Wetsus innovations

Wetsus Innovations

Examples 2015 – 2020

colophon Publisher Text Pictures Cover art Editing Design Printing November 2020

www.wetsus.eu

Wetsus Hans Wolkers Wetsus and participants Marleen Annema Wetsus BW H ontwerpers Rekladruk

Preface

Since the official inauguration of Wetsus by our current King Willem Alexander in 2004, some 190 companies and 100 professors/ principle investigators have collaborated in the Wetsus innovation program on the creation of breakthrough science & technology that contributes to solving major societal challenges and strengthens the water technology sector at the same time. The Wetsus program has led to the creation of some 90 patents and 27 technologies that were demonstrated at pilot plant scale at least. At the same time, over 700 high impact scientific papers have been published in peer-reviewed journals and more than 1000 multidisciplinary trained and application-orientated water technology specialists have been educated in the Wetsus program during the 2004-2020 period.

In 2015 we published our first innovation book, highlighting a selection of the technologies developed since the start of Wetsus. From 2015 onwards, many new Wetsus innovations have seen the light and this has inspired us to publish this new edition. In this book, a distinction has been made between a) innovations originating from other institutes that have been accelerated

by Wetsus, b) current innovations available for application, directly resulting from the Wetsus program and c) innovations from the Wetsus program that are expected to be available on the market in the near future.

For all organizations and people connected to our program, the enormous potential the unique Wetsus approach offers for a fairer and more sustainable world, is a source of inspiration to continue our joint innovation mission for the years to come.

We are very proud of the outcome of the Wetsus program as presented in this book and thank everybody who has in the past 17 years in whatever way contributed to this remarkable achievement.

cees buisman & johannes boonstra Executive Board Wetsus

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table of contents

Preface

accelerated innovations 1 The Wetsus network as an accelerator for innovation

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current innovations 2 Recovering phosphate from sludge using magnets

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3

Testing water pipelines using ultrasound

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4

ccurate groundwater flow measurements to efficiently manage A drinking water wells

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5

Energy-efficient nitrogen recovery from wastewater

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6

hosphate recovery from animal manure: closing nutrient cycles P and improving soil health

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7

Energy storage with minimal environmental impact

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8

I mproved seawater desalination using innovative membranes and smart designs

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9

mart UV technologies to eliminate micropollutants in drinking S water sources

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10 Theoretical models to improve drinking water quality 11

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usty granules: the key ingredient for stopping algal blooms R by reaching extremely low phosphorus concentrations

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future innovations 12 Hollow fiber nanofiltration to remove micropollutants from toilet wastewater

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13 Designing aligned pore membranes for resource recovery

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14 Calcium (bi-) carbonate nanoclusters in water: a key to reduce scaling

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15 Removing sodium to save water for crops

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16 E fficient electrochemical recovery and reuse of phosphate in salty waste waters

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Acknowledgments

accelerated innovations

1 The Wetsus network as an accelerator for innovation

Since 2004, Wetsus has successfully brought together scientists and companies from all over the world. This innovation melting pot has not only led to innovations that directly result from the Wetsus program, but has also been instrumental in advancing technological developments that have their origin outside Wetsus. In this chapter, three examples of such accelerated innovations are described. But before that, some of the hidden secrets of the model leading to the innovations described in this book are revealed in an interview with the two Program Directors, Bert Hamelers and Jan Post. They reflect on 17 years of successful innovation and Wetsus’ role as a connecting party.

‘Mutual trust is the basis.’

Wetsus as inspirer for cooperation Wetsus functions as a platform where businesses and knowledge institutes join forces to boost innovation and solve actual problems in the field of water technology. This is put into practice in the so-called research Themes, into which the overall research program is divided.

Each Theme focuses on a specific topic or challenge. Within these Themes, universities, students and companies with a variety of backgrounds and expertise collaborate to develop innovative technologies. These networks prove to be very effective. ‘Developing innovations imply sharing knowledge between people with a different perspective: quite often the most interesting and relevant expertise is coming from people you do not know yet’, says Bert Hamelers. ‘But sharing this knowledge requires that parties trust each other. Therefore, building trust and confidence is a key factor responsible for the success of Wetsus.’ Trust among the different theme participants is catalyzed by the exchange of specific expertise between them: sharing expert knowledge inspires confidence. To further support this confidence, five main values drive the organization: innovation, cooperation, partnership, reliability and joy. ‘These values should be intrinsically present in people that

bert hamelers

Program Director, Wetsus

jan post

Dep. Program Director, Wetsus

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Bert Hamelers, Program Director of Wetsus, addressing the theme members

work at Wetsus’, says Jan Post, ‘for example, by acknowledging the importance of companies as full innovation partners, not just as sponsors.’

against competitors.’ A third aspect that builds trust is benevolence and the opportunity to continue and influence the project if successful.

‘Theme members have great influence on follow-up questions, again inspiring confidence’, says Jan Post. ‘Within Themes it all works like a self-reinforcing effect: confidence and trust stimulate knowledge sharing and that in turn stimulates trust.’

Transparency and integrity are other requirements supporting trust within the network and accelerating innovation: a wait and see attitude due to insufficient trust inhibits the cooperation process. Furthermore, clear rules and rights for both companies and universities in the dedicated Wetsus IPR regulations create transparency and are instrumental for creating a level playing field. In addition, within the research Themes the basic attitude of integrity and mutual respect is crucial, according to Hamelers: ‘Different participants should be open and respectful and take each other’s interests seriously.’ It is important to acknowledge that companies investing knowledge and money in a theme expect something in return. Sharing the research output between Theme participants is therefore crucial. To further stimulate trust, companies have a veto right when it comes to welcoming new partners. Hamelers: ‘It gives confidence if you can protect your interests

Besides trust, also the different perspectives of theme participants on a similar problem stimulate collaboration and innovation and broadens the views on the problem. ‘Companies are often the end users of the technology and consequently have a practical approach to a problem: their focus is on specific, real-life problems’, Post explains. ‘For example, even though companies focus on practical feasibility, they take the entire manufacturing process into account as well. They may ask themselves, for instance, how can the production process be re-designed without the use of carcinogenic substances? This also accelerates the innovation process.’

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Accelerated development of bioplastics Not all innovations from Wetsus have originally started there. In some cases, companies or universities come with concepts that originate from outside Wetsus and shift their research into a Wetsus Theme to accelerate the innovation. The Wetsus network accelerates the development of projects. This happened, for example, with research on the recovery of valuable biopolymers from wastewater, while simultaneously treating it. Before Wetsus was involved, Paques and Delft University on the one hand, and Veolia Water Technologies, Stowa (Applied Water Research Foundation), five Dutch water authorities and SNB (Slibverwerking Noord-Brabant) on the other hand, developed their own method for efficient biopolymer production in wastewater. Both groups enriched biological wastewater processes with natural bacteria that can produce and store biopolymers from the organic contamination present. ‘Up to 80 percent of all biomass can be converted into these so-called polyhydroxyalkanoates (PHA)’, João Sousa, Head of Emerging Technologies of Paques Technology BV says. ‘These PHA’s are attractive ingredients for bioplastics and are biodegradable.’ The project aimed to combine water quality with resource recovery, while the recovered biopolymers contribute to the

joão sousa

Head of Emerging Technologies, Paques Technology BV

B acterial biomass (red) with accumulated PHA (green)

P HA recovered from municipal wastewater

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Bioplastic production at lab scale (below) and pilot scale (middle); the research team (above)

circular economy. However, at some point in the process, Veolia decided to withdraw from the project. But the other participants of both consortia wanted to continue and decided to join forces and bring their research under the Wetsus umbrella. A new Wetsus Theme, Biopolymers from water was started, that embraced the parties, individuals, experience and know-how from the two parallel research developments. These former competitors are now successfully collaborating, while benefiting from the Wetsus approach, network and facilities. This results in synergy in the form of coupling of ideas and methods towards otherwise harder to anticipate possibilities for innovation and the recognition of fruitful opportunities in the real-world application of those innovations. Sousa: ‘The PHA technology involves many different steps and requires a highly interdisciplinary approach. The unique infrastructure of Wetsus gave both the capacity and the flexibility to combine research involving a wide variety of expertise.’

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Full scale facility of Thiopaq process treating low pressure sour gas

Detoxification of toxic gas mixtures Sulfur removal from gas is another example of a technology that was not developed at Wetsus, but where Wetsus played an important role in accelerating its development. ‘Paqell markets a worldwide successful biological technology to remove hydrogen sulfide (H2S) from waste gas using microorganisms’, says Jan Klok, R&D Manager at Paqell. ‘But in the real world, these waste gasses also contain other toxic components that inhibit microbiological activity.’ As a result, the technology may not work optimally in practice. Therefore, in 2011 Paqell joined Wetsus to start research around this issue. ‘Wetsus mainly focused on how the system can handle these toxic substances, without loss of efficiency’, Klok says.

jan klok

R&D Manager, Paqell

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F ull scale facility of Thiopaq process treating high pressure natural gas

SEM image of sulfur particles

‘That resulted in a search for the right microorganisms that would be able to deal with these toxic gas mixtures.’ They eventually found their ‘miracle bacterium’ at factories that biologically treated highly toxic gas mixtures.

Much to the scientist’s surprise, tests showed that by using these bacteria the technology worked, despite highly toxic components present in the gas mixture. ‘Collaborating with skilled people within the project motivated and helped to set big steps and eventually forced a breakthrough’, Klok says. ‘At Wetsus, there is an effective network of scientists and experts and a lot of expertise. They communicate extensively and work really well together. There is a high level of trust and that is needed to make progress. This is an enormous added value.’

