IWA Biofilms 2020

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Book of Abstracts

IWA Biofilms 2020

Emerging Trends and Developments

December 7 - 9, 2020



IWA Biofilms 2020 Virtual Conference:

Emerging Trends and Developments

This conference brought together academics, industry members, consultants, and end users to discuss the latest trends and needs for biofilms in the water field.

Major themes were:

Brainstorming on grand challenges and critical needs related to biofilms

Engaging with colleagues within workshops, sessions, panel discussions, breaks, and

poster sessions

Promoting interactions and collaborations among all participants, especially among junior/senior members, and high/low income countries, and industry/end


Promoting engagement with the IWA Biofilms Specialist Group

We hope this conference helped share cutting edge developments in biofilm research and application, and will help lead to new and more sustainable solutions for the water environment.


Rob Nerenberg and Patricia Perez-Calleja

IWA Biofilms 2020 co-organizers




This virtual conference is a collaborative effort among the members of the Organizing Committee, listed below.

Organizing Committee

Robert Nerenberg - University of Notre Dame, USA (main conference organizer) Patricia Perez-Calleja - University of Notre Dame, USA (main conference co-organizer) Joshua Boltz - Arizona State University, USA

Fabrizio Sabba - Northwestern University, USA Kelly Gordon - Black & Veatch, USA

Manish Kumar - University of Texas at Austin, USA Eberhard Morgenroth - EAWAG and ETH, Switzerland Sudhir Murthy - NEWhub Corp, USA

Barth Smets - Technical University of Denmark, Denmark

Kim Soerensen - Veolia Water Technologies/AnoxKaldnes, Denmark Akihiko Terada - Tokyo University of Agriculture and Technology, Japan Mark van Loosdrecht - Delft University of Technology, The Netherlands Rongchang Wang - Tongji University, China

Stefan Wuertz - Nanyang Technological University, Singapore



International Scientific Committee

Robert Nerenberg - University of Notre Dame, USA Patricia Perez-Calleja - University of Notre Dame, USA Joshua Boltz - Arizona State University, USA

Doris Brockmann - INRAE Transfert, France Fabrizio Sabba - Northwestern University, USA Kelly Gordon - Black & Veatch, USA

Manish Kumar - University of Texas at Austin, USA

Susanne Lackner - Technical University Darmstadt, Germany Mohamed Mahmoud - Badr University Cairo, Egypt

Eberhard Morgenroth - EAWAG, Switzerland

Sudhir Murthy - NEWhub Corp, Columbia University, USA Maria Piculell - AnoxKaldnes AB, Sweden

Bruce Rittmann - Arizona State University, USA

Barth Smets - Technical University of Denmark, Denmark

Kim Soerensen - Veolia Water TechnologiesAnoxKaldnes, Denmark Akihiko Terada -Tokyo University of Agriculture and Technology, Japan Mark van Loosdrecht - Delft University of Technology, Netherlands Eveline Volcke - Ghent University, Belgium

Rongchang Wang - Tongji University, China

Stefan Wuertz - Nanyang Technological University, Singapore




Platinum Sponsors



Gold Sponsors

Biosurface Technology Corporation



Silver Sponsors



IWA Biofilms 2020:

Emerging Trends and Developments

7-9 December 2020

Book of Abstracts


Table of contents

Conference committee ………..………ii


Keynote Speakers………1


Granular Sludge Session……….……….12

Oral Presentations……….. 12

Flash Presentations……….………35

Poster presentations………..…………...47

Biofilm Control Session………...60

Oral Presentations……….. 60

Flash Presentations……….………78

Poster presentations………..………..90

MABR Session………..105

Oral Presentations………..….105

Flash Presentations……….….…….. 127

Poster presentations………..……….…..139

Biofilms GHG & EPS Session………154

Oral Presentations……… 154

Flash Presentations……….………… 171

Poster presentations………..……….…..184

Biofilms in Drinking Water Systems Session……….…..….188

Oral Presentations……….….….188

Flash Presentations……….….….. 208

Poster presentations……….…..……..221

MBBR/Reactive Biofilms Session………... 237

Oral Presentations……… 237

Flash Presentations………...…. 255

Poster presentations……….….…266

Biofilms in Mainstream Deammonification Session……….. 294

Oral Presentations……… 294

Flash Presentations……….………… 315

Poster presentations………..……….…..328

Emerging Biofilm Topics Session………..……….…… 344

Oral Presentations……… 344

Flash Presentations………...…. 365

Poster presentations………...……..376




Bruce Rittmann

Dr. Bruce E. Rittmann is Regents' Professor of Environmental Engineering and Director of the Biodesign Swette Center for Environmental Biotechnology at Arizona State University. His research focuses on the science and engineering needed to “manage microbial communities to provide services to society.” Dr. Rittmann is a member of the National Academy of Engineering; a Fellow of AAAS, WEF, IWA, AEESP, and NAI;

and a Distinguished Member of ASCE. Dr. Rittmann was awarded the first Clarke Prize for Outstanding Achievements in Water Science and Technology from the NWRI, the Walter Huber Research Prize and the Simon Freese Award from ASCE, the G.M. Fair Award from AAEES, and the Perry L. McCarty/AEESP Founders Award. He is the co- winner of the 2018 Stockholm Water Prize. Dr. Rittmann has published over 740 journal articles, books, and book chapters, and he has 17 patents.

Belinda Sturm

Dr. Belinda Sturm is a Professor in the Department of Civil, Environmental &

Architectural Engineering at the University of Kansas. She also serves as an Associate Vice Chancellor for Research. Belinda earned her B.S. in Public Health from the University of North Carolina at Chapel Hill and her PhD in Civil Engineering and Geological Sciences from the University of Notre Dame. In 2012, the American Academy of Environmental Engineers awarded Belinda and KU an Excellence in Environmental Engineering honor award for her research on coupling nutrient removal with algae-mediated energy recovery. Belinda currently serves as Chair of the International Water Association’s USA National Committee Executive Board and as Vice-Chair of the Water Environment Federation’s Municipal Design Symposium.

Charles B. Bott

Dr. Charles B. Bott joined HRSD in 2009 and is the Director of Water Technology and Research. He manages technology innovation and R&D for HRSD’s sixteen wastewater treatment plants (249 MGD combined capacity). Dr. Bott is also an Adjunct Professor in the Departments of Civil and Environmental Engineering at Virginia Tech and Old Dominion University. He was formerly an Associate Professor in the Department of Civil and Environmental Engineering at the Virginia Military Institute (VMI) and a consulting engineer with Parsons Engineering Science. Dr. Bott has a BS in Civil Engineering from the Virginia Military Institute, a MS in Environmental Engineering from the Johns Hopkins University, and a Ph.D. in Civil and Environmental Engineering from Virginia Tech. He is a fellow of the Water Environment Federation, a Professional Engineer in Virginia, a Board Certified Environmental Engineer, and a licensed Wastewater Treatment Plant Operator – Virginia Class I. Charles’ biofilm interests include mainstream IFAS, mainstream polishing partial denitrification-anammox in MBBRs and deep bed filters, sidestream granular and MBBR partial nitritation- anammox, and ozone-biofiltration processes for potable reuse.



