This month's article is the third in-stallment of a year-long series authored by members of the Solid Waste Association of North America.
You say wood waste, I say waste wood. I say green waste, you say organic waste. No matter how you refer to this part of the waste stream, the high volume of this material has caught the at-tention of both the public and private sectors.
Traditional methods of wood waste management include landfilling and open burning. Today, however, more states are encouraging wood waste recycling to meet recycling goals and save landfill space.
More than 60 percent of the states regulate wood waste, according to a Solid Waste Association of North America project, which was funded by the Department of Energy's Nat-ional Renewable Energy Laboratory.
For example, 20 states ban wood waste at solid waste disposal facilities (or plan to do so in the immediate future). An additional five states allow their counties and municipalities to ban wood waste disposal. Al-so, some states include wood waste materials in their mandated recycling goals.
Federal regulations affecting wood waste include the Clean Water Act, which regulates compost production from the sludge produced at waste-water treatment plants, and the Na-tional Pollution Discharge Elimina-tion System, which requires a permit and a plan for managing stormwater runoff. Additional federal regulations include RCRA, which classifies wood waste as a non-hazardous solid waste; the Clean Air Act, which regulates wood waste combustion; and the National Energy Policy Act, which provides incentives for manufacturers to use wood as a bio-fuel.
Opportunities to contract wood waste management services are in-creasing, as are markets for the end products, according to study participants. Respondents, however, cited factors such as economies of scale, funding, start-up costs and end-markets as the primary constraints to wood waste management systems.
Meeting governments regulations and permit requirements are another constraint. However, since wood waste facilities are relatively new, they are often difficult to regulate. Many jurisdictions regulate wood waste as yard waste or as municipal solid waste, which is often incompatible with wood waste.
As part of the study, 14 geographically diverse facilities were selected as case studies. Following is a brief description of some of the sites.
Guadalupe Landfill. This San Jose, Calif., landfill is part of the private alliance between the Palo Alto Landfill and several trucking companies. The alliance has contracted to accept more than 1,000 tons per day of green waste. This high-volume of green waste is brought by landscaping and land clearing operations as well as from the City of San Jose, which collects materials at the curbside in dedicated yard waste vehicles before transporting it to Guadalupe.
Guadalupe has taken an innovative approach to managing the high percentage of redwood materials it receives from demolition projects. New World Furniture, an affiliated company, separates and reprocesses the redwood material before an on-site carpenter re-works the wood to create home and garden items.
The company grinds the unsuitable material to a 2-inch minus size, markets it as redwood mulch and sells it through Valley's Pride Organ-ics, a Guadalupe Landfill division.
The Worm Concern. The Worm Concern, a privately-owned, Simmi Valley, Calif.-based company, uses the vermiculture method, or worm farming, to process wood wastes.
This method uses a system which reportedly eliminates odors, resists pests and provides soil products that are marketed as soil amendments and topsoil blends. In addition, the company markets worm castings and bins for home composting and recycling residential yard debris.
Education is the company's focal point. For example, "Worms Go To School," an outreach program targeted at more than 50 schools, features an interpretive education specialist who presents complete worm bins and educational activities.
Monroe County, N.Y. The county provides a service whereby leaves are applied to local farms. Operated through a contract with the Cornell Cooperative Extension Service, the county acts as an intermediary be-tween local collection programs and farmers accepting the leaves.
A modified manure spreader is a-vailable to farmers who want to ap-ply the leaves directly to land. This practice has been successful be-cause it reduces capital investments and site management.
The Greater Cleveland Ecology Association (GCEA). To increase recycling efforts, Cleveland communities, local conservation groups and the Ohio State University Extension Service created this non-profit association. Participating municipalities pay a one-time membership fee and a tipping fee is charged at the gate.
GCEA uses a trapezoidal or "spacious windrow" system, which is a cross between the static pile and the turned windrow. The trapezoidal method places the ground material in a flat-top pile approximately 175 feet wide and 375 feet long by eight to 10 feet high.
This system reportedly conserves space by reducing the number of in-dividual windrows over a certain area. With less surface area exposed, odors are suppressed and compost remains active inside the pile. Since the flat top absorbs more precipitation, less run-off is produced and more moisture is retained.
