1
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Qiu Y, Hug T, Wágner DS, Smets BF, Valverde-Pérez B, Plósz BG. Dynamic calibration of a new secondary settler model using Cand. Microthrix as a predictor of settling velocity. WATER RESEARCH 2023; 246:120664. [PMID: 37816276 DOI: 10.1016/j.watres.2023.120664] [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: 07/23/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 10/12/2023]
Abstract
Climate change is projected to increase the frequency of hydraulic shocks on urban water systems, affecting water resource recovery facilities (WRRFs). In these facilities, the settleability of activated sludge is a critical hydraulic bottleneck. However, to date, the dynamic prediction of hindered settling velocity (v0/rH) has remained unresolved. To address this significant knowledge gap, this study presents an assessment of microbial community predictors of hindered settling velocity. Through a regression analysis of independent laboratory and full-scale experimental data, we identified a close association between the relative abundance of Candidatus Microthrix filamentous bacteria and hindered settling velocity parameter values. While no direct association was observed between filamentous abundance and compression settling parameters, we propose linking the dynamic calibration of the compressive solid stress function to v0/rH. Notably, our results demonstrate, for the first time, the efficacy of dynamic calibration of SST models using the relative abundance of filamentous microbial predictors in a simulation model of the Kloten-Opfikon full-scale WRRF. Furthermore, besides Cand. Microthrix, Thiothrix is found to be a putative predictor for biomolecular SST calibration. These findings shed light on the potential of microbial communities to predict hindered settling velocity in WRRFs and offer valuable insights for improving wastewater treatment processes in the face of climate change challenges.
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Affiliation(s)
- Yuge Qiu
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Thomas Hug
- Hunziker-Betatech AG, Pflanzschulstrasse 17, Winterthur 8400, Switzerland
| | - Dorottya S Wágner
- Department of Environmental and Resource Engineering, Technical University of Denmark, Bygningstorvet, Bld. 115, Kgs. Lyngby 2800, Denmark
| | - Barth F Smets
- Department of Environmental and Resource Engineering, Technical University of Denmark, Bygningstorvet, Bld. 115, Kgs. Lyngby 2800, Denmark
| | - Borja Valverde-Pérez
- Department of Environmental and Resource Engineering, Technical University of Denmark, Bygningstorvet, Bld. 115, Kgs. Lyngby 2800, Denmark
| | - Benedek G Plósz
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK; Department of Built Environment, Oslo Metropolitan University, Postboks 4 St Olavs plass, Oslo 0130, Norway.
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2
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Kirim G, Torfs E, Vanrolleghem PA. An improved 1D reactive Bürger-Diehl settler model for secondary settling tank denitrification. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2022; 94:e10825. [PMID: 36518000 DOI: 10.1002/wer.10825] [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: 09/12/2022] [Revised: 11/22/2022] [Accepted: 11/26/2022] [Indexed: 06/17/2023]
Abstract
An improved 1D reactive settler model is pursued in order to increase the understanding of reactive settling processes and obtain a better prediction of the nitrogen mass balance in wastewater treatment systems. The developed model is based on the 1D Bürger-Diehl settler model with compression function and the Activated Sludge Model No. 1 biological reactions. Specific attention was paid in the model development phase to optimal selection of settling velocity functions and integration of the correct clarifier geometry. A unique measurement campaign was carried out with different operational scenarios to quantify the denitrification in a secondary settling tank. A detailed step-wise calibration effort demonstrated that by choosing an appropriate settling velocity function (power-law structure) and considering the true clarifier geometry allows to accurately capture the biomass concentration profile, total sludge mass, sludge blanket height, and the reaction rates. The resulting model is able to accurately describe total suspended solids (TSS) and nitrate concentration profiles throughout a settling tank under different operational conditions. As such the model can be applied in further scenario analysis and system optimization. PRACTITIONER POINTS: A unique measurement campaign was carried out to obtain detailed data for a reactive settler model development. A 1-D reactive settler model is developed based on the Bürger-Diehl framework including ASM1 biokinetics and the clarifier geometry. An extensive calibration and model selection effort was performed. The model accurately predicts measured concentration profiles in the settling tank. The developed model can be integrated in a plant-wide model to properly calculate the nitrogen mass balance of a WRRF.
