From 2026, new installation will recover energy and raw materials from the waste water of 4 million Flemish citizens

13 June 2022

Water treatment company Aquafin is to build a sewage sludge processing installation on the ArcelorMittal site in the port of Ghent, to be operational by 2026. Both companies will apply the green energy produced there to further reduce their CO2impact. Aquafin is also planning the large-scale recovery of phosphorus, used among other things in fertiliser. The contract for the design, construction and financing of the installation and its maintenance until 2046 has been awarded to the BESIX/Indaver consortium.

The installation is intended to process the biomass that remains after the purification of domestic waste water. This biomass, created by the growth of the micro-organisms that do the purifying work, contains a wealth of energy and raw materials. Aquafin already produces fully green energy on this basis, in the form of biogas, and right now at one Antwerp location also biomethane, for injection into the natural gas network. The new installation, which should be operational in 2026, will be able to make even more use of the biomass delivered to it. As this is a mono-processor, the sludge will not be diluted with other substances, enabling maximum recovery of energy and raw materials.

An example for Europe

Using a European tender procedure with competition-oriented dialogue, Aquafin went in search of a partner for the design, construction, financing and maintenance of the mono-processor. The DBFMO contract was recently awarded to the BESIX-Indaver consortium, which is setting up a Special Purpose Vehicle (SPV) for this purpose.

Pierre Sironval, Deputy CEO of BESIX Group: “BESIX is particularly proud to have been selected for the design, construction, financing, operations and long-term maintenance of this state-of-the-art mono-combustion sludge treatment plant. The installation is exemplary in terms of circularity and net environmental impact. BESIX has built up a global portfolio of different industrial projects of similar or greater size that take advantage of the diversity of expertise available in the Group: project financing, design, engineering, environmental considerations, construction, operations and maintenance. We look forward to developing the project together with our partner Indaver, a top player in many different types of waste processing installations. We will be joining forces to deliver a groundbreaking installation to our customer Aquafin, whom I would like to thank for their trust in awarding us this future-oriented project.”
“Indaver has long been a pacesetter in the transition to a circular economy”, says Indaver CEO Paul De Bruycker. “The circular economy will succeed only if everyone in the chain assumes their role and responsibilities. By closing high-quality material cycles, we can use raw materials again and again and contribute to the circular economy. Waste is no longer an unwanted end product, but a stream from which we create value. In close cooperation with our partner BESIX and with all stakeholders, we will also be maximising the value of Aquafin's water treatment sludge by recovering phosphorus in the longer term.”

On the ArcelorMittal site

The location of the new installation has been determined for some time. ArcelorMittal is giving Aquafin a building right on the site and will purchase, 100% of the steam produced by the sludge processor. For the steel company, this is an additional energy source for their internal steam network, further reducing the use of fossil fuels. The direct uptake of the entire steam production combined with the focus on raw material recovery makes this installation an example for Europe.

“In determining the ideal location, the ecological arguments were decisive for us,” says Jan Goossens, CEO Aquafin. “We took as our starting point a model in which we could see, for each potential location, the CO2-impact of all sludge transportation in Flanders. It is important that the sludge transporters drive as few kilometres as possible through Flanders to get their cargo to its final destination. Also essential were the possibilities to make optimal use of the energy produced at and around potential sites, with a view to an optimal solution for Flanders as a whole. The initiatives for carbon capture that are in the pipeline in the port of Ghent further strengthened ArcelorMittal's position.”
“ArcelorMittal Belgium has a passion for energy efficiency and circularity”, says Manfred Van Vlierberghe, CEO ArcelorMittal Belgium. “We continue to invest and launch new projects to fulfil our pioneering role in energy and climate transition. By using the high-pressure steam from Aquafin's sludge processing process in our steel production process, we are making our energy consumption even greener. In this way we give an additional impetus towards the concrete implementation of our sustainability strategy for an increasingly energy-efficient company, while heading towards climate neutrality in 2050.”