Caitlin Proctor

Dr. Caitlin Proctor is a soon to be Assistant Professor of Engineering at Purdue University, where she just finished a 2 year postdoctoral fellowship. She completed her PhD in Life Sciences at the Swiss Federal Institute of Aquatic Science and Technology through ETH Zurich. Caitlin’s research is at the nexus of civil engineering, molecular microbiology, and drinking water, with a major focus on the impact of biofilms on drinking water quality. Much of her research has centered on the ecology of showers. In her new lab, she will continue to explore the biofilm dynamics that can affect system functionality and public health.

Mark van Loosdrecht

Dr. Mark van Loosdrecht is Professor in Environmental Biotechnology at Delft University of Technology,The Netherlands. His research is characterized by the combination of scientific understanding of complex systems and development of new processes. Dr. van Loosdrecht’s scientific interests are mainly related to biofilm processes, nutrient conversion processes and the role of storage polymers in microbial ecology. His research has resulted in several processes currently applied on full scale such as the Sharon process, Anammox process and Nereda process. Currently PHA, Kaumera and Vivianite recovery processes are in scale-up phases. He was Editor in Chief of Water Research (2010-2019). He obtained several prizes for his work, including the Lee Kuan Yew Singapore Water Prize, Stockholm Water prize, Spinoza Award, Simon Stevin Award and the IWA grand award. He is member of the Royal Dutch Academy of Arts and Sciences, the Dutch Academy of Engineering (AcTI) and the Chinese and USA National Academy of Engineering. He was awarded a knighthood in the order of the Dutch Lion and honorary doctorates from U-Gent and ETH-Zurich. He has published over 800 scientific papers, has 20 patents and has supervised over 60 PhD students.

Eveline Volcke

Dr. Eveline Volcke is a Professor and the founder and head of the research unit Biosystems Control (BioCo) at Ghent University. Eveline graduated as a Chemical Engineer (1999) and obtained a PhD in Environmental Technology (2006) from Ghent University. In 2007, she took up a EU Marie Curie fellowship at the Laboratory of Environmental Biotechnology, INRA, France. Her research is focused on efficient and sustainable process design and control, applying a combination of physical-based modeling and experimental techniques. The application domain concerns environmental technology, with a prime focus on biological wastewater treatment, besides other bioconversion processes. A vast expertise has been gathered concerning innovative nitrogen removal processes, granular sludge reactors, microbial population dynamics, and greenhouse gas emissions from wastewater treatment. Eveline is a Fellow of the International Water Association (IWA).



Per Henrik Nielsen

Mr. Per Henrik Nielsen, is a Project Director of Special Projects at VCS Denmark, the oldest and third largest water utility in Denmark. Mr. Nielsen brings more than 25 years of experience leading and participating in multi-disciplinary teams in a large number of sanitary infrastructure projects and general environmental projects. The work over the past years has been aiming at making the major treatment facilities energy producing and to prepare VCS Denmark for wastewater treatment of the future, studying needs for system centralization and decentralization, adopting of the water resource recovery paradigm, increasing resiliency, and identifying technology gaps and developing corresponding applied research efforts. He was instrumental in making VCS the first Danish Water Research Foundation Subscriber in 2014 and from the beginning has been seeking active involvement in the Foundation’s activities, currently serving in their prestigious Research Council. He also helps coordinate and actively participates in VCS efforts of providing assistance to water utilities around the world in the strengthening of their technical and institutional capabilities.

Lutgarde Raskin

Lutgarde Raskin is the Vernon L. Snoeyink Distinguished University Professor of Environmental Engineering and the Altarum/ERIM Russell O'Neal Professor of Engineering at the University of Michigan (UM), where she has been a professor of Environmental Engineering since 2005. She currently serves as an Associate Dean for Academic Programs and Initiatives at the Rackham Graduate School. Before her UM appointment, she was a professor at the University of Illinois at Urbana-Champaign (UIUC) for 12 years. She received BS/MS degrees in Bioscience Engineering and Economics from the University of Leuven (KU Leuven, Belgium). Her PhD degree is in Environmental Engineering from UIUC. Raskin is globally recognized as an expert in microbial aspects of anaerobic waste treatment and drinking water treatment technologies. She is passionate about graduate education and has mentored approximately 20 postdocs and 100 graduate students, including 27 PhD students. She is an elected Fellow of the American Academy of Microbiology, the International Water Association, and the Water Environment Federation. Past honors include the University of Michigan Rackham Distinguished Graduate Mentor Award, the International Society for Microbial Ecology-International Water Association BioCluster Award, the Association of Environmental Engineering and Science Professors Frontier Award in Research, and the Water Research Foundation Paul L. Busch Award for Innovation in Applied Water Quality Research. She is an Associate Editor for Environmental Science & Technology and was the Association of Environmental Engineering and Science Professors Distinguished Lecturer in 2018-19.

Zhiguo Yuan AM

Professor Yuan received his PhD degree in aeronautical engineering in 1992 from Beijing University of Aeronautics and Astronautics, China. He changed research direction to wastewater management in 1994, when he took up a postdoctoral research fellow position at Ghent University, Belgium. He joined the Advanced Water Management Centre (AWMC) at The University of Queensland in 1998 and is currently the Director. His research focuses on development of innovative solutions for urban water management through effective integration of fundamental science and applied engineering. He has to date published ~450 fully refereed journal papers including a paper in Nature (2013) and Science (2014). He is the founder of three biotechnology businesses namely SeweX, Cloevis and Lodomat.



Maria Piculell

Dr. Maria Piculell is a process specialist in the AnoxKaldnes R&D team at Veolia Water Technologies, Sweden. She completed her MSc in Environmental Engineering at Lund University, Faculty of Engineering (LTH) in 2011, and started working at AnoxKaldnes the same year. In 2012, Maria started her PhD project at the Department of Chemical engineering, Water and Environmental engineering (Lund University). Her PhD, titled

“New Dimensions of Moving Bed Biofilm Carriers - Influence of biofilm thickness and control possibilities”, was completed in 2016. Since then, Maria has continued to work on evolving the Moving Bed Biofilm Reactor technology and its different applications, focusing especially on understanding the impacts of different biofilm carrier designs and materials. In 2018, she was part of initiating a Swedish biofilm processes user group and in 2019, the Swedish Association for Water awarded Maria with the New Generation award. In 2020, Maria led the organization of the Swedish conference on

“Biofilm Systems in Municipal Wastewater Treatment”, which attracted a large Nordic audience.