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Affiliation(s)
- Gamze Kirim
- modelEAU, Université Laval, Québec, Québec, Canada
- CentrEau, Quebec Water Research Centre, Québec, Québec, Canada
| | - Elena Torfs
- modelEAU, Université Laval, Québec, Québec, Canada
- BIOMATH, Department of Data Analysis and Mathematical Modelling, Ghent University, Ghent, Belgium
- CentrEau, Quebec Water Research Centre, Québec, Québec, Canada
- Centre for Advanced Process Technology for Urban Resource recovery (CAPTURE), Ghent, Belgium
| | - Peter A Vanrolleghem
- modelEAU, Université Laval, Québec, Québec, Canada
- CentrEau, Quebec Water Research Centre, Québec, Québec, Canada
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3
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A hindered settling velocity model related to the fractal dimension and activated sludge flocs characteristics: Application to a sludge with a previous fragmentation and flocculation process. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.121812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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4
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Westesen A, Wells B, Peterson R. Identifying challenge sludges to process at the Hanford site. PARTICULATE SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1080/02726351.2022.2116372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Amy Westesen
- Nuclear Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Beric Wells
- Nuclear Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Reid Peterson
- Nuclear Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
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5
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Modelling filamentous bacteria in activated sludge systems and the advancements of secondary settling tank models: A review. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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6
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Roche C, Medina MEV, Schmitt P, Pallarès A, Pallarès G, Meilliez M, Laurent J. Densification of activated sludge for better settling performances: experimental characterization in batch column and model parameters calibration. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 86:110-127. [PMID: 35838286 DOI: 10.2166/wst.2022.192] [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
Conventional activated sludge (CAS) and densified sludge obtained using hydro-cyclone selective wasting were compared at a full-scale water resources recovery facility. The densified tested sludge, containing around 30-50% of aerobic granules, showed enhanced settleability with low and stable sludge volume index (SVI) compared to CAS, which suffered recurrent filamentous bulking. Further in-depth batch settling tests were carried out using a 40 cm diameter column fitted with ultrasonic transducers to monitor both sludge blanket height and vertical velocity profiles. Hindered settling and compression parameters were calibrated from the experiment for latter modelling use. Test sludge displayed more than doubled settling velocities compared to CAS, with hindered settling velocities remaining >3 m·h-1 even at high solids concentrations of 6.85 g·L-1. The compression regime was attained at much higher critical concentration for the test sludge. It also displayed enhanced thickening properties, with concentrations obtained after 30 min of settling being 20.9 and 8.5 g·L-1 respectively for test and control sludge. This allows for a substantial reduction of recirculation rates in practice. These results open perspectives in optimizing existing plant operation as well as clarifier design and modelling using densified sludge.