Accumulation of elemental sulfur in a bioreactor

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Inside the Puurwaterfabriek

Unexpected micropollutant removal The removal of micropollutants from wastewater is another example of scientific research that started at other institutes, and where Wetsus accelerated the technological development. In this case it involved a biological oxygen-dosed activated carbon filter (BODAC) that performed well beyond expectations. The Puurwaterfabriek in Emmen (The Netherlands), operated by company NieuWater B.V. (owned by Drinking Water company WMD and Waterboard Vechtstromen) produces ultrapure water from the effluent of a wastewater treatment plant.

Water technology company WLN is responsible for water quality control and advice on process technology. To produce this ultrapure water, several treatment stages are involved and are preceded by the BODAC filters. The microporous carbon particles present in these filters form a good material for microorganisms to grow on, while removing the pollutants. As a result, biofilm formation is reduced, resulting in an

dennis de vogel

Senior Water Technologist, WLN

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Close up of BODAC filters in Puurwaterfabriek

BODAC research setup at Wetsus

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Boosted Innovations According to Hamelers and Post, these three examples illustrate how Wetsus with its network not only starts innovations in water technology, but also accelerates innovative research that was initiated by research groups elsewhere. Wetsus can scale up the research very fast by involving additional companies and universities using its fixed format for cooperation, avoiding time that would be wasted for new contract negotiations. The basic attitude of integrity, mutual respect and trust within the network, proves to be a key to Wetsus’ success as a connecting party to boost innovations.

extended lifetime of the membranes used in the purification process. ‘To our surprise, the BODAC filters also remove a variety of micropollutants’, says WLN senior technologist Dennis de Vogel. ‘In addition, we found out that the filters continue to remove micropollutants up to now for already 10 years, without the need of re-activation of the carbon!’ To better understand what was exactly going on in these carbon filters and improve the current design, the scientists decided to start a collaboration with Wetsus to study what fundamental processes were going on. Currently, one Wetsus PhD student studies the microbiology and micropollutant removal at the Advanced Water Treatment Theme, while another PhD student in the Biofilms Theme is looking at optimizing filter engineering and fouling prevention. ‘This project is an excellent example of how a company can bring a new finding to Wetsus, and together find out how things work to further improve the technology’, says de Vogel. ‘This is an important added value of collaborating with Wetsus.’

^

G ranular activated carbon used in the BODAC filters

>

Biofilm developed on activated carbon from previous research by Wetsus PhD Vytautas Abromaitis

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current innovations

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Recovering phosphate from sludge using magnets

Using a surprisingly simple method, Wetsus and TU Delft and their industrial partners enabled phosphate recovery from wastewater sludge. When adding iron to the sludge, eventually a special iron-phosphate, vivianite, is formed. This paramagnetic compound can subsequently be recovered by electromagnets. Bengt Hansen from partner company Kemira is pleased: ‘Wetsus has shown excellent scientifi c skills and great creativity during the project.’

Wetsus has a strong focus on developing new technologies for phosphate recovery from waste streams, such as wastewater sludge.

Capturing phosphate from wastewater and reusing it closes the phosphorus cycle.

However, current recovery techniques are insufficient. ‘Many technologies are aimed at phosphate recovery by producing magnesiumammonium-phosphate, or struvite’, says Mark van Loosdrecht, Professor in Environmental biotechnology, at Delft University of Technology.

‘But this technology only recovers about 10-15 percent of all phosphate present.’ In addition, struvite contains a lot of impurities, making it less suitable as a fertilizer.

mark van loosdrecht

Professor in Environmental biotechnology, Delft University of Technology

Unexpected solution Many wastewater treatment plants use iron salts, like iron chloride, to remove phosphate from wastewater and bind it in the sludge.

However, the resulting iron (ferric, Fe3+) phosphate binds phosphorus very strongly.

Because the phosphate in ferric phosphate is less readily available to crops than in mineral fertilizers, it is not the most suitable phosphorus fertilizer. In their quest to find a method to recover this phosphate, the scientists found an unexpected solution: the subsequent fermentation of the sludge to produce biogas converted the ferric (Fe3+) phosphate into ferrous (Fe2+) phosphate, also called vivianite. Van Loosdrecht: ‘More than 90 percent of all phosphate in sludge

bengt hansen

Manager of Application Development, Kemira

ivianite crystals concentrated from V sludge via magnetic extraction

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The ViviMag pilot containers at the wwtp Nieuwveer of waterschap Brabantse Delta

Attractive partner The different participants are quite excited with the project’s progress. ‘The formation and recovery of vivianite using electromagnets is a fantastic idea of the researchers from Wetsus and partners, and forms the basis of a novel technology’, says Bengt Hansen, Manager of Application Development of Kemira, in Sweden. ‘The technology was demonstrated at pilot-scale at the wastewater treatment plant Nieuwveer of Wetsus partner Waterschap Brabantse Delta. The next step is to show the proof of concept in a commercially-sized pilot installation.’ Hansen is, as he says, ‘absolutely happy’ with the contribution of Wetsus.

According to him, the level of science is high, there is broad experience in water treatment technologies and they are at the forefront of

can eventually be present as vivianite.’ This compound has several important advantages: it is paramagnetic, meaning that it becomes magnetic when a magnet is present. As a result, this compound can easily be retrieved by using (electro)magnets, a technique applied in the mining industry. Another advantage is that the phosphate present is more loosely bound, making it a useful fertilizer, for example for olive trees: these often need extra phosphate as well as iron for optimal growth. ‘But it is also possible to separate phosphate and iron’, says van Loosdrecht. ‘It can subsequently be used as fertilizer while the iron recovered can be reused in the water treatment process.’ The now patented technology not only recovers P, but also reduces costs for sludge removal by 10-20 percent.

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innovations in the field. This makes them a very attractive partner. ‘Wetsus also creates an international environment with a broad approach to water treatment’, he says. ‘They create novel solutions to both old and new problems, while linking the research institutes to the industry. This brings them closer to the world problems.’

Van Loosdrecht also compliments the special approach of Wetsus in bringing different parties with their unique expertise together.

‘They join knowledge and capacities from all Dutch Universities to develop innovative technologies to solve real-life problems’, he says.

‘With the expertise of participating companies, pilot plants are quick to be build, accelerating a marketable technology. This is very stimulating and effective!’

SEM image of a vivianite crystal

Pilot scale magnetic separator

S tudying vivianite crystallization in a small-scale fluidized-bed reactor

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3

Testing water pipelines using ultrasound

To prevent water leakage from drinking water pipelines, drinking water companies need to know which pipes need replacement before they break. The company Acquaint and Wetsus in partnership with several drinking water companies and University of Twente, developed a novel pipeline inspection device. Sensors using ultrasound technology measure pipe condition and associated leakage risk. The method is now already being used for inspection. A miniature robot, to carry the sensors through the pipes, is currently being developed and planned to be operational within two years.

Drinking water pipelines age over time due to material degradation, finally resulting in leakage. In some European countries this may result in losses of over 40 percent.

Pipeline materials, like cast iron, steel, PVC and concrete degrade due to corrosion, microbial activity or pH. ‘To prevent water losses due to leaking, we needed to have a reliable technology to test the degradation and quality of pipelines’, Rudy Dijkstra says. Dijkstra is CEO of Acquaint, a young company specialized in developing and marketing inspection techniques for pipelines. In the Netherlands, water losses due to leaking pipes are one of the lowest, roughly 3-4 percent. But many of the 120.000 kilometer of pipelines are old and about two percent is in bad shape. Replacing this two percent all at the same time is logistically impossible and costly. Therefore, reliable inspection and detection techniques are needed to assess pipeline condition and prioritize pipe replacements, avoiding high costs. To apply and use the technology extensively, Acquaint and Wetsus are jointly working on developing prediction models as well. Based on big data like age, inspection data, open data and real-time sensors, predictions about the risk of pipe leakage can be modeled.

doekle yntema

Scientific Project Manager, Wetsus

rudy dijkstra CEO, Acquaint

igh tech ultrasound inspection technology H in a handheld mouse

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Broken pipe element replacement

Modified ultrasound technology The principle of the pipe-inspection method developed by Acquaint and Wetsus, is based on modified ultrasound technology that can penetrate pipeline walls. ‘Sound waves behave differently in, for example, PVC or concrete that is becoming brittle due to aging’, says Doekle Yntema, scientific project manager and theme coordinator of the smart water grids theme at Wetsus. ‘Our research has resulted in a patented technology that is built into a small sensor by Acquaint. The sensor can be moved through a pipeline to monitor and evaluate the state of the wall material.’ The way these sound waves travel through the wall or how they are reflected gives information about pipeline degradation.

Visualized

data from a piece of inspected pipe

Jump start The collaboration between Wetsus and Acquaint proved beneficial for both parties.

When Acquaint was established in 2014, they directly became a member of the Wetsus Smart Water Grids Theme. This enabled the young company to make a jump start to develop pipeline inspection technology. ‘This was an essential step of fundamental importance to us’, Dijkstra says. ‘The development of new inspection technology went really fast and

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Laboratory setup at Wetsus, developing and testing new inspection technologies

gave us a head start. It took only about two years from research to a working prototype for assessing pipeline conditions.’ The company offered lots of practical input to the scientists and formulated important requirement for the technology to work in practice. Yntema: ‘It was a joint trajectory with a lot of communication going on. Acquaint kept us sharp and made sure that we thought of all details of interest.

They tested the prototypes in practice and gave us feedback for improvements.’ Also, Dijkstra praises the small gap between lab research and practice due a continuous, fast and dynamic exchange of information and data between Wetsus and Acquaint.

Intelligent PIG used for monitoring water pipes

Excellent product Now that the sensors to evaluate pipeline condition have been successfully tested for concrete and PVC pipelines, it is time for the next step: a small carrier that can move the sensors through the pipelines autonomously.

Dijkstra: ‘We have come so far and so quickly thanks to the role of Wetsus in developing the sensor technology. This has been crucial for us and has resulted in an excellent product: a good working inspection technology, that enables us to assess pipeline lifespan and risk of leakage.’

