitoring and data collection processes. This study offers a multi-step simulation-based methodology to evaluate and optimize the energy consumption of the largest Italian WWTP using limited, preliminary energy audit data. An integrated modeling platform linking wastewater treatment processes, energy demand, and production sub-models is developed. The model is calibrated using a stepwise procedure based on available data. Further, a scenario-based optimization approach is proposed to obtain the non-dominated and optimized performance of the WWTP. The results confirmed that up to 5000 MWh annual energy saving in addition to improved effluent quality could be achieved in the studied case through operational changes only.
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Affiliation(s)
- Sina Borzooei
- Department of Civil and Environmental Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 10129, Torino, Italy.
| | - Youri Amerlinck
- Department of Data Analysis and Mathematical Modelling, BIOMATH, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Deborah Panepinto
- Department of Civil and Environmental Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 10129, Torino, Italy
| | - Soroush Abolfathi
- Warwick Water Research Group, School of Engineering, The University of Warwick, Coventry, CV4 7AL, UK
| | - Ingmar Nopens
- Department of Data Analysis and Mathematical Modelling, BIOMATH, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Gerardo Scibilia
- SMAT (Società Metropolitana Acque Torino) Research Center, Corso Unità d'Italia 235/3, 10127, Torino, Italy
| | - Lorenza Meucci
- SMAT (Società Metropolitana Acque Torino) Research Center, Corso Unità d'Italia 235/3, 10127, Torino, Italy
| | - Maria Chiara Zanetti
- Department of Civil and Environmental Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 10129, Torino, Italy
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Vandekerckhove TGL, Bodé S, De Mulder C, Vlaeminck SE, Boon N. 13C Incorporation as a Tool to Estimate Biomass Yields in Thermophilic and Mesophilic Nitrifying Communities. Front Microbiol 2019; 10:192. [PMID: 30814983 PMCID: PMC6381052 DOI: 10.3389/fmicb.2019.00192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 01/23/2019] [Indexed: 11/13/2022] Open
Abstract
Current methods determining biomass yield require sophisticated sensors for in situ measurements or multiple steady-state reactor runs. Determining the yield of specific groups of organisms in mixed cultures in a fast and easy manner remains challenging. This study describes a fast method to estimate the maximum biomass yield (Ymax), based on 13C incorporation during activity measurements. It was applied to mixed cultures containing ammonia oxidizing bacteria (AOB) or archaea (AOA) and nitrite oxidizing bacteria (NOB), grown under mesophilic (15-28°C) and thermophilic (50°C) conditions. Using this method, no distinction could be made between AOB and AOA co-existing in a community. A slight overestimation of the nitrifier biomass due to 13C redirection via SMP to heterotrophs could occur, meaning that this method determines the carbon fixation activity of the autotrophic microorganisms rather than the actual nitrifier biomass yield. Thermophilic AOA yields exceeded mesophilic AOB yields (0.22 vs. 0.06-0.11 g VSS g-1 N), possibly linked to a more efficient pathway for CO2 incorporation. NOB thermophilically produced less biomass (0.025-0.028 vs. 0.048-0.051 g VSS g-1 N), conceivably attributed to higher maintenance requirement, rendering less energy available for biomass synthesis. Interestingly, thermophilic nitrification yield was higher than its mesophilic counterpart, due to the dominance of AOA over AOB at higher temperatures. An instant temperature increase impacted the mesophilic AOB yield, corroborating the effect of maintenance requirement on production capacity. Model simulations of two realistic nitrification/denitrification plants were robust toward changing nitrifier yield in predicting effluent ammonium concentrations, whereas sludge composition was impacted. Summarized, a fast, precise and easily executable method was developed determining Ymax of ammonia and nitrite oxidizers in mixed communities.
