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Water Quality

Graph of Weyerhaeuser's Cellulose Fiber Mills Water Quality Measures

We continually work to improve water quality, in particular by reducing biodegradable organic materials in wastewater. When left untreated, biodegradable organic materials can contribute to low dissolved oxygen levels in receiving waters, which may harm some aquatic organisms. High levels of untreated solids, measured as total suspended solids, can reduce river clarity, inhibit photosynthesis, and damage fish and aquatic insect sediment habitat.

We also work to protect water quality in areas where we grow and manage timber. We grade and maintain roads so runoff is channeled to the forest floor, keeping silt away from streams. We build culverts and bridges to allow fish passage, and we seed exposed road banks with grasses to prevent erosion.

Wood Products — Water-Quality Measures
Estimated discharge of selected pollutants in pounds per ton of production
2004 2005 2006 2007 2008
Biochemical oxygen demand 0.03 0.02 0.03 0.03 0.03
Total suspended solids 0.02 0.01 0.02 0.01 0.01

Discharge of Adsorbable Organic Halides

Because we no longer use elemental chlorine for pulp and paper bleaching, our discharges of adsorbable organic halides have decreased by more than 93 percent between 1990 and 2008.

Discharges of Adsorbable Organic Halides
Pounds of AOX discharged per ton of bleached production from Weyerhaeuser's cellulose fibers mills2
19901 2004 2005 2006 2007 2008
AOX 5.1 0.4 0.3 0.3 0.3 0.3
  1. Base year is 1990.
  2. Data reflects performance of Weyerhaeuser’s 2009 portfolio of cellulose fibers mills. In March 2007, Weyerhaeuser’s fine paper business and related assets were combined with Domtar Inc. to create a new fine paper company, Domtar Corporation. In August 2008, Weyerhaeuser’s containerboard, packaging and recycling business was sold to International Paper. Operations involved in those transactions have been removed from historical data.

Wastewater Dioxins

Weyerhaeuser eliminated the use of elemental chlorine to bleach and whiten pulp at all of our mills in the late 1990s. As a result, the concentration of dioxins—-a byproduct of elemental chlorine—has dropped to nondetectable levels in treated mill wastewater across company operations.

Our pulp is produced using advanced technologies such as extended delignification (removing lignin, a chemical that binds wood fibers together), that further reduce the amount of bleaching chemical used in the production process. These improvements have virtually eliminated dioxins from our wastewater while continuing to meet customer expectations for brightness in our paper products.

Pollution-control systems

Minute amounts of dioxin are released through permitted air emissions, such as from biomass-fired boilers, which burn wood residuals such as bark. Just as campfires release dioxin, so do our mills when we burn biomass fuel. We're addressing the environmental impact through techniques that improve combustion efficiency and temperature controls.

Dioxin is also found in some of the residuals, such as boiler ash, from our mill operations and in some solids that are removed during restoration work on our wastewater-treatment systems. These solids are handled according to federal, state and provincial regulations.

Last updated Jun. 1, 2009.