IWA Biofilms 2020 hosted the following pre-conference workshops:


MABR Workshop: Current Status and Emerging Applications (lead organizer: Glen

Daigger, USA)


Biofilm Reactors Reduce Selenium Oxyanions in Industrial and Agricultural Wastewater Treatment (lead organizer: Josh Boltz, USA)


The Ecology of Biofilms in Water Engineering (lead organizers: Barth Smets,

Denmark, and Ameet Pinto, USA)


The role of biofilms in mainstream anammox process (lead organizer: Shihu Hu,



Current status, challenges, and opportunities of biofilm-based technologies for controlling N2O (lead organizers: Akihiko Terada, Japan, and George Wells, USA)


Disrupting building plumbing biofilms: pathogens, ecology and environment (lead

organizer: Frederik Hammes, Switzerland)


How to write a strong research paper and get it published in a scientific

journal? (lead organizers: Eberhard Morgenroth, Switzerland, and Stefan Wuertz,



Biofilm Modeling Topics at the Interface of Research and Application (lead organizer:

Kelly Gordon, USA)


I have a Ph.D.! Now what? Exploring Career Pathways Outside of Academia (lead

organizer: Kelly Gordon, USA)

10. Time Scaling in Biofilm Experiments (lead organizer: Jeseth Delgado, USA, and Andrew

Jones, USA)




Monday, December 7 2020

7:30- 7:45 Plenary Session

Introduction, conference overview

7:45 - 8:00 Keynote - Mark van Loosdrecht, TU Delft, (The Netherlands): Extracellular Polymers 8:00 - 8:15 Keynote - Maria Piculell, AnoxKaldnes, Sweden: Opportunities to meet tomorrow's challenges using MBBR

8:15 - 8:30 Discussion with keynotes

8:30 - 8:45 Short Break

8:45 - 9:30 Panel Discussion - Grand Challenges and Critical Needs for Biofilm Processes in the Water Sector (all keynotes)

9:30 - 10:00 BREAK

10:00- 10:15

Granular sludge Biofilm control

Keynote - Belinda Sturm, Kansas U., (USA)

Kinetic drivers for granule formation: EPS formation and species selection

Keynote - Lutgarde Raskin, U. of Michigan (USA)

Role of Biofilms in Anaerobic Biotechnologies for Recovery From Waste Streams 10:15 - 10:30


Could the treatment capacity of a continuous flow reactor be increased with aerobic granular sludge?

Laurence Strubbe (Ghent University) Role of dynamic membrane biofilm development on chain elongation for medium chain carboxylic

acids production. Shilva Shrestha (University of Michigan)

10:30 - 10:45 Biomass densification through controlled microbiome shift, a successful partial granulation in continuous

flow bioreactors in Dijon WWTP, France. Sylvain Donnaz (Suez International) Using Shear Rheometry and image analysis to asses enzymes for biofilm control. Yanina Nahum (University of Notre Dame)

10:45 - 11:00 Efficient carbon, nitrogen and phosphorus removal from low C/N real domestic wastewater with aerobic

granular sludge. Riccardo Campo (Università degli Studi di Firenze) Reducing the impacts of biofouling in reverse osmosis membrane systems through low fluence pretreatment employing UVC-LED irradiation. Philipp Sperle (Technical University of Munich)

11:00- 11:15 Short Break Short Break

11:15 - 11:30 Evaluation of the impact of the feeding regime on granulation process treating industrial wastewater

from food industry. Eirini Tsertou (University of Antwerp) Biofilm growth control with minor maintenances for an optimized operation of gravity-driven membrane filtration with hollow fiber membranes. Céline Jacquin (EAWAG)

11:30 - 11:45 Sustained nitrogen loss in a symbiotic association of Comammox Nitrospira and Anammox bacteria.

Ekaterina Gottshall (University of Washington) Quantification and Modeling of the Response of Surface Biofilm Growth to Continuous Low Intensity UVC Irradiation. Ezra L. Cates (Clemson University)

11:45 - 12:00


Anammox Granule Enlargement by Heterogenous Granule Self-assembly. Weigang Wang (Tongji

University) In situ Synthesizing Silver Nanoparticels by Bio-Derived Gallic Acid to Enhance Antimicrobial

Performance of PVDF Membrane. Liang Xuan (Tongji University) Impact of substrate concentration on granular fermentation for caproic acid production. Quinten Mariën

(Ghent University) Effectiveness of fluidized fibrous carrier in a membrane bioreactor for biofouling mitigation: A pilot-

scale demonstration. Hiroyuki Yoshino (Tokyo University of Agriculture and Technology) Conductivity based dynamic control of the anaerobic step in an EBPR AGS SBR treating dairy wastewater.

Flinn De Vleeschauwer (University of Antwerp) An industry perspective of Microbiologically Influenced Corrosion (MIC): From biofilms to asset integrity management. Torben Lund Skovhus (VIA University College)




Tuesday, December 8 2020 – First Half


7:30- 7:45

Membrane Aerated Biofilm Reactors (MABR) Greenhouse gases (GHG) & Extracellular polymeric substances (EPS) Keynote - Per Nielsen, VCS (Denmark): MABR – a Solution for Utilities? Keynote - Eveline Volcke, U. of Ghent, Belgium: Biofilms: what’s in the gas phase?


7:45 - 8:00 Advancing Resource Recovery Using Hybrid Membrane Aerated Biofilm Reactor Processes. Glen T.

Daigger (University of Michigan) Denitrification of nitrous oxide is unaffected by electron competition in Accumulibacter. Samarpita Roy (Nanyang Technological University)

8:00 - 8:15 Algal-Bacterial membrane-aerated biofilm reactor: synergistic metabolism and microbial community

structure. Rongchang Wang (Tongji University) Aeration control strategies to improve N removal and reduce N2O emissions in granular sludge partial nitritation anammox reactors. Xinyu Wan (Ghent University)

8:15 - 8:30 Impact of intense scouring on the performance of Membrane Aerated Biofilm Reactors. Philipp Bunse

(Technical University of Darmstadt) PAOs Got Talent?! Effect of the substrate composition on N2O formation in aerobic granular sludge.

Lennert Dockx (University of Antwerp)

8:30 - 8:45 Short Break Short Break

8:45 - 9:00 A predictive oxygen transfer-based Membrane Aerated Biofilm Reactor model. Tanush Wadhawan

(Dynamita North America) Protective role of sialic acids in the extracellular polymeric substances of "Ca. Accumulibacter

phosphatis". Sergio Tomas-Martinez (Delft University of Technology)

9:00 - 9:15 Analysis of mass transfer in a polyurethane-foam-based counter-diffusional biofilm. Bruno Garcia Silva

(University of São Paulo) Sulfated glycosaminoglycan-like polymers present in acidophilic biofilm. Stefan de Bruin (Delft

University of Technology)

9:15 - 9:30


Improved nitrogen removal in a membrane-aerated biofilm reactor with advanced biofilm control.

