Processor Cultivates Green Waste Market

Paul B. Harder

In 1968, the Porter family's Western Pine Industries' five sawmills were in trouble. The U.S. Environmental Protection Agency had outlawed teepee burning of sawmill waste, leaving many mills with a lot of sawdust and nowhere to put it. But where some people saw a problem, two teenage cousins, Doug and James Porter, saw an opportunity.

Initially, the family had attempted to sell the sawdust. But when that project failed, the cousins found that sawdust, blended with other ingredients, could easily sell as landscape mulch. Shortly after, the Arizona cousins created Western Organics, a green waste reduction and mulch distribution firm.

However, their successful incursion into the sawdust-based mulch market was not enough to save the family sawmills from the logging restrictions. The mills' closing also put an end to their primary source of fiber. To save their mulch business, and their jobs, they began to look for a new source.

The Porters located that source in the mid-80s, when the city of Phoenix opened its 27th Ave. Landfill adjacent to Western Organics' newly opened mulch facility. Local restrictions on green waste disposal in landfills created an instant fiber source for Western Organics. The Porters decided to offer low tipping fees and a dump site for the green wastes.

To quickly learn about the green wastes conversion, the cousins initially did not charge a tipping fee. At first, truckloads of green wastes often turned out to be camouflaged garbage. "It was a big problem," said James. "And to some extent, it still is with us. We never know what's going to come out of a truck." An intense education program by the city and load inspections by Western Organics crews have eased, but not eliminated, the problem.

Various types and sizes of fibrous wastes make processing more labor-intensive, expensive and slower than processing sawmill wastes, which still arrive in diminished volume from the few sawmills still operating.

An Infant Industry Western Organics not only processes the materials, it also searches for potential markets. "Linking green waste collection and processing to the international marketing and distribution of the products it produces is a new industry," said Doug Porter. "That's one of our problems. We're developing the parameters of our industry as we grow."

However, the two aspects are not blurred together. The prime function is to sell and distribute green waste-based soil amendments. The secondary function is to maintain an incoming flow of green waste at a cost and volume that meets the company's marketing requirements. Flow control and tipping fees are critical.

Reducing construction lumber, palm and citrus trees, lawn clippings and wooden pallets to a mulch that is useful requires large investments in grinding and screening equipment, much of which was still in the design phase five years ago. As recently as a year ago, a large amount of the green wastes coming into Western Organics' yard required two-step processing: pre-chipping waste over six inches in size, then a second grinding in tub grinders before final screening and blending.

If the material is pre-chipped, the tub grinders can reduce the material at 1,500 cubic yards per hour (plus the cost of pre-chipping). If un-chipped trees and stumps are fed to these grinders, production drops by over 50 percent, and grinder downtime skyrockets due to jams and overheating.

Hammermills, developed for the aggregate industry and modified for green wastes, reportedly can grind a wide range of materials. Western Organics operates two of them, one in Phoenix and the other adjacent to a sawmill in New Mexico; both are powered by 100-hp electric motors. However, immobility is the hammermills' drawback.

To satisfy its mulch sales, Western Organics needs to reduce approximately 10,000 cubic yards of waste per day. Their newest tub grinder, manufactured by Vermeer, processes a wide range of green wastes and can be moved quickly along the face of the waste piles and away from accumulated grinding spillage.

Installed on the front of the 37-foot dual-axle semi-trailer, a 402-hp Caterpillar 3406C DITA diesel engine drives through a triple disc clutch, turning a hammermill whose replaceable carbide-tipped teeth grind trees and stumps.

From a daily diet of trees, stumps and brush, it reportedly can produce 1,500 cubic yards of fine fiber, which is then mixed with soil, fertilizers, processed sludge and inert materials to produce 150 bags of mulch and amendment products.

Western Organics' cost of processing large green waste is $5 a ton, or two to four cubic yards, comparable to the cost of processing pre-chipped trees, lawn clippings and garden waste in smaller tub grinders.

Tipping fees, in addition to exercising green waste flow control, are a critical determinant of the marketability of the company's mulches. In Arizona, low tipping fees for garbage ($27 per ton) and for green wastes at landfills ($14) have forced the company to hold its tipping fee at $10 per ton to maintain waste volume. That's not enough to allow the price reductions necessary to sell in bulk to big volume agricultural markets, or to pay for shipping bagged product to high-return metropolitan markets, according to Doug.

"It's a Catch-22," he said. "We need higher tipping fees to open bigger markets. But if we raise our tipping fees, our supply of green waste goes elsewhere."

Eliminating low-cost landfill disposal of green wastes will give this young industry the boost it needs, he said. "When it costs between $6 and $7 per cubic yard to make mulch products - and recycled green waste makes up the bulk of these products - a $10 tipping fee from the green waste doesn't give us much help in lowering mulch prices," he said.