BioCycle Magazine

Completing the Cycle: Composters, Wood Grinders Find Expansion Opportunities

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 Composters, Wood Grinders Find Expansion Opportunities

Interesting evolutions have taken place over the past ten years in the organics processing industry. Sites that opened to compost yard trimmings gradually transitioned into processing woody materials, while wood processors expanded into the composting arena. Other businesses that started with no plans for recycling wood discovered that it pays to refine and market the residuals they handle. In all of these cases, the end result is an enterprise with the flexibility to process a wide range of feedstocks and sell a full spectrum of landscaping and soil amendment products.

Several factors have combined to create these multifaceted companies. First is the fact that the generators being serviced are also prime customers for the finished products. A full truck going out has become equally, if not more, important than a full truck of feedstocks coming in. Second, the same or upgraded equipment can be used to handle the various feedstocks and end products. Third, especially for wood processors, is the growth markets for mulch, compost and blends as compared to the shrinking markets for hog fuel in many regions. The following profiles demonstrate the opportunities being seized by processors of organic feedstocks.


County Conservation in Sewell, New Jersey opened a composting site in 1992, taking in yard trimmings from 35 municipalities in Camden and Gloucester Counties. To take advantage of the steady stream of landscapers who came through the gates to drop off compostable material, the company had to generate more products. At first, the business concentrated on composting and purchased mulch from land clearing operations for resale. In a few years, it started accepting wood chips for its own mulch production, and a few years after that, County Conservation jumped into the colored mulch market. The philosophy is to serve as a one-stop shopping location for landscapers and other customers by offering the full range of organic products (as well as items like sand, road salt, stone and pavers) for maximum convenience. About 60 percent of this business is from landscapers, 30 percent from the garden industry and the rest from individuals.

The company receives about 100,000 cubic yards of organic material annually. The average tipping fee for yard trimmings is $8/cy. Leaves are dropped off for $5/cy because they do not have to be processed before composting. Clean wood that can be ground once for colored mulch is tipped at no charge.

Fourteen acres of the 21-acre site are dedicated to composting. Yard trimmings, grass, leaves and brush are put through a Willibald grinder that is pulled along for three or four passes to start a windrow. A bucket loader completes pile formation. The windrows are turned with a Wildcat about two or three times in the first several weeks, depending on precipitation and wind conditions, then about once/month. “We get enough grass clippings to create moisture, so we don’t have to add water,” says John Petrongolo, managing partner. To control odors during the heavy grass season, five to ten gallons of an odor suppressant are added to a 2,500-gallon batch of water and sprayed onto the piles after turnings.

After five months or so, compost is placed in piles about 15 feet high around the perimeter of the facility for curing. Usually, it takes about a year from the time material comes through the front gate until the finished compost has been put through a screen set at three-eighths inch. About 12,000 cy/year of compost are sold and roughly 10,000 cy/year are mixed in a 1:2 ratio with sandy New Jersey soil, then rescreened in a Powerscreen trommel for soil blends.

#Feedstock contamination is the main difficulty in composting. The primary culprits are haulers that use trash trucks to pick up yard trimmings at curbside. “We have two or three guys on-site behind the screening plant pulling plastic out of the overs,” says Petrongolo. “We’ve tried a lot of different processes to get out the plastic, but the best way is by hand. If I can clean up the overs close to 100 percent, I can get some decent money from them.” The overs are piled up for a year, rescreened and sold as low-grade mulch for $8/cy. Compost prices range from $8 to $12/cy, and soil blends cost $12 to $15/cy.

The remaining County Conservation property is used for mulch production. Wood chips from pallet companies, transfer stations and custom grinders come in at six inches to one foot long. “I like to avoid taking whole pallets to reduce time and cost, but in the long run, I probably won’t be able to,” says Petrongolo. “Right now, the challenge is getting enough sources of wood for the coloring end of the market. It seems to have really taken off. If we had another 20,000 to 30,000 yards of wood chips, I know that we could sell them.”

The chips are reduced in a Morbark tub grinder to about one inch. They are piled up no more than 15 feet high in concrete bins with 2,000 to 6,000 cy in each. “As high as the buckets from the loaders will reach is as high as we go,” says Petrongolo. “The tighter you pack them in, the greater potential for a fire. Smoldering fires going through veins in the pile are hard to get out. They create a bad smell to the wood and the possibility of the whole pile going up in flames.”

