Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, May 13, 1990 TAG: 9005100560
SECTION: BUSINESS PAGE: BUS-1 EDITION: METRO
SOURCE: BARNABY J. FEDER THE NEW YORK TIMES
DATELINE: LENGTH: Long
But environmentalists say the new technology still falls short of conquering on its own a problem that has become one of the nation's most notorious.
Everyone agrees that the most environmentally sound way to deal with a used tire is to retread it.
But that only temporarily staves off the day when the tire is too damaged or worn to be safely renovated.
Last year, according to government estimates, American drivers threw out 279 million tires.
Those tires joined 2.5 billion to 3 billion already choking landfills and blighting roadsides, vacant lots and riverbanks, where they attract disease-carrying mosquitoes and pose fire hazards.
The dumping occurs even though improvements have been made in systems that shred tires for re-use or better disposal in landfills, in processes that burn tires as a fuel in place of coal, oil or wood, and in breaking up old tires into raw materials.
Those materials can then be used in new rubber and plastic products or as substitutes for concrete in road paving.
The problem: none of the recycling methods have been attractive enough economically even to keep up with newly disposed tires, much less make a dent in the existing mountain of scrap tires.
"It is simply cheaper to throw them away than to recycle," Rep. Esteban Torres, D-Calif., said in a bill filed in February to encourage tire recycling.
The Torres bill and a similar measure in the Senate set out to change that economic balance.
They would force the tire industry to recycle about a quarter of its products - and to increase that figure by about 5 percent annually - or buy "permits" from others who run tire-recycling programs.
Tire producers would get twice as much credit toward their quota, under the legislation, for tires that are recycled into new products and for tires burned as fuel.
It is easy to see why backers of the bill feel that government intervention is needed.
Tires have been getting more complicated as manufacturers tinker with their design and composition to improve performance.
In addition to natural and synthetic rubber, tires may now incorporate a wide range of chemicals, minerals, natural fibers and metals.
No one wants to tell the manufacturers to stop improving tires.
But each change seems to have added to the technical challenge of efficiently burning the tires or, better yet, breaking them down into components that can be re-used.
The machinery required to separate materials and cut the tire down to "crumb rubber" or even smaller salt-sized grains for easy reprocessing into new products can easily cost $2 million or more.
When rubber is further reduced to particles the size of those in talcum powder, it can be cooked with various oils in devices known as digesters to make a polymer that can be easily molded into a wide variety of products.
That expensive process, known as reclaiming, was used at more than 30 plants as late as the 1960s.
But as tires became more complicated, tire companies shut down their reclaiming operations, and only two independents survive.
"It's pretty much a lost art," said Michael Rouse, president of Rouse Rubber Industries of Vicksburg, Miss.
But as interest in tire recycling grows, more and more machinery companies are attempting to improve shredding and related equipment.
And start-up concerns like Phoenix Technologies Inc., which is based in Jacksonville, Fla., are working on new designs in the hope of sharply reducing operating costs.
Phoenix's approach relies on standard chopping and steel recovery equipment to produce halves of passenger tires that can be flattened under 1,000 pounds of pressure, then fed into a rotating drum with carbide-alloy teeth that mesh with teeth on a base plate.
Phoenix says that on the first pass its shredder can cut 350 tires an hour into 3/8-inch pieces, a size that requires multiple trips through most existing shredders (or one trip through a sequence of shredders).
The shredder will be coupled with other equipment, such as demagnetizers to remove metal, cyclones to blow fibers like nylon out of the mix and granulators for further shredding.
Even when rubber is finally separated from other tire components, a major hurdle remains for those who want to recycle it.
In making tires, rubber is strengthened in a heat-intensive process known as vulcanization that links strands of rubber with sulfur bonds.
No one has figured out a simple, environmentally acceptable method to break those links.
That drastically limits the ability of recycled rubber to bond with new rubber or other materials.
"Trying to use rubber again is like trying to grind up old bread into flour and then baking a new loaf from it," said John Zimmer, a business and technology analyst at Goodyear Tire & Rubber Co.
While a number of entrepreneurs have proclaimed breakthroughs in processing that allow them to use high proportions of reclaimed rubber in new plastic products, they have stumbled on their way to market.
Rubber Research Elastomerics Inc. of Minneapolis persuaded public and private investors to put up nearly $10 million for a recycling plant in northern Minnesota to make the granular "crumb rubber" it needed to produce a material it calls Tirecycle, for a number of household and industrial uses.
But the plant functioned poorly, piled up heavy losses and was surrendered last autumn to the local county government.
Small amounts of Tirecycle are being produced for Elastomerics at a plant in Wadsworth, Ohio.
Similarly, RW Technology Inc. of Cheshire, Conn., has had trouble getting its Typlax out of the starter's gate.
It has demonstrated that the material - which consists of reclaimed rubber that has been chemically altered so that its surface bonds well with plastics - can be used to make products like carpet backing that is two-thirds recycled tires.
But RW has yet to show it can reliably produce Typlax in significant quantities.
Recycling experts say such products may well succeed, but only when they attract both manufacturing and marketing expertise.
And success is likely to come in a series of niche markets that may not have a major effect on the overall disposal problem.
"People like RW have tried to sell this as a commodity, like rubber itself," said Greg Koski, president of Phoenix Resources Ltd. of Leominster, Mass., who developed Typlax under a research contract with RW.
"But it's more like an engineered plastic that requires a sharp strategic marketing plan with plenty of technical help for each customer in fine tuning the formulation and developing methods for processing it into products."
Tire companies say that using scrap tires as a "sweetener" to improve the quality of fuel used in a boiler makes sense because their energy value per pound is higher than coal's.
While expensive scrubbers are needed to cope with the air emissions from burning tires, some users, like cement companies, can use many of the metals and other unburned components in their products.
The most ambitious effort to date to use tires as fuel is at Oxford Energy Corp.'s power-generating station outside Modesto, Calif., which burns up to 5 million tires annually, producing 100 kilowatts of electricity - enough to power 15,000 homes.
The plant burns whole tires.
But it has experienced repeated problems with its system for feeding tires into the boiler and shutdowns to deal with accumulations of slag on the boiler walls that interfered with thorough burning.
It operated at a loss last year despite receiving 8.5 cents a kilowatt hour from Pacific Gas & Electric Co., about five times what it would cost the utility to generate that electricity from steam plants fired by natural gas.
Oxford, based in Santa Rosa, Calif., is confident it can cut costs and improve efficiency with new plants.
It is building a larger plant in Sterling, Conn., and plans several others.
Those who believe that burning tires is nearly as environmentally shortsighted as dumping them see rubber-based road pavement as the best hope for creating a mass market for recycled tires.
Rubber-based asphalt costs 40 percent more than concrete, but can be laid more thinly and saves money in the long run because it lasts up to three times as long, said the Rubber Asphalt Producers Group, a Phoenix-based trade association.
It estimates that 45,000 tons of rubber - about six million tires' worth - went into roads last year.
If 25 percent of the nation's annual paving work used rubber asphalt, 200 million scrap tires annually would be consumed, said Russell Schnormeier, the group's technical director.
Demand is growing steadily, but proponents of rubber asphalt need to reduce the price differential, develop equipment that makes it easier to store and apply their product, and overcome a legacy of quality problems.
They also have to overcome powerful opposition from traditional paving contractors, some of which fear a decline in business if pavement lasts longer, and the wariness of state highway officials about paving roads with proprietary products instead of standard concrete-asphalt.
by CNB