Useful bacteria have been devouring Myllykoski Paper's wastewater impurities for more than ten years already. Biological cleaning is today one of the most efficient cleaning methods used by the chemical forest industry.

Myllykoski Paper, which is located on the bank of the Kymi river in Southern Finland, pumps its wastewater across the river to its biological wastewater facility.

The facility first frees the wastewater of solids - tiny bits of bark, fibre and filling and coating agents - after which the living microbes are put to work. They feed on the organic substances contained in the wastewater and in this way purify its oxygen consuming substances. The process removes up 95 per cent of the oxygen consuming load dissolved in the water during pulp preparation. This is of utmost importance because oxygen consuming particles let loose into the environment are harmful to fish.

As a final stage, the facility removes the microbe stock from the wastewater. The cleaned water is discharged back into the Kymi river. Liquid oxygen added to this water ensures that no noxious smells are emitted into the environment, and the dried sludge produced by the cleaning process is transported to an industrial refuse dump.

Less waste water

During the 1990's, the Myllykoski Paper mill produced about 10 million cubic meters of waste water a year. The advent of closed water circulation and the decreased use of water has reduced wastewater amounts by nearly a million cubic meters. And considering that the mill has simultaneously increased output, this means that it has achieved even more substantial reductions in harmful emissions.

During the same period, the Myllykoski mill reduced its phosphoric emissions by a quarter, and this trend continues. Phosphor causes eutrophication in waterways, i.e. it stimulates the growth of aquatic plant life.

>> From environmental protection to corporate responsibility (7.6.2002)

>> Forest industry spotlight on water protection (25.7.2002)

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