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Affiliation(s)
- Clément Roche
- SUEZ Infrastructures de Traitement, Tour CB 21-16, place de l'Iris, Paris-la-Défense Cedex F-92040, France
| | | | - Philippe Schmitt
- Université de Strasbourg, CNRS, ENGEES, ICube UMR 7357, Strasbourg F-67000, France E-mail:
| | - Anne Pallarès
- Université de Strasbourg, CNRS, ENGEES, ICube UMR 7357, Strasbourg F-67000, France E-mail: ; Université de Haute Alsace, Mulhouse F-68100, France
| | - Gwenaël Pallarès
- Université de Strasbourg, CNRS, ENGEES, ICube UMR 7357, Strasbourg F-67000, France E-mail:
| | - Mélanie Meilliez
- SUEZ Infrastructures de Traitement, Tour CB 21-16, place de l'Iris, Paris-la-Défense Cedex F-92040, France
| | - Julien Laurent
- Université de Strasbourg, CNRS, ENGEES, ICube UMR 7357, Strasbourg F-67000, France E-mail:
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7
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Juan-García P, Rieger L, Darch G, Schraa O, Corominas L. A framework for model-based assessment of resilience in water resource recovery facilities against power outage. WATER RESEARCH 2021; 202:117459. [PMID: 34358908 DOI: 10.1016/j.watres.2021.117459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
Current practice to enhance resilience in Water Resource Recovery Facilities (WRRFs) is to ensure redundancy or back-up for most critical equipment (e.g. pumps or blowers). Model-based assessment allows evaluation of different strategies for quantitatively and efficiently enhancing resilience and justifying the allocation of resources. The goal of this study is to provide guidance for the development of tailored deterministic models of full-scale WRRFs. A framework for model-based resilience assessment is proposed that provides guidance on data collection, model selection, model calibration and scenario analysis. The framework is embedded into the Good Modeling Practice (GMP) Unified Protocol, providing a new application for resilience assessment and an initial set of stressors for WRRFs. The usefulness of the framework is illustrated through a resilience assessment of the WRRF of Girona against power outage. Results show that, for the Girona facility, limited energy back-up can cause non-compliance of WRRF discharge limits in the case of a blower power shut-down of 6 h, and around 12 h when the blower shut-down is also combined with a shut-down of the recirculation pumps. The best option to enhance resilience would be increasing the power back-up by 218%, which allows the plant to run with recirculation pumps and blowers at minimum capacity. In such a case, resilience can be further enhanced by manipulating the air supply valves to optimise the air distribution, to balance oxygen needs in each reactor with the overall system pressure. We conclude that, with industry consensus on what is considered an acceptable level of resilience, a framework for resilience assessment would be a useful tool to enhance the resilience of our current water infrastructure. Further research is needed to establish if the permit structure should accommodate levels sof functionality to account for stress events.
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Affiliation(s)
- Pau Juan-García
- Atkins (member of SNC Lavalin), 500 Park Avenue - The Hub, Aztec West, Almondsbury, Bristol BS32 4RZ, UK; Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Emili Grahit 101, Girona 17003, Spain
| | - Leiv Rieger
- inCTRL Solutions Inc., 7 Innovation Dr., Suite 107, Dundas, Ontario L9H 7H9, Canada
| | - Geoff Darch
- Anglian Water Services Limited, Thorpe Wood House, Thorpe Wood, Peterborough PE3 6WT, UK
| | - Oliver Schraa
- inCTRL Solutions Inc., 7 Innovation Dr., Suite 107, Dundas, Ontario L9H 7H9, Canada
| | - Lluís Corominas
- Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Emili Grahit 101, Girona 17003, Spain; Universitat de Girona, Plaça de Sant Domènec 3, Girona 17004, Spain.
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8
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Ferreira DJDO, Fiuza MPDM, Cardoso M, Oliveira IM. Use of the
Weibull
model on sizing thickeners ‐
Part I
: Sedimentation curve representation. CAN J CHEM ENG 2020. [DOI: 10.1002/cjce.23904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Matheus Pires de Mattos Fiuza
- Department of Chemical Engineering/School of Engineering Federal University of Minas Gerais (UFMG) Belo Horizonte Brazil
| | - Marcelo Cardoso
- Department of Chemical Engineering/School of Engineering Federal University of Minas Gerais (UFMG) Belo Horizonte Brazil
| | - Idalmo Montenegro Oliveira
- Department of Chemical Engineering/School of Engineering Federal University of Minas Gerais (UFMG) Belo Horizonte Brazil
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9
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van Dijk EJH, Pronk M, van Loosdrecht MCM. A settling model for full-scale aerobic granular sludge. WATER RESEARCH 2020; 186:116135. [PMID: 32891906 DOI: 10.1016/j.watres.2020.116135] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/22/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
The settling behavior of aerobic granular sludge (AGS) in full-scale reactors is different from the settling of normal activated sludge. Current activated sludge models lack the features to describe the segregation of granules based on size during the settling process. This segregation plays an important role in the granulation process and therefore a better understanding of the settling is essential. The goal of this study was to model and evaluate the segregation of different granule sizes during settling and feeding in full-scale aerobic granular sludge reactors. Hereto the Patwardhan and Tien model was used. This model is an implementation of the Richardson and Zaki model, allowing for multiple classes of particles. To create the granular settling model, the most relevant parameters were identified using aerobic granular sludge from different full-scale Nereda® reactors. The settling properties of individual granules were measured as was the bulk behavior of granular sludge beds with uniform granular sludge particles. The obtained parameters were combined in a model containing multiple granule classes, which then was validated for granular sludge settling in a full-scale Nereda® reactor. In practice a hydraulic selection pressure is used to select for granular sludge. Under the same hydraulic selection pressure the model predicted that different stable granular size distributions can occur. This indicates that granular size distribution control would need a different mechanism then the hydraulic selection pressure alone. This model can be used to better understand and optimize operational parameters of AGS reactors that depend on granular sludge size, like biological nutrient removal. Furthermore insights from this model can also be used in the development of continuously fed AGS systems.
