Waste is an issue for many wood processors. It isn’t a new problem, but it has confounded many an industry veteran since air-quality regulations outmoded teepee burners. Fortunately, wood-processing companies have more options in 2021 than they’ve had in past decades, not only for getting rid of their waste but for making it into value-added coproducts. New technologies even make it possible for companies that produce waste tainted with resins, waxes, and other chemicals to profitably utilize the material.
Among options for getting rid of waste, there are two obvious ones, which we will mention briefly. The first is selling it as is. You can sell mulch and woodchips as landscape cover. Shavings you may be able to package and sell as animal bedding (note that modern, high-speed planer mills do not produce shavings suitable for bedding). Your success in doing this will depend on whether there’s a good market in your area for these products and what volume the market can absorb. Many mills are too large to get rid of their waste by selling it in this manner, but waste management is rarely confined to one solution.
The second option is to secure an offtake agreement to sell your waste to a secondary processor. Such contracts are usually stable and provide a steady source of income. They’re not going to bring in as much revenue as investing in the equipment and personnel necessary to make a coproduct yourself, but they are less risky and allow you to focus on what you already do well. Businesses that commonly purchase waste biomass include manufacturers of particleboard/MDF, specialty products, composite wood products, pulp, biomass energy, biogas, biochar, activated carbon, charcoal, wood briquettes, industrial pellets, and grill pellets. Organizations that operate a biomass boiler may also purchase wood waste.
Consume the Waste
Wood processors are not always close to a secondary processor, however, so it is not always feasible to obtain an offtake agreement. Companies that use waste biomass also close from time to time, leaving their suppliers without an immediate means to rid themselves of their waste.
In such circumstances, you may consider consuming your waste as fuel in a biomass boiler. Boiler technology has been around for decades, but developments have made these systems increasingly efficient over the years. Tax incentives and grants have made them more affordable, as well, though this doesn’t mean a quality system comes cheap. With a boiler, you can produce steam, hot water, and electricity to decrease your reliance on the grid. Combined heat and power (CHP) systems are also available to make both heat and electricity simultaneously. Which of these options makes sense for you depends on your operational needs and the cost of other energy sources in your region.
If you create waste with resins, waxes, and other chemicals, you won’t be able to burn much of the material due to the pollution it creates, so a boiler may not be much help. Until recently, there were few options for such materials besides the landfill, but advancements in pyrolysis technology show excellent prospects for using this waste in a manner that doesn’t harm the environment. Research has shown that pyrolysis—a process in which material decomposes in a heated, oxygen-free environment—effectively breaks down the resins and waxes in MDF, particleboard, and plywood to create gasses for industrial use and biochar, a soil amendment that has gained headlines for its ability to retain nutrients and store carbon. The research implies that pyrolysis can also break down other resins, such as those in OSB.
How a pyrolysis system is designed will affect whether it produces more or less biochar and industrial gasses. A system that’s tuned to maximize gas emissions is called a gasification system. The gasses can either be refined and sold or burned directly to produce electricity. Its design can make it suitable for consuming other materials, too. Sludge, plastic, garbage, and C&D waste have all been studied in gasification systems.
Make It into a Higher-Value Product
Besides consuming the product, a wood-product manufacturer can become a secondary processor and make their waste into a higher-value product.
Pyrolysis, as mentioned, accomplishes this, but there is a plethora of other options, among which is the production of utility pellets, grill pellets, wood briquettes, charcoal, and specialty products. Each of these deserves its own discussion (we’ve done so for grill and utility pellets here), but suffice it to say, the attributes of the waste and the available markets will drive which options are viable for your mill.
At the end of the day, the goal is to find some use for the waste that avoids dumping fees. Nothing is worse than paying to get rid of your waste. If you’ve done your research and are ready to invest in secondary-processing equipment, contact Biomass Engineering & Equipment. We’ve been involved in countless biomass projects and are prepared to assist you today.