Original article in Dutch, by Waterforum Magazine, Pieter van den Brand can be found here!
Waterboard De Dommel aims to implement a fourth stage at the Tilburg wastewater treatment plant for the advanced removal of pharmaceutical residues and nutrients. For the development of technology, the waterboard leverages the innovation capabilities of the market. The goal is to develop a new generation of state-of-the-art activated carbon and ozone systems with a low CO₂footprint.
The procurement method is called “Innovatiepartnerschap (IPS)”, and with the Tilburg wastewater treatment plant, waterboard De Dommel is the first to implement it in our country. European procurement methods have been applied previously for dike reinforcements, but this is a first in the municipal water market. The goal of the IPS is to challenge the market to come up with innovative solutions, in this case with state-of-the-art activated carbon and ozone technology, ensuring that the effluent from the wastewater treatment plant complies with European regulations. And preferably in the most cost-efficient manner, with a low CO₂ footprint.
From 2027, strict nitrogen and phosphate standards will apply under the Water Framework Directive (WFD). By 2035, all wastewater treatment plants must meet the removal targets for pharmaceutical residues set out in the European Urban Wastewater Treatment Directive. The bar is set high for “De Dommel”. The area of the waterboard in Brabant is characterized by streams and ditches with high natural value, but fed by rainwater, meaning it has a small volume of surface water and is sensitive to drought. This clearly requires the cleanest possible effluent from the wastewater treatment plant.
Photo: Waterschap De Dommel
“Although the obligation to remove pharmaceutical residues is still a long way off, we have decided to immediately combine multiple challenges.”
Combination of challenges
The first step at the Tilburg wastewater treatment plant is a pilot study, which, if successful, will be followed by the design and implementation of a full-scale fourth stage. According to the national analysis dating from 2017, this wastewater treatment plant is considered one of the hotspots in our country, with a significant impact of pharmaceutical residues on the receiving surface water “Although the obligation to remove pharmaceutical residues is still a long way off, we immediately decided to combine these challenges.” says Bas Peeters, daily board member of waterboard De Dommel. “We want to protect surface water as effectively as possible and use our resources efficiently.”
With the integrated approach, the waterboard also expects to be able to more easily achieve the CO₂ reduction targets set in the Dutch Climate Agreement. However, the technology to remove nutrients and pharmaceutical residues simultaneously is not yet available on such a scale, so this requires innovation, explains Peeters, justifying the choice for the Innovation Partnership. “We are presenting the challenge to the market.”
Design
An additional challenge is that the Tilburg wastewater treatment plant is quite large, with specific requirements due to the energy factory, which digests the sludge using a thermal pressure hydrolysis system (Cambi) to produce energy-rich biogas. As a result, the effluent has twice the organic matter content (DOC), which likely requires a higher ozone dose than a typical wastewater treatment plant (the ozone dosing is controlled based on the organic matter content).
It is not advisable, explains wastewater advisor Ruud Schemen, to create a design solely based on effluent sampling and a laboratory test. 'We want to treat the wastewater for a year to ensure that the design for the full-scale installation is correct,' he refers to the pilots from the Innovation Program for Micropollutants in wastewater (IPMV, see the article on pages 14 and following in the latest edition of Waterforum magazine). 'We know that with these types of pilots, you can generate a great deal of knowledge and accelerate the process.'
Photo: Waterschap De Dommel
Interreg project “Clean Waterways through O3G” aims for improved use of ozone and activated carbon technology.
In the Flemish-Dutch Interreg project 'Clean Waterways through O3G', funded by the European Union, De Dommel, together with several partners, focuses on the improved use of ozonation (O3) and granular activated carbon (G). The goal is to improve the water quality in streams and ditches in Flanders and the Netherlands. Aquafin already applies these conventional removal techniques combined at one of its treatment plants. Both are efficient techniques, but with obvious drawbacks, such as high energy consumption and a large CO₂ footprint. The Interreg project, running until mid-2026, focuses on scientific research into how both techniques can be better aligned to remove as many unwanted substances (pharmaceutical residues and other micropollutants) as possible, and to develop technology that eliminates the previously mentioned drawbacks while meeting all legal requirements.
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“Tendering the entire process for a full-scale installation all at once results in significant time savings.”
Additionally, the IPS offers the waterboard the opportunity to tender the entire process for a full-scale installation all at once. “This results in significant time savings, as we don't need to go back to the market for the implementation phase.” explains Schemen. “And this way, we avoid the risk of another party taking over the project without any knowledge of the innovation that has been developed. If the pilot proceeds as planned, we can start the construction immediately, with the parties that have built up the knowledge for it and can deliver the best solution.”
Investing
From the tender completed last November, engineering firm Witteveen+Bos and Nijhuis Saur Industries emerged as innovation partners. Eddie Broeders from the latter water technology company praises the chosen approach. As the manager of the municipal division, he focuses on rolling out innovations in the municipal water market.
