Brightsite is committed to a sustainable chemical industry. In addition to the transition to sustainable energy and green raw materials, circular water is also high on the agenda. To make the water system at Chemelot future-proof, cooperation between all stakeholders is essential. In collaboration with USG, Sitech services, Royal HaskoningDHV and with input from the companies, Brightsite has created a ‘Roadmap Circular Water’. This roadmap lists possible interventions to significantly reduce emissions to surface water and water consumption.
Making the chemical industry more sustainable is necessary and water is an important element in this. Climate scenarios show that the availability of water will come under increasing pressure. “As a site, we depend on water for the functioning of the plants (see box ‘Water use at Chemelot’). Moreover, our treated wastewater (effluent) ends, near the Grensmaas Natura 2000 area, in the river Meuse, a source of drinking water. We are very aware of the importance of good water treatment. We also have to deal with European and national ambitions in terms of a clean living environment. This results in stricter permits, which tell us what we are allowed to discharge as a site through the Waste Water Treatment Plant (WWTP). On top of that, the raw materials and energy transition will result in process changes at Chemelot, which will affect water use and the composition of plant wastewate”, says Lianne van Oord, program manager of Brightsite’s program line 3 ‘Process and site innovation‘.
Water use at Chemelot
Chemelot, with 44 million cubic meters per year, is a major water user. Water is necessary for basic processes such as cooling and heating (steam), needed for transportation and as solvent and firefighting water. Water is taken by USG from the Juliana Canal (1.5 m3/s). About 0.5 m3/s is lost through evaporation in the cooling towers. The remaining water (1 m3/s) goes as wastewater to the WWTP, which is managed by Sitech services. The WWTP is a biological waste water treatment plant that breaks down and extracts substances in wastewater, after which the purified water is discharged into the Ur, a stream that flows into the river Meuse.
The special feature of the WWTP is that the biological treatment is completely adapted to the substances of the Chemelot site and therefore has high treatment efficiency.
Future-proof water system
How can the processes at Chemelot keep running while respecting the water we discharge into? “To answer this question, it is necessary to look at the complete picture. This is why we developed a roadmap in 2022, which serves as a guideline for the ‘Circular Water’ program for Chemelot. The Roadmap Circular Water ‘Towards zero emission and zero waterintake’, created in collaboration with Royal HaskoningDHV (RHDHV), Utility Support Group (USG) and Sitech services, is a first step toward achieving a future-proof water system”, says Van Oord.
The Circular Water Roadmap was approved by the Chemelot Board in December 2022. “The Chemelot board was positive and recognizes water as an important theme for the site. At the same time, water comes on top of all the other actions linked to climate transition. Hopefully the roadmap can create awareness”, says Jan Appelman, water strategy projectleader at Royal HaskoningDHV.
Lianne van Oord, Brightsite program manager:
“We have identified the knobs we can turn.”
For the creation of the Circular Water Roadmap, employees and managers of the plants were interviewed about their ambitions regarding water. In addition to possible expansions or plans to downsize, possibilities to make factory wastewater cleaner were examined. “Now that we know what ideas are out there, we can outline the expected water use in the future and the bottlenecks and opportunities. Some companies, like Fibrant, are working on their own water roadmap. That helps to set common goals. With our overarching Circular Water Roadmap, we connect to the needs of the companies, describe what steps can potentially be taken and what techniques are available to optimize our water use and its treatment. In short, we have identified the knobs we can turn. Although the ultimate goal is to prevent discharge of substances and intake of water, that is sort of a ‘moonshot,’ hence ‘Towards zero emission and zero water intake’”, Van Oord explains.
Where is profit to be made?
There are plenty of opportunities to optimize water use and water treatment site-wide (see Figures 1 and 2). For starters: phasing out cooling water conditioners. Van Oord: “Now cooling water conditioners are used to prevent scale, microbiological contamination and corrosion in cooling systems. Many plants at Chemelot have already recently switched to a more environmentally friendly conditioner. We are also looking at low-chemistry alternatives to conditioning, at ways to remove lime from water, for example. Ideally, you want to move from removing substances from water to emission-free design. Therefore, we are also looking at alternative materials and designs for cooling systems.