András Németh (OxyMem Lted)

Analysis of formation and characterization of hydrogels originated from structural extracellular polymeric substances (sEPS) extracted from aerobic granular sludge (AGS). Tommaso Lotti (Università degli Studi Firenze)

NOB Suppression in a Single ZeeNAMMOXTM Biofilm with the Coexistence of AOB and Anammox. Zebo

Long (Suez Water Technologies and Solutions) Extraction conditions govern the quantity and properties of gel-forming EPS recovered from aerobic granules. Bou sarkis Abdo (Université de Toulouse)

Multi parameter testing and comparison of MABR on several full-scale pilot plants. Ronen Shechter (Fluence corporation)

Effect of mass transfer on the S0 and N2O accumulation in sulfide-oxidizing autotrophic denitrification process: batch experiments and modeling evaluation. Xu Zou (The Hong Kong University of Science and Technology)

9:30 - 10:00 BREAK

Tuesday, December 8 2020 – Second Half

Drinking water biofilms MBBR/Reactive biofilms

10:00- 10:15 Keynote - Caitlin Proctor, Purdue U. (USA):

Not all bad: biofilms in drinking water systems Keynote - Bruce Rittmann, Arizona State U. (USA):

Biofilms on Active Substrata – Hyper-partnering with Microorganisms


10:15- 10:30 Understanding the effect of extended and intermittent stagnation on the quality of drinking water in

an above-ground test bed. Mats Leifels (Nanyang Technological University) The use of a hydrogen-based Membrane Biofilm Reactor for carboxylate production. Diana C. Calvo (Arizona State University, USA.)

10:30 - 10:45 Dominance of comammox Nitrospira abundance over canonical nitrifiers irrespective of electron donor

mode and availability. Katherine J. Vilardi (Northeastern University) Electro-anammox: A novel anaerobic process for the oxidation of ammonium by anammox bacteria.

Dario Rangel Shaw (King Abdullah University of Science and technology, KAUST)

10:45 - 11:00 Characterizing fungal communities in new and established full-scale slow sand filters producing

drinking water. Tage Rosenqvist (Lund University, Sweden) A membrane-based biofilm photobioreactor (MB-PBR) for enhanced algal growth rates. J. Saul Garcia- Perez (University of Notre Dame)

11:00- 11:15 Short Break Short Break

11:15 - 11:30 Bacterial communities adapt quickly during start-up: study of biofilm spatial-temporal dynamics in RSFs

for drinking water. Thomas Etcheberry (INSA Toulouse) Achieving Partial Nitritation at Elevated Loading Rates: Kinetics, Design curves, and Microbial Communities. Alexander Schopf (University of Ottawa, Canada)

11:30 - 11:45 Characterizing the development of biofilm in PE pipes through 1.5 years in the non-chlorinated Danish

drinking water distribution system. Ditte A. Søborg (VIA University College, Denmark) EBPR and Partial Nitrification in SB-MBBRs Treating Cheese Production Wastewater. Alexandra Tsitouras (University of Ottawa, Canada)

11:45 - 12:00


Factors Shaping Young and Mature Bacterial Biofilm Communities in Two Drinking Water Distribution

Networks. Dan Cheng (Singapore Centre for Life Sciences Engineering) Substrate dependent degradation of micropollutants in Moving bed biofilm reactors. Kai Bester (Aarhus University, Denmark)

Effect of Detachment Promoting Agents on Disruption of Single-Species and Multi-Species Simulated Drinking Water Biofilms. Fayzul Kabir (University of Alaska Fairbanks)

Comparison COD, BOD, and Nitrogen removals and Microbial Communities Abundance of Hybrid Biofilm Full-Scale on Municipal Wastewater Treatment Systems. Pongsak (Lek) Noophan (Kasetsart University, Thailand)

Effect of non-phosphorus corrosion inhibitors on biofilm pore structure and mechanical properties.

Conghui Huang (University of Illinois at Urbana-Champaign) Unique effects of predation on nitrifying membrane-aerated biofilm reactors (MABRs) - Bumkyu Kim (University of Notre Dame)




Wednesday, December 9 2020


Mainstream Deammonification Emerging Biofilm Topics

7:30- 7:45 Keynote - Zhiguo Yuan, U. of Queensland (Australia):

Partial nitritation and anammox (PN/A) via biofilm: expanding from sidestream to mainstream

Keynote - Charles Bott, HRSD (USA):

Biofilm Process Innovations at HRSD: Advancing Short-Cut N Removal &

Demonstrating Potable Reuse with Ozone-Biofiltration


7:45 - 8:00 Design considerations gleaned from evaluation of full-scale performance of a sidestream Moving Bed Biofilm Reactor (MBBR) Partial Nitritation/Anammox (PN/A) process. Carolyn Coffey (Colorado School of Mines, USA)

Viscoelastic Characterization of Biofilms by Optical Coherence Elastography (OCE). Ziwei Wang (Northwestern University, USA)

8:00 - 8:15 Long solid retention times and biofilms influence prevalence of complete ammonia oxidizing bacteria in wastewater treatment plants. Irmarie Cotto (Northeastern University)

Tracking metabolic versatility in biofilms: modelling photoorganoheterotrophic and

photolithoautotrophic niches of a single purple phototrophic bacterium. Marta Cerruti (Delft University of Technology)

8:15 - 8:30 Successful startup of mainstream partial denitrification/anammox in pilot MBBRs and a full-scale deep-

bed filter without anammox seed. Stephanie Klaus (Hampton Roads Sanitation District, USA) Intracellular versus extracellular DNA: Microbiome, resistome and mobilome profiling of a full-scale granular sludge wastewater treatment plant. David Calderón-Franco (Delft University of Technology)

8:30 - 8:45 Short Break Short Break

8:45 - 9:00 Resource Efficient Partial Nitritation/ Anammox and Biological Phosphorus Removal in a Single Integrated Fixed-film Activated Sludge (IFAS) Bioreactor under Mainstream Conditions. Zhen Jia (Northwestern University, USA)

Mapping the heterogeneous diffusion of polystyrene nanoparticles in a model biofilm. Joann M.

Rodriguez-Suarez (University of Massachusetts Amherst)

9:00 - 9:15 AnAOB Integration Options for Mainstream Short-cut N removal via partial denitrification – anammox.

Mojolaoluwa Ladipo-Obasa (DC Water; The George Washington University, USA) Impact of mechanical heterogeneity on biofilm deformation with a viscoelastic phase field model.

Mengfei Li (University of Notre Dame)

9:15 - 9:30


Influence of media type and feed characteristics on performance of Partial denitrification-anammox

(PdNA) in polishing filters. Rahil Fofana (DC Water; Howard University, USA) A rapid prototyping approach to explore the interaction between hydrodynamics and biofilm. Erifyli Tsagkari (University of Glasgow, Scotand)

Adding hydroxylamine to achieve nitritation in conventional and MABR biofilms – a modelling study.

Sarajane Roenke (University of Notre Dame) A comprehensive floc model with external mass transfer to simulate activated sludge system. Xuanye Bai (University of Waterloo, Canada)

Anammox prevalence in sponge-bed trickling filters treating anaerobic effluents - just a matter of time?