G raphical depiction of an intelligent PIG (Pipeline Inspection Gauge)

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4 Accurate groundwater flow measurements to efficiently manage drinking water wells

Using fiber-optic cables, a cooperation of Wetsus, Arcadis, Deltares and drinking water company Vitens developed a reliable system to accurately measure groundwater flows around drinking water wells. This knowledge is crucial to improve well management and guarantee a reliable drinking water supply. Vitens manager Johan Driessen: ‘Developing innovative technologies at Wetsus proved cost-effective and very efficient.’

Drinking water companies fulfill a crucial role in society by providing a steady supply of clean and reliable drinking water to consumers.

Vitens is the largest drinking water company in The Netherlands, distributing high-quality drinking water in five Dutch Provinces. ‘We exclusively extract water from groundwater wells’, says Johan Driessen, Manager of the Technology Centre, Vitens. ‘This has several advantages. In the area covered by Vitens, groundwater is generally present at high quality and in high enough abundancy. So, even during dry summers, the supply of sufficient drinking water will not be compromised.’

johan driessen

Manager Technology Centre, Vitens

Important knowledge Groundwater percolates through different ground layers of, for example sand and clay, before it is collected in an underground well. ‘We extract water from at least 1200 of such wells’, Driessen says. ‘The problem is that you never know exactly where this water comes from and how groundwater flows to and around the well.’

This is important knowledge to manage the wells: Vitens wants to avoid poor-quality water, containing for example salt, or iron, flowing into a well: these can clog the filters of the vertical water-extraction tubes. To understand how this water moves, groundwater flow is mapped using flow models. But these only give a very general picture of what is happening deep down. ‘It is crucial to know exactly how the water is flowing towards the well and how to keep the filters clean as long as possible’, Driessen says. ‘Therefore, we needed to refine our knowledge regarding groundwater flows in the vicinity of our wells.’

wiecher bakx

PhD researcher, Wetsus & Arcadis

rilling of 60m deep bore holes for the D installation of the fibre-optic cables

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S et-up in the Deltares Geo Model Laboratorium to validate the fi bre-optic cables

R ig in which multiple fi bre-optic cables were tested in the laboratory set-up

P reparation of fi bre-optic cables for fi eld-testing

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E xample of well clogging from previous research by KWRVU-Wetsus researcher Diego Bustos-Medina

Efficient well management Measuring groundwater flows directly, could give a detailed picture of groundwater movements around the well at any moment.

Wetsus PhD scientist Wiecher Bakx developed a setup to accurately measure groundwater flows using fibre-optic cables. Bakx, also working at Arcadis as a scientist, explains: ‘Groundwater flow can be measured by using a fiber-optic cable to measure temperature in combination with a heating cable. By heating this cable, the measured temperature by the fiber-optic cable will increase and eventually reach an equilibrium. This equilibrium temperature is, however, related to the groundwater flow velocity. The faster the groundwater is flowing around the fiber-optic cable, the stronger the cooling, resulting in a lower equilibrium temperature. So, using this setup, we have a way to measure groundwater flows!’ His system was tested and validated in the lab and in 2019 field tests were completed successfully.

The method is now ready to be applied around water wells. The beauty of his finding is that groundwater flows may possibly also predict

I nstallation of the data acquisition system

filter clogging, at least in theory. Bakx: ‘Suppose that a blockage slowly develops in a filter at a certain depth, then we will see a slow decrease in water flow over time at that depth. So, our measurements will show a higher equilibrium temperature indicating that there is a potential blockage developing.’

Knowledge network The motivation for this innovation came from the companies. ‘At Arcadis we want to use groundwater flow measurements to provide better and more accurate solutions for clients such as Vitens.’ Thanks to the effective cooperation between Arcadis, Deltares, Vitens and Wetsus, we were able to develop, build, validate and field-test the innovation in less than four years, with Bakx as part-time PhD researcher at Wetsus.’ For Vitens, the collaboration with Wetsus was not only about fast and effective innovation. Driessen: ‘When participating in a Wetsus Theme, you become part of a knowledge network. This is crucial, since this environment generates new ideas and solutions.’

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5 Energy-effi cient nitrogen recovery from wastewater

Together with partner W&F Technologies, Wetsus scientist Philipp Kuntke developed a novel method to recover nitrogen from waste streams. Their collaboration eventually resulted in a cost-effective nitrogen removal technology and an EUfunded project to demonstrate the technology at wastewater treatment plants. Pieter Hack, Chairman of the Board of W&F Technologies: ‘If you want innovative technologies that are also practically applicable, Wetsus is an excellent partner’ Nitrogen is an important element in agricultural fertilizers. Typically, in an energy-intensive process, nitrogen gas (N2) is converted into ammonia (NH3), the raw material for fertilizers.

This nitrogen is taken up by crops and is eventually excreted again by animals and humans as ammonium (NH4+). Ammonium ends up in wastewater, where it has to be removed to prevent pollution of the surface waters. During wastewater treatment, ammonium is converted into N2 by microorganisms, a process that costs energy. ‘This is an uneconomical situation, using energy twice’, Pieter Hack, Chairman of the Board of W&F Technologies says. ‘First, energy is used to make ammonia for fertilizers from nitrogen gas in the air, while later energy is also used to convert the ammonium back into nitrogen gas again.’ In addition, this process leads to the release of nitrous oxide, N2O, a very potent greenhouse gas.

philipp kuntke

Scientific Project Manager, Wetsus

Concentrated ammonia stream Together with the company W&F Technologies, Wetsus scientists Philipp Kuntke and his team developed and patented a more energy-efficient two-step process for nitrogen recovery from different waste streams. The technology is based on his research at Wetsus on ammonia recovery from urine.

The first step concentrates the ammonium present in wastewater via an electrodialysis cell.

Such a cell consists of multiple compartments, separated by so-called ion exchange membranes.

Inside the cell, the cathode attracts all positive

pieter hack

Chairman of the Board, W&F Technologies

maller scale NEWBIES system S at Wetsus with co-inventor Philipp Kuntke

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NEWBIES pilot

ions in the solution, including the ammonium to be recovered, while a cation-exchange membrane leaves anions and organic pollutants behind. At the same time, at the cathode water is split into H2 gas and hydroxide (OH-), elevating pH. As a result, the ammonium is subsequently converted into ammonia gas. The H2 is used at the anode again to save on electricity.

In a second step, this ammonia gas is recovered from the solution by using a gas-permeable membrane, allowing only gaseous ammonia to pass through. Using phosphoric or sulphuric acid, the ammonia gas is converted into an ammonium-phosphate or – sulphate concentrate and subsequently used for fertilizer production.

Kuntke: ‘The beauty of our technology is that we close the nitrogen cycle and don’t waste energy by first producing ammonia from nitrogen and later destroy it by converting it back into nitrogen gas again.’

V isitors at NEWBIES pilot during operation in Spain

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More than happy What started as an idea in 2017, became a working technology in 2019. Kuntke showed the proof of principle in the lab with a reactor treating 100 liters per day. Energy use was substantially lower than in the conventional ammonia recovering techniques. In the newly funded EU project, ‘LIFE-NEWBIES’, Wetsus and W&F Technologies BV, together with other partners (Evides Industriewater and the Catalan research institute ICRA), built a pilot plant with a capacity to treat 2 m3 wastewater per day and recover 1 kilogram of nitrogen per day.

The different parties are more than happy with their collaboration, where they complement each other’s knowledge: ‘The input from the company is indispensable’, Kuntke says. ‘We need their knowledge to build a large pilot plant to further improve the technology as well as learn about the daily operation.’ Pieter Hack also sees many advantages of the collaboration.

‘Wetsus basically developed the technology by creating original solutions. They dealt creatively and flexibly with setbacks and were very solution-oriented’, he says. ‘In addition, Wetsus supplies a network of knowledge where different parties, including potential clients, meet and exchange knowledge. There is a lot of trust and confidence. This paves the fast road to implementation and success.’

Early Prototype of the NEWBIES electrodialysis cell

Membrane electrode assembly

Cathode mesh for water splitting

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6 Phosphate recovery from animal manure: closing nutrient cycles and improving soil health

By adapting the phosphate recovery technology developed for human toilet waste, Wetsus scientists and company Oosterhof Holman, managed to recover phosphate from animal manure.

The first pilot plant recovers about 70 percent of phosphorus from cow manure. The next challenge will be to commercialize this novel technology in Dutch agriculture.

Phosphorus is an important nutrient for life, but its excessive discharge into the environment can be harmful to ecosystems. It is present in different waste streams, like wastewater, but also in manure. In the Netherlands, 71 million kilograms of this nutrient are annually produced mainly, by cows and pigs. Part of it is reused by farmers to fertilize their crops, but legal limits apply to avoid excess phosphorus to wash out from the soil. As a result, there is a substantial manure surplus, that often is incinerated or transported to other countries, at high economic and environmental costs. ‘It is beneficial for famers and the environment to keep as many nutrients and organic material from manure as possible at the farm’, says Wetsus partner Sietze van der Velde, R&D Project Engineer at Oosterhof Holman. ‘This can be achieved by separating these nutrients from organic matter. Farmers can subsequently use the organic component to improve soil health, while the phosphorus recovered can be used to fertilize crops in a controlled way.’

sietze van der velde

R&D Project Engineer, Oosterhof Holman

Challenges Some years ago, Wetsus successfully developed a technology to recover phosphorus from human toilet waste, using the famous Upflow Anaerobic Sludge Blanket (UASB) reactor. After mechanical separation of dairy manure into a thick fraction, rich in organic material, and a thin fraction, rich in phosphorus and nitrogen, the latter is used for nutrient recovery. To do so, this fraction is anaerobically digested to produce biogas while nutrients are recovered simultaneously. ‘By

renata van der weijden

Researcher, Wageningen University

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C ontainer with the pilot UASB reactor fed with dairy manure at a dairy farm in Grijpskerk, Groningen.