“The IPS is an obvious choice. We will further develop the ozone and activated carbon technology with groundbreaking innovations. By embarking on a long-term journey together, innovation can be fully realized, and the optimal conditions are created for everyone to invest in technology development and long-term collaboration. We are not only undertaking a pilot study, but with a favorable outcome, we will immediately proceed to the implementation of a full-scale installation. This signals that all parties involved are willing to invest in a successful installation.”
Over the past few years, Nijhuis Saur Industries has implemented various ozone systems, powder carbon dosing systems, and granular activated carbon filters at several wastewater treatment plants (WWTPs) for the removal of pharmaceutical residues, ammonium, and phosphate. The majority of these have been designed in collaboration with Witteveen+Bos. There is ample room for optimization to make promising technologies more cost-effective and sustainable. Examples include the energy-efficient and compact Ozone Strong Water technology developed together with Air Liquide, and the BODAC system for biological activated carbon filtration, which also enables the removal of nutrients. The combination of both technologies qualifies for the IPS and could provide the first optimized building blocks for the technology.
“By entering into a long-term collaboration, you create the optimal conditions for everyone to invest in technology development.”
Broeders: “This is definitely a great technological match, and these technologies are ready for scaling up. At the same time, we're aiming for further optimization to reduce costs and lower the CO₂ footprint. We've chosen a flexible concept that allows for the application of ozone both before and after the activated carbon, in order to determine the best configuration. We are also considering a high-rate denitrifying filter. However, this may prove unnecessary if sufficient nitrogen is already removed in earlier treatment stages. If certain process components can be omitted, it can lead to significant savings in construction costs. That is exactly what we aim to demonstrate in this pilot. The cost of activated carbon has quadrupled, so any reduction in its use results in substantial savings. Ultimately, this will allow us to reduce both the carbon footprint and the overall costs.”
Sharpness
At Witteveen+Bos, Jair Dan, team leader of Wastewater Technology, is also excited about how the waterboard has approached the project in the market. “In recent years, many pilots have been carried out for the removal of pharmaceutical residues. It is up to the market to optimize and scale up the proven technologies. De Dommel is taking the first step in that direction. As an engineering firm, we can join forces with the waterboard and the technology supplier. Thanks to this collaboration, we can bring much more focus to the design and construction of the full-scale fourth stage in the pilot.”
Witteveen+Bos has been involved in nearly all the installations at wastewater treatment plants (WWTPs) that have been adapted for the removal of pharmaceutical residues. Most of them have only recently become operational. “When the results from these installations come in, we can leverage this knowledge in Tilburg and arrive at the best configuration of the system.” says Dan.
“We have full confidence in the results regarding water quality. Our main focus is on how much we can reduce the use of auxiliaries and energy, and how we can build as small and efficiently as possible to save on construction costs. Waterboards have an important task to become climate-neutral and to keep the management of the water system and the water chain affordable. Innovations are required to meet these ambitions. The developed technologies serve as a tool to remove pharmaceutical residues and nutrients as cost- and CO₂-efficiently as possible, while producing an ecologically healthy effluent that meets the applicable standards. This will be the basis for designing the full-scale installation. The entire water sector will ultimately reap the benefits of this.”
“Thanks to this collaboration, we are able to bring much more focus to the design and construction of the full-scale fourth stage in the pilot.”
Expert group
Broeders anticipates that a successful technology development could provide a European blueprint for future installations. “Foreign countries are also watching with interest.” he notes. Within the IPS, knowledge sharing takes place in an expert group, where a group of renowned international specialists in the field of pharmaceutical residue removal advises, contributes knowledge, and gathers knowledge, both nationally and internationally. “The Netherlands is currently the innovation hub in Europe when it comes to pharmaceutical residue removal. It would be fantastic if we could serve the entire European water sector through this project.”
Sector-wide knowledge sharing is also a key focus for Bas Peeters, daily board member of the waterboard De Dommel. “With the IPS, we can make an additional contribution to further knowledge acquisition. Other waterboards are also busy with the construction of a fourth stage to address nutrients and pharmaceutical residues in an integrated manner.”
De Dommel also brings its own knowledge and experience into the IPS, including the ozone installation commissioned last year at the wastewater treatment plant in Hapert, for the removal of pharmaceutical residues. Both market parties in the IPS have also contributed to this installation. At its wastewater treatment plant in Eindhoven, which, based on pollution units, is one of the largest in the country, De Dommel aims to make the biggest leap after the construction of the fourth stage in Tilburg. “For that, we can use all the knowledge developed so far.” says Peeters.
Photo: Waterschap De Dommel
Valuable Collaboration
Peeters emphasizes that the IPS is a unique project for the water sector at a wastewater treatment plant. “In a few years, we may achieve an integrated technology design for the removal of pharmaceutical residues and nutrients with a minimal CO₂ footprint. Everyone can benefit from that. There is nothing more beautiful than profiting from each other's solutions. The interaction in the sector is immensely valuable: we learn from others, and others learn from us. Everyone is welcome here; we are happy to share our experiences. And it would be wonderful if our innovations also become visible outside of the Netherlands.”
According to the schedule, the pilot installation at the Tilburg wastewater treatment plant will be operational after the summer. The full-scale fourth stage could be up and running by 2029 or 2030.