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Affiliation(s)
- Edward J H van Dijk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft, 2629, HZ, the Netherlands; Royal HaskoningDHV, Laan1914 35, Amersfoort, 3800, AL, the Netherlands.
| | - Mario Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft, 2629, HZ, the Netherlands; Royal HaskoningDHV, Laan1914 35, Amersfoort, 3800, AL, the Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft, 2629, HZ, the Netherlands
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10
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Plósz BG, Climent J, Griffin CT, Chiva S, Mukherjee R, Penkarski-Rodon E, Clarke M, Valverde-Pérez B. Hindered and compression solid settling functions - Sensor data collection, practical model identification and validation. WATER RESEARCH 2020; 184:116129. [PMID: 32755732 DOI: 10.1016/j.watres.2020.116129] [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: 12/19/2019] [Revised: 06/23/2020] [Accepted: 06/28/2020] [Indexed: 06/11/2023]
Abstract
Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in activated sludge water resource recovery facilities (WRRF). Mathematical models for predicting activated sludge solids settling velocity include parameters that show irreducible epistemic uncertainty. Therefore, reliable and periodic calibration of the settling velocity model is key for predicting activated sludge process capacity, thus averting possible failures under wet-weather flow- and filamentous bulking conditions. The two main knowledge gaps addressed here are: (1) Do constitutive functions for hindered and compression settling exist, for which all velocity parameters can be uniquely estimated? (2) What is the optimum sensor data requirement of developing reliable settling velocity functions? Innovative settling column sensor and full-scale data were used to identify and validate amended Vesilind function for hindered settling and a new exponential function for compression settling velocity using one-dimensional and computational fluid dynamics simulations. Results indicate practical model identifiability under well-settling and filamentous bulking conditions.
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Affiliation(s)
- Benedek G Plósz
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath, BA2 7AY, UK; Dept. of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800, Kgs. Lyngby, Denmark.
| | - Javier Climent
- Universitat Jaume I, Department of Mechanical Engineering and Construction, Av. Vicent Sos Baynat, s/n 12071, Castellón, Spain.
| | - Christopher T Griffin
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Sergio Chiva
- Universitat Jaume I, Department of Mechanical Engineering and Construction, Av. Vicent Sos Baynat, s/n 12071, Castellón, Spain.
| | - Rani Mukherjee
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Elena Penkarski-Rodon
- Dept. of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800, Kgs. Lyngby, Denmark.