Sustainable recovery of phosphorus

In a follow-up phase, Aquafin is planning to start up full-scale phosphorus recovery, representing some 2,000 tonnes of pure phosporus a year. By opting for mono-processing, phosphorus can be recovered more efficiently from biomass. Phosphorus is an essential building block for life, being among other things an important component of our DNA, our cell walls and our bones. We ingest it via our food, and it is also a basic component in mineral fertilisers for agriculture and horticulture. Phosphate ores are, however, a finite resource, and with only limited supplies naturally present in Europe. Via our food, phosphorus finds its way into domestic waste water, from where Aquafin will recover it with this new sludge processor.

The sludge mono-processor will carry out the end treatment of two-thirds of all Flemish sludge from domestic waste water. Aquafin is leading this extensive DBFMO project with tight reins to ensure that the far-reaching ecological objectives can be achieved.

The project is fully in line with Aquafin's ambition to cease using fossil fuels by 2030 and to evolve towards climate-neutral business operations in the long term.

About Aquafin

Aquafin is responsible for the financing, expansion and operation of the supra-municipal infrastructure for waste water treatment in Flanders. The company purifies waste water so that streams and rivers become clean again and also brings water into harmony with the living environment. Aquafin is keen to achieve its objectives in a socially responsible manner. Reducing the ecological footprint and recovering energy and raw materials from waste water is one way of achieving this.

About BESIX-Indaver

BESIX-Indaver is a consortium of two respected international and value-driven industrial partners on the Belgian market: Indaver and BESIX. Each in its field, they have already successfully completed many large industrial projects, both in Belgium and abroad. Both companies create added value for the customer and for society by putting care for people, safety and the environment first. To make a success of this sludge mono-processor project, they are purposefully combining their largely complementary knowledge and experience.

BESIX is a leading Belgian group, based in Brussels and active in 25 countries on 5 continents. The company operates in the construction, real estate development and concessions sectors. The group, which has been in operation since 1909, includes the Burj Khalifa in Dubai in its list of emblematic achievements. The Group's in-house engineering department enables BESIX to carry out projects that are complex and unique, particularly in terms of their technical and environmental aspects.

In addition to design and construction, the Group also offers its customers advanced tailor-made solutions for the financing, operation and maintenance of their projects. In the Benelux and the Middle East, BESIX's public-private partnerships and concessions include environmental installations for water and waste treatment, buildings, and infrastructure works like motorways, tunnels and lock complexes. More info:

Indaver is a European player in the waste sector with installations and operations in Belgium, the Netherlands, Germany, Portugal, Italy, Ireland, the United Kingdom and France. Indaver manages and treats industrial and household waste in specialist facilities for the industrial sector, waste collectors and governments Indaver recovers valuable raw materials and energy from these treated waste streams. Indaver is thus creating value from waste and by doing so is helping to close the materials loop in a safe, low-carbon and energy-efficient manner.In this way, This makes Indaver the ideal partner in the pursuit of a sustainable circular economy. In 2020, Indaver had a turnover of 600.8 million euros with around 1900 staff throughout Europe. More information:

About Arcelor Mittal

ArcelorMittal Belgium, with production sites in Ghent, Liège, Genk and Geel, employs more than 5,000 people. Total direct and indirect employment is estimated at 30,000 jobs. The company produces high-quality steel for the most diverse applications in the automotive sector and other industrial sectors such as the green energy sector, construction, white goods, packaging, etc.


  • For Aquafin: Sam Geerts – manager Procestechnologie – +32 484 75 18 79
  • For BESIX/Indaver: Lennert Rasking – BESIX-Indaver Bid Manager - +32 497 93 65 50
  • For BESIX:
  • For Indaver: Silvia Colazzo, Communicatiemanager, +32 476 63 18 27
  • For Arcelor Mittal: Jan Cornelis, Country Manager | | +32 9 347 35 72 | +32 499 599 394