U ASB reactor with a conical bottom to facilitate effective recovery of phosphorus.

L ab set up of manure storage to feed the UASB reactor.

L ab scale UASB reactors treating pig and dairy manure

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S EM image of a calcium phosphate granule with biofi lm

S chematic overview of UASB reactor treating dairy manure

Improve soil health The adapted UASB method has resulted in a pilot plant of 4.5 cubic meter. This retains about 70 percent of phosphorus present in cow manure, but the scientists believe 80% is feasible. The remaining organic matter, containing 20 percent or less of the original phosphorus concentration, can be used to improve soil health. So, no incineration or transport of manure is needed anymore.

This approach increases the value of animal manure and stimulates circular agriculture.

The different parties involved are very positive about the collaboration: ‘To solve the phosphorus recovery problem, we have successfully linked Wetsus research to agriculture’, van der Velde says. ‘This has resulted in an innovative phosphorus recovery technology based on a biological process that has a large positive impact on the sector.’

Also van de Weijden is enthusiastic about the collaboration: ‘We now have an excellent contact with farmers and we have installed a pilot plant to optimize the technology’, she says.

‘But also PhD students benefit. They have access to a fantastic network right away.’

adding extra calcium and elevating the pH locally in a micro environment, we are able to recover as much as 90 % phosphorus as Calcium Phosphate (CaP) granules, a perfect raw material for the fertilizer industry’, says Renata van der Weijden, researcher at the Department of Environmental Technology at Wageningen University and Research Center. ‘But we needed to adapt this method to work in animal manure as well.’

Here, the scientists faced some challenges.

For example, in cow manure phosphorus is chemically bound and needs an additional chemical treatment to release it. And although the principle eventually worked for both cow and pig manure, the CaP granules formed were initially too small for efficient recovery: they did not settle easily in a recoverable layer as the large and dense CaP granules produced from human waste. According to van der Weijden, this could be due to roughly 10 times higher concentrations of minerals and organic materials in animal manure as compared to human waste. To improve granule growth, the scientists are now fine-tuning the method, for example by adjusting the flow through the reactor bed and using a two-step process.

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Energy storage with minimal environmental impact

Together with Wetsus, the company AquaBattery developed a sustainable battery, based on fully recyclable and readily available materials, mostly water and salt. The ‘GreenBattery’ is a completely new concept, and several patents have been fi led already. It can be applied as stationary energy storage for a wide range of applications. ‘Thanks to Wetsus’ expertise in membrane technology, and the fact that our teams complemented each other very well, the project is running smooth’, says Emil Goosen, Chief Operating Offi cer at AquaBattery, a spin-off of the Wetsus theme Blue Energy, aiming at developing sustainable electrical energy storage.

More and more energy is generated by sustainable energy sources, like wind and solar. The growing share of renewable energies however requires an increasing energy storage capacity. To balance energy supply and demand, while keeping the electricity grid reliable, asks for large-scale energy storage by batteries. However, current battery technologies suffer from safety as well as environmental issues. ‘Lithium batteries have a major impact on the environment due to mining of metals such as lithium and cobalt, compromising local fresh water supplies as well as the release of toxicants’, says Emil Goosen from AquaBattery.

emil goosen

COO, AquaBattery

Sustainable battery The so-called ‘BlueBattery’, developed by AquaBattery, was a first step towards a safe and sustainable battery. It consists of materials that are abundant and easily extractable and recyclable. In this design, electricity is stored by separating salt and fresh water. By mixing these, electricity can be generated. ‘Although BlueBattery is sustainable, energy density and power density are relatively low’, says Michele Tedesco, Scientific Project Manager at Wetsus.

‘Therefore, together with partners, we are developing a new, environmentally-friendly, more powerful battery in the EU-funded BAoBaB project.’

michele tedesco

Scientific Project Manager, Wetsus <

F irst generation design of the acid-base fl ow battery

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Testing facilities at AquaBattery

The acid-base fl ow battery

6 Volt battery stack based on work of co-inventor Jan-Willem van Egmond

The team used BlueBattery as a starting point, but adapted the design to an acid-base battery.

The principle of this ‘GreenBattery’ is similar to BlueBattery: a stream of ions through a membrane stack generates electricity. But an important difference is the presence of a so-called bipolar membrane: here is where the magic happens. ‘During charging, water (H2O) is split inside the membrane into protons (H +) and hydroxide (OH-) ions’, Goosen explains.

‘These ions are subsequently separated and collected into separate compartments: an acid (H +) and a base (OH-) compartment.

This generates a charge difference between these sections, resulting in a charged battery.’

To generate electricity, the acid and base compartments are mixed in a controlled way inside the battery. This results in a flow of H +

and OH- across the membranes, generating electricity, while inside the membrane, H + and OH- form water.

Several advantages GreenBattery is a new sustainable battery concept with several advantages. It is easily scalable, while costs remain low, even when applied in small systems. In addition, its performance is better than that of BlueBattery.

‘We are continuing to improve GreenBattery’, Tedesco says. ‘For example, partner Fujifilm is developing a better bipolar membrane to boost the battery’s performance’. The project’s end goal is to validate GreenBattery in a real-life situation. Tedesco: ‘A working pilot plant is being installed at the power plant in Pantelleria, a small island near Sicily, and will be operated

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BAoBaB pilot plant

for one year’. These real-world tests are an important step toward market introduction, for example as a safe and sustainable energy storage in residential areas.

Excellent collaboration Both Goosen and Tedesco agree that the project is going very well. Goosen: ‘The different team members complement each other very well and this accelerates the development.’

He also acclaims the Wetsus network, the high expertise and the excellent collaboration between the different participants in the Blue Energy theme. These were key to success.

‘Especially Wetsus’ expertise on membrane technology proved essential’, Goosen says. ‘This helped us choosing the right membrane as well as designing the first pilot plant.’

Upcaled battery design by AquaBattery

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8

Improved seawater desalination using innovative membranes and smart designs

Desalination of sea water is still challenging due to relatively high costs. Together with partner institutes and companies, Wetsus aims to revive the electrodialysis (ED) desalination technology and make it more energy and cost efficient.

Jan Post, Deputy Program Director and theme coordinator at Wetsus: ‘By applying state of the art membrane technologies and redesigning the system, we are developing a more costeffective desalination method based on ED’.

Fresh water scarcity is an increasing problem for many countries in the world. Especially arid countries and islands have little options to make fresh water for their water supply, industries and agriculture. ‘Desalination of sea water usually is the last choice, due to relatively high costs and energy consumption’, says Jan Post. ‘Nevertheless, seawater makes up 97.5% of the world’s water resources. Therefore, efficient desalination solutions will be a crucial part of providing sufficient levels of good quality drinking water for growing fresh water needs.’

jan post

Energy inefficient Reverse osmosis (RO) is the most common method to desalinate seawater. This fully developed technology works by pressing salty water through a membrane that allows the passage of water only and retains the salt. However, during the process, the salt concentration of the retaining sea water increases, requiring increasing pressure for continued fresh water production. ‘Currently, there is no possibility to gradually increase the pressure depending on the remaining salinity in the sea water’, Post explains. ‘Therefore, RO uses high pressure during the whole cycle. This is quite energy inefficient.’

Dep. Program Director, Wetsus

simon grasman

Process Engineer, REDstack

Advances The EU project REvivED water, led by Wetsus participant FujiFilm, aims to develop low-energy solutions for drinking water. The researchers

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P ilot installation (Afsluitdijk)

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xperimental setup E with electrodialysis (ED) stages

Full scale stacks from RED stack ( 3 stage ED)

Pilot location (Afsluitdijk)

applying improved membranes. ’But in addition to energy costs, also the total costs of the operation and equipment should be taken into account’, he says. ‘If we want to reduce energy consumption below 1.5 kWh per cubic meter, we need a lot of membranes. Since membrane prices are still relatively high, costs will then be higher compared to RO desalination.’ Therefore, when balancing material costs and energy consumption, it could be smart to accept a somewhat higher energy consumption until membrane prices have dropped. The scientists are also considering ED-RO hybrid systems.

‘Since ED uses most energy when removing the last bits of salt, RO could be applied during this final stage of desalination’, says Post. ‘Then only about 10 bar of pressure is needed to achieve this, instead of the commonly used 80 bar.’

aim to halve the energy consumption for sea water desalination, using a different technology: electodialysis (ED). Like RO, this technology also uses membranes, but instead of water, only salt ions can pass the membrane.

An electrical current forces the dissolved salts to move over so-called ion-exchange membranes.

Eventually, the dissolved salts are moved from one side of the membrane to the other, resulting in fresh water and a highly concentrated salty waste stream. However, conventional ED systems are considered economical feasible to desalinate brackish water, but not seawater.

But due to advances in membrane technology and smart designs of the ED units, currently the technology is a promising candidate to improve desalination. ‘We can for example reduce energy use by adjusting the voltage that moves the ions during the process step by step’, Post explains. ‘In the beginning, when a lot of salt is present, a low voltage suffices to force the salt ions pass the membranes. With decreasing ion concentrations, a higher voltage is required to remove the remaining ions as well.’

Practical applications Grasman appreciates the collaboration with Wetsus, because of their focus on answering important fundamental questions, paving the way for practical applications. ‘Wetsus also offers an environment where different disciplines of water technology come together’, he says. ‘This speeded up our research and it enabled us to realize our first scaled up pilot plant for testing.’