| | - Matthew Clarke
- Department of Chemical Engineering, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Borja Valverde-Pérez
- Dept. of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800, Kgs. Lyngby, Denmark
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11
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Neumann TV, Facchine EG, Leonardo B, Khan S, Dickey MD. Direct write printing of a self-encapsulating liquid metal-silicone composite. SOFT MATTER 2020; 16:6608-6618. [PMID: 32613217 DOI: 10.1039/d0sm00803f] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Silicone composites featuring inclusions of liquid metal particles are soft and stretchable materials with useful electric, dielectric, mechanical, and thermal properties. Until recently, these materials have primarily been cast as films. This work examines the possibility of using uncured liquid metal-elastomer (LME) composites as inks for direct writing. The liquid metal inclusions act as rheological modifiers for the silicone, forming a gel-structure that can be extruded from a nozzle and hold its shape after printing. Additionally, by tuning the particle size, larger particles in the printed structures can settle to form metal-rich regions at the bottom of the structures, encased by metal-depleted (insulating) regions. Using mechanical force, the liquid metal-rich interior can be rendered conductive by sintering without affecting the insulating exterior. Thus, it is possible to print this soft and stretchable material while creating conductors with self-insulating shells.
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Affiliation(s)
- Taylor V Neumann
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Emily G Facchine
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Brian Leonardo
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Saad Khan
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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12
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Gao H, Stenstrom MK. Development and applications in computational fluid dynamics modeling for secondary settling tanks over the last three decades: A review. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2020; 92:796-820. [PMID: 31782964 DOI: 10.1002/wer.1279] [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: 09/19/2019] [Revised: 11/15/2019] [Accepted: 11/23/2019] [Indexed: 06/10/2023]
Abstract
Secondary settling tanks (SSTs) are a crucial process that determines the performance of the activated sludge process. However, their performance is often far from satisfactory. In the last 30 years, computational fluid dynamics (CFD) has become a robust and cost-efficient tool for designing new SSTs, modifying the geometries of existing SSTs and improved control techniques in wastewater treatment plants. The first part of this review paper discusses the different approaches to model the motion of particles in SSTs. The applications of different multiphase approaches and the widely applied single-phase approach in different SST studies are reviewed. The second part reviews current CFD research and engineering practice, focusing on the formation and the effect of density currents, effects of different design variables, parameter uncertainties in modeling structures, and atmospheric conditions. Finally, challenges and future improvements of sub-models (sludge settling, rheology, turbulence, and flocculation) in the SST model framework are identified. PRACTITIONER POINTS: The first journal review for the CFD applications in SSTs over the last decade. The controversy over the relationship between SOR and SST performance can be largely explained by the prediction of the CFD model. Density decoupling in the turbulence model is possible for well-baffled SSTs. The relative importance of three modeling parameters is summarized. Recommendations for future data collection are provided.
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Affiliation(s)
- Haiwen Gao
- Department of Civil and Environmental Engineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Michael K Stenstrom
- Department of Civil and Environmental Engineering, University of California Los Angeles, Los Angeles, CA, USA
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13
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Hunter TN, Peakall J, Egarr D, Cowell DM, Freear S, Tonge AS, Horton L, Rice HP, Smith I, Malone K, Burt D, Barnes M, Randall G, Biggs S, Fairweather M. Concentration profiling of a horizontal sedimentation tank utilising a bespoke acoustic backscatter array and CFD simulations. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2020.115560] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Bürger R, Careaga J, Diehl S. A review of flux identification methods for models of sedimentation. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:1715-1722. [PMID: 32644963 DOI: 10.2166/wst.2020.113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Most models of sedimentation contain the nonlinear hindered-settling flux function. If one assumes ideal conditions and no compression, then there exist several theoretically possible ways of identifying a large portion of the flux function from only one experiment by means of formulas derived from the theory of solutions of partial differential equations. Previously used identification methods and recently published such, which are based on utilizing conical vessels or centrifuges, are reviewed and compared with synthetic data (simulated experiments). This means that the identification methods are evaluated from a theoretical viewpoint without experimental errors or difficulties. The main contribution of the recent methods reviewed is that they, in theory, can identify a large portion of the flux function from a single experiment, in contrast to the traditional method that provides one point on the flux curve from each test. The new methods lay the foundation of rapid flux identification; however, experimental procedures need to be elaborated.