Wood for red mulch is loaded into the hopper of a mulch coloring system, while chips for black and brown dyed mulch are aged about three to four months. This year, County Conservation upgraded from a 10-cy batch coloring unit to a Fecon continuous feed system. The machine increased capacity from 400 cy/day to 1,800 cy/day. “I like the mulch to sit two to three days for curing,” adds Petrongolo. “If I sell it too quickly, a heavy rain will wash the dye off.”

Colored mulch sells for $14 to $20/cy. Traditionally, red mulch has dominated with about 80 percent of colored mulch sales, but the trend this year is toward 50 percent red mulch, 25 percent brown and 25 percent black. The dyed mulches are becoming more popular among landscapers because their consistent color lasts just about a whole season, says Petrongolo, whereas natural hardwoods tend to dry out and turn a cinnamon color, and hardwood root chips take on a charcoal or gray hue.

Hardwood chips dropped off by tree surgeons and tree trimmers are reground and moistened, selling for $12.50 to $16.50/cy. Roots are reground, moistened and sold as root mulch for $13 to $17/cy. County Conservation produces about half of the 70,000 to 80,000 cy of mulch it sells annually and buys the rest, including a licorice root imitation popular in the Delaware Valley.

Three to seven trucks are leased each day to deliver mulch, ranging from a 10-cy vehicle to a 100-cy walking floor trailer. Rates are based on about $60/hour roundtrip. “I try to build in an extra five percent for administrative costs, but I’m happy if I can just cover the cost of trucking,” says Petrongolo.


Grimm’s Fuel Company in Lake Oswego, Oregon is a family owned and operated business that has been producing landscaping products since the late 1940s, when it began grinding and selling fir bark dust as a sideline to its fuel oil business (see “Innovative Approaches to Equipment and Methods,” July, 1995). The Portland area company makes compost and soil blends on a 11.5-acre site, and uses an adjoining 45-acre area for finished product storage and a dirt screening operation. Grimm’s also sells some wood residuals as hog fuel, but that low-end market often only covers the cost of transportation. “Without a doubt, the compost makes out better,” Jeff Grimm, general manager. “If we didn’t have the machine time to fill, we’d shut the hog fuel process down.”

Tipping fees are $4/cubic yard (cy) for self-haul materials, $3.50/cy for landscapers, $6.50/cy for compacted loads from haulers; $6/cy for woody materials that have to be sheared; $3.50/cy for food residuals; and $1/cy for chipped material. Last year, the company accepted 306,000 cy of yard trimmings, 91,000 cy of wood residuals, 13,500 cy of stumps and woody material, and 1,200 cy of primarily preconsumer vegetative food residuals from grocery stores, produce companies and food processors.

Most of the materials are run through one of three modified Jeffrey hammermills, two of which primarily are in support roles. The main advantages of the stationary grinders, says Grimm, are high tolerance for difficult materials such as metal and low operational costs from running on electricity — fairly cheap in Oregon — as opposed to a diesel-powered portable grinder. But last month, Grimm’s added a Beast portable horizontal grinder for increased processing flexibility. “We’ve been looking at getting one for quite some time,” says Grimm. “We can move it from one end of the property to another, enabling us to do small batches. We also can go out and do some contract grinding.”

After being ground, yard trimmings and wood residuals are composted in large piles on two to three acres. In the summer, collected stormwater runoff or well water is added through a sprinkler system. The piles are turned three or four times over three to six months. “To most people, it looks like one big pile, but we keep track of how old each section is,” says Grimm. After processing, the compost is put through one of the grinders for screening to five-eighths inch.

Plastic contamination and odors are two of the larger challenges for Grimm’s. In some cases, grass already is anaerobic when it arrives at the site. To reduce compaction and maintain air flow, the operators stopped driving on the piles with loaders to add or move material, and switched to using large tractors. Incorporating larger coarse materials up to a foot long also facilitates air flow.

Weather has a large effect on sales. About 75 percent of product is sold from April to June, and last year, it rained for much of that time. “By July 4, it starts getting warm and people go on vacation,” says Grimm. “They don’t like to landscape at that point.” Sales dropped from 16,000 units (each 7.4 cy) of compost, or “Garden Mulch,” in 1998 to about 11,000 units last year. Sunny weather has Grimm predicting a much better season this year.

The proportion of nursery customers — who use compost as a component in potting mixes — has been increasing. The breakdown is about 20 percent nurseries, 40 percent landscape contractors and 40 percent homeowners.