Thiago Bressani Ribeiro (Ghent University / Federal University of Minas Gerais)

Insights on a methodology to characterize the gel-forming ability of structural extracellular polymeric substances (EPS) from aerobic granular sludge (AGS). Benedetta Pagliaccia (Université de Toulouse, University of Florence)

9:30 - 10:00 BREAK

Closing Session

10:00- 10:45 Workshop summaries

10:45 - 11:00 Summary of conference, future events

11:00- 11:15 Short Break

11:15 - 11:45 Biofilms SG priorities - discussion with participants

Poster sessions:

Monday, December 7 2020

12:00 - 1:00

Granular sludge / Biofilm Control Sessions

A Metagenomic Insight into Biofilm Populations in Industrial Water Systems Using a New, Real Time Biomonitoring Technology - Angela Delegard (Chem- Aqua/Mowhak Labs)

Algal-sludge membrane bioreactor (As-MBR) for sustainable municipal wastewater treatment - Vincenzo Senatore (University of Salerno)

Blocking Biofilm Formation in Anaerobic and Aerobic Environments by Facultative Quorum Quenchers - Syed Salman Ali Shah (Kyungpook National University) Membrane foulings in aerobic granular sludge membrane bioreactor - Zhengjian Yang (Oregon State University)

Genome-centric metagenomics of saline anaerobic granular sludge reactors identifies microbial drivers for granulation and adaptation to halotolerance - Pranav Sampara (The University of British Columbia)

Spatial growth activity patterns in non-spherical fermentative granular biofilms - Pieter Candry (University of Washington)

A performance comparison of aerobic granular sludge and hybrid bio-granular activated carbon treating recalcitrant and toxic dissolved organic compounds under hypersaline conditions- Abdullah Ibrahim (University of Mosul)



Tuesday, December 8 2020 – First half

6:30 - 7:30

MABR, GHG, AND EPS Sessions Urban waterway biofilms have the potential to act as a methane filter - Koen A.J. Pelsma (Radboud University)

Xanthobacter Dominated Biofilm makes High Value Rhamnose from Synthetic Acid-Phase Digestate - Raymond RedCorn (University of Washington) Effect of Temperature on Membrane Aerated Biofilms - Emily Clements (University of Notre Dame)

MABR Enables Nitrification Below "Washout" SRT and Enhanced TIN Removal - Matt Reeve (SUEZ Water Technologies and Solutions) Process Intensification Using MABR Technology: Subiaco WRRP Pilot Plant - Isabel Telles Silveira (Water Corporation – Australia)

Development of a comprehensive mathematical model for membrane aerated biofilm reactor and calibration with pilot operation data - Ahmed Tarek Elsayed (McMaster University)

Unique effects of predation on nitrifying membrane-aerated biofilm reactors (MABRs) - Bumkyu Kim (University of Notre Dame)

VCS Denmark’s Experience with O&M Requirements of Full-Scale MABR Demonstration during the COVID-19 Pandemic - Nerea Uri (VCS Denmark)

Tuesday, December 8 2020 – Second half

12:00 - 1:00

Drinking Water, MBBR, and Reactive Biofilm

Taxonomic composition and diversity of biofilms and bulk water in four municipal drinking water distribution systems - Christopher Anderson (West Virginia University)

Biofilm management; investigating the inhibitory effects of chlorine-based disinfectants on biofilms - Gillian Clayton (University of the West of England) Is Controlling Biofilm Thickness a Viable Approach for Enhancing Organic Micropollutants Removal in Drinking Water and Water Reuse Systems? – Mahmudul Hasan (The George Washington University)

Contrast analysis of enzymatic activity measurement methods applied to bank filtration sites (BF) - Marcelle Martins (Universidade Federal de Santa Maria)

Point-of-use filters intended for lead removal fail to remove lead and increase bacteria following a stagnation period in elementary school drinking water - Gemma G Clark (University of Illinois at Urbana-Champaign)

Haloalkaliphilic nitrate-reducing electroactive microbial biofilms dominated by Pseudomonas, Natronococcus, and Pseudoalteromonas spp. - Srishti Chaudhary (Indian Institute of Science Education and Research Mohali)

Novel electroactive Geoalkalibacter spp. isolated from the haloalkaliphilic microbial exoelectrogenic biofilm - Sukrampal Yadav (Indian Institute of Science Education and Research Mohali)

Investigating the mass transfer and microbial activity in a “needle structure” biofilm using multidimensional modeling - Yan Yang (University of Notre Dame, Chongqing University)

Ammonium nitrogen removal in counter diffusional layered biofilms of single-chamber microbial fuel cells to treat domestic wastewater - Jaecheul Yu (Pusan National University)

Adhesion and development of biofilm in polypropylene (PP) and high density polyethylene (HDPE) media for Moving bed biofilm reactors - Anjani Parsotamo (Cranfield University)

Concentration dependent degradation of pharmaceuticals in WWTP effluent by moving bed biofilm reactors – Kai Bester (Aarhus University) Prediction of the effect of biofilm thickness on MBBR performance for the treatment of municipal sewage - Sankar Ganesh Palani (BITS Pilani) Effect of micropillar ordered array electrode for early biofilm electroactivity signature - Solange Elizabeth Astorga (Nanyang Technological University)



Wednesday, December 9 2020

6:30 - 7:30

Mainstream Deammonification and Emerging Biofilm Topics

Anammox prevalence in spongebed trickling filters treating anaerobic effluents - just a matter of time? - Thiago Bressani Ribeiro (Ghent University)

Biofilm-based mainstream partial nitritation/anammox with complete suppression of nitrite oxidizing bacteria by continuously low oxygen levels - Michiel Van Tendeloo (University of Antwerp)

Sustained organic loading disturbance favors nitrite accumulation in bioreactors with variable resistance, recovery and resilience of nitrification and nitrifiers - Ezequiel Santillan (Nanyang Technological University Singapore)

Start-up of one-stage partial denitratation-anammox MBBR systems with a partial nitritation-anammox inoculum and different carbon sources - David J. I.

Gustavsson (VA SYD/Sweden Water Research)

The influence of the COD: N alterations on mainstream deammonification in an IFASSBR - Mohammad Azari (University of Duisburg-Essen)

Aerobic activity during biofilm development with intermittent flow: Effect of organic loading rate on enhanced sewer self-purification - Tiffany Joan Sotelo (The University of Tokyo)

Influence of hydraulic retention time and phosphate supplementation on the quality of biofilms and efficiency of anaerobic sequencing batch reactors - Elaine Cristina Latocheski (Paraná Federal University)

Effect of Mixture of Nanoparticles on Algal and Bacterial Communities in Periphytic Biofilms-A Theoretical Perspective - Samridhi Rana (IIT Delhi) The mcyB gene and the effect on microcystin production on biofilms - Gisella Lamas-Samanamud (University of Kentucky - Paducah Extended Campus) Using the Total RNA approach to gain insight into the activity and function of the microbial community of Moving Bed Biofilm Reactors: an adaptation study - Joseph D. Martin (Aarhus University)

How to Measure Diffusion Coefficients in Biofilms: A Critical Analysis - Lenno van den Berg (Delft University of Technology)

Temperature Effects on the Biofouling Rate of Flat Sheet Membranes in Anaerobic Membrane Bioreactors (AnMBRs) - Sudeep Popat (Clemson University) Key filamentous organisms in industrial activated sludge plants in Flanders (Belgium) - Karina Seguel (University of Antwerp)

Methane oxidation coupled to selenate reduction with formate as an electron shuttle - He-Ping Zhao (Zhejiang University)

Characterization of Biomolecules Present in Dairy Wastewater through various Techniques - Basanti Ekka (Riga Technical University) The study of Biofilms in an Undergraduate Setting - Gisella Lamas-Samanamud (University of Kentucky - Paducah Extended Campus)






Granular Sludge Session

Oral presentations



Could the treatment capacity of a continuous flow reactor be increased with aerobic granular sludge?

