May 24, 2006 | General

Colored Mulch Production Options

BioCycle May 2006, Vol. 47, No. 5, p. 34
Portable grind/colorize unit and a trommel mixing system are among the innovations being offered to wood recyclers, arborists and pallet manufacturers.

SPRINGTIME not only brings out the spectrum of colors in tree blossoms and flowers, but the vibrant colors adorning commercial and residential landscapes. Ten years ago, it was unusual to see anything but brown mulch. Today, there is quite a variety, from more subtle black to vibrant red.
When BioCycle first started covering colored mulch production and markets a number of years ago, it seemed that pallets were the preferred wood to colorize because they are dry and the chips absorb the colorant well. Since then, demand for the colored products has outpaced the supply of recycled pallets, so other recycled woods are being processed. “There are not nearly enough pallets to supply demand for colored mulch and more can’t be obtained in a cost-effective manner,” says Scott Thompson, Vice-President of Sales for Amerimulch in Twinsburg, Ohio. “Today, about 50 percent of the wood supply comes from land clearing debris.”
Amerimulch markets mulch colorization equipment and colorants. The company is recognized as being the first on the market with equipment specifically dedicated to wood colorization. Greg Rondy of Barberton, Ohio was the owner/operator of a pallet shop that was paying too much to dispose of waste wood. He decided to try to do something besides sending pallets to the landfill, and thus Amerimulch was born in 1991 when Rondy introduced a piece of equipment for coloring waste wood (a patent was granted in 1993). While general industry statistics on growth of the colored mulch market are difficult to come by, Thompson notes that their customers’ current market growth is in the low 20 percent range annually: “These are companies that have been in business for 10 to 15 years using our equipment, and the fact that their markets are still growing at that pace speaks to the growth of the market overall.”
Not only are consumers buying more colored mulch these days, they also are asking for a more refined product. The challenge with providing a finer product is that more water is required to cover the surface area. “Water is the carrier to cover the surface, and from a production standpoint, the question is how to do that effectively and still minimize water usage,” says Thompson. Amerimulch designed a high rate mixing system that greatly reduces water rates, and works with clients to modify existing systems to conserve as much water as possible.
Another consideration with coloring a finer product is its final weight for shipping. The need for more water to cover finer particles increases the weight. The bottom line, says Thompson, is producers need to find the right balance between particle size, water usage, and transport to markets.
In 2005, Amerimulch introduced the ColorTrom, which uses a trommel to mix ground wood and colorant. The system is simpler to use and maintain than more traditional mixing equipment such as the company’s twin paddle-shaft color mills, however it is not able to provide dramatic water reduction. “The color mills can get jammed if a log or large rock gets inside the unit,” he adds. “With the trommel, the drum keeps spinning and the foreign object comes right out the other end.”
Ultimately, which unit a client decides to buy depends on how critical weights and water use are to the bottom line. “With pallets, it not as big a deal with weights and shipping,” says Thompson. “They seem to absorb the water and not take on a lot of extra weight.”
In 1997, another Midwest company introduced a technology that has advanced the mulch colorization industry. Rotochopper – based in St. Martin, Minnesota – patented and began selling the CM-497 coloring system, which grinds and colors wood fiber in a single pass. The design injects water and colorant directly into the grinding chamber. “There is a row of ports in the top of the grinding chamber, and metered amounts of colorant and water flow in through the ports,” explains Vince Hundt of Rotochopper. “All the speed and horsepower of smashing and grinding the wood comes to bear on atomizing and forcing the color into the wood.”
What amazed Hundt from the beginning are the profit margins with this type of product: “At the time, waste handlers who sold their ground wood for $10/ton for fuel were selling the same wood, only colored, for over $60/ton.” Those profit margins continue today, he adds. “We have pallet companies who were paying to get rid of their pallets four or five years ago who are now selling over 100,000 cubic yards of colored mulch to retail outlets. In these instances, the machine can pay for itself in less than 12 months.”
Recognizing that the sources of wood to grind and color needed to be expanded beyond pallets, Rotochopper introduced a tow-behind unit (the CP-118) that has caught on with the arborists/tree care and land clearing industries. The unit has a 5-cubic yard hopper, grinding mill and colorizer that can process up to 70 cubic yards of woody debris/hour. It has enabled smaller operators to get into the highly profitable colored mulch business. “Some of our customers are ultimately selling the tree right back to the person they took it down for,” says Hundt. “When a tree care company is producing a consumer product, i.e., colored mulch, a number of factors need to be considered to determine the profitability. These include cost of the raw material and transportation. In this case, the tree care companies have the raw material close to the retail customer – and the raw material is free to them. All they have to do is purchase the colorant. And in some markets, colored mulch retails for as much as $55/cubic yard, so the payback is quite dramatic.”
Tree care companies that have been chipping and stockpiling during the winter months are using mobile units to regrind and color their chips. “By springtime, there is a large pile of ragged chips that include long sticks and vines,” he adds. “This is a cost-effective way to create a higher value product out of that material.”
With the “green” wood, a larger amount of colorant/cubic yard may need to be used for the color to adhere well, in contrast to when dry wood like pallets is being used. To address that issue, Amerimulch recommends that producers coloring green wood fibers use its Ultra™ line of colorants. “That will produce a vibrant red versus a brown-downed red as the material starts cooking,” notes Thompson. – N.G.

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