Ausenco Sandwell provided conceptual engineering, capital cost estimating, detailed engineering and equipment procurement for the $60 million upgrade of effluent treatment facilities at the Alberni pulp and specialities mill.

A split treatment concept was developed to meet special effluent quality regulations issued by the federal and provincial governments for the Alberni mill in December 1990. The upgraded facility utilises a new air activated sludge system for paper mill and mechanical pulping effluents and the existing aerated stabilisation basin (ASB) for kraft mill effluents; the kraft mill has since been shut down. The major components of the activated sludge plant are a lift station, primary clarifier, cooling tower, rectangular aeration basin, two secondary clarifiers, centralised sludge dewatering facility, sludge belt conveyors and nutrient addition. The original primary clarifier was converted to a secondary clarifier because of its location and elevation.

The former kraft mill effluent lift station was upgraded to enable the entire mill flow to be pumped to the aerated stabilisation basin in the event of a failure of the primary clarifier lift station. Detailed design was commenced in July 1991 and the new activated sludge plant was started up in January 1993.

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