Terrafame’s new centralised water purification plant enters trial use 18.11.2016 13:18

A new centralised water purification plant has been completed at Terrafame Ltd. in Sotkamo. With the completion of the plant, water purification in the area will be concentrated to one location. The centralised water purification plant will greatly simplify the water purification process, leading to more cost-efficient purification as well as further improved consistency of purification results. The plant is an investment of about EUR 8 million.

The plant will use the same best available technology (BAT) that has been in decentralised use at the mine’s different water purification plants until now. The purification technique is based on raising pH with milk of lime which precipitates the metals in the water and the water is purified. The plant’s purification process is automated, and its purification capacity is about 1,400 cubic metres of water per hour.

The centralised water purification plant now operates according to the trial use notice left by Terrafame. The plant’s environmental permit application is currently being processed at the Regional State Administrative Agency (AVI) of Northern Finland. Along with the actual implementation of the plant, to be done at a later date, the water treated at the centralised purification plant will be led to the Latosuo pond after settling and, from there, to the Lake Nuasjärvi discharge pipe. Currently, about 1,000 cubic metres of treated water per hour is led into the discharge pipe.

“The treated water to be discharged into Lake Nuasjärvi has met the quality requirements detailed in the permit conditions already before the centralised water purification plant. Measurement results show that the autumn circulation of Lake Nuasjärvi has been successful, down to the depressions. The new centralised water purification plant will further improve water management at the mine,” says Veli-Matti Hilla, Chief Sustainability Officer at Terrafame Ltd.

With the new purification plant, Terrafame’s water treatment will operate as an efficient whole. The rainfall and runoff water gathering in the area will in the future be treated at the centralised water purification plant, and the waters forming in the production process are treated at the reverse osmosis plant. The water which has been treated with the reverse osmosis is used in the production process of the metals recovery plant, and the sulphate-containing reject is returned to the bioleaching heaps, which provides significant benefits to Terrafame’s sulphate balance management.

Emeritus Professor and Astronomer Esko Valtaoja from the University of Turku attended the celebration marking the beginning of the trial use of the centralised water purification plant. Valtaoja also started the plant’s trial use. He is familiar with the Kainuu area from spending time at his cottage.

“The double challenge of the new century is to save both people and the Earth. We must maintain economic growth, without which we cannot create a better, more humane and more just world. But we must also decrease the strain we put on the rest of nature. It is delightful that after a lengthy and difficult journey, Terrafame is now on the right path to achieve both goals,” says Esko Valtaoja.

Water management will be developed at Terrafame’s mine in the future as well. Terrafame Ltd.’s holding company Terrafame Group Ltd. continues the water technology project Ariel where four different solutions to process water management are currently being piloted at the Sotkamo mine. The main goal of the project is to significantly decrease the sulphate concentration of the waters discharged from the mine and to simultaneously improve Terrafame’s business opportunities.


Further information:

Chief Sustainability Officer Veli-Matti Hilla, veli-matti.hilla@terrafame.fi


Terrafame Ltd. is a Finnish multi-metal company producing primarily nickel and zinc by bioheapleaching at its mine located in Sotkamo. The aim is environmentally sustainable, safe and economically viable mining operations. Terrafame is owned by Terrafame Group Ltd.



Article subjects: EnvironmentTerrafame