As the importance of recycling becomes more apparent, questions about it linger. Is it worth the effort? How does it work? Is recycling waste just going into a landfill in China?
Since 1960 the amount of municipal waste being collected in America has nearly tripled, reaching 245m tonnes in 2005. According to European Union statistics, the amount of municipal waste produced in western Europe increased by 23% between 1995 and 2003, to reach 577kg per person.
As the volume of waste has increased, so have recycling efforts. In 1980 America recycled only 9.6% of its municipal rubbish; today the rate stands at 32%.
A similar trend can be seen in Europe, where some countries, such as Austria and the Netherlands, now recycle 60% or more of their municipal waste. Britain’s recycling rate, at 27%, is low, but it is improving fast, having nearly doubled in the past three years.
Studies that look at the entire life cycle of a particular material can shed light on this question in a particular case, but WRAP decided to take a broader look.
It asked the Technical University of Denmark and the Danish Topic Centre on Waste to conduct a review of 55 life-cycle analyses, all of which were selected because of their rigorous methodology.
The researchers then looked at more than 200 scenarios, comparing the impact of recycling with that of burying or burning particular types of waste material. They found that in 83% of all scenarios that included recycling, it was indeed better for the environment.
Recycling has many other benefits, too. It conserves natural resources. It also reduces the amount of waste that is buried or burnt, hardly ideal ways to get rid of the stuff.
But perhaps the most valuable benefit of recycling is the saving in energy and the reduction in greenhouse gases and pollution that result when scrap materials are substituted for virgin feedstock.
“If you can use recycled materials, you don’t have to mine ores, cut trees and drill for oil as much,” says Jeffrey Morris of Sound Resource Management, a consulting firm based in Olympia, Washington.
Extracting metals from ore, in particular, is extremely energy-intensive. Recycling aluminium, for example, can reduce energy consumption by as much as 95%.
Savings for other materials are lower but still substantial: about 70% for plastics, 60% for steel, 40% for paper and 30% for glass. Recycling also reduces emissions of pollutants that can cause smog, acid rain and the contamination of waterways.
Originally