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Affiliation(s)
| | - Samuel Bodé
- Isotope Bioscience Laboratory (ISOFYS), Ghent University, Ghent, Belgium
| | - Chaïm De Mulder
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Ghent, Belgium
| | - Siegfried E. Vlaeminck
- Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
- Research Group of Sustainable Energy, Air and Water Technology, University of Antwerp, Antwerp, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
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Amaral A, Bellandi G, Rehman U, Neves R, Amerlinck Y, Nopens I. Towards improved accuracy in modeling aeration efficiency through understanding bubble size distribution dynamics. WATER RESEARCH 2018; 131:346-355. [PMID: 29305229 DOI: 10.1016/j.watres.2017.10.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/19/2017] [Accepted: 10/28/2017] [Indexed: 06/07/2023]
Abstract
Aeration is the largest energy consumer in most water and resource recovery facilities, which is why oxygen transfer optimization is fundamental to improve energy efficiency. Although oxygen transfer is strongly influenced by the bubble size distribution dynamics, most aeration efficiency models currently do not include this influence explicitly. In few cases, they assume a single average bubble size. The motivation of this work is to investigate this knowledge gap, i.e. a more accurate calculation of the impact of bubble size distribution dynamics on oxygen transfer. Experiments were performed to study bubble size distribution dynamics along the height of a bubble column at different air flow rates for both tap water and solutions that mimic the viscosity of activated sludge at different sludge concentrations. Results show that bubble size is highly dynamic in space and time since it is affected by hydrodrynamics and the viscosity of the liquid. Consequently, oxygen transfer also has a dynamic character. The concept of a constant overall volumetric oxygen transfer coefficient, KLa, can thus be improved. A new modeling approach to determine the KLa locally based on bubble size distribution dynamics is introduced as an alternative. This way, the KLa for the entire column is calculated and compared to the one measured by a traditional method. Results are in good agreement for tap water. The modeled KLa based on the new approach slightly overestimates the experimental KLa for solutions that mimic the viscosity of activated sludge. The difference appears to be lower when the air flow rate increases. This work can be considered as a first step towards more accurate and rigorous mechanistic aeration efficiency models which are based on in-depth mechanism knowledge. This is key for oxygen transfer optimization and consequently energy savings.
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Affiliation(s)
- Andreia Amaral
- BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, 9000, Ghent, Belgium; MARETEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisbon, Portugal.
| | - Giacomo Bellandi
- BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, 9000, Ghent, Belgium; Department of Civil and Environmental Engineering, University of Florence, Via di S. Marta 3, 50139, Florence, Italy
| | - Usman Rehman
- BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Ramiro Neves
- MARETEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisbon, Portugal
| | - Youri Amerlinck
- BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Ingmar Nopens
- BIOMATH, Department of Mathematical Modeling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
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Amaral A, Schraa O, Rieger L, Gillot S, Fayolle Y, Bellandi G, Amerlinck Y, Mortier STFC, Gori R, Neves R, Nopens I. Towards advanced aeration modelling: from blower to bubbles to bulk. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2017; 75:507-517. [PMID: 28192345 DOI: 10.2166/wst.2016.365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Aeration is an essential component of aerobic biological wastewater treatment and is the largest energy consumer at most water resource recovery facilities. Most modelling studies neglect the inherent complexity of the aeration systems used. Typically, the blowers, air piping, and diffusers are not modelled in detail, completely mixed reactors in a series are used to represent plug-flow reactors, and empirical correlations are used to describe the impact of operating conditions on bubble formation and transport, and oxygen transfer from the bubbles to the bulk liquid. However, the mechanisms involved are very complex in nature and require significant research efforts. This contribution highlights why and where there is a need for more detail in the different aspects of the aeration system and compiles recent efforts to develop physical models of the entire aeration system (blower, valves, air piping and diffusers), as well as adding rigour to the oxygen transfer efficiency modelling (impact of viscosity, bubble size distribution, shear and hydrodynamics). As a result of these model extensions, more realistic predictions of dissolved oxygen profiles and energy consumption have been achieved. Finally, the current needs for further model development are highlighted.
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Affiliation(s)
- Andreia Amaral
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, Ghent 9000, Belgium E-mail: ; MARETEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, Lisboa 1049-001, Portugal
| | - Oliver Schraa
- inCTRL Solutions Inc., 470 Anthony Drive, Oakville, ON L6J 2K5, Canada
| | - Leiv Rieger
- inCTRL Solutions Inc., 470 Anthony Drive, Oakville, ON L6J 2K5, Canada
| | - Sylvie Gillot
- Irstea, UR MALY, centre de Lyon-Villeurbanne, 5 rue de la Doua, Villeurbanne cedex F-69926, France
| | - Yannick Fayolle
- Irstea, UR HBAN, centre d'Antony, 1 rue Pierre-Gilles de Gennes, Antony cedex F-92761, France
| | - Giacomo Bellandi
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, Ghent 9000, Belgium E-mail: ; Department of Civil and Environmental Engineering, University of Florence, via di S. Marta, 3, Florence 50139, Italy
| | - Youri Amerlinck
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, Ghent 9000, Belgium E-mail:
| | - Séverine T F C Mortier
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, Ghent 9000, Belgium E-mail:
| | - Riccardo Gori
- Department of Civil and Environmental Engineering, University of Florence, via di S. Marta, 3, Florence 50139, Italy
| | - Ramiro Neves
- MARETEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, Lisboa 1049-001, Portugal
| | - Ingmar Nopens
- BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, Ghent 9000, Belgium E-mail:
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