Water treatment company Aquafin is to build a sewage sludge processing installation on the ArcelorMittal site in the port of Ghent, Belgium, to be operational by 2026. According to the statement, both companies will apply the green energy produced there to further reduce their CO2 impact. Aquafin is also planning the large-scale recovery of phosphorus, used among other things in fertilizer. 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 wastewater. This biomass, created by the growth of the microorganisms that do the purifying work, contains a wealth of energy and raw materials, the statement said. 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. 

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 said: “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. We look forward to developing the project together with our partner Indaver, a top player in many different types of waste processing installations.” 

“Indaver has long been a pacesetter in the transition to a circular economy”, said 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.”

On the ArcelorMittal site

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. Talking about the project, Manfred Van Vlierberghe, CEO ArcelorMittal Belgium said, “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 determining the ideal location, the ecological arguments were decisive for us,” said 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."

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, accordingto the statement. By opting for mono-processing, phosphorus can be recovered more efficiently from biomass. The sludge mono-processor will carry out the end treatment of two-thirds of all Flemish sludge from domestic waste water.