State-Of-The-Art Effluent Treatment for a Scandinavian Pulp and Paper Mill, 1995 Environmental Conference Proceedings

Rune Andersen

Norske Skog Teknikk

Per Hallan

Norske Skog Saugbrugsforeningen

A new effluent treatment plant was put in operation at Norske Skog Saugbrugsforeningen in 1992/93. The plant was delivered by the Finnish company Ahlstrom Aquaflow OY. The treatment plant comprise four steps; pre-treatment, anaerobic biological treatment (UASB), aerobic biological treatment (activated sludge) and tertiary flotation. The design of the treatment plant was made on basis of a pilot plant test made on-site a few months before the start of construction. This test showed among others that anaerobic treatment was a suitable way to treat this type of wastewater, achieving low sludge production and reduced operating costs. Construction was begun on 1. November 1991, and the first effluent was sent to the plant in the middle of November the following year. After two years of operation, the plant has achieved very good results. The COD-soluble reduction averaged 82% over the past year, and the concentrations of suspended solids, nitrogen and phosphorous in the effluent leaving the plant were 20 mg/l, 4.3 mg/l and 0.36 mg/l, respectively.