Hybrid system Simon Grasman, Process Engineer at REDstack BV, is also convinced that reducing energy consumption of ED is feasible, for example by

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9

Smart UV technologies to eliminate micropollutants in drinking water sources

wolfgang gernjak

Wetsus and partners develop improved UV technologies to degrade organic micropollutants in drinking water sources. By using shorter UV wavelengths than conventional UV technology, hydroxyl (•OH) radicals breaking down the pollutants, are more effi ciently generated. As a result, a more effective oxidation of these pollutants is achieved, consuming less energy, without the need of additional oxidizing chemicals, like hydrogen peroxide.

Research Professor, ICRA

Traditional wastewater treatment plants are rather inefficient in removing organic micropollutants (OMP), such as medicine and pesticide residues. Hence, they accumulate in the environment with all the negative ecological impact on, for example, the hormonal system of animals. As a result, feminization of fish has been observed in several rivers. In drinking water sources, the presence of OMPs may pose a human health hazard. To remove these substances during drinking water treatment, an advanced treatment process, like a combination of UV and hydrogen peroxide (H2O2), is needed. This method is based on splitting H2O2 by intensive UV radiation into two very reactive hydroxyl radicals (•OH). These radicals oxidize most OMPs into less harmful compounds. However, this treatment is still rather energy inefficient because only a small fraction of UV reaches the dissolved H2O2, while the use of this chemical also increases costs.

domenico santoro

Senior Research and Innovation Manager, Trojan Technologies

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U V lamp used for water treatment

<< F ull-scale UV peroxide advanced oxidation installation <

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E xperimental collimated beam setup

1 6-lamp pilot installation at PWN Andijk site

P ilot with alternative lamp confi guration

Better oxidation To create conditions for better oxidation of OMPs, novel methods are explored to generate hydroxyl radicals in water. One of the options is to use shorter UV wavelengths, 185 nm instead of 254 nm, the latter conventionally used in combination with H2O2. ‘By using 185 nm UV, hydroxyl radicals are produced directly from water without the need to use H2O2’, says Wolfgang Gernjak, research professor at the Catalan Institute for Water Research (ICRA). ‘However, a disadvantage is that the 185 nm UV wavelength cannot penetrate the usual glass used in photoreactors.’ Therefore, the first step was to redesign the system to facilitate the passage of shorter wavelengths into the water.

the configurations proposed by PhD student Nimmy Kovoor George, while using different water streams provided by our partner PWN. From there it’s a small step to a full-scale system.’ According to Domenico Santoro, Senior Research and Innovation Manager at Trojan Technologies in Canada, scale-up issues can be solved by modeling fluid dynamics, UV radiation in water, and OMP photo-oxidation.

Santoro: ‘Theoretical calculations indicate that, if properly engineered, using 185 nm UV wavelength is 2-3 times more effective than the conventional method using 254 nm UV. We can probably also completely eliminate the need for additional chemicals like H2O2, thereby cutting energy costs considerably’.

Impressive information structure Santoro is pleased with the project and the collaboration with Wetsus. ‘The main advantage of working with Wetsus is the possibility to test ideas rapidly and repeating the cycle of trial and error until a solution is found’, he says. ‘This can be done in a lean and agile manner because Wetsus can mobilize their impressive information structure and knowledge network quickly and efficiently.’

Gernjak is also positive about the project. ‘The level of engagement of all parties involved was excellent’, he says. ‘It connects the different players very well. In addition, I appreciate the Wetsus network, that supported good contacts with other researchers and with companies.’

Difficulties After the proof of principle was demonstrated at lab scale, the scientists started to design and build an optimized, scaled-up reactor, based on the use of 185 nm UV. This approach confronted the team however with challenges related to applying this concept at larger scale. ‘One of the main obstacles was the limited penetration depth of UV 185 nm in water, around 1-5 millimeters. So, we had to find a solution for how to efficiently illuminate larger volumes of water’, Gernjak says. ‘The positioning of the UV lamps in the water flow path was a key question to be addressed. Once we solved that problem, the next step is to test some of

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10

Theoretical models to improve drinking water quality

Wetsus is developing a state-of the art theoretical model for the prediction of reverse osmosis (RO) membrane performance in drinking water production. This helps drinking water company Dunea to produce highquality drinking water from brackish dune water using the most suitable membranes. ‘Thanks to Wetsus’ know-how on modeling, the process is substantially more efficient and cost-effective’, says Dunea Researcher Franca Kramer.

Reverse osmosis (RO) is the most common method to produce drinking water from a source also containing salt. Water recovered from rivers or brackish water sources is pressed through a membrane, allowing the passage of water, while retaining dissolved components, like salt ions, and organic substances. In newly designed RO plants, commercially available models are widely used to predict which membrane type is the most suitable to produce high-quality drinking water from a specific source. However, these models are based on just empirical data and fall short in predicting the ion retention of complex salt solutions.

‘Especially, the removal of reactive ions like ammonium (NH4+) cannot be reliably predicted by the current models’, Wetsus researcher Li Zhang says. ‘Therefore, we started developing a model based on the detailed physical and chemical interactions in transport through RO membranes. This results in a better prediction of ion removal in complex salt solutions.’

franca kramer

Researcher Membrane Filtration, Dunea

li zhang

Postdoctoral Researcher, Wetsus

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Schematic for drinking water production from the infiltration ponds

Predictive tool Developing a new model was started by a single MSc student, mainly as an academic project. But its practical importance was soon picked up by drinking water company Dunea.

‘Currently, we mainly use the river Muse as our source of drinking water’, says Franca Kramer, Researcher Membrane Filtration at Dunea.

‘Dry summers and continued industrial and household discharge result in higher pollutant concentrations in the river during the summer months. Therefore, we are exploring additional, more reliable water sources to ensure safe and continuous drinking water from the tap.’ One of Dunea’s options is the brackish water supply under the coastal dunes near Scheveningen.

However, this brackish water source contains a complex salt mixture and the commercial models are not reliable enough in predicting the most suitable membrane. For an optimal

operation of a novel RO plant, they started a collaboration with Wetsus. ‘Our new model has the potential to serve as a suitable and effective predictive tool to describe the ion retention in RO membranes’, Zhang says. ‘It can therefore help Dunea to select the most suitable membrane to apply in their new RO plant, producing high quality drinking water from this brackish water source.’

Pilot plant The scientists recently named the model the “WESP model”, Dutch for “WASP”. This acronym refers to: Wetsus, Extended, Steric and Pore model, the key elements of the model. The WESP model is based on physical details regarding membrane characteristics as well as data on the different ions and other components present in the water source. Currently, Wetsus is performing lab experiments to characterize

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and test different membranes. By further developing the new model, Wetsus scientists will also acquire a better understanding of the detailed transport processes of different ions, especially those of reactive ions, like ammonium, carbonate and boron. This will help predict the retention of these ions in relation to the pH of the solution and the membrane used. Based on the lab results, the most suitable membranes will be selected and further tested in the onsite pilot plant built by Dunea. Based on the data generated in the pilot plant, Wetsus can further refine and calibrate their model to reliably predict the membrane processes, performance and ion retention. ‘Eventually, Wetsus can help us to design the full-scale plant’, Kramer says.

Infiltration ponds in the dune area of Dunea

For Dunea, the collaboration with Wetsus resulted in a far more efficient and costeffective exploitation of a new water resource.

Kramer: ‘A fundamental and theoretical approach of membrane performance is an important addition for our company, since we have less know-how and possibilities to perform this kind of research. The collaboration with Wetsus has turned out really well!’

Experimental setup for reverse osmosis measurements located at Wetsus

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11

Rusty granules: the key ingredient for stopping algal blooms by reaching extremely low phosphorus concentrations

Water technology company Aquacare and Wetsus developed a sustainable method to remove phosphorus from water down to extremely low concentrations. Their technology is now competing for the George Barley Water Prize, a 10-million-dollar competition to prevent Algal Blooms. Wetsus and Aquacare have won all the stages so far, and currently they are one of the four finalists that can test their technology at full scale.

‘My collaboration with Wetsus was fantastic, I worked with top scientists, the synergy was just great!’, says Koos Baas, director of Aquacare enthusiastically. Aquacare is a company that develops water treatment technologies.

Over the years, the company expanded the application window of their technologies to remove phosphorus from water streams of different phosphorus content. Aquacare has been a Wetsus theme participant for more than 15 years. In the last few years, they joined the phosphate recovery theme and have jointly developed an efficient technology for the removal of phosphorus at low concentrations.

This technology was based on Aquacare’s BiOPhree adsorption technology using porous plastic beads of a few millimeters diameter, coated with iron oxide nanoparticles. Together with Wetsus, the process was further developed and optimized, resulting in an efficient, marketable and sustainable technology.

koos baas

Director, Aquacare

Massive algal blooms Phosphorus is a key nutrient for plant growth.

This is, however, also the reason that when this fertilizer ends up in surface waters, it can cause eutrophication, resulting in massive algal blooms, damaging the ecosystem. Although sewage treatment plants remove around 80-90 percent of all phosphorus present, only 40 percent of the European surface water meets the standards for a healthy ecology. In the near future, EU regulations for this nutrient in surface waters will most likely be reinforced, demanding the removal from wastewater to lower levels.

leon korving

Scientific Project Manager, Wetsus

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Pilot site in Canada showing surface water with algal bloom

Both Wetsus and Aquacare are among the finalists for the George Barley Water Prize

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adsorption technology worked, but the method needed a lot of the adsorbing iron oxide to be efficient.’ Therefore, the scientists at Wetsus looked to optimize the total recovery process, including regeneration and re-use of chemicals and purifying the phosphorus stream, reducing costs and turning waste into a sellable product. Aquacare took care of further developing the practical aspects, like building a marketable device using the right materials and dimensions. The combined knowledge of Wetsus and Aquacare made it possible to compete successfully in the Barley prize, where the technology was tested during three months at pilot scale under real-life conditions, paving the road for further scaling up the technology.