Strubbe, L.*, Pennewaerde, M.*, Baeten, J.* and Volcke, E.*

*BioCo, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, 9000 Gent, Belgium, Laurence.Strubbe@UGent.be, Margot.Pennewaerde@UGent.be, Janis.Baeten@UGent.be, Eveline.Volcke@UGent.be Keywords: aerobic granular sludge; continuous flow reactor; diffusion limitation

Summary of key findings

The maximal treatment capacity of a continuously operated reactor for nitrogen removal is studied through simulation in which activated sludge is compared to aerobic granular sludge. Aerobic granular sludge differs from activated sludge based on two characteristics: higher settling velocity and diffusion limitation. The effect of better settling increases the maximal treatment capacity with 40% compared to activated sludge, as a higher settling velocity allows a higher biomass concentration in the reactor.

However, diffusion limitation can almost totally counteract the positive effect of better settling for a non-optimized continuous system. The continuous system can be optimized for aerobic granular sludge by increasing the aerobic reactor volume, but at a lower oxygen set-point to increase the anoxic volume in the granule and benefit from simultaneous nitrification-denitrification. The optimization led to a 20%

improvement in treatment capacity and a 10% reduced energy consumption compared to a conventional activated sludge system.

Background and relevance

The treatment capacity of existing activated sludge plants needs to be increased due to higher loading rates and more stringent effluent criteria in the future (Jeppsson et al., 2002; Zhang et al., 2016).

Replacement or extension of existing water treatment plants is very expensive and sometimes impossible due to lack of space. A bottleneck of the activated sludge plants is the poor sedimentation of the bacteria. As a result, large settling tanks are required to give the activated sludge sufficient time and space to separate from the purified water. Aerobic granular sludge is a promising water

purification technique as the compact granules settle much faster and thus separate themselves much more efficiently from the purified water (de Kreuk and van Loosdrecht, 2004), resulting in compact installations and thus a higher treatment capacity for the same surface area. Moreover, in some cases energy consumption can be as much as 50% lower (Pronk et al., 2015). In newly built installations, these promising granules are used in batch reactors in which wastewater concentrations are relatively high and the growth process of granules can be well controlled. Existing activated sludge plants, however, are mostly continuous flow reactors, in which the wastewater concentrations are lower.

Because of the clear advantages of aerobic granular sludge, research focuses worldwide on how to get stable granules in a continuous flow design (Kent et al., 2018). However the effect of aerobic granular sludge on the maximal treatment capacity is not known yet. Is replacing activated sludge in our current continuous water treatment plants with aerobic granular sludge at all a good idea?


14 Results

Aerobic granular sludge differs from activated sludge based on two characteristics: higher settling velocity and diffusion limitation. Diffusion limitation is the inevitable result of the compact structure of a granule, making it more difficult for solutes to reach the core of the granule (Wang et al., 2004).

As a result, the conversion of these solutes by the bacteria is slowed down, leading to reduced

purification. The individual and collective effect of both improved settling and diffusion limitation on the maximum treatment capacity and energy consumption of continuous flow reactor for nitrogen removal was investigated. The simulation study assumed that cultivation of aerobic granules with long-term stability in continuous systems is possible.

The improved sedimentation capacity of aerobic granular sludge increased the maximum treatment capacity of the water treatment plant by almost 40% (Figure 1 - 'better settling sludge'), in line with expectations. However, taking the existing diffusion limitation into account resulted in a clear negative effect. In the aerobic granular sludge system where both better settling capacity and diffusion limitation were modelled, the maximum treatment capacity was only 7% higher than that of the original activated sludge system. Moreover, this was at the expense of higher energy consumption, about 40% more for aerobic granular sludge than for the original activated sludge system. This higher aeration energy was because of the strong diffusion limitation due to the lower concentration of solutes in the continuous flow reactor compared to batch reactors. As a result, more oxygen had to be added to allow the purification reactions to continue sufficiently.

Figure 1: Maximal treatment capacity (left) and energy use (right) of a continuous system for different scenarios.

As a following step, the operation of the water treatment plant was optimized. The oxygen input into the various reactor compartments was tuned to the adverse diffusion limitation, which was thus positively utilized. Concretely, if one ensures that oxygen cannot reach the core of the granule, an anoxic environment is created and denitrification can take place. As nitrification and denitrification took place simultaneously, the separate anoxic reactors were no longer required. This led to an

improvement in treatment capacity of 21%, while the energy consumption was also 10% better than in the conventional activated sludge process. It is clear that an optimization of the operational strategies is necessary to take full advantage of the aerobic granular sludge.


Due to better settleability of sludge, the downward solid fluxes in the settler are increased, leading to more efficient separation of sludge from the clean effluent. Hence, better settling sludge increases the biomass retention capacity of the reactor which increases the volumetric removal rates and thus the treatment capacity. Diffusion limitation, however, decreases the volumetric removal rate for a certain biomass concentration. To reach the same volumetric removal rate as without diffusion limitation, a



higher biomass concentration and/or higher oxygen concentration is needed as this will counteract the severe nitrification reduction (Figure 2).

Figure 2: Effect of a higher biomass concentration, diffusion limitation and oxygen set-point on the volumetric ammonium removal rate. Diffusion limitation is modelled by increasing the apparent half- saturation coefficient 𝐊𝐊𝐎𝐎𝟐𝟐

(Baeten et al., 2018).

A low oxygen concentration, on the other hand, enhances the denitrification capacity and promotes simultaneous nitrification-denitrification. In the optimized configuration without seperate anoxic reactors, denitrification only happens via simultaneous nitrification-denitrification which influences positively the energy use of the treatment plant as no mixer, no internal recycle and a lower oxygen set-point is used.

The completely mixed operation conditions in most continuous configurations makes that the substrate concentration in the reactor is everywhere and always as low as in the effluent. The lower substrate concentrations result in lower substrate gradients in the granules and thus poor diffusion. Continuous plug flow reactors might enhance diffusion limitation due to higher influent concentrations in the beginning of the anaerobic phase (Sun et al., 2019). This design could positively influence the treatment capacity.

The main conclusion is that diffusion limitation in continuous flow aerobic granular sludge reactor has a significant influence, even though this property is often overlooked in aerobic granular sludge. For the realization of continuous aerobic granular sludge systems in the future, one should therefore not only pay attention to the growth and stabilization of the granules, but also take into account a much larger diffusion limitation than in the typical batch reactors. It is advisable to keep the diffusion limitation in continuous systems as small as possible through smart operational strategies and process design.

