PM White Water Treatment at Metsa-Serla Kirkniemi Mill in Finland, 1999 Environmental Conference Proceedings

Milan Teppler

Valmet Flootek AB

Pasi Nurminen

Valmet Flootek Oy

Henrik Damen

Metsä-Serla Kirkniemi

Jan Kastensson

Valmet Flootek AB

Kristian Lundberg

Valmet Flootek AB

During 1996 an ultrafiltration system was installed at a pulp and paper mill in Finland. The purpose was to recycle a larger amount of PM-water and thereby reduce the water consumption in papermaking. The paper machine produces fine paper with a capacity of approx. 300 000 ton/year.

The installation consists of 9 ultrafilter units (total membrane area of 720 m²) which produces 200-250 m 3 /h water free of colloidal matter. The treated water is used in different positions around the paper machine, such as dilution waters and shower waters. A continuous volume flow of the PM water is cleaned by ultrafiltration in order to reduce the colloidal disturbing matter in the water loops. With these means the consumption of water has been brought down to 8-10 m 3 /ton uncoated paper.

The operational experience of the ultrafilter system has been very good. A high operability combined with long membrane lifetime and low fouling effects have together resulted in low operational costs. Expressed in relation to capacity the operational costs for the system is below USD 0.2 /m 3 .

During 1999 steps and research towards further closure of the Metsä-Serla, Kirkniemi mill will be taken.