 Blended soil is mixed from 50 percent sandy loam, 25 percent compost and 25 percent mushroom compost. It is delivered for $100/four cubic yards and sold at the site for $20/cubic yard. “Gardeners use it for topdressing like bark dust, or as a soil amendment in poor quality soil,” Grimm says. “They’ll also use it if they need more soil for a raised bed or berm.”

Garden Mulch also is mixed with equal amounts of mushroom compost. “This is strictly a soil amendment,” says Grimm. “It’s a lot higher in nitrogen than straight Garden Mulch. Because there’s a lot of manure in there, it’s a better soil amendment, but it doesn’t lend itself well to topdressing.”

The company also buys bark dust from local and regional mills as far as 160 miles away. It is used as a topdressing in landscaping and by nurseries as a component in container mixes. “Some of it we’ll haul in at 1.5-feet minus, which is coarse and nasty stuff that we have to reprocess,” says Grimm. “We don’t have to pay much, but then we incur costs in grinding it up. We also pay $35 to $65/unit for pure virgin bark dust that’s ready to sell. Sometimes we have to buy bark dust in winter so we have enough. When we stockpile large quantities, it turns darker and there’s some pile loss, so we try to avoid that.” The widespread availability of bark dust in the area would make it very difficult to market wood mulch, he adds.


When Greg Kaknes was hired to manage a Woburn, Massachusetts operation that received wood residuals and yard trimmings in 1987, the approach had been simply to take in tipping fees and reduce material volume through grinding (see “Expansion Options For Mulch Producers,” May, 1998). “At that point, nobody knew what they were doing,” recalls Kaknes. “We were really a stepsister of the waste business — a way to save money by avoiding the cost of landfilling.” Kaknes switched the revenue strategy from relying on tipping fees to producing and selling high quality product to landscapers. “I got sick of seeing them leave here with empty trucks,” he explains.

In the beginning, he sent wood residuals to power plants in northern New England and had bark back hauled to his site. In 1993, Kaknes bought the business and named it Kaknes Wood Products and Landscape Supply. One of his first moves was to cut out the lower grade wood being received by the site, which had comprised about 30 percent of the business. He has since built up a mulch and composting business that serves the Boston area with six locations. Sales are on pace this year to total 100,000 cy of mulch and 15,000 cy of soil and compost products.

Tipping fees are $3/cy for clean tree chips; $6/cy for pallets and mixed yard trimmings and leaves; $9/cy for brush and tree limbs; and $16/cy for large stumps. Yard trimmings and leaves are put through a CBI grinder and composted for six months in piles about eight to ten feet high and 15 to 18 feet wide. A front-end loader is used to turn the piles just a few times during the process. “We’re not real concerned with speed because it’s a very seasonal business,” says Kaknes. “The material won’t be sold until the next year anyway.” The compost is put through an Erin star screen set at half-inch minus; the fines are recomposted. “Unlike almost everybody else in the industry, we regrind our fines,” he adds. “It’s a pretty expensive way to mix and blend, but it produces a good product.” The other soil amendment and planting products include topsoil screened to quarter-inch minus, a blend of compost and topsoil called Superloam, and a finely screened version of Superloam.

Wood for mulch is ground and put in piles 16 to 17 feet high, about 50 to 60 feet wide and 200 to 300 feet long. Enough rain usually falls to provide moisture without watering the piles. After aging, the mulch is ground again. Kaknes produces several different mulches at 1.75-inch minus. The one exception is Enviromulch, a one-inch minus jet black mixture of hardwoods and softwoods, with pine the predominant type. Another mulch combines aged hemlock with pine and other barks. “We use smaller screens for our mulches, which increases our costs and slows productivity, but it meets our niche,” Kaknes says. “Landscapers like a consistently finely ground product.” The company also purchases bark from the timber industry and grinds it for resale.

Kaknes was impressed when he observed an early coloring system demonstrated about ten years ago, but held off on entering the colored mulch market until it matured. “The market went through some serious growing pains in New England with many inferior quality colored mulches,” he says. “I didn’t want any part of that. About five years ago, some major bark producers in Maine started coloring bark, which we emulated a year or so later.” Pine bark and wood chips are mixed together, ground and dyed in a Wood’N Colors machine. Because the color mirrors the dark appearance of aged hemlock, a little aging of the stockpile before the dyeing process is not a big concern.

Another marketing avenue is providing mulch application service, most of which landscapers subcontract to Kaknes. “Being the manufacturer of finished product, we can meet the specifications for our Rexius and Finn blower trucks,” says Kaknes. “We also sell quite a bit of mulch to other people with blower trucks because they know our material goes through our own. The only reason we’re in the blower business is to sell more mulch.”