The hopefull results show that if the operational strategies of the current continuous water treatment plants is optimized, a significant improvement in treatment capacity and reduced energy consumption can be realized. Additional optimization can be achieved, for example, by finding the particle size in which there is a good balance between the advantages of better settling sludge and diffusion limitation.

Thanks to aerobic granular sludge, expensive expansion of existing wastewater treatment plants can be avoided in certain cases and surface area can be saved. Further research will show exactly how to design the continuous installation and companies to take full advantage of aerobic granular sludge.


16 References

Baeten, J.E., van Loosdrecht, M.C.M., Volcke, E.I.P., 2018. Modelling aerobic granular sludge reactors through apparent half- saturation coefficients. Water Res. 146, 134–145. https://doi.org/10.1016/j.watres.2018.09.025

Bathe, S., de Kreuk, M., McSwain, B., Schwarzenbeck, N., 2015. Aerobic Granular Sludge. Water Intell. Online.


De Kreuk, M.K., Picioreanu, C., Hosseini, M., Xavier, J.B., Van Loosdrecht, M.C.M., 2007. Kinetic model of a granular sludge SBR: Influences on nutrient removal. Biotechnol. Bioeng. 97, 801–815. https://doi.org/10.1002/bit.21196

de Kreuk, M.K., van Loosdrecht, M.C.M., 2004. Selection of slow growing organisms as a means for improving aerobic granular sludge stability. Water Sci. Technol. https://doi.org/10.2166/wst.2004.0792

Jahn, L., Svardal, K., Krampe, J., 2019. Comparison of aerobic granulation in SBR and continuous-flow plants. J. Environ.

Manage. https://doi.org/10.1016/j.jenvman.2018.10.101

Kent, T.R., Bott, C.B., Wang, Z.W., 2018. State of the art of aerobic granulation in continuous flow bioreactors.

Biotechnol. Adv. https://doi.org/10.1016/j.biotechadv.2018.03.015

Li, Y., Liu, Y., 2005. Diffusion of substrate and oxygen in aerobic granule. Biochem. Eng. J.


Pronk, M., de Kreuk, M.K., de Bruin, B., Kamminga, P., Kleerebezem, R., van Loosdrecht, M.C.M., 2015. Full scale performance of the aerobic granular sludge process for sewage treatment. Water Res. 84, 207–217.


Sun, Y., Angelotti, B., Wang, Z.W., 2019. Continuous-flow aerobic granulation in plug-flow bioreactors fed with real domestic wastewater. Sci. Total Environ. https://doi.org/10.1016/j.scitotenv.2019.06.291

Wang, Q., Du, G., Chen, J., 2004. Aerobic granular sludge cultivated under the selective pressure as a driving force. Process Biochem. https://doi.org/10.1016/S0032-9592(03)00128-6

Zhang, Y., Zhao, T., Zhou, A., Zhang, Z., Liu, W., 2016. Scenario based municipal wastewater estimation: Development and application of a dynamic simulation model. Model. Simul. Eng. https://doi.org/10.1155/2016/1746310

Presenting Author

Strubbe Laurence Doctoral fellow of FWO Ghent University

Is the presenting author an IWA Young Water Professional? Y/N Bio: Laurence Strubbe is currently a Doctoral fellow of FWO at Ghent University. Her research topic is optimal design and control of aerobic granular sludge reactors for sustainable wastewater treatment.



Biomass densification through controlled microbiome shift, a successful partial granulation in continuous flow bioreactors in Dijon WWTP, France

Donnaz, S.*, Roche, C.*, Wett, B.** and Murthy S.***

* Suez International, 183 avenue du 18 juin 1940, 92500 Rueil-Malmaison

**ARA Consult, Dorfgasse 46, 6020 Innsbrück, Austria

***Newhub Corp., 12602 Denmark Drive, Herndon, VA 20170, USA

Keywords: biomass densification; continuous biological process; conventional activated sludge; enhanced biological phosphorus removal; process intensification

Summary of key findings

Full scale technological demonstration of activated sludge densification has been implemented over long term using external gravity selection. Two identical lines, one operated in conventional activated sludge and the other in densified sludge, are compared. The densified biomass obtained has increased settling characteristics and makes it possible to stabilize the sludge volume index between 50 and 100 mL/g, including the winter period during which the conventional activated sludge shows expansion of sludge index > 200 mL/g. The production of floating and stable organic foams is significantly reduced and even eliminated. The quality of clarified water is also improved via further removal of particulate fractions, with total suspended solids maintained <10 mg/L throughout the winter.

Key finding includes the uniqueness of the controlled microbiome-shift implemented at full-scale over a full period of 12 months and beyond. This paper reveals the method for operating a controlled shift of existing activated sludge biomass into a new densified biomass displaying reliably superior settling and thickening abilities, in particular in a continuous flow activated sludge process. Density-based or densified biomass aggregates either show increased gravitational density or density in terms of higher diffusion resistance due to compact structure or size, specified by a higher percentage of densified biomass aggregates greater than 100 μm in the biomass. The result of this densification is a controlled and narrower dSVI operating span, which allows for increased clarifier upflow velocities, both in operation and design. Biomass densification is a mixture of “dense biomass aggregates” and “flocculated activated sludge biomass”, with the properly adjusted and controlled proportions of “dense (aerobic granular) biomass aggregates” to ballast the mixture, thus conferring to the overall “densified sludge”

mixture some very good and controlled settling ability. Specifically, densified biomass is described as being a biomass showing a dSVI (diluted SVI) of between 35 and 100 mL/g with a mass proportion from 10 to 50% of particles greater than 100 μm (up to 1000 μm; but preferably between 200 μm and 500 μm).

The development of this technology paves a new way in the field of activated sludge for continuous flow bioreactors. Both in terms of brownfield infrastructure, throught improvement of existing baselines performance, and of new greenfield projects.

Background and relevance

This paper reveals the method for operating a controlled shift of existing activated sludge biomass into a new densified biomass displaying reliably superior settling and thickening abilities, in particular in a continuous flow activated sludge process. It describes the full-scale demonstrations implemented in France in Dijon Wastewater Treatment Plant. Outstanding performance results will be shared including detailed demonstration of the controlled-shift of microbiome implemented to achieve the new specific definition of densified biomass, together with key process results obtained.

With a nominal capacity of 400,000 PE, the WWTP on which the full-scale demonstration unit is installed consists of:

- Pretreatment: coarse screening (40mm), fine screening (6mm), grit removal, oil removal

- Secondary biological treatment stage, spread over 4 identical independent lines, each composed of a biological basin, in anaerobic configuration + sequenced channel, and an associated clarifier.

- Sludge treatment consisting of dynamic gravity thickeners followed by centrifuges dewatering The biological treatment lines are independent from one another, without any mixing of the activated



sludge upstream of the clarifiers or at the recirculation (RAS). This feature allowed a comparison of two perfectly independent parallel lines (one densified, the other left intact) and under the same operating conditions (temperature, load, flow). The underlying objective is to be able to explicitly compare the differences in performance and behavior between densified biomass and conventional biomass.

