Circular water use of Colruyt Group proves useful after dry summer: 8000 m³ of water saved during the summer holiday

Thursday, September 1, 2022 ​

On this first day after the summer holiday, we look back at very dry months with July and August. This causes a serious drought in our country. We are equalling the historical rain shortage of 1976, and companies and individuals were - and still are - told to use water sparingly. For years, retail group Colruyt Group has been keeping its own water footprint as small as possible, among other things by using water in a circular manner. At the end of 2021, after an intense cooperation with partners such as Waterleau, it started using a new water treatment plant at the distribution centre Dassenveld. In addition, the capacity of the existing water basin for the capture of rainwater was expanded to a capacity of 9500 m³¹. These initiatives immediately proved their worth: Colruyt Group thus already reduced the city water consumption of the 3 sites in the start-up phase² with 8000 m³ - which corresponds to around 3 Olympic-sized swimming pools. In the coming days and weeks, those water savings will only increase and the group will become less and less dependent on city water: a crucial aspect in times of drought.

Minimising the dependence on city water: new purifying plant and up-scaling rainwater buffers

This summer showed once again that every drop of water counts, also for companies. For years, Colruyt Group has been keeping its water print as small as possible and fully going for circular water management, both in the stores and at production sites, as well as in distribution centres and offices. By collecting rainwater and waste water as much as possible and - if necessary - purifying it, the retail group brings this water back into the cycle where it is reused.

At the end of 2021, Colruyt Group started using a brand-new water treatment plant at the distribution centre Dassenveld in Halle. That installation, for which the retail group received an Ecology subsidy (EP+) via Vlaio, purifies industrial and sanitary waste water for three sites in Halle: distribution centre Dassenveld, head office Wilgenveld, and the offices and warehouses at the Elbeek site. With a production capacity of 11 m³ drinking water per hour, the installation can purify 90,000 m³ of waste water into 81,000 m³ of so-called “process water” annually([1]). For use as tap water, this water must be remineralised. This is done by adding 1/5th of city water to it.

For the project team of Colruyt Group, it was important to find a balance between technology, quality and efficiency with this new installation. In the long term, it is more interesting to concentrate the purification process on one site, because the project involves more than just purifying waste water. It is also about constructing underground and aboveground double water pipes: waste water in one direction and purified drinking water in the other. For example, the head office in Wilgenveld, which is located about 1.2 km from the plant, was connected to the plant first, followed by the Elbeek site. If all goes well, the distribution buildings of the nearby site Hellebroek will also be connected: the pipes are currently being installed for this.

In addition to the brand-new plant, the existing buffers for the capture of rain water at the distribution centre Dassenveld were expanded with 5.400 m³ in the past year. "Those buffers now have a total capacity of 9.500 m³. The water is purified by, among others, a sand and UV filter and then used for the cooling systems and the sanitary facilities," says Peter Basteleus, responsible for the project. That way, Colruyt Group reduces the city water consumption of these sites with 90%; the dependency of city water is thus reduced as much as possible - a crucial aspect in times of drought. The project at Dassenveld was executed in close cooperation with water technology company Waterleau. Process and sales engineer Hannah Vandewiele: "We designed the installation and via the digital platform Smartlab we can monitor both the system and the water quality via inline measurements. All data and dashboards are also available to Colruyt Group straight away. Colruyt Group thus also plays a pioneering role in the digital transformation of water purification and reuse. I expect that this project will greatly increase support for water reuse as drinking water among both companies and the general public."

Not a first for Colruyt Group in the field of waste and rain water reuse: clear objectives

The sustainable use of water: it is an objective that is incorporated into all Colruyt Group projects. In addition to the new water treatment plant at Dassenveld, it is also continuously researched how water can be purified - also at a smaller scale. Victor De Meester, Head Environment at Colruyt Group specifies: "By 2025, we want 50% of the total water consumption of our own operations to come from rain water - rain, snow, hail and/or thaw - and waste water. We thereby strive towards a zero discharge of rain water in the sewers and less use of 'new' tap water (city water). In 2021, 33.37% of the total water consumption came from the rain and waste water".

The meat-processing activities at the Stroppen site and the distribution centre Dassenveld in Halle together amount to around half of the total water consumption of Colruyt Group. In 2001, the group already built a water treatment plant at Fine Food Meat, the meat-processing site. Since 2004, we have been upgrading the treated ​ water to drinking water to use it again in a closed loop in production. Two years later, we added an installation to do the same with rain water. Victor De Meester, Head Environment adds: "In 2021, we producedno less than 101.943 m³ of drinking water from waste water from our meat division Fine Food Meat. Good for a recovery rate of 56%. At Fine Food Meat, some of the collected rain water goes to the sanitary facilities and some is upgraded to drinkable water. In 2021, we purified 7,732 m³ of rainwater through the PURA (PUrification of RAinwater) process."

Another, very special project within Colruyt Group logistics is the brand-new water tunnel. Beneath the Dassenveld site lies a tunnel that originally was meant to let automated transport drive through it. However, this never actually happened. This tunnel was adapted and is now used as an additional buffer of 5400 m³ for both rain water and process water. Thus, a maximum capacity of 9500 m³ buffer is available. The objective of the tunnel is also to further reduce the consumption of city water at the Dassenveld site.

At store level, the store formulas of Colruyt Group reduce their city water intake by recovering rain water for sanitary and vegetation. Good for 18% of the water consumption in the stores. Peter Basteleus concludes: "By consuming less city water, we conserve groundwater resources and reduce our water bills. Fewer costs, and thus a useful initiative to keep realising the competitive prices at our store formulas. In addition, we are now also looking into the possibilities to purify the remaining rain water at store sites as well."

^{[1]. According to the VMM, an average Flemish family of 4 persons uses 348 litres of city water per day, which amounts to 127 m³ on an annual basis. The standard family in Flanders counts 2.3 persons and has an average water consumption of 89 litres of tap water per person per day, which equals 74m³ on an annual basis for the family
​[2]. Between 1 July and 18 August
​[3]. Process water is so pure (it contains no more minerals) that it is actually not good to drink. Such pure water draws minerals from your body - which is not healthy. To make it potable water, we add 1/5 city water. Thus, we have potable water again.}

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