‘In addition, we need to treat agricultural water, for example in ditches’, says Leon Korving, scientific project manager and theme coordinator of the phosphate recovery theme at Wetsus. ‘This water has lower phosphorus concentrations than wastewater, so we need a removal technology that is efficient at these low concentrations as well.’

Appropriate adsorbent To optimize the adsorption, Korving first focused on the different forms of iron oxide. ‘There are about 16 different iron oxides, and they all have a different affinity for phosphorus’, Korving explains. ‘So, we dug into the literature to find out which one had the highest adsorbing potential at low concentrations of this nutrient.’

Their research resulted in a few suitable adsorbing iron oxides allowing both phosphorus removal and regeneration of the adsorbent.

Based on properties like surface area, particle size, and pore size distribution, Wetsus scientists chose the most appropriate commercially available adsorbent for further testing in a pilot study. The design of the first adsorbing device was relatively simple: the scientists just directed the water through a large column filled with small iron oxide-coated plastic granules. Within 3 minutes, about 99.9 percent of all phosphorus present was adsorbed to the iron oxide. A subsequent step released the phosphorus from the adsorbent by rinsing it with a strong base.

By this step, the iron oxide was also regenerated, making it available for reuse. In the final step, phosphorus was recovered by separating it from the base solution by using a membrane. Korving: ‘Our circular and cost-effective technology has resulted in a marketable, efficient and sustainable technology, producing a minimal amount of waste. We can re-use the adsorbent as well as the chemicals used, while recovering the phosphorus.’

A compact pilot plant of Wetsus used to remove and recover Phosphorus from surface water

Overcoming the challenge via successful collaboration It is quite a challenge to remove low concentrations of phosphorus. ‘We knew that iron oxide, rust, has a high potential to bind phosphorus’, Korving says. ‘Aquacare’s

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ifferent iron oxide based D adsorbents used in small scale column adsorption experiments

future innovations

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The removal of micropollutants from toilet wastewater by hollow fi ber nanofi ltration

A novel method to remove micropollutants from wastewater is currently being tested at pilot scale

by Wetsus and partners. After the usual biological treatment, hollow fiber nanofiltration membranes are applied to remove the remaining micropollutants. The resulting ultraclean effluent can be re-used for many purposes.

Wastewater treatment plants are based on the biological cleaning of wastewater by using microorganisms. However, this method is rather ineffective regarding the removal of new emerging contaminants, such as residual medicines, pesticides, microplastics, antibiotic resistant bacteria and viruses. As a result, these micropollutants remain in the effluent. ‘This is a problem due to the danger they pose for human health and nature, while it also limits the possibilities for re-use’, says Sybrand Metz, Technical Director of DeSaH. This company develops sustainable water treatment solutions, for example, for the rather concentrated waste water discharged by vacuum toilets.

erik roesink

Founder, NX Filtration

Effective technology Current methods to remove micropollutants include adsorption using activated carbon, or oxidation using UV and hydrogen peroxide.

But a new and more efficient technology is coming up. ‘Hollow fiber nanofiltration is an emerging technique to effectively remove micropollutants from wastewater, creating clean effluent, which can be re-used for all kind of applications’, says Erik Roesink, founder of NX Filtration and part time professor at University of Twente. ‘The nanocoating on the

sybrand metz

Technical Director, DeSaH

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P lant treating black and grey water (left), visit by the king (right)

>

Decentralized sewage treatment plant for 250 houses in Sneek

inside of the thin, tubular-shaped membranes allows water to pass, while micropollutants, but also pathogens, phosphorus and nitrogen are retained.’ The permeate is of high quality, and can be reused for industrial applications, natural swimming water, and after posttreatment, even drinking water. In addition,

there is a more efficient recovery of nutrients like phosphorus and nitrogen from the remaining concentrate. Another advantage of the new generation hollow fiber membranes is that they are robust, allowing for cleaning with hypochlorite solutions, without damaging the membrane.

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Crucial role Most knowledge on the efficiency of these membranes is based on lab experiments.

Therefore, the membranes are further tested under real-life operational conditions, as well as over longer time periods. Currently, a pilot plant in Sneek integrates these membranes into the biological wastewater cleaning system of 200 households. ‘Our goal is to remove 100 percent of all micropollutants’, Metz says. ‘We don’t know yet if we will manage, but confidence is high.’

Wetsus plays a crucial role in the success of the project. ‘Through Wetsus’ innovative network we got in contact with the hollow fiber membrane technology from NX Filtration’, Metz explains, ‘and with excellent researchers active within the Advanced Water Treatment theme of Wetsus with crucial understanding of transport mechanisms through nanofiltration membranes. ‘This also resulted in a joint PhD project.’ Likewise, for Roesink, Wetsus also provides an opportunity to be in touch with potential partners. Roesink: ‘We meet the right companies to test and apply our membranes in practice.’

P ilot setup for micropollutant removal N XF nanofi ltration membranes manufactured by so called“layer-by-layer” process, where multiple nano-scale layers are deposited on a membrane support

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Designing aligned pore membranes for resource recovery

chris dotremont Senior Researcher, FrieslandCampina

By developing a new generation of membranes using different materials, Wetsus and partners intend to improve membrane separation. Potential applications range from membranebased desalination to the selective recovery of valuable products from residual streams.

Membranes are widely used in many applications, from desalination and wastewater treatment to drinking water production, among others. However, current membranes are not very selective for specific components. For example, reverse osmosis (RO) membranes, that are used to produce drinking water from seawater, allow the passage of water but retain all ions and other matter dissolved in the water. This limitation is due to two main factors. ‘Pores present in membranes are not uniform, but vary in size. This has an adverse effect on the selective separation and the purity of the end product’, says Kitty Nijmeijer, Professor of Membrane Materials and Processes of Eindhoven University of Technology. ‘Moreover, the pores have a somewhat meandering pathway through the membrane. This also decreases the separation performance.’

kitty nijmeijer

Professor Membrane Materials and Processes, Eindhoven University of Technology

<

Membrane installation for water treatment

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Diffusion cell to test the membrane S quare patterned support filled with liquid crystals forming aligned pores

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Organized structure To develop a new generation of membranes, Nijmeijer, together with other Wetsus partners, studies the application of so-called liquid crystalline polymers as membrane building blocks. These long molecules solve current membrane issues: the polymer molecules form an organized structure in a perfectly aligned shape resulting in pores with exactly the same size, that go straight through the membrane. Nijmeijer: ‘These membranes can potentially separate components in a much more selective way. This opens a route to the selective recovery of specific, desired components present in a variety of residual streams.’ For example, at dairy company FrieslandCampina, one of the important waste streams contains diluted lactose mixed with salts. ‘Currently, recovering lactose is not efficient’, says senior researcher Chris Dotremont. ‘Possibly, the new membranes can

recover this valuable component from this salty waste stream.’ The development of these membranes is still in its infancy, but Nijmeijer is confident that the technology will continue to develop step by step. In four years-time the scientists hope to have a functional membrane about the size of an A4 sheet.

Added value The collaboration with Wetsus benefits the project in many ways. ‘In this project we collaborate with Wetsus and industrial partners that are interested in applying the technology, while we also have contact with researchers with very different but valuable expertise, such as microbiology’, Nijmeijer says. ‘That is an enormous added value.’ Dotremont is equally satisfied: ‘The project gave FrieslandCampina the opportunity to participate in the development of a new technology and test it in practice for relevance. A win-win situation.’

Labscale membrane diffusion cell

Polymeric membrane with distributed pore sizes

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14

Calcium (bi-) carbonate nanoclusters in water: a key to reduce scaling

elmar c. fuchs

Program Manager, Wetsus

Calcium carbonate is one of the chemical compounds responsible for clogging pipes (scaling). When calcium carbonate dissolves, part of the dissolved calcium is present as calcium ions (Ca2+), but it can also be present in another form, as part of calcium carbonate nanoclusters.

To minimize scaling, Wetsus and partners are studying the dynamics between Ca2+ and these nanoclusters.

Elmar C. Fuchs, Program Manager at Wetsus: ‘We study how to promote the formation of these nanoclusters from Ca2+, because they seem to prevent or at least reduce scaling.’

Unwanted crystal formation is a major problem for many water companies. For example, calcium carbonate crystals can deposit on pipe walls, slowly but steadily clogging them. Companies like IPF/Grander in Austria, successfully reduce this process by using a magnetic field gradient.

‘Although we had no clear idea about the exact mechanism of the anti-scaling effect of our method, it clearly worked’, says IPF Research Director Johannes Larch. ‘But to improve our technology, we wanted to better understand how and why our water core magnets reduce this scaling effect. That was one of the reasons why we came to Wetsus.’

johannes larch Research Director, IPF

<

Calcium carbonate scaling on pipe

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B iofi lm in drinking water pipe.

Inset shows scraped biofi lm

Super molecules The effect of a magnetic or electrical field on scaling can possibly be explained by the way calcium carbonate dissolves. ‘Part of the dissolved calcium is present as Ca2+, that is associated with scaling’, says Elmar C. Fuchs.

‘But some calcium is present as a polymer-like molecular structure’. These so-called DOLLOPs (dynamically ordered liquid-like oxyanion polymers) are amorphous, differently sized nanoclusters, resembling super molecules.

They contribute to the total calcium present, and consequently to water hardness, but don’t contribute to scaling according to Fuchs’ and Larch’s hypothesis. ‘In tap water there are always DOLLOPs and dissolved Ca2+ ions.

Magnetic field gradients may push towards more DOLLOP formation’, Fuchs explains ‘This way the precipitation of calcium carbonate, and with that scaling, can be diminished.’

In addition, since calcium ions also play a crucial role in biofilm formation, it will also be interesting to investigate the effect of a magnetic field gradient on biofilm formation.