The densification process is based on the implementation of an external gravimetric selection, carried out on the extraction of excess sludge (WAS). The selector is in the form of a hydrocyclone battery fed by the activated sludge to be extracted. The sludge with superior settling characteristics is recovered by underflow from the hydrocyclones to then be sent back to the head of the biology, while the sludge with low settling characteristics goes overflow and is evacuated towards the sludge line, constituting the new WAS of biological system.

The technology presented allows the progressive bio-increase of organisms adopting the densest forms (dense aggregates), because they are preferentially retained in the system, to the detriment of the light forms (pine flocs, filamentous bacteria) which are now primarily extracted from the biological system.

This results in the establishment of a biomass densification present in the biological system, the settling characteristics of which are then increased compared to conventional activated sludge.

The implementation of the process remains relatively easy and can be carried out in just a few weeks of work, with little or no civil engineering work. Figure 1 shows this implementation which consists of abandoning the current WAS line (1), adding pumping (2) to the hydrocyclone battery (3), generally installed on board or at proximity to the aeration basin; the establishment of a return line for the dense sludge retained at the head of the biological reactor (4), and the return, by gravity or by pumping, of the light sludge to the sludge thickening stage (5).

Figure 1.1 Implementation principle of the external gravimetric selector in the water treatment line (image copytright: Suez International); Experimental principle of the installation for sampling and characterization of water

quality (inlet, outlet) during the comparative study

The quality of the treated water from the 2 lines is monitored weekly from 24-hour average composite samples collected by refrigerated automatic samplers located in the outlet of each clarifier of the two lines to be compared (see Figure 1.1). The physico-chemical parameters monitored are pH, COD, CODsoluble

(0.45µm), BOD5, N-NH4, N-NO3, N-NO2, TN, TP, P-PO4, Turbidity, TSS. NTK is deduced by subtracting the N-NOX from the TN measured.


This paper presents the operational results of a full-scale demonstration unit for the densification of activated sludge by external gravimetric selection. The device is installed on an existing installation comprising 4 biological treatment lines with a nominal unit capacity of 100,000 PE. This configuration allows the comparative study of the densified biomass (1 line) with the standard activated sludge reference (1 of the other 3 lines).



Figure 1.2 Comparison of SVI at 2 gMLSS/L between experimental densified line (green) and witness baseline (blue) in similar operational conditions

Figure 1.3 Three charts highliting seasonal statistical repartitions of dSVI and % aggregate observed during trials of CAS line compared to densified sludge line



Figure 1.4 Evolution of TSS outlet, 24-hour average composite sample, for WWTP discharge (black), witness baseline (blue) and densified line (green)


External gravimetric selection allows the transition from conventional activated sludge to densified biomass with relatively low effort and time. Easy to implement, the hydrocyclone sludge densification system can be easily adapted to a WWTP without major work and without interruption of service.

The experience feedback from this full-scale study, on a treatment line with a nominal capacity of 100,000 PE, demonstrated the capability of densified sludge to:

- Smooth the normal fluctuations of seasonal variability of sludge settling

- Stabilize the sludge indices below 100 mL/g even in winter climatic conditions where the classic activated sludge would undergo expansion (dSVI>250 mL/g)

- Improve the sludge volume index down to 45 mL/g in favorable climatic conditions

- Maintain sludge settling velocities, measured in a column, clearly greater than 1.5 m/h for sludge concentrations between 3 and 4 gTSS/L

- Improve the quality of the treated water, all parameters combined: carbon, nitrogen, phosphorus, by a higher reduction of pollution in particulate form

- Substantially reduce stable biological foaming and the production of floats

Through the densification of biomass, this study paves a new way towards a new approach to operating WWTPs, applicable to biological treatment processes using activated sludge.

Figure 1.4 Implementation of densification technology on Dijon WWTP, installation lay-out (left) and hydrocyclones (right)

Figure 1.5 Implementation of densification technology on Dijon WWTP, installation lay-out (left) and hydrocyclones (right)


21 References

J.P. Canler, J.M. Perret. La clarification : approche dimensionnelle basée sur le couple aération - clarification.

Fondements et évolutions. Techniques Sciences Méthodes, ASTEE/EDP Sciences, 2005, 2, pp.44-55. ⟨hal-02586303⟩

J.P. Canler. Dysfonctionnements des stations d'épuration : origines et solutions. Cemagref Editions, pp.123, 2005, Documentation technique FNDAE, n° 33. ⟨hal-02586808⟩

J.P. Hazard, P. Descamps (2010), Procédé de régulation de l'apport d'oxygène pour le traitement d'eau résiduaire, et installation pour sa mise en œuvre. INPI - Brevet FR2943335A1 publié 2010-09-24

CEN (European Committee for Standardization), 2006, Characterisation of Sludges – Settling Properties – Part 1:

Determination of Settleability (Determination of the Proportion of Sludge Volume and Sludge Volume Index). EN 14702-1, Brussels

Torfs E. et al. (2016). Experimental Methods In Wastewater Treatment. Edited by M.C.M. van Loosdrecht, P.H. Nielsen, C.M. Lopez-Vazquez and D. Brdjanovic. ISBN: 9781780404745 (Hardback), ISBN: 9781780404752 (eBook). Published by IWA Publishing, London, UK, pp 235-262

Kynch, C.J. (1952). A theory of sedimentation. Transactions of the Faraday Society, Vol 48, 1952, pp 166-176.

Ekama G. A. et al (1997) Secondary settling tanks: Theory, Modeling, design and Operation. International Association on Water Quality, Scientific and technical report No.6 – ISBN 1 90022 03 05

ATV-DVWK (2000) ATV-DVWK Standards A 131E, Dimensioning of Single-Stage Activated Sludge Plants, ATV- DVWK, Water, Wastewater, Waste, Hennef, Germany

Metcalf and Eddy Inc. Wastewater Engineering: Treatment, Disposal, Reuse (third ed.), McGraw Hill, New York (1991)

Presenting Author

Mr Sylvain Donnaz

Deputy Director of Strategic Development, Suez International

Is the presenting author an IWA Young Water Professional? NO

Bio: Sylvain has been in the field of wastewater treatment for 18 years. He spent 8 years commissioning with Suez International (ex-Degrémont) more than 9 million PE of WWTPs in different countries, mainly for large plants.

He’s been 4 years in the Technical Direction of Suez Water France and CIRSEE (Group R&D center) acting as O&M process expert. He focused on the operational efficiency of more than 18 million PE of WWTP.

He is inventor and co-inventor of 4 Patents, all filed in the field of wastewater treatment.

He is an active fellow member of IDA, IWA and SIWW, where he has been poster judge, session co-chair and session chairman & published >28 Papers with oral presentation.

In November 2017, he received the Award of “Environment And Sustainability” at IDA World Congress 2017 for Water Reuse & Desalination in recognition of best paper and its associated presentation on Water Reuse in Agriculture for As Samra Water Reclamation Plant in Jordan, which illustrated how water reuse or desalination can be applied while respecting the environment and ensuring sustainability.




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