Aquiris scores major improvement in water treatment

Capacity increases by 12%
Research & Analysis
5 September 2017

Aquiris, a water treatment company in Brussels, Belgium, has increased the capacity of its treatment plants by 12% in cooperation with Air Liquide.

Population growth requires additional capacity

“The Aquiris water treatment plant was designed and built to treat the waste water of 1.1 million inhabitants of Brussels,” explains Bernard Lambrey, Technical Director at Aquiris. “However, population growth far exceeded any predictions. This meant we reached our maximum capacity far sooner than expected, while the Brussels region continued to grow. We had two options for solving this problem: either building an additional plant or improving the treatment capacity of existing plants. To explore our options, we contacted Air Liquide.”



Nexelia for Biological Treatment

Nexelia is one of the many total solutions Air Liquide has developed which combines their vast capability for supplying industrial gases, broad industrial scale expertise and advanced technology. Nexelia for Biological Treatment was specifically developed for the treatment of waste water. This process involves the injection of ozone (O3) or pure oxygen (O2) into the waste water by means of advanced gas injectors.

“In a water treatment plant, waste water is first mixed with activated sludge (biomass),” explains Rudy Lamond, Growth Leader Water Treatment & Gas in Liquid Applications at Air Liquide. “This sludge breaks down the effluent and increases the volume. In a second phase, the sludge is separated from the purified water and can be discharged, either by gravity or by means of membranes.”

“Because the growth process of the sludge in the Aquiris plant wasn’t ideal, we decided to inject dosed amounts of ozone,” continues Lamond. “This enabled us to substantially improve the health – and thus the growth process – of the sludge. Ozone is a highly oxidative molecule that rapidly breaks down the excess thread-forming bacteria. By injecting this gas, we were able to restore the equilibrium of the flocculating bacteria. This resulted in better sedimentation so that a higher sludge concentration could be applied. The final result is a substantially increased throughput of the plant, with no expansion of the ecological footprint.”

In the case of Aquiris, an increase of 12% was achieved.

Capacity grows faster than expected

Aquiris is part of the Veolia group and is one of the largest water treatment plants in the Benelux. “The group’s innovation centre is located at Aquiris and the Brussels plant is therefore the most advanced in the group. It’s not uncommon for new treatment technologies to be tested at our facility,” says Lambrey.

“We were expecting a 10% increase – which is also what Air Liquide promised – but the final results were even better. We are obviously very pleased, not in the least because the costs are much lower than investing in new installations or in a new plant.”

Fish in the water

“Today, the quality of our treatment is better than what the standards require, and we’re really rather proud of that. The water that we’ve purified now ends up in a river that is once again full of healthy fish. That says it all.”

“We have signed a long-term contract with Air Liquide so that we can also apply this new technology at two other sites in China. Our relationship with Air Liquide is excellent in every respect. We see them as a partner rather than just a supplier. The fact is that their solution, together with our expertise, has led to impressive results.”


*bactéries filamenteuses: forment des réseaux de filaments qui perturbent le processus de décantation

**bactéries floculantes: s'agglomèrent les unes aux autres pour former de plus grosses particules appelées "flocs", lesquels sont plus faciles à traiter.

Learn more about biological treatment and Nexelia

Contact our specialist in waste water treatment, Rudy Lamond ✉