A reality of pulp and paper production is the creation of waste products. When we process a tree or recycle a piece of waste paper there is always a part of the raw material we can’t use. Our challenge is to limit the quantity of, and find a good use for these by-products.
At the Thunder Bay Operation, we manage 5 major types of waste by-products: wood wastes, ash, recaust waste, de-inking residues and wastewater treatment residues. Although we can reduce some of these by-products by increasing our efficiency, some waste will always be generated.
All of the “
process wastes” generated at our mill are considered
NON-hazardous industrial waste by the regulatory authorities. This means that they meet the strict restrictions outlined in the government’s
hazardous waste regulations. It also means our process waste can be handled by any landfill licensed to take non-hazardous industrial waste.
Our Thunder Bay Operation pulp and paper mill either uses these materials on site as fuel—to make steam and electricity—or sends them off-site to one of two licensed landfills in the Thunder Bay area. A portion of our waste materials is used in other applications such as soil conditioning for farmers’ fields, daily cover and lining cells for
landfill sites.
One of the major wastes generated in the process is wood waste. This includes parts of the tree such as bark, knots and fines that aren’t suitable for use in pulp or paper making. Over 99% of the wood waste generated at the mill is used as fuel in one of our two bark burning power boilers. Wood waste is fed into the boiler on a continuous basis. The heat generated creates high-pressure steam, which is used to generate electricity and in other manufacturing processes. Unfortunately, some wood waste has to be sent to the landfill because it contains stones or dirt that we can’t remove, making it unsuitable for use as fuel.
After the wood chips are pulped, the pulp is cleaned to ensure that only the strongest fibres are used in our pulp and paper machines. The weak, unusable fibres are sent to our effluent treatment plant—where they’re removed from the wastewater in primary
clarifiers. These clarifiers settle out and separate this solid material. Using filters and screw presses the material is dried, resulting in what we call “primary wastewater treatment
bio-solids.”
The remaining (liquid) effluent is sent on to our secondary effluent plant—where it undergoes a biological treatment to remove organic material. Part of this process is the generation of a “secondary
bio-mass.” This material is made up of dead microorganisms, which were used for the secondary process.