The Year of Geology 2016

Learning water treatment methods from the forest industry

Methods used by the Finnish forest industry can also be used by other industries. One example of this is the chemical water treatment process, which is based on rapid mixing techniques. This is currently being tested in Siilinjärvi at the plant of Yara Suomi Oy, a company manufacturing fertilisers.

The goal is to find out how nitrogen compounds can be removed from the plant’s wastewater. The lime softening methods does not work optimally in removing nitrogen.

Yara was excited to participate in the research project, when GTK suggested it, says Yara Suomi Oy’s environmental manager Leena Huttunen.

“It is important for us to prevent the environmental impact of our operations. That is why we participate in different kinds of research projects all the time. There is no requirement to remove nitrogen, but we try to minimise the nitrogen load of our plants,” Huttunen says.

In addition to removing nitrogen, the iFormine project tests the removal of sulphates from wastewater. The research is still ongoing, but according to Huttunen, the new method seems to work well for sulphates.

Removing nitrogen from mine water?

If the nitrogen removal method works, it may also prove useful for the mining industry. Rocks are often exploded with an explosive that contains nitrogen and as a result, nitrogen accumulates in the mine water.

“We are also investigating the possibility of including this kind of water in the study,” Huttunen mentions.

The plant established in Siilinjärvi in 1969 is one of Yara Suomi Oy’s three plants. Its main products are fertilisers, especially for Finnish arable farming, and phosphoric acid, which is used by fertiliser, feed, and food industries. The phosphate mine operating in the area is the only operating phosphate mine in Western Europe.

The location of Siilinjärvi close to Kuopio is attractive from the point of view of different research projects.

The University of Eastern Finland, Savonia University of Applied Sciences, GTK, and Yara are large local actors. “Usually we have multiple projects going on, and their results have also been useful to us. It would be great, if the results could also be applied in other fields,” Huttunen says.