New water treatment plant for DOT

One of Denmark's leading surface treatment companies is getting strong results with a new treatment plant based on a simple and low-tech solution from Dansand

As one of the country’s leading specialist companies in surface treatment such as hot dip galvanizing and wet painting, DOT is careful to comply with all environmental requirements. Therefore, the company has been working for a number of years to improve the purification of the surface water from its factories.

The water currently complies with all legal requirements, but DOT wants to be at the forefront of any new legal requirements. In 2018 DOT initiated a test period with Dansand, during which the newly developed filter system Dansand Blueguard was to be tested at the factory in Brande, Denmark.

“It is crucial for us to comply with all environmental requirements at our factories. It is also an important competitive parameter. Therefore, we have invested time and energy in developing our new treatment plant for surface water”, says QHSE manager at DOT, Lene Gavnholt Rasmussen.

New requirements for heavy metals in surface water

DOT expects that new requirements for the content of heavy metals in surface water will come into place within a few years. Therefore, DOT initiated a collaboration with Dansand on testing the Blueguard filter system. DOT needed to investigate the effect of the plant in advance, and Dansand was interested in acquiring more practical experience with the new product.

“Dansand contributed with their expertise, so we got all the relevant tests started. It quickly turned out that the effect of Blueguard was truly impressive. In fact, we found that it cleaned the water surprisingly well in all the scenarios we created. We only detected problems at an extremely low pH value below 3, and under operating conditions we will never experience such low values. All tests actually showed a much better purification than we had dared to hope for”, explains Lene Gavnholt Rasmussen.

Strong results with no chemicals

DOT and Dansand agreed on a short initial test period to ensure that Blueguard could solve DOT’s future problems. The tests quickly convinced DOT of Blueguard’s strong cleaning properties, after which a long-term pilot project was launched. The test period has ensured important knowledge and great validity of the collected results, giving DOT the optimal decision basis for the new investment.

“All the analyzes we have carried out over the past year show that the Blueguard plant has removed an average of 97 % of the zinc in the surface water. It is noticeable over a long period in 36 different analyzes. It is a very impressive result, especially since we do not add chemicals at all. It is a simple and low-tech structure where we only use the natural mineral called olivine”, explains Lene Gavnholt Rasmussen.

DOT had previously investigated the market for conventional treatment plants, but the choice fell on a test plant from Dansand, as the price is much lower than for the conventional plants.

“We are really pleased with the collaboration with DOT. It emphasizes that our Blueguard plant has great potential to help the Danish industry in an efficient and cheap way. And even without the use of chemicals or large amounts of energy for the cleaning process,” says Steen Frantzen, who is an environmental specialist at Dansand.

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