Challenging Studying DOLLOPs and how to promote their formation in water can improve anti-scaling technologies, like the method used by IPF/ Grander. But to investigate and analyze the formation of these super-molecules is challenging. ‘That’s exactly why we came to Wetsus’, Larch says. ‘They have excellent lab facilities and have the know-how to develop new measurement techniques.’

The project has just started, but confidence is high: ‘In about four years’ time we will know how to influence DOLLOP formation and how to measure them in a solution’, Fuchs says. ‘We also aim to redefine water hardness: in addition to the total amount of Ca2+ and Mg2+ ions, we aim to include information about these DOLLOPS as well. It may be that the distribution of Ca2+ over solid calcium carbonate precipitate and DOLLOPS defines the scaling potential of water.

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<

ater core magnet used for generating W a magnetic gradient

S EM picture of deposits from drinking water pipe

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15

Removing sodium to save water for crops

Together with partners from Delft University and company van der Knaap, Wetsus aims to develop a technology to selectively remove sodium ions from nutrient mixes, used in horticulture systems.

A complicated task, it turns out.

Many greenhouses use so-called hydroponic systems for growing their crops. With this form of hydroculture, plants root in a substrate, like rock wool, or more organic substrates such as coconut fiber. Water and nutrients needed for crop growth are dosed using a precisely balanced nutrient mix in water. ‘About 30 percent of this mix can be recycled, saving costs’, says Jeroen Jansen, who is part of the Research & Product Development of the Van der Knaap group, a company that produces sustainable substrates for the greenhouse sector. But because the substrates as well as the nutrient mix contain sodium ions (Na+), that is not taken up by plants because of its toxicity, Na+ accumulates in the (recycled) drainage water.

Recycling of the drainage water stops as soon as the Na+ level reaches a level that becomes toxic for the particular crop species. Cleaning the drainage water of sodium, thereby retaining its concentration below the toxic level, will take away the limitation on the number of recycling steps. However, the selective removal of Na+ from the nutrient mix is challenging. Therefore, in 2015 the company contacted Wetsus to find a solution.

ernst sudhölter

Professor Organic Materials & Interfaces, Delft University of Technology

jeroen jansen

Research & Product Development, Van der Knaap

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E lectrodialysis set-up for measuring Na+ and K+ fluxes over the membrane >

he supported liquid T membrane (SLM) (left) with an additional support (right) for rendering mechanical strength

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S EM image of the surface of the SLM >

ydroponic cultivation of H tomatoes

Trial and error To remove Na+ without also losing potassium (K+), a useful nutrient for plants, proved to be a tricky process which led to trial and error experiments. Na+ and K+ ions are chemically very similar, except that the latter is slightly larger. The first idea was to design a membrane that could, in theory, selectively bind and transport the smaller Na+ and remove it from the solution. ‘We designed a membrane with so-called polycyclic ether molecules attached.

These molecules could selectively bind Na+, but not the larger K+ ions’, Ernst Sudhölter, professor of Organic Materials & Interfaces at Delft University of Technology, explains. ‘This is due to the fact that polycyclic ethers possess a cavity, precisely fitting the smaller Na+ but not the larger K+.’ Surprisingly, in practice the opposite was achieved, K+ was preferentially transported by the membrane. From this result, a two-step process can be engineered for the removal of Na+ from greenhouse drain water:

in the first step K+ is removed and collected from the solution, and in the second step Na+ can easily be removed, where after K+ can be returned to the feed solution. Ultimately, however, in future this can be done in a single step, and that is still the aim of the research.

Sudhölter: ‘I think we will find the solution eventually in this direction, but quite a bit of work still needs to be done to achieve this. It is a learning process with trial and error.’

Commitment Despite these setbacks, Jansen is positive about the collaboration with Wetsus: ‘This is part of research, you never know how fast a technological solution will be found. We did very much appreciate the commitment and perseverance of all parties involved and the excellent communication and explanation about the ins and outs of the project. Also, we could influence the direction of research, so it met our requirements.’

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16 Effi cient electrochemical recovery and reuse of phosphate from salty waste waters

cees buisman

Scientific Director, Wetsus

Wetsus and partners developed an electrochemistry-based technology for phosphate recovery from waste streams. The technology is patented and could provide a good solution to recover phosphate from salty waste streams as produced, for instance, during cheese manufacturing. The technology will be extensively tested in 2020 together with the companies Lascon and North Water.

Eutrophication of surface waters due to the release of phosphorus-containing wastewater results in massive algae bloom, damaging the ecosystem. In addition, phosphorus reserves are limiting, urging their recycling. Currently, the most common method for phosphorus removal is by precipitation as iron or aluminum salts. However, the sludge containing these precipitates is often discarded as waste. Also, magnesium ammonium phosphate, called struvite, can be produced during wastewater treatment, but this requires the addition of extra magnesium. This increases costs and the use of raw materials.

perry van de marel

Managing Director, North Water

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A n example of mining area points out the fi nite nature of phosphate rock

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An industrial wastewater treatment plant in Groningen that suffers from excess phosphorus input

Easily harvested Mined phosphate predominantly consists of calcium phosphate. Therefore, all phosphorus logistics are currently centered around this compound. ‘It makes therefore more sense to aim for the production of calcium phosphate for efficient reuse’, says Cees Buisman, Scientific Director of Wetsus. Recently, Wetsus and the partners from the Resource Recovery theme managed to develop a new method for phosphorus removal and recovery, resulting in the formation of calcium phosphate. The beauty of the novel technology is hidden in its simplicity. An electrical current applied in wastewater generates hydroxide ions (OH-) at the cathode. This results in a locally elevated pH. As a result, calcium and phosphate ions, already present in wastewater, form calcium phosphate that precipitates at the cathode. The method is unique due to its efficiency, especially in saline wastewaters, for example from cheese manufacturers.

S EM image of deposits collected from the cathode after treating real wastewater

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Promising North Water owns and operates an industrial biological saline wastewater treatment plant. They treat about 50 percent of all salty wastewater streams from cheese manufacturers in the north of The Netherlands.

Besides salt, these waste streams contain relatively high amounts of phosphate, organic compounds and calcium. ‘The new technology is promising, but despite the positive lab results, in particularly the local precipitation of calcium phosphate on the cathode, we are not just there yet’, Perry van de Marel, Managing Director of North Water says. ‘There are still practical issues to be solved, for example, how to harvest the precipitate from the cathode at a large scale? The aim is to realize, together with Wetsus partner and engineering company Lascon, a pilot plant at a North Water site.

Cathode

covered with calcium phosphate deposits

E lectrode before (top) and after the process (bottom) which results in calcium phosphate deposition

Acknowledgments

All the Wetsus innovations have been possible because of the team work and contributions from various partners involved in the projects. While some of the representatives from the projects have been interviewed, we realize there have been many others who could not be mentioned within the chapters.

Thus, we have dedicated a separate acknowledgments section to thank those involved in the innovations.

Accelerated development of bioplastics Innovations are often fuelled by creative ways to do something differently based on known information - smarter, better, cheaper, and unexpected. The unexpected nature of innovation often falls out of mistakes that challenge conventional wisdom and assumptions, but also out of the epiphany from unique couplings of information and ideas. Coupling of ideas is an art of realization from connecting the dots. Bringing bits of information together in ways that introduces a novel realization or method for an opportunity to do something differently and better. Connecting the dots thus requires that the founding ideas are somehow made available in a melting pot that stews with the opportunity for the” artists” (researchers) to paint with. Wetsus created such a melting pot in the establishment of the research theme Biopolymers from water. This research theme is led by Dr. Alan Werker together with STOWA (representing the Dutch water boards), Slibverwerking Noord-Brabant (SNB), Paques, and Delft University of Technology (Professor Mark van Loosdrecht and Associate Professor Robbert Kleerebezem). The theme uniquely pools together disparate but interrelated histories of experience over many years in the fundamental and practical developments of open culture polyhydroxyalkanoate (biopolymer) production and recovery from the treatment of residual and waste organic streams coming from industry and municipal sectors. That melting pot is warmed by the

member organizations daring, and a group of individuals believing. The pot is stirred and spiced by the individuals doing. Hats off to the organizations and the individuals stoking the warmth and working the stew of new opportunity for innovation: Leon Korving, Cora Uijterlinde, Luc Sijstermans, João Sausa, Henk Dijkman, Rene Rozendal, Etteke Wypkema, Bart Jooose, Esther van Meersbergen, Yede van der Kooij, Ruizhe Pei, Angel Estevez Alonso, Erik de Vries. The list goes on and grows with acknowledgement including the bioplastics committee of the Dutch “Energie en Grondstoffen Fabriek”, and semester by semester, to an evolving pedigree of valued, often international, students (interns, Masters, and visiting researchers) bringing smiles and grit to the mix. The work of the theme would not be possible without the skills and humour of a well-seasoned in-house team of technical, analytical and administrative staff and their ongoing support to stir the brew.

There is unfortunately no space to mention individually all the valued contributors and the extended team but special thanks to getting the “workhorse” out of the stables to John Ferwerda and Jan Tuinstra.

Detoxification of toxic gas mixtures We thank the participants of the research theme “Sulfur” for the fruitful discussions and Paqell for their financial support. In particular we would like to thank Pawel Roman who helped developing methods, experiments and piloting.

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held with these motivated companies with motivated people leading to a true applied research direction, where new developments are jointly implemented in real life applications.

In the past Andre Arsenio, Andriejus Demcenko, Mahmoud Ravanan, Lucas Mainini, Maurits Maks, Hector Delgadillo and many master and bachelor students have brought the knowledge further. Now Caspar Geelen, Nandini Chidambaram and Cao Vinh Tran are working together as inspiring researchers. From the University Twente there has been invaluable input on the ultrasound and material science topic from Richard Loendersloot, Roy Visser, Remko Akkerman and Tiedo Tinga.

