Paper, pulp and packaging company Sappi has won the American Forest & Paper Association’s (AF&PA) 2023 Leadership in Sustainability Award for Water Management.

Sappi was recognised for its “Cloquet Mill Effluent TSS Reduction” project, designed to find a new chemical treatment program to reduce the TSS (total suspended solids) and biological oxygen demand (BOD) substances in the Cloquet Mill’s effluent. The overall aim is to reduce the load being sent to the Western Lake Superior Sanitary District (WLSSD) in Minnesota.

The project reportedly achieved an immediate and consistent reduction in TSS of 11,500lbs per day, a reduction in BOD of 1,800lbs per day and a decrease in mercury to WLSSD from 37.9 ppt to 6.3 ppt.

There have been three phases of the program between 2015 and 2022. Phase I and Phase II focused on introducing a coagulant to the clarifier and reducing chemicals needed for pH control for the paper mill clarifiers, reducing TSS.

Phase III, finalised in 2022, addressed the old program chemistry, which was not effective for both clarifiers due to the chemistry differences in the two separate influent streams. To remedy this, Sappi trialled three new chemical programs and vendors to find a coagulant that worked in both systems, leading to the current resolution.

Since the start of Phase I in 2015, the Cloquet Mill’s effluent TSS has been cut in half. As a result of the project’s impact, Sappi North America has saved approximately $304,000 year-to-date annually due to reduced TSS treatment charges from WLSSD, with an estimate to save approximately $450,000 by the end of 2023.

The substantial reduction in mercury to WLSSD has also allowed the organisation to achieve compliance with its mercury effluent limit for a record ten consecutive months.

A fellow recipient of the 2023 AF&PA awards was Ahlstrom for its sustainable pet food packaging.