The mulch has to be finely ground and relatively low in moisture, or it will clog the machine. “You really want to stay with larger applications,” adds Kaknes. “If you get into small tree rings and condominium complexes where each townhouse has a one-yard bed, it’s faster to do it by hand. The bigger the mulch bed, the more appropriate the automation.”

Kaknes generally has a six-cy minimum for residential blowing jobs. “Some houses may only have five to six yards, but we’ll go out with a whole load and use it up in the neighborhood,” he says. Application charges are site specific and determined in part by a saleman’s visit, but they generally decrease per cubic yard as volume increases. “We try to get, on average, $20/cubic yard just on installation, which is in addition to the cost of the mulch,” says Kaknes.

The most recent marketing move was to open five additional sites this spring. One of them is similar to the Woburn headquarters in that it receives, processes and markets material. The others are satellite locations that receive feedstock back hauled to the processing sites in exchange for finished product. The five new locations bear the name “LandscapExpress” to reflect the full-service convenience they offer. “These enable us to reach a whole new market of landscapers and residential clients,” says Kaknes.


Lashway Logging in Williamsburg, Massachusetts began in 1965 as a logging company, then grew into a sawmill. In the mid-1980s, the company purchased a tub grinder to process its own wood byproducts into mulch. As demand grew, it upgraded equipment and started bringing in end trimmings and slab trimmings from other area sawmills.

Today, the company operates a W.H.O. and two F.H.E. grinders to produce seven different mulches — some singular, some blended and some coupled with colored chips. The company sends out five tractor trailers daily to serve wholesalers during busy periods, and several smaller trucks for local markets.

Bark for Forest Mix mulch is purchased from several different sources, then combined, ground and screened to 2.5 or three inches. It is aged for about a week in a pile no larger than 1,000 cy. A darker version is aged for two to three months, or even longer during winter. “If it’s during the season, we’ll roll the pile periodically with front-end loaders,” says Lashway. “Otherwise, it’s not aerated, so it doesn’t darken as quickly. In past years that were very dry, we had smaller piles and had to add water. Now the larger piles seem to retain moisture better, and we don’t have to add water.”

Lashway also produces higher-end hemlock mulches sized at 1.25 to 1.5 inches. One is natural and another is ground with dyed wood chips for brighter and longer-lasting color. To prevent darkening of the chips, piles are no higher than eight to ten feet, processing closely matches demand to prevent aging, and hardwood — which accelerates decomposition — is kept out.

The company got into colored mulch four years ago when the prices paid by paper companies for slab wood chips dropped, says Lashway. Red, brick red and chocolate mulches are produced in a Becker Underwood coloring system. “As colored mulches have become more popular, we entered the market to protect our customer base,” says Lashway. “The more we can provide for our customers, the more stick they’ll with us. We hesitated for a year or two, but felt we had to take the plunge.”


Jim McAndrews started in the firewood business in 1980, then expanded in 1985 by reselling bark mulch. A few years later, he struck an agreement with a paper company to take its leftover bark and started processing his own mulch. He also marketed wood residuals as an energy source, and in 1993, to increase profits, he started turning them into colored mulch instead. In June, 1999, his company, Frontier Wood Products in Quakertown, Pennsylvania, was bought out by Jolly Gardener in Poland Springs, Maine and operates as a division of that firm.

The main wood suppliers are pallet manufacturers and waste management companies that supply kiln-dried wood and tree chips from land clearing. Size of the incoming wood is not an issue. The main requirements are that the wood be clean, unpainted and nontreated. A Morbark tub grinder and three Mighty Giant grinders are used to reduce much of the wood to an inch minus. The ground wood then is watered and piled up. Pile height is kept at 13 feet or less; however, kiln-dried wood heats less intensively and can be stacked in larger quantities, says McAndrews. Most of the mulch piles are built in July and August and aged until the following spring. No turning is necessary, except for restacking and watering during extended dry spells.

Wood for colored mulch is loaded into an Amerimulch dyeing system. Frontier also produces hardwood, root, pine and cedar mulches, as well as topsoil and potting soil. The colored mulches outsell the organic mulches by five to one, says McAndrews. “The main question is whether a mulch will keep its color,” he notes. “I feel that 90 percent of mulches are used for decoration, and colored mulches hold their color for about a year.” The main customers are landscaping companies, retail garden centers, chain stores and other retail centers.

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