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Noutsopoulos C, Gkoutzioupa V, Katsou E, Frison N, Fatone F, Malamis S. Integrated selection of PHA-storing biomass and nitrogen removal via nitrite from sludge reject water: a mathematical model. ENVIRONMENTAL TECHNOLOGY 2024; 45:73-86. [PMID: 35794016 DOI: 10.1080/09593330.2022.2099311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
One of the most recent innovations to promote a circular economy during wastewater treatment is the production of biopolymers. It has recently been demonstrated that it is possible to integrate the production of biopolymers in the form of polyhydroxyalkanoates (PHA) with nitrogen removal via nitrite during the treatment of sludge reject water. In the present study, simulation of a new process for bioresource recovery was conducted by an appropriate modification of the Activated Sludge Model 3. The process consists of the integrated nitrogen removal via nitrite from sludge reject water and the selection of PHA-storing biomass by inducing a feast and famine regime under aerobic and anoxic conditions. According to the results, it is anticipated that simulation data matched very satisfactorily with the experimental data and confirmed the main experimental observation, showing that during the famine period the PHA depletion was almost complete due to the availability of nitrite as the electron acceptor. Simulation results indicate that the selection of the volumetric organic loading rate and of the relative duration of the aerobic feast/anoxic famine duration is critical in order to allow for the effective denitritation of the internally stored PHA during the famine phase.
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Affiliation(s)
- Constantinos Noutsopoulos
- Sanitary Engineering Laboratory, Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, Athens, Greece
| | | | - Evina Katsou
- Department of Civil & Environmental Engineering, Uxbridge Campus, Institute of Environment, Health and Societies, Brunel University London, Uxbridge, UK
| | - Nicola Frison
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Francesco Fatone
- Department of Science and Engineering of Materials, Environment and Urban Planning-SIMAU, Marche Polytechnic University, Ancona, Italy
| | - Simos Malamis
- Sanitary Engineering Laboratory, Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, Athens, Greece
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2
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Koskue V, Pyrhönen VP, Freguia S, Ledezma P, Kokko M. Modelling and techno-economic assessment of (bio)electrochemical nitrogen removal and recovery from reject water at full WWTP scale. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 319:115747. [PMID: 35849924 DOI: 10.1016/j.jenvman.2022.115747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/29/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
At conventional wastewater treatment plants (WWTPs), reject waters originating from the dewatering of anaerobically digested sludge contain the highest nitrogen concentrations within the plant and thereby have potential for realising nitrogen recovery in a reusable form. At the same time, nitrogen removal from reject waters has potential to reduce the energetic and chemical demands of the WWTP due to a reduced nutrient load to the activated sludge process. In recent years, (bio)electrochemical methods have been extensively studied for nitrogen recovery from reject waters in laboratory-scale but not yet implemented in real WWTP environments, particularly due to concerns about the need for large capital investments. This study assessed the techno-economic feasibility of retrofitting a (bio)electrochemical nitrogen removal and recovery (NRR) unit into the reject water circulation line of a full-scale WWTP through modelling. Data from laboratory-scale (bio)electroconcentration ((B)EC) experiments was used to construct a simple, semi-empirical model block integrated into the Benchmark Simulation Model No. 2 (BSM2) simulating a generalised WWTP. The effects of nitrogen removal from the reject water on both the effluent quality and operational costs of the WWTP were assessed and compared to the BSM2 performance without an NRR unit. In all studied scenarios, the effluent quality index was improved by 4-11%, while both the aeration (7-19% decrease) and carbon (24-71%) requirements were reduced. The additional energy consumed by the NRR unit increased the total operational cost index by >18%, but the revenue assumed for the generated nutrient product (20 EUR kgN-1) was enough to make the BEC-NRR scenarios at realistically low current densities (1 and 5 A m-2) economically attractive compared to the control. A sensitivity analysis revealed that electricity price and nutrient product value had the most notable effects on the feasibility of the NRR unit. The results suggest a key factor in making (bio)electrochemical NRR economically viable is to reduce its electricity consumption further, while the anticipated increases in nitrogen fertiliser prices can help accelerate the adoption of these methods in larger scale.