SKB Environmental. Located in Minnesota's Twin City region, SKB Environmental is the state's largest yard waste processing service. The company composts brush, leaves and grass clippings and grinds brush and other wood wastes into landscaping mulch at facilities throughout the St. Paul region.
SKB's static pile composting process uses conveyer systems and tub grinders to aerate materials while also mixing in a precise amount of leaves and brush. In addition, SKB works with regulators and legislators as well as the local community for educational and outreach programs.
Pinellas County, Fla. Pinellas County, Florida's smallest and most populous county, has formed a co-operative effort between the St. Petersburg Sanitation Department, the Pinellas City Department of Solid Waste Management, Pinellas County Cooperative Extension Services, the University of Florida Institute of Food and Agricultural Sciences and 11 municipalities. To comply with the state's ban on landfilling yard waste, the county manages its wood waste, which represents 22 percent of the waste stream, at its Solid Waste Management Facility.
Pinellas County conducted a two- year pilot study to demonstrate how yard waste can be processed into mulch. A state grant funded labor expenses, windrow processing e-quipment, the disposal of reject ma-terials and mulch distribution. The study recommended the county contract the grinding services.
The Pinellas facility uses a "win-drow location board" to track the temperature, moisture and turning dates of the material as well as an on-site map of windrow locations. The county uses a computer to de-termine the amount of wood waste processed and delivery locations.
With a compliance rate of nearly 100 percent, Pinellas County attrib-utes its success to the compost distribution program. The county distributes compost material to home- owners, landscapers and municipalities throughout the county free of charge. It also operates a county-wide mulch hotline and will deliver material for no charge.
The county's mulch is used as a landscape border along a 47-mile trail and to beautify interstate medians. Unprocessable compost material is used on-site for roads, erosion control and landfill cover.
Rainier Wood Recyclers. The search for cost-efficient alternatives to landfilling, as well as outdoor bur-ning restrictions, has led to the de-velopment of Rainier Wood Rec-yclers, Kent, Wash.
In addition to grinding wastes at their two facilities, the company also offers mobile, on-site grinding for land clearing jobs.
At Rainier's facilities, the wood waste is processed with a grinder that uses a pan and disc refiner; 12 various-sized screens along the bottom and outside of the turning pan allow rock and metal to fall through without the contaminants contacting the cutting disc. Rainier also uses flexible processing equipment so that the end products can change according to market needs.
GreenCycle of the Northeast. In Newington, Conn., GreenCycle of the Northeast Inc. operates three composting facilities and two yard waste transfer stations. With a 100,000-tons-per-day capacity, the facilities serve municipalities, private haulers and landscape contractors throughout central Connecticut.
GreenCycle Inc. finances companies that provide yard waste composting services to municipalities, waste haulers and landscape contractors.
At the Hartford Transfer Station, West Hartford, Conn., leaves, grass clippings and brush are delivered by city collection vehicles and private haulers for transfer to a GreenCycle composting facility, or are processed on-site as compost or mulch.
GreenCycle Inc. uses mobile e-quipment including a specially de-signed screener which uses a screen shaped like a television satellite antenna, reportedly half the size of conventional screeners.
Trees Inc. Trees Inc., Houston, manages wood waste for the right of way clearing activities of Houston Power and Light. To minimize hauling costs, Houston Power and Light pre-processes the smaller land clearing debris and deposits it at five lo-cations throughout Houston. Trees Inc. then picks up the material from these satellite sites and delivers it to their Houston processing facility.
The company sells their processed material to a paper mill for fuel.
Prince George County, Md. In 1989, Prince George County developed a yard waste recycling program in response to the county's "Right to Recycle" legislation. As a result, two sites were selected to process yard and wood waste into compost.
Once the material arrives on-site, the bags are separated and the ma-terial is ground and screened. After processing, the materials are off-loaded from the live floor trailers into windrows on the pad. During Jan-uary, Scarab windrow turners are used to turn the material approximately once a month. In April, the windrows are turned one to two times a week to help the composting process.
The county and Maryland En-vironmental Service (MES) signed an Inter-Governmental Agreement to manage the facility. MES is a quasi-private state agency that contracts with both public and private entities. MES markets and sells the processed material under the trade name "Leafgro." Any remaining wood chips are sold to mulch producers or donated to civic groups to use for playgrounds on trails.