We are also trying to get a better picture of how many and which microplastics are present in wastewater and how we can prevent this. A field in development, there are no standards and measurement methods for microplastics, and it is a challenge to take representative samples in large streams. Effluent reuse is also a great way to reduce water intake. “If we take the components out of the water, we can reuse the water (circular water). You then also have to do something with the brine stream – the concentrated stream of removed substances – that remains. A challenge, because to date there are no simple ways to process the brine stream. Moreover, we must weigh the energy required for treatment against the benefit of not discharging. It requires a systems approach to assess what puts the least pressure on the ecosystem. Ultimately, you want to prevent waste by reusing as many components as possible, preferably in on-site processes”, says Van Oord.
Companies get to work
It is very important that the companies at Chemelot themselves know how to reduce their water use and emissions. “Solutions close to the source are usually simpler. Of substances classified as ‘Substances of Very High Concern’ (ZZS) and A-substances the discharge must be reduced, an important part of individual water roadmaps of the plants, in addition to possibilities to reduce the total amount of water and discharged substances. From the Circular Water program, we like to think with the companies to come up with optimal solutions for the site. But it would be good if the companies themselves have a plan of action”, Van Oord emphasizes. “Sometimes one company’s waste stream can be used as input at another. There are big gains in more economical water use by individual plants. The more economically they use water, the less waste water there is in total. It is necessary to stay in conversation with the companies and regularly stress the importance of water”, Appelman says.
Jan Appelman, water strategy projectleader at Royal HaskoningDHV.
“In addition to the roadmap for Chemelot, Circular Water also encourages reduction of water use at the companies in their own processes.”
At Fibrant – producer of caprolactam, ammonium sulfate and cyclohexanone – water is also an agenda item. “We already had a roadmap for water and we have tightened it up. We have closely mapped where we use water and where savings or reuse is possible. This is particularly the case in cooling”, explains Menno Wijnen, who worked on improving Fibrant’s roadmap water as an intern and is now a technologist at Fibrant. “Our previous roadmap was roughly created and we noticed that there was more and more pressure on the discharge to WWTP. We were running on demand from WWTP, now we communicate proactively with WWTP”, adds Mark Jochems, senior chemical engineer at Sitech. “This has to do with the new permit (see box ‘Stricter water permit’), the bandwidth of the WWTP has become narrower. That works its way down to the plants”, says Van Oord. “The challenge for Fibrant is that we are dealing with several plants that date back to 1952 and were not built for water efficiency”, Jochems says. “Another factor is that Fibrant is in the process of becoming more sustainable. The first step we are taking in terms of water use is to reduce the amount of water used for cooling. For this, we are optimizing the thickening, first looking at how far we can go with current, conventional techniques.“
Mark Jochems, senior chemical engineer at Sitech:
“The challenge for Fibrant is that we are dealing with several plants that date back to 1952 and were not built for water efficiency.”
Stricter water permit
Chemelot has a special water permit, where wastewater is assessed at the substance level. By 2027, all water bodies must meet the goals of the ‘European Water Framework Directive’ and thus specified chemical and ecological standards. Chemelot was the first, large industrial site in the Netherlands to go through the more stringent permitting process. Previously, standards were issued for substance categories; now they look at the component level. As a result, the number of substances to be measured has increased by a factor of twenty, and no standard was previously known for about two-thirds of them. Over 600 substances that can be transported from the factories to the WWTP have been assessed. Incidentally, by no means all of these substances are actually in the effluent, and there are some substances of concern whose concentrations in the wastewater must be reduced.
Looking towards the future
“We are now going to develop and implement pilots. In 2025 or 2026 the first results will be known. We can then translate the insights we gain from these into the future. 2027 is a benchmark because that’s when the new water license has to be issued”, Van Oord says. “Companies need to prepare in good times. If you have a plan and think in advance about what you will do if, for example, a cooling tower needs to be replaced, you can seize the momentum to improve”, Appelman concludes.