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Affiliation(s)
- R Bürger
- CI2MA and Departamento de Ingeniería Matemática, Universidad de Concepción, Casilla 160-C, Concepción, Chile E-mail:
| | - J Careaga
- Centre for Mathematical Sciences, Lund University, P.O. Box 118, S-221 00 Lund, Sweden
| | - S Diehl
- Centre for Mathematical Sciences, Lund University, P.O. Box 118, S-221 00 Lund, Sweden
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15
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Hanashiro RHR, Stoco CB, de Oliveira TV, Lenzi MK, Mariano AB, Vieira RB. Experimental validation of hindered settling models and flux theory applied in continuous flow process for harvesting
Acutodesmus obliquus. CAN J CHEM ENG 2019. [DOI: 10.1002/cjce.23467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Raí H. R. Hanashiro
- Department of Chemical EngineeringGraduate Program in Chemical EngineeringFederal University of ParanáCEP 81531‐980 CuritibaPRBrazil
| | - Caroline B. Stoco
- Department of Chemical EngineeringGraduate Program in Chemical EngineeringFederal University of ParanáCEP 81531‐980 CuritibaPRBrazil
| | - Thamayne V. de Oliveira
- Department of Chemical EngineeringGraduate Program in Chemical EngineeringFederal University of Santa CatarinaFlorianopolisSCBrazil
| | - Marcelo K. Lenzi
- Department of Chemical EngineeringGraduate Program in Chemical EngineeringFederal University of ParanáCEP 81531‐980 CuritibaPRBrazil
| | - André B. Mariano
- Department of Electric EngineeringGraduate Program in Materials Engineering and Science (PIPE)Nucleus of Research and Development in Self‐sustaining Energy (NPDEAS)UFPR ‐ Federal University of ParanáCP 19011, 81531‐980 CuritibaPRBrazil
| | - Rafael B. Vieira
- Department of Chemical EngineeringGraduate Program in Chemical EngineeringFederal University of ParanáCEP 81531‐980 CuritibaPRBrazil
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16
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Effect of Aluminium Salt Dosing on Activated Sludge Settleability Indicators: A New Settleability Model Development. WATER 2019. [DOI: 10.3390/w11010179] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
There has been a significant rise in the use of aluminium salts (Al3+) for the chemical precipitation of phosphates in wastewater treatment plants due to growing stricter regulatory requirements for wastewater effluent release to the environment. The modelling of the settleability of the resultant Al3+ sludge in present engineering practice for design and optimisation are still based on conventional sludge settleability models. This paper describes a novel activated sludge settleability model which is designed to analyse the effects of Al3+ dosing on activated sludge settleability indicators, zone settling velocity (ZSV), and stirred specific volume index (SSVI). The impact of Al3+ dosing concentrations on ZSV and SSVI of full scale activated sludge plant were analysed in the laboratory over a three years’ period and the exponential form of the Vesilind equation was optimised and validated to include alum chemical dosing parameters. The proposed model equation was found to effectively describe the settleability of Al3+ dosed sludge for dosing concentrations range of 0 to 100 mg/L.
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17
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Bürger R, Careaga J, Diehl S, Merckel R, Zambrano J. Estimating the hindered-settling flux function from a batch test in a cone. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2018.07.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Bürger R, Careaga J, Diehl S. A simulation model for settling tanks with varying cross-sectional area. CHEM ENG COMMUN 2017. [DOI: 10.1080/00986445.2017.1360871] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Raimund Bürger
- Departamento de Ingeniería Matemática, Facultad de Ciencias Físicas y Matemáticas, Centro de Investigación en Ingeniería Matemática, Universidad de Concepción, Concepción, Chile
| | - Julio Careaga
- Departamento de Ingeniería Matemática, Facultad de Ciencias Físicas y Matemáticas, Centro de Investigación en Ingeniería Matemática, Universidad de Concepción, Concepción, Chile
- Centre for Mathematical Sciences, Lund University, Lund, Sweden
| | - Stefan Diehl
- Centre for Mathematical Sciences, Lund University, Lund, Sweden
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