Site Prep Can Feed Wood Waste Market

By: Greg Ehm, Technical Writer • Two Rivers Marketing, Des Moines, Iowa | September 28, 2010

While there are many forces that drive alternative uses for wood and green waste, understanding customer needs is an important factor in determining current market trends. For example, demand for green and wood waste byproducts such as mulch, organic compost and biomass for cogeneration has increased due to their popularity. Fortunately, this trend is helping eliminate green and wood waste that, years ago, would have been taken to the landfill or burned.

As more and more landfills divert green and wood waste into their facilities, there is an increased need to find alternative end uses for these organic materials, such as mulch and organic compost.

The primary driver in this movement is the governmental and consumer driven diversion of green and wood waste from our rapidly filling landfills, says Byram. These feed stocks are easier than others to divert from landfills and the general public is becoming more concerned about recycling and green efforts.

Green and wood waste can be used in a variety of ways. Green waste comprises vegetative materials, such as tree trimmings, lawn clippings and leaves. Green waste is a key product in the production of compost which can be used for plantings, erosion control and to reinvigorate soil. Wood waste, on the other hand, includes materials like tree trunks and limbs. These sources can be converted into mulch for decorative landscaping, playground ground cover and as fuel for use in cogeneration.

Contractors and developers are routinely faced with the challenge of finding a home for processed green and wood waste from land clearing or tree trimming projects. From mulch and compost to heat and electric generation, many contractors are taking an innovative approach to finding new markets for these processed end products. They are also helping add value to the raw materials and to their bottom line.

Reclaiming Ground

Located approximately 70 miles north of Vancouver, British Columbia, along the Sea to Sky Highway, the Whistler Blackcomb ski resort is the site of the Whistler Nordic Competition Venue, which includes areas for the upcoming 2010 Olympic Winter Games events such as the biathlon, cross-country skiing and ski jump.

Frazer Excavation based in Maple Ridge, British Columbia, was hired to clear this site for the upcoming Olympic events. As with most Frazer projects, the resulting processed green and wood waste would typically be hauled away. Instead, the resulting end-product was converted into a compost blanket known as EcoBlanket, a product of Rexius that uses specifications from the American Association of State Highway and Transportation Officials.

The compost blanket was used to help control erosion on the sub alpine region slopes. Hydroseeding had already been tried with no success, so the compost blanket was being used as a growing medium. It also provided a perfect way for the product to be returned to the area.

"This process spoke to a number of things in terms of being environmentally sensitive," says Dave Eales with Frazer Excavation. "Something could be done with the product that's advantageous."

After Frazer Excavation completed the initial grind, the product was re-ground to an exact specified size for the compost blanket. It was then mixed with chicken litter and bio-solids from the municipality of Whistler. Nitrogen and water also were added before the mixture was put into ag-bags to compost for three months. One round of this composting project has been completed with two more to come, Eales says.

Once the composting is complete, the product will be blown back onto the slopes in all the disturbed areas. Eales says the product is also used in filter socks for a different treatment on the ski jump venue area.


Efforts to find renewable energy sources are increasing at local, state and federal levels. While ethanol and biodiesel are receiving much of the attention, biomass is quietly gaining interest as a potential energy source. Biomass is organic matter, especially plant matter, which can be converted to fuel — and wood waste is one example of a biomass source.

"As heating fuel and electricity costs soar each year, power companies have begun to use wood waste for cogeneration purposes — burning wood to create heat and electricity," says Mike Byram, senior director for environmental solutions for Vermeer Manufacturing Company.

In St. Paul, Minn., Environmental Wood Supply LLC locates and purchases wood waste from public and private vendors in the Twin Cities area to provide fuel to the St. Paul Cogeneration renewable fuel combined heat and power (CHP) plant. This plant produces up to 33 megawatts of electricity and up to 65 megawatts of thermal energy for local district heating provider District Energy St. Paul.

Of the estimated 600,000 tons of wood waste generated annually in the Twin Cities metro area, the St. Paul Cogeneration plant turns 280,000 tons of this into green energy each year, replacing 80 percent of District Energy's use of coal and oil. Because of this effort, carbon dioxide, sulfur dioxide and soot emissions have been reduced.

The wood waste used in the cogeneration process must meet specific guidelines to ensure the product is uniform in size for quality control. This requires attention to detail and assurances that vendors are using the same equipment to create a consistent product.

"Originally, we were going to rely on the local infrastructure to bring the product to us," says Michael Marsollek, biomass fuel manager for Environmental Wood Supply. Shortly thereafter, however, Marsollek says they began experiencing quality control issues with some of the companies they had subcontracted to grind the wood waste. "So we decided to take matters into our own hands and not have the vulnerability of the entire operation in the hands of somebody else," he says.

Usually, the raw wood is delivered after being ground with a 6-inch screen. The Environmental Wood Supply crews grind it again using one of the company's three horizontal grinders equipped with a 3-inch screen. "I need to have the product at a 4-inch minus for it to go though the power plant," he says.

As the cost of fuel continues to rise, Marsollek predicts more cogeneration plants like that in St. Paul will surface across the country. In this industry, he says having exemplary customer service is important because it keeps wood waste flowing into the recycling center and the St. Paul Cogeneration plant successful.

Market Considerations

There are ample opportunities to find new markets for processed green and wood waste. However, before a contractor buys a grinder or jumps into one of these markets there are a number of issues to consider.

"First and foremost, end-users require that the contractor deliver the processed green or wood waste to exact specifications," says Byram. "These specifications can dictate the type of equipment you use in the reduction process."

For example, mulch should not contain long spears of wood and playground mulch typically needs to be in the form of a nugget. The cogeneration industry has stricter guidelines. The feeding systems sometimes require a consistent length or shape of processed wood waste for optimal feeding and Btu value. This market also requires that the fines be removed from the processed wood waste, which may require the use of a trommel screen.

Choosing the Right Equipment

"If you are trying to build business plan around a certain market don't get carried away with the volume of material the equipment can process," says Byram. "Verify that the machine can produce the end-product to the market specifications as this will ultimately determine if you can make money."

Tub and horizontal grinders will create a different end product. A horizontal grinder can easily process longer, brushy material, but will produce a less uniform product. On the other hand, a tub grinder will produce a more uniform end product and is better suited for regrinding applications. However, some areas don't allow the use of tub grinders as they have a longer thrown object zone.

It's also important to understand how much it will really cost to produce the end product. Can the desired end product be produced in one or two passes through the grinder? Will you need a different set of screens? What additional handling equipment is required?

Byram encourages contractors to figure out the cost and determine if they can be justified. With research and planning contractors have the potential to add value to green and wood waste by tapping into these alternative markets.

Research the Market

Byram recommends that the contractor take time to thoroughly research the market.

"The Internet is a great resource to research these markets and products," he says. "I also encourage contractors to visit with end-users to understand their needs, industry guidelines, restrictions, and demand."

Byram also recommends visiting with other contractors already in the business for advice and contact the local landfill or government agencies to understand what factors are driving these markets in your area. Don't forget your local dealer. They probably know people already in these markets and can be a valuable resource.

Information Provided By: Vermeer Manufacturing Company Pella, Iowa