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Affiliation(s)
- Veera Koskue
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland.
| | - Veli-Pekka Pyrhönen
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
| | - Stefano Freguia
- Department of Chemical Engineering, The University of Melbourne, Grattan Street, Parkville, VIC 3010, Australia
| | - Pablo Ledezma
- Australian Centre for Water and Environmental Biotechnology, University of Queensland, Gehrmann Laboratories Building (60), Brisbane, QLD 4072, Australia
| | - Marika Kokko
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
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3
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Kirim G, McCullough K, Bressani-Ribeiro T, Domingo-Félez C, Duan H, Al-Omari A, De Clippeleir H, Jimenez J, Klaus S, Ladipo-Obasa M, Mehrani MJ, Regmi P, Torfs E, Volcke EIP, Vanrolleghem PA. Mainstream short-cut N removal modelling: current status and perspectives. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:2539-2564. [PMID: 35576252 DOI: 10.2166/wst.2022.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This work gives an overview of the state-of-the-art in modelling of short-cut processes for nitrogen removal in mainstream wastewater treatment and presents future perspectives for directing research efforts in line with the needs of practice. The modelling status for deammonification (i.e., anammox-based) and nitrite-shunt processes is presented with its challenges and limitations. The importance of mathematical models for considering N2O emissions in the design and operation of short-cut nitrogen removal processes is considered as well. Modelling goals and potential benefits are presented and the needs for new and more advanced approaches are identified. Overall, this contribution presents how existing and future mathematical models can accelerate successful full-scale mainstream short-cut nitrogen removal applications.
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Affiliation(s)
- Gamze Kirim
- modelEAU, Université Laval, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada E-mail: ; CentrEau, Quebec Water Research Centre, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada
| | - Kester McCullough
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA; Hampton Roads Sanitation District, 1434 Air Rail Ave., Virginia Beach, VA 23455, USA
| | - Thiago Bressani-Ribeiro
- BioCo Research Group, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, Gent 9000, Belgium
| | - Carlos Domingo-Félez
- Department of Environmental Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Haoran Duan
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ahmed Al-Omari
- Brown and Caldwell, 1725 Duke St. Suite 250, Alexandria, VA 22314, USA
| | - Haydee De Clippeleir
- DC Water and Sewer Authority, 5000 Overlook Ave., SW., Washington, DC 20032, USA
| | - Jose Jimenez
- Brown and Caldwell, 1725 Duke St. Suite 250, Alexandria, VA 22314, USA
| | - Stephanie Klaus
- Hampton Roads Sanitation District, 1434 Air Rail Ave., Virginia Beach, VA 23455, USA
| | - Mojolaoluwa Ladipo-Obasa
- DC Water and Sewer Authority, 5000 Overlook Ave., SW., Washington, DC 20032, USA; Department of Civil & Environmental Engineering, The George Washington University, 800 22nd Street NW, Washington, DC 20037, USA
| | - Mohamad-Javad Mehrani
- Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Ul. Narutowicza 11/12, Gdansk 80-233, Poland; Department of Urban Water and Waste Management, University of Duisburg-Essen, Universit¨atsstraße 15, 45141, Essen, Germany
| | - Pusker Regmi
- Brown and Caldwell, 1725 Duke St. Suite 250, Alexandria, VA 22314, USA
| | - Elena Torfs
- Centre for Advanced Process Technology for Urban Resource recovery (CAPTURE), Frieda Saeysstraat 1, Gent 9000, Belgium; BIOMATH, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent 9000, Belgium
| | - Eveline I P Volcke
- BioCo Research Group, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, Gent 9000, Belgium; Centre for Advanced Process Technology for Urban Resource recovery (CAPTURE), Frieda Saeysstraat 1, Gent 9000, Belgium
| | - Peter A Vanrolleghem
- modelEAU, Université Laval, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada E-mail: ; CentrEau, Quebec Water Research Centre, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada
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4
