Few issues make Americans more anxious than how to dispose of waste materials. Since Earth Day 1970, the desire to clean up America has been growing. Encouraged by support from the general public as well as many commercial interests, most environmental organizations have demanded a cleaner America and less wasteful use of its resources. In this climate of concern, lawmakers at the Federal, State, and local levels have proposed more than 3,000 pieces of legislation on recycling waste.

Each Year?60 Million Tons of Waste ×Ö´®1

What are we to do with the 160 million tons of municipal solid waste that we generate each year? Municipal solid waste—that is, postconsumer solid waste generated at residences, commercial establishments, and institutions—is something we all had a stake in producing.

The United States is running out of acceptable sites for landfills for municipal solid waste. Our Nation, which once had 18,000 landfills, now has only 6,000; in the year 2000, we anticipate a shortage of space for 54 million tons of waste products per year. There is an additional downward spin to this news: The data, and the problems they suggest, do not include industrial waste, waste from construction sites, or sludge from wastewater.

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Forest Product Waste: What Happens to It? ×Ö´®7

Disposal of the 84 million tons of paper and wood products annually consumed in the United States occurs in many ways. Of this, 58 million tons, mostly paper, goes to landfills—where it represents the largest component of municipal trash. Methods to reduce the amount of municipal forest product waste would have a good potential to reduce landfill space needed to dispose of trash.

Landfill. About 57 percent of all paper and wood products consumed in the United States is disposed of in landfills near cities. The waste is layered with a series of compact layers of dirt over a large area and left to decompose. That decomposition can be surprisingly slow. Studies of landfills have shown, for instance, that paper products are still readable after 20 years in a landfill.

Recycling. Another 25 percent of used paper and wood products is recycled. The material is collected, separated, stored, broken down chemically to fiber, and reprocessed to make new paper products. Recycled paper is usually a mixture of recycled and virgin fiber whose composition depends on the required properties of the final product. A wide variety of fiber products, from photocopier paper to boxboard, are made from recycled fiber.

Incineration. Eleven percent of paper and wood product wastes are burned. This burning converts wood to carbon dioxide and water with minimal residual ash and generates energy. ×Ö´®3

Export. The remaining 7 percent of our paper and wood waste is exported to other countries. The United States is the world's largest exporter of waste paper, with over half going to the industrialized countries of the Far East such as Taiwan, Korea, and Japan.

The Best "Use" of Waste Products ×Ö´®6

A look at this breakdown of how we dispose of our wood fiber wastes leads us to the next question: What's the best "use" of waste products? Even asking the question about the disposal of wastes in this way rests on a new way of thinking about waste materials. Now, it is assumed that a waste "product" has utility. ×Ö´®1

Saving space and reducing contamination of our natural resources are very important goals. If there is an economic incentive to reuse wood-fiber waste products, recycling will increase and less material will be sent to landfills. Another important side benefit is that there will be less landfill waste to contaminate the water systems.

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Conservation. If recycling were to increase, demand for timber would decrease substantially, and our timberlands could be conserved for other uses. Each year, discarded paper and wood products equal 86 million cords of pulpwood, or the annual harvest from almost 3 million acres of southern pine plantations.

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Economic Return. Recycling and exporting waste material for reuse returns economic benefits to the provider of the waste material as well as to the manufacturer of the product made from the waste material. ×Ö´®9

How Can Research Contribute?

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For researchers, two important areas of research focus are (1) recycling for better use of waste products and (2) more rapid decomposition of waste products in an environmentally sensitive way.

Recycling. Two great challenges facing the U.S. forest products industry are to find environmentally benign, low-cost recycling methods and to increase the number of products that can be made from waste-wood fiber. In a major commitment, the U.S. pulp and paper industry, through the American Paper Institute, has announced its goal of increasing recovery (recycled and exported waste paper) from 31 percent in 1988 to 40 percent in 1995. Research will help but available technology and recovery systems are not likely to achieve higher recovery rates. New methods will be needed to expand the recovery of waste paper beyond the 1995 goal of 40 percent. ×Ö´®5

Technology is needed for recycling paper and wood wastes into high-value products if recycling is to be economical on a widespread basis. Current recycling technology fills narrow product niches, such as tissue papers and toweling, and serves limited geographic areas. In order to develop the technology essential for expanding recycling possibilities, new research is needed in three areas—separation, cleaning, and alternative processes and products.

Separation. Research is needed on separating paper and wood waste from the municipal waste stream. This research will develop new mechanical sorting methods to reclaim paper and wood wastes, such as packaging materials and disposable diapers, from other urban garbage at incinerators and landfill sites. ×Ö´®1

Cleaning. Research is needed on cleaning separated paper and wood wastes. Current knowledge and technology limit the large-scale use of most paper waste to the production of relatively low-valued or colored paper products. New cleaning methods are needed to produce whiter, brighter pulps suitable for manufacturing a wide variety of high-valued paper products. Advances in this area would include:

• Development of new methods for cleaning fiber—removing inks, dyes, and other contaminants from waste paper—to make recycled pulps competitive with virgin market pulps.
• Development of pulp-bleaching technologies that are environmentally safe and appropriate for recycled fibers and urban environments.

Alternative Products and Processes. Research is needed to develop alternative products—such as structural products for furniture and housing components—that are capable of using paper and wood waste and the processes and facilities to produce them. ×Ö´®8

• Development of new products and processes to combine recycled wood fibers with other recycled materials such as plastics, glass, and metals, for example, to produce molded automobile parts from recycled wood fiber and plastic.
• Development of new forming and drying processes to use waste fiber in structural products and panels.
• Determination of methods to recondition used wooden pallets and to use pallets for fuel and fiber.
• Measurement of changes in fundamental structure and chemistry from recycling processes to improve the performance of recycled products.
• Development of new bonding concepts for wood fiber products so that these products will retain their strength when they are wet.
• Development of methods to convert organic wastes from recycling mills into fertilizer, energy, and other useful products.

Decomposition. Fortunately, wood-fiber waste materials decompose or degrade with time. Our need at the time of disposal, however, is to speed up this process. The rate of decomposition depends on landfill or water conditions such as temperature, moisture, oxygen level, and acidity. In theory, wood fiber waste should eventually decompose, but as the studies referred to earlier report, decomposition in landfills is not as quick as first thought. ×Ö´®5

Some of our successes in making wood last longer now add to the difficulties of speeding up that process at the end of its product life. Chemicals are sometimes added to wood-based materials so that the wood can remain in the ground or be exposed to the weather without degradation. For instance, wooden posts are often treated with pentachlorophenol to reduce the degradation of wood in the ground. The treated wood poses a problem for us: How do we now make this wood degradable?

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Enhancing Decomposition Rates ×Ö´®7

Redesigning Landfills. Researchers suggest that the decomposition rate of organic material can be enhanced by carefully changing the design of landfills. These landfill designs may incorporate such methods as the collection and recycling of leachate (water and dissolved chemicals) back into the landfill and the use of above-ground containment mounds and chemical and bacterial inoculation of landfills. ×Ö´®3

Biodegradation. One recent development has been the use of fungi to degrade wood fiber materials as well as to change hazardous organic chemicals into benign products. Fungi that degrade lignin, the binding material in wood, have been successfully used to degrade pentachlorophenol in soil contaminated with a commercial wood preservative product. ×Ö´®3

Research is needed to identify factors necessary to control the growth of lignin-degrading fungi to allow for optimum growth in landfill conditions. Further work is needed to understand the biochemistry of the fungal degradation and to identify those fungal strains that are most effective in degrading wood fibers in landfills. ×Ö´®1