Unexpected micropollutant removal The high micro-pollutant removal in the BODAC filter at the Puurwaterfabriek in Emmen was discovered by NieuWater B.V. and their partner WLN. That research was supported by STOWA. The research at Wetsus on the BODAC system is carried out in the Advanced water treatment theme under supervision of Prof. Gert Jan Euverink from University of Groningen, and in the Biofilms theme under the supervision of prof. Huub Rijnaarts from Wageningen University and Robbert Kleerebezem from TU Delft.

Recovering phosphate from sludge using magnets The ViviMag development is a running train to which a lot of people and organisations are contributing. First of all we thank our past and present members of the phosphate recovery theme: Kemira, STOWA, ICL Fertilizers, Waterschap Brabantse Delta, Waterschapsbedrijf Limburg, Aquacare, VandCenter Syd). The discussions with their representatives contributed significantly to this development. Then there is of course the Wetsus P-team: Philipp Wilfert, Thomas Prot, Prashanth Kumar, Leon Korving, Wokke Wijdeveld and Philipp Kuntke that initiated and still drive this development. They do this in closed collaboration with Delft University of Technology where especially professors Mark van Loosdrecht, Geert-Jan Witkamp and Peter Rem contributed to this work, but we also thank Iulian Dugulan and Kees Goubitz of the TU Delft Reactor institute for their invaluable support in characterising the vivianite using advanced Mossabauer and XRD techniques. Furthermore we should not forget all the Masters and Bachelor students that worked on this topic.

Accurate groundwater flow measurements to efficiently manage drinking water wells The development of the accurate groundwater flow measurement system was part of the groundwater technology theme, which is supported by Vitens, Arcadis, A.Hak, BioSoil, Deltares, UTwente and Wageningen University.

Wiecher Bakx was both the initiator and main researcher. Prof. Mark Bakker and Gualbert Oude Essink from Deltares provided academic support. Pieter Doornenbal from Deltares was a key person as he coordinated the installation of the system in the field, together with Sjoerd Rijpkema from Vitens. The validation was done at the Geo Model Laboratory of Deltares with the help of Rob Zwaan.

Energy-efficient nitrogen recovery from wastewater The electrochemical ammonia recovery technology originates from the ValueFromUrine project (2012-2016), which was funded by the EU’s Seventh Framework Programme for Research (grant agreement No. 308535). In this FP7 project, Mariana Rodríguez-Arredondo laid the groundwork for this technology as a PhD student. Her work is carried on by a new generation of PhD students, Steffen Georg and Mariana Rodrigues, who focus on ammonia recovery with bioelectrochemical systems and electrochemical systems, respectively.

The excellent advice and supervision by Cees Buisman, Annemiek ter Heijne, Tom Sleutels,

Testing water pipelines using ultrasound The ongoing research on improving ultrasound techniques is done in the Wetsus Smart Water Grids research theme since 2009, with participants Applus, Oasen, PWN and Vitens.

In a later instance Acquaint, Brabant Water, Evides and Wavin joined this theme. Many discussions on the research directions were

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program, Grant Agreement no. 731187) (www. baobabproject.eu). We would like to thank all the partners of the BAoBaB project, i.e., University of Palermo, Fujifilm, SMEDE, CIRCE, and AquaBattery. Moreover, a special thanks to the Wetsus PhD researchers currently working on the BAoBaB project, Emad Al-Dhubhani and Ragne Pärnamäe, as well as all the MSc and BSc students that contributed to this topic in the past three years.

Michel Saakes, and Bert Hamelers was essential for technological progress made to this date.

The commitment and hard work of Pieter Hack, Adriaan Jeremiasse and Sam Molenaar from W&F technologies B.V. made it possible to scale up this technology. The upscaling and pilot testing of the technology is carried out

by W&F Technologies B.V., Wetsus, Evides and ICRA within the LIFE-NEWBIES project (20182021), which received funding from the LIFE Programme of the European Union (LIFE17 ENV/ NL/000408).

Improved sweater desalination using innovative membranes and smart designs This work was performed within the REvivED project (Low energy solutions for drinking water production by a Revival of ElectroDialysis system), funded by the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement no. 685579 (www. revivedwater.eu) with FujiFilm as the lead partner. We thank the participants of the research themes “Desalination” and “Blue Energy” for the fruitful discussions and their financial support.

Furthermore, the ongoing research into ammonia recovery is supported by the members of the Resource Recovery theme of Wetsus and its members: W&F Technologies B.V., Evides Waterbedrijf, Waternet, Waterschap De Dommel, and Lascon.

Phosphate recovery from animal manure: closing nutrient cycles and improving soil health We want to thank the Milieutechniek department of Oosterhof Holman, especially Karst and the technical team of Jacob, Freddie, and Henk for designing and building the pilot unit; Inigo for operating and monitoring the pilot unit during the ReFARM project; the analytical and technical department of Wetsus and special thanks to the students: Ao, Nike, Alon, Aisha, Ambra, and Ugne, for contributing in the lab research. Furthermore, a thank you to Chris, Ricardo, and Cees, for supervising and guiding the project at Wetsus.

Smart UV technologies to eliminate micropollutants in drinking water sources This research received funding from the TKI Watertechnologie, project number 2017WET001.

We thank the participants of the research theme “Priority Compounds & Virus Control” for the fruitful discussions and their financial support.

Theoretical models to improve drinking water quality We thank the participants of the research theme Advanced Water Treatment for fruitful discussions and financial support.

Energy Storage with minimal environmental impact The research on the acid-base flow battery started in 2015 at Wetsus within the Blue Energy theme as part of the PhD project of Jan Willem van Egmond (under the supervision of M. Saakes and H.V.M. Hamelers). The concept idea was later further developed by Wetsus and AquaBattery (especially J. Post and D. Vermaas) as a European project proposal, which in 2017 was successfully granted as the BAoBaB project (under the European Union’s Horizon 2020 Research and Innovation

Rusty granules: The key ingredient for stopping algal blooms by reaching extremely low phosphorus concentrations The research on phosphate adsorption was initially funded by STOWA, the organization for applied research of the Dutch water authorities. They supported the initial vision that adsorption may help to achieve ultra low phosphate concentrations in sewage effluent.

Their initial funding and the support from

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NWO-Wetsus on the Impact of Water Research on Energy, Industry, Health, Economy and Environment 2016 (NWO no. ALWET2016.004).

We thank the participants of the research theme “Desalination” for the fruitful discussions and their financial support. We would like to thank Wetsus researcher Ettore Virga for providing a SEM picture of polymeric membrane with distributed pore sizes.

Kemira, ICL Fertilizers, Waterschap Brabantse Delta, Waterschapsbedrijf Limburg, Aquacare, VandCenter Syd helped to drive this topic further. Prashanth Kumar was the first PhD that took up this work and he drove this development together with Philipp Wilfert, Raimonda Buliauskaitė and Leon Korving.

Recently Carlo Belloni has taken over the baton from Prashanth and continues the work on this topic. The collaboration on this topic with TU Delft by prof. Geert-Jan Witkamp, prof Mark van Loosdrecht and prof Ekkes Bruck has been excellent. In this framework we also particularly want to thank the Everglades Foundation for having the vision to initiate the George Barley Water Prize. This prize made it possible to show the world how our ideas about phosphate adsorption could work in practice. Miriam Kuiper and Jeroen Blok did an excellent job running our pilot installation under difficult conditions in winter and spring in Bradford Canada, but this would not have been possible without the excellent team work with the technicians of Aquacare. Finally but not the least we should not forget all the Masters and Bachelor students that worked on this topic.

Calcium (bi)carbonate nanoclusters: a key to reduce scaling The experimental work in the Wetsus laboratory is performed by PhD students Talie Zarei and Xiaoxia Liu under the academic supervision of Profs. Herman Offerhaus, Denis Gebauer and Jakob Woisetschläger, and Profs.

Loiskandl and Zarfel, respectively. Former Wetsus researchers Martina Sammer and Astrid H. Paulitsch-Fuchs are acknowledged for their valuable input regarding the project. We thank the participants of the research theme “Applied Water Physics” for the fruitful discussions and their financial support.

Removing sodium to save water for crops The experimental work in the Wetsus laboratory is performed by PhD student Zexin Qian. Karel de Bruijn of Van der Knaap and Louis de Smet of the WUR are acknowledged for their valuable input regarding the project.

Hollow fiber nanofiltration to remove the micropollutants from toilet wastewater We thank the participants of the research theme “Advanced Water Treatment” for the fruitful discussions and their financial support.

We want to thank two great contributions to the implementation of NF membranes in source separation sanitation: Sam Rutten, PhD researcher and Paraschos Chatzopoulos, process engineer at Desah, not just for providing pictures for this book but for their great commitment and enthusiasm for this project.

We would also like to mention Lucia Hernandez Leal for her support and years of dedication to source separated sanitation.

Efficient electrochemical recovery and reuse of phosphate in salty waste waters This research has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement number 665874 and funding from the Netherlands Organization for Scientific Research (NWO), NWO Take-off Grant, project number 18283. We want to thank Mark and Perry from Northwater for their kind support in wastewater sampling and pilot design; the lab support team of Wetsus; and special thanks to the students: Bingnan, Jorrit, Mengyi, Ipan, Santosh, Emilio and Zhengshuo; the participants of the research theme “Resource Recovery” for fruitful discussions and financial support.

Designing aligned pore membranes for resource recovery This research received funding from the Netherlands Organisation for Scientific Research (NWO) in the framework of the “Sustainable water technology Partnership Programme

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Wetsus Innovations

Examples 2015 – 2020

colophon Publisher Text Pictures Cover art Editing Design Printing November 2020

www.wetsus.eu

Wetsus Hans Wolkers Wetsus and participants Marleen Annema Wetsus BW H ontwerpers Rekladruk