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Design of Feedback Control Strategies in a Plant-Wide Wastewater Treatment Plant for Simultaneous Evaluation of Economics, Energy Usage, and Removal of Nutrients. ENERGIES 2021. [DOI: 10.3390/en14196386] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Simultaneous removal of nitrogen and phosphorous is a recommended practice while treating wastewater. In the present study, control strategies based on proportional-integral (PI), model predictive control (MPC), and fuzzy logic are developed and implemented on a plant-wide wastewater treatment plant. Four combinations of control frameworks are developed in order to reduce the operational cost and improve the effluent quality. As a working platform, a Benchmark simulation model (BSM2-P) is used. A default control framework with PI controllers is used to control nitrate and dissolved oxygen (DO) by manipulating the internal recycle and oxygen mass transfer coefficient (KLa). Hierarchical control topology is proposed in which a lower-level control framework with PI controllers is implemented to DO in the sixth reactor by regulating the KLa of the fifth, sixth, and seventh reactors, and fuzzy and MPC are used at the supervisory level. This supervisory level considers the ammonia in the last aerobic reactor as a feedback signal to alter the DO set-points. PI-fuzzy showed improved effluent quality by 21.1%, total phosphorus removal rate by 33.3% with an increase of operational cost, and a slight increase in the production rates of greenhouse gases. In all the control design frameworks, a trade-off is observed between operational cost and effluent quality.
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Flores-Alsina X, Feldman H, Monje VT, Ramin P, Kjellberg K, Jeppsson U, Batstone DJ, Gernaey KV. Evaluation of anaerobic digestion post-treatment options using an integrated model-based approach. WATER RESEARCH 2019; 156:264-276. [PMID: 30925373 DOI: 10.1016/j.watres.2019.02.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/16/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
The objective of this paper is to present the main results of an engineering-research project dealing with model-based evaluation of waste streams treatment from a biotech company. This has been extensively done in domestic treatment systems, but is equally important, and with different challenges in industrial wastewater treatment. A new set of biological (activated sludge, anaerobic digestion), physicochemical (aqueous phase, precipitation, mass transfer) process models and model interfaces are required to describe removal of organics in an upflow anaerobic sludge blanket (UASB) reactor plus either traditional nitrification/denitrification (A1) or partial nitritation (PN)/anammox (ANX) (A2) processes. Model-based analysis shows that option A1 requires a decrease in digestion energy recovery (Erecovery) in order to have enough organic substrate for subsequent post NO3 reduction treatment (95 kWh.kg N-1). In contrast, A2 in an aerobic granular sludge reactor allows for higher UASB conversion since N removal is carried out autotrophically. The study also reveals that the addition of an aerated pre-treatment unit prior to the PN/ANX (A2) reactor promotes COD and H2S oxidation, CO2 and CH4 stripping, a pH increase (up to 8.5) and a reduction of the risk of intra-granular precipitation as well as sulfide inhibition. Simulations indicate clear differences regarding the microbial distribution/abundance within the biofilm in A2 when comparing the two operational modes. Final results show the effects of different loading and operational conditions; dissolved oxygen (DO), Total Suspended Solids (TSSop), energy recovery (Erecovery); on the overall process performance; N removal, aeration energy (Eaeration), net energy production (Erecovery); using response surfaces, highlighting the need of integrated approaches to avoid sub-optimal outcomes. The study shows the benefits of virtual plant simulation and demonstrates the potential of model-based evaluation when process engineers in industry have to decide between competing options.
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Affiliation(s)
- X Flores-Alsina
- Process and Systems Engineering Centr (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building, 229, DK-2800 Kgs. Lyngby, Denmark.
| | - H Feldman
- Process and Systems Engineering Centr (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building, 229, DK-2800 Kgs. Lyngby, Denmark
| | - V T Monje
- Process and Systems Engineering Centr (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building, 229, DK-2800 Kgs. Lyngby, Denmark
| | - P Ramin
- Process and Systems Engineering Centr (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building, 229, DK-2800 Kgs. Lyngby, Denmark
| | - K Kjellberg
- Novozymes A/S, Hallas Alle 1, DK-4400 Kalundborg, Denmark
| | - U Jeppsson
- Division of Industrial Electrical Engineering and Automation, Department of Biomedical Engineering, Lund University, Box 118, SE-221 00, Lund, Sweden
| | - D J Batstone
- Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, Brisbane, Queensland, 4072, Australia
| | - K V Gernaey
- Process and Systems Engineering Centr (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building, 229, DK-2800 Kgs. Lyngby, Denmark
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Fernández-Arévalo T, Lizarralde I, Fdz-Polanco F, Pérez-Elvira SI, Garrido JM, Puig S, Poch M, Grau P, Ayesa E. Quantitative assessment of energy and resource recovery in wastewater treatment plants based on plant-wide simulations. WATER RESEARCH 2017; 118:272-288. [PMID: 28456110 DOI: 10.1016/j.watres.2017.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/16/2017] [Accepted: 04/01/2017] [Indexed: 06/07/2023]
Abstract
The growing development of technologies and processes for resource treatment and recovery is offering endless possibilities for creating new plant-wide configurations or modifying existing ones. However, the configurations' complexity, the interrelation between technologies and the influent characteristics turn decision-making into a complex or unobvious process. In this frame, the Plant-Wide Modelling (PWM) library presented in this paper allows a thorough, comprehensive and refined analysis of different plant configurations that are basic aspects in decision-making from an energy and resource recovery perspective. In order to demonstrate the potential of the library and the need to run simulation analyses, this paper carries out a comparative analysis of WWTPs, from a techno-economic point of view. The selected layouts were (1) a conventional WWTP based on a modified version of the Benchmark Simulation Model No. 2, (2) an upgraded or retrofitted WWTP, and (3) a new Wastewater Resource Recovery Facilities (WRRF) concept denominated as C/N/P decoupling WWTP. The study was based on a preliminary analysis of the organic matter and nutrient energy use and recovery options, a comprehensive mass and energy flux distribution analysis in each configuration in order to compare and identify areas for improvement, and a cost analysis of each plant for different influent COD/TN/TP ratios. Analysing the plants from a standpoint of resources and energy utilization, a low utilization of the energy content of the components could be observed in all configurations. In the conventional plant, the COD used to produce biogas was around 29%, the upgraded plant was around 36%, and 34% in the C/N/P decoupling WWTP. With regard to the self-sufficiency of plants, achieving self-sufficiency was not possible in the conventional plant, in the upgraded plant it depended on the influent C/N ratio, and in the C/N/P decoupling WWTP layout self-sufficiency was feasible for almost all influents, especially at high COD concentrations. The plant layouts proposed in this paper are just a sample of the possibilities offered by current technologies. Even so, the library presented here is generic and can be used to construct any other plant layout, provided that a model is available.
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Affiliation(s)
- T Fernández-Arévalo
- Ceit-IK4 and Tecnun (University of Navarra), 15 Paseo Manuel de Lardizabal, San Sebastián, 20018, Spain; Conaqua Consulting, Paseo Manuel de Lardizabal 15, San Sebastián, 20018, Spain.
| | - I Lizarralde
- Ceit-IK4 and Tecnun (University of Navarra), 15 Paseo Manuel de Lardizabal, San Sebastián, 20018, Spain.
| | - F Fdz-Polanco
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, C/Dr. Mergelina, s/n, 47011, Valladolid, Spain.
| | - S I Pérez-Elvira
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, C/Dr. Mergelina, s/n, 47011, Valladolid, Spain.
| | - J M Garrido
- Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
| | - S Puig
- LEQUIA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003, Girona, Catalonia, Spain.
| | - M Poch
- LEQUIA, Institute of the Environment, University of Girona, Campus Montilivi, C/Maria Aurèlia Capmany, 69, E-17003, Girona, Catalonia, Spain.
| | - P Grau
- Ceit-IK4 and Tecnun (University of Navarra), 15 Paseo Manuel de Lardizabal, San Sebastián, 20018, Spain.
| | - E Ayesa
- Ceit-IK4 and Tecnun (University of Navarra), 15 Paseo Manuel de Lardizabal, San Sebastián, 20018, Spain.
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Solon K, Flores-Alsina X, Kazadi Mbamba C, Ikumi D, Volcke EIP, Vaneeckhaute C, Ekama G, Vanrolleghem PA, Batstone DJ, Gernaey KV, Jeppsson U. Plant-wide modelling of phosphorus transformations in wastewater treatment systems: Impacts of control and operational strategies. WATER RESEARCH 2017; 113:97-110. [PMID: 28199867 DOI: 10.1016/j.watres.2017.02.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 05/06/2023]
Abstract
The objective of this paper is to report the effects that control/operational strategies may have on plant-wide phosphorus (P) transformations in wastewater treatment plants (WWTP). The development of a new set of biological (activated sludge, anaerobic digestion), physico-chemical (aqueous phase, precipitation, mass transfer) process models and model interfaces (between water and sludge line) were required to describe the required tri-phasic (gas, liquid, solid) compound transformations and the close interlinks between the P and the sulfur (S) and iron (Fe) cycles. A modified version of the Benchmark Simulation Model No. 2 (BSM2) (open loop) is used as test platform upon which three different operational alternatives (A1, A2, A3) are evaluated. Rigorous sensor and actuator models are also included in order to reproduce realistic control actions. Model-based analysis shows that the combination of an ammonium ( [Formula: see text] ) and total suspended solids (XTSS) control strategy (A1) better adapts the system to influent dynamics, improves phosphate [Formula: see text] accumulation by phosphorus accumulating organisms (XPAO) (41%), increases nitrification/denitrification efficiency (18%) and reduces aeration energy (Eaeration) (21%). The addition of iron ( [Formula: see text] ) for chemical P removal (A2) promotes the formation of ferric oxides (XHFO-H, XHFO-L), phosphate adsorption (XHFO-H,P, XHFO-L,P), co-precipitation (XHFO-H,P,old, XHFO-L,P,old) and consequently reduces the P levels in the effluent (from 2.8 to 0.9 g P.m-3). This also has an impact on the sludge line, with hydrogen sulfide production ( [Formula: see text] ) reduced (36%) due to iron sulfide (XFeS) precipitation. As a consequence, there is also a slightly higher energy production (Eproduction) from biogas. Lastly, the inclusion of a stripping and crystallization unit (A3) for P recovery reduces the quantity of P in the anaerobic digester supernatant returning to the water line and allows potential struvite ( [Formula: see text] ) recovery ranging from 69 to 227 kg.day-1 depending on: (1) airflow (Qstripping); and, (2) magnesium ( [Formula: see text] ) addition. All the proposed alternatives are evaluated from an environmental and economical point of view using appropriate performance indices. Finally, some deficiencies and opportunities of the proposed approach when performing (plant-wide) wastewater treatment modelling/engineering projects are discussed.
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Affiliation(s)
- K Solon
- Division of Industrial Electrical Engineering and Automation, Department of Biomedical Engineering, Lund University, Box 118, SE-221 00, Lund, Sweden
| | - X Flores-Alsina
- CAPEC-PROCESS Research Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building 229, DK-2800, Kgs. Lyngby, Denmark
| | - C Kazadi Mbamba
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - D Ikumi
- Water Research Group, Department of Civil Engineering, University of Cape Town, Rondebosch, 7700, South Africa
| | - E I P Volcke
- Department of Biosystems Engineering, Ghent University, Coupure Links 653, B-9000, Gent, Belgium
| | - C Vaneeckhaute
- BioEngine, Department of Chemical Engineering, Université Laval, Québec, QC, G1V 0A6, Canada
| | - G Ekama
- Water Research Group, Department of Civil Engineering, University of Cape Town, Rondebosch, 7700, South Africa
| | - P A Vanrolleghem
- modelEAU, Département de Génie Civil et de Génie des Eaux, Université Laval, Québec, QC, G1V 0A6, Canada
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - K V Gernaey
- CAPEC-PROCESS Research Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building 229, DK-2800, Kgs. Lyngby, Denmark
| | - U Jeppsson
- Division of Industrial Electrical Engineering and Automation, Department of Biomedical Engineering, Lund University, Box 118, SE-221 00, Lund, Sweden.
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Bertanza G, Papa M, Canato M, Collivignarelli MC, Pedrazzani R. How can sludge dewatering devices be assessed? Development of a new DSS and its application to real case studies. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2014; 137:86-92. [PMID: 24603031 DOI: 10.1016/j.jenvman.2014.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 11/28/2013] [Accepted: 02/02/2014] [Indexed: 06/03/2023]
Abstract
A key issue in biological Waste Water Treatment Plants (WWTPs) operation is represented by the sludge management. Mechanical dewatering is a crucial stage for sludge volume reduction; though, being a costly operation, its optimization is required. We developed an original experimental methodology to evaluate the technical (dewatering efficiency) and financial (total treatment costs) performance of dewatering devices, which might be used as a DSS (Decision Support System) for WWTP managers. This tool was then applied to two real case studies for comparing, respectively, three industrial size centrifuges, and two different operation modes of the same machine (fixed installation vs. outsourcing service). In both the cases, the best option was identified, based jointly on economic and (site-specific) technical evaluations.
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Affiliation(s)
- Giorgio Bertanza
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, via Branze 43, I-25123 Brescia, Italy.
| | - Matteo Papa
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, via Branze 43, I-25123 Brescia, Italy
| | - Matteo Canato
- DICAr, Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 1, I-27100 Pavia, Italy
| | | | - Roberta Pedrazzani
- DIMI, Department of Mechanical and Industrial Engineering, University of Brescia, via Branze 38, I-25123 Brescia, Italy
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9
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Flores-Alsina X, Rodríguez-Roda I, Sin G, Gernaey KV. Multi-criteria evaluation of wastewater treatment plant control strategies under uncertainty. WATER RESEARCH 2008; 42:4485-4497. [PMID: 18804255 DOI: 10.1016/j.watres.2008.05.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 05/13/2008] [Accepted: 05/29/2008] [Indexed: 05/26/2023]
Abstract
The evaluation of activated sludge control strategies in wastewater treatment plants (WWTP) via mathematical modelling is a complex activity because several objectives; e.g. economic, environmental, technical and legal; must be taken into account at the same time, i.e. the evaluation of the alternatives is a multi-criteria problem. Activated sludge models are not well characterized and some of the parameters can present uncertainty, e.g. the influent fractions arriving to the facility and the effect of either temperature or toxic compounds on the kinetic parameters, having a strong influence in the model predictions used during the evaluation of the alternatives and affecting the resulting rank of preferences. Using a simplified version of the IWA Benchmark Simulation Model No. 2 as a case study, this article shows the variations in the decision making when the uncertainty in activated sludge model (ASM) parameters is either included or not during the evaluation of WWTP control strategies. This paper comprises two main sections. Firstly, there is the evaluation of six WWTP control strategies using multi-criteria decision analysis setting the ASM parameters at their default value. In the following section, the uncertainty is introduced, i.e. input uncertainty, which is characterized by probability distribution functions based on the available process knowledge. Next, Monte Carlo simulations are run to propagate input through the model and affect the different outcomes. Thus (i) the variation in the overall degree of satisfaction of the control objectives for the generated WWTP control strategies is quantified, (ii) the contributions of environmental, legal, technical and economic objectives to the existing variance are identified and finally (iii) the influence of the relative importance of the control objectives during the selection of alternatives is analyzed. The results show that the control strategies with an external carbon source reduce the output uncertainty in the criteria used to quantify the degree of satisfaction of environmental, technical and legal objectives, but increasing the economical costs and their variability as a trade-off. Also, it is shown how a preliminary selected alternative with cascade ammonium controller becomes less desirable when input uncertainty is included, having simpler alternatives more chance of success.
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Affiliation(s)
- Xavier Flores-Alsina
- Laboratory of Chemical and Environmental Engineering, University of Girona, Girona, Spain.
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