2023-08-17 11:12:00
Soft and of a neutral taste, the water which comes out of the tap which Wim Jacobs has just opened was just two hours ago of an unbearable taste. It has in fact just been pumped from the other side of the road, directly into the canal which connects Bruges to Ostend and which passes a few meters from this building installed in the industrial zone of the port of Ostend.
Here we are only three kilometers from the sea, whose water can seep into the channel. Result: the water pumped into the channel is brackish, that is to say with a quantity of salt that makes it undrinkable. “In winter, the canal is fresh water and over the months it becomes more and more brackish, since there is less and less rain, explains Wim Jacobs, head of the innovation at the water distributor Farys, active alongside and in the Ghent region, in its factory facing the canal. Indeed, when it rains less, even the rivers of the region become brackish, and arrive here in the canal. When it rains, the salt water is pushed down, when it rains less, the water from the sea “rises” from the ground. In addition, when the locks are open, water from the sea can also flow into the canal.”
The population of Ostend
The salinity of the water is measured here in millisiemen per centimetre: fresh water remains below 1000 mS/cm, while sea water is at 40,000. The water in the canal oscillates between 500 and 11,000 depending on the season. However, it supplies 100,000 people in Ostend and Middelkerke, and beyond if necessary. The Farys company has indeed built a desalination plant, the first in Belgium (and even in Western Europe), to make it drinkable. Delivering 500 m3/hour when it opened in 2020, the plant grew to 1,000 m3/hour in just a few months. “We only thought we would do this following years… It’s because of climate change.”
Initially, when Farys, who must supply water to a large part of the coastal and Ghent region, implemented this project around 2010, the objective was “simply” to have water on site even when the two pipes that bring water from outside were out of order or under maintenance. Because the situation is very particular in this area of Flanders, whose soil has difficulty storing water and therefore has few aquifers. Ninety-five percent of the water is produced elsewhere: 50% comes from the Albert Canal (in Flanders, via the water company Water-link) and almost all the rest… from Wallonia. Farys buys 25 to 30% of its water from the Brussels company Vivaqua – “this water actually comes from Tailfer (which transforms water from the Meuse into drinking water), near Dinant” – while around 12% comes from the Ath region, where Farys has a catchment and pumps water there.
Inside the Farys desalination plant in Ostend. ©Sophie Devillers
As soon as it was commissioned in 2020, Farys was delighted with his choice, because several years of drought had passed by. “Less rain and higher evapotranspiration have resulted in significantly increased precipitation deficits over the past 10 years. Climate change introduces a new problem,” the company believes. During the year, the supply problem actually arises over a few weeks, in August-September, given the severe slowdown, during this period, of the flow in the rivers which supply Farys with water, specifies Wim Jacobs. Even though it operates all year round, the desalination plant in Ostend comes in handy at this time during dry years.
Transforming salt water into drinking water, a false good idea?
Deafening sound
In the halls of the factory, in a noise of wind tunnel, follow one another tanks and pipes of all sizes and all colors. But you hardly meet anyone: everything is monitored by a computer and managed remotely. “We start with metal filters, in three stages, the thinnest of which is 0.1 mm, explains Wim Jacobs. Then, as there is no finer point, we move on to membranes: the first system is microfiltration where all the parts that float in the water are eliminated. The salt can pass but will be rejected by the second system, reverse osmosis. It consists of a very fine filter, through which the water is pushed. Only water molecules can pass because H2O is a small molecule”, explains Wim Jacobs, who shows us the rows of beige microfiltration tubes – “unfolded, the membranes inside take up the equivalent of 15 football pitches ”-, then takes us past the big white reverse osmosis pipes, still with a deafening noise. “If there is more salt in the water, you need more pressure to push the water, so it uses more energy”.
The Bruges-Ostend canal, from which water is pumped to the Farys desalination station. ©Sophie Devillers
“But following this filtering, we still don’t get drinking water because it no longer contains any minerals (almost everything is rejected). It is therefore an aggressive water that takes minerals from the body. We must therefore remineralise the water.” The water therefore passes through dolomite, stored in bright blue tanks, regarding ten meters high. Opposite, their binoculars contain activated carbon, which serves as a second barrier to clean up the water.
By opening the drinking water tap placed at the outlet, Wim Jacobs explains that the process is so fast and the consumers so close to the source, that during hot summers, the water coming out of the users’ taps can be at 25 ° C and, conversely, very cold, in winter…
Wim Jacobs, in the Farys desalination plant in Ostend. ©Sophie Devillers
In terms of brine discharge, the impact is minimal, assures Wim Jacobs: the canal water remains “saltier” for a very short time, because the water consumed by users is reprocessed at the water treatment plant. Aquafin, this fresh water then being reintroduced into the canal a kilometer further on. Energy consumption is, however, significant. “To have fresh water in Flanders, the average cost is 0.4 kilowatt hours per m3. For the desalination of brackish water, it ranges from 1.1 (currently, it has rained a lot, the water is softer) to 1.6 last (dry) summer, because it rained little and the water was therefore much saltier. Indeed, it is therefore when we need the most water that production consumes the most energy…” But it is always worth it, according to Wim Jacobs, because “we save the price of transport. You have to use energy to pump water from Brussels or Ath to Ostend”. Farys consumers see no impact on their water bill, especially since production – of which electricity is only a part – only accounts for 25% of the price of water.
No risk of conflict
For Wim Jacobs, the project also has the great advantage of responding to future droughts without encroaching on the water supply of other sectors or people; with this brand new source, there is no risk of conflict. “Because we now know that the sources of water that we thought were infinite (coming in particular from rivers or aquifers in Flanders or Wallonia, Editor’s note) are in reality not so”, he underlines. But if currently, the desalination plant in Ostend provides 7% of Farys’ water, making it the main source “would cost far too much”. “We keep in mind several principles: how to provide water in a robust way (that is also to say a method that continues to work even if global warming increases), without disturbing others, with the lowest possible environmental impact, but also at the lowest price”, comments Wim Jacobs. Who specifies: “Politicians like to say that this project makes it possible to be “independent from Wallonia”. For us, the two objectives of taking less water in the Walloon Region were delivery security and economy. It’s pragmatic, not political! Our relations with Vivaqua and the SWDE are very good.”
Wim Jacobs, head of innovation at Farys, in front of the Bruges-Ostend canal, from which comes the brackish water pumped by the desalination plant. ©Sophie Devillers
Farys is also testing various seawater desalination technologies in Nieuport (and no longer just brackish water), an experiment whose results are not expected before 2027. There, the energy consumption of such desalination would amount to 3.5 to 4 kilowatt hours per m3, which would increase the price of water by 10 to 20%. Farys is also considering supplying this future factory with renewable energy. Furthermore, the salinity discharged would also be 3 to 4 times higher. “But we are not going to salt the sea! An independent office will carry out studies on the environmental impact, it is the law. But these releases would be very localized”. Farys ensures not to consider this project on a large scale. The object is above all to “master the technology”, in case it proves necessary in the future.
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