Shrinking the Waste Stream
Compared to landfilling and incineration, recycling saves money, energy, raw materials, and land space, and it reduces pollution. Recycling, as the term is used in solid waste management, is the reprocessing of discarded materials into new products. Sometimes the same products are remade: old aluminum cans and glass bottles are usually melted and recast into new cans and bottles, lead from car batteries can be made into new batteries. Sometimes entirely new products are made. Old tires, for instance, are shredded and turned into rubberized playground or road surfacing. Newspapers become cellulose insulation, and steel cans become new automobiles and construction materials.
There have been some dramatic successes in recycling in recent years. Nationally, the United States recycles or composts one-third of municipal solid waste. Minneapolis and Seattle claim a 60 percent recycling rate, something thought unattainable a decade ago. San Francisco is aiming for 100 percent recycling. Residents are now required to separate recyclables, compostables, or trash, in order to aid this effort. All this recyling makes good environmental sense, but it also saves San Francisco the cost of waste disposal.
Recycling Continues to Face Challenges
Aluminum is probably the easiest and most valuable material to recycle. The lightweight, high-value scrap can be reused for thousands of purposes. Still, only half of aluminum cans are recycled in the United States. This rate is up from only 15 percent 20 years ago, but Americans still throw away nearly 350,000 metric tons of aluminum beverage containers each year. That is enough to make 3,800 Boeing 747 airplanes. This is especially unfortunate because producing new aluminum is extraordinarily energy intensive, while recycling is relatively easy.
Wild fluctuations in commodity prices are a challenge in developing a market for recycled materials. Newsprint, for example, cost $160 a ton in 1995; by 1999 it dropped to just $42 per ton and then climbed to $650 per ton in 2009. Low prices for new materials is also an obstacle. New plastic, made from oil, is usually cheaper than the cost of collecting and transporting used plastics (when the cost of disposal and other expenses are not considered). Consequently, less than 7 percent of the United States’ 30 million tons of plastic waste is recycled each year. Contamination is a major obstacle in plastics recycling. Most plastic soft drink bottles are made of PET (polyethylene terphthalate), which can be re manufactured into carpet, fleece clothing, plastic strapping, and nonfood packaging. However, even a trace of vinyl—a single PVC (polyvinyl chloride) bottle in a truckload, for example—can make PET useless. Because single-use beverage containers are so costly to recycle, they have been outlawed in Denmark and Finland.
The growing popularity of bottled water is producing a serious waste disposal problem. Of the 300 billion bottles of water consumed each year globally, less than 20 percent are recycled. It takes around 75 billion liters (500 million barrels) of oil to manufacture and ship these bottles. In most American cities, tap water is safe and is subjected to more rigorous testing than bottled water. The best way to control this problem is through bottle deposits. States with deposit laws recover about 78 percent of all beverage containers, while those without generally have recycling rates of 20 percent or less.
Recycling Saves Money, Energy, and Space Curb side pickup of recyclables costs around $35 per ton, as opposed to the $80 paid to dispose of them at an average metropolitan landfill. Many recycling programs cover their own expenses with materials sales and may even bring revenue to the community. Recycling also encourages individual awareness and responsibility for the refuse produced. Recycling drastically reduces pressure on landfills and incinerators. Philadelphia is investing in neighborhood collection centers that will recycle 600 tons a day, enough to eliminate the need for a previously planned, high-priced incinerator. New York City, down to one available landfill but still producing 27,000 tons of garbage a day, set a target of 50 percent waste reduction to be accomplished by recycling office paper and household and commercial waste. In 2002 Mayor Michael Bloomberg discontinued most recycling, arguing that the program was too expensive. The city quickly found that disposing of waste was more expensive than recycling, and most programs were reinstated.
Japan probably has the most successful recycling program in the world. Half of all household and commercial wastes in Japan are recycled, while the rest are about equally incinerated or landfilled. The country has begun a push to increase recycling, because incineration costs almost as much. Some communities have raised recycling rates to 80 percent, and others aim to reduce waste altogether by 2020. This level of recycling takes a high level of participation and commitment. In Yokohama, a city of 3.5 million, there are now 10 categories of recyclables, including used clothing and sorted plastics. Some communities have 30 or 40 categories for sorting recyclables.
Recycling lowers demand for raw resources. The United States cuts down 2 million trees every day to produce newsprint and paper products, a heavy drain on its forests. Recycling the print run of a single Sunday issue of the New York Times would spare 75,000 trees. Every piece of plastic made in the United States reduces the reserve supply of petroleum and makes the country more dependent on foreign oil. Recycling 1 ton of aluminum saves 4 tons of bauxite (aluminum ore) and 700 kg of petroleum coke and pitch, as well as keeping 35 kg of aluminum fluoride out of the air.
Recycling also reduces energy consumption and air pollution. Plastic bottle recycling could save 50 to 60 percent of the energy needed to make new ones. Making new steel from old scrap offers up to 75 percent energy savings. Producing aluminum from scrap instead of bauxite ore cuts energy use by 95 percent, yet the United States still throws away more than a million tons of aluminum every year. If aluminum recovery were doubled worldwide, more than a million tons of air pollutants would be eliminated every year. Reducing litter is an important benefit of recycling. Ever since disposable paper, glass, metal, foam, and plastic packaging began to accompany nearly everything we buy, these discarded wrap- pings have collected on our roadsides and in our lakes, rivers, and oceans. Litter is a costly as well as unsightly problem. Americans pay an estimated 32¢ for each piece of litter picked up by crews along state highways, which adds up to $500 million every year. “Bottle bills” requiring deposits on bottles and cans have reduced littering in many states.
Composting recycles organic waste
Pressed for landfill space, many cities have banned yard waste from municipal garbage. Rather than bury this valuable organic material, they are turning it into a useful product through composting: biological degradation or breakdown of organic matter under aerobic (oxygen-rich) conditions. The organic compost resulting from this process makes a nutrient-rich soil amendment that aids water retention, slows soil erosion, and improves crop yields.
Many cities and counties provide centralized composting, to help people keep compostables out of the municipal waste stream. You can also compost your own organic waste. All you need to do is to pile up lawn clippings, vegetable waste, fallen leaves, wood chips, or other organic matter in an out-of-the way place, keep it moist, and turn it over every week or so. Within a few months, naturally occurring microorganisms will decompose the organic material into a rich, pleasant-smelling compost that you can use to enrich your yard or garden.
As noted in the opening case study, some composting systems produce methane fuel. Worldwide, at least one-fifth of municipal waste is organic kitchen and garden refuse. In developing countries up to 85 percent of the waste stream is food, textiles, vegetable
matter, and other biodegradable materials.
Methane is captured from this material at many landfills, but it’s much more efficient to convert organic waste to methane in a contained, anaerobic digester. Germany and Switzerland now have at least 30 municipal-scale waste-to-methane plants. Anaerobic digestion also can be done on a small scale. Millions of household methane generators provide fuel for cooking and lighting for homes in China and India. In the United States some farmers produce all the fuel they need to run their farms—both for heating and for running trucks and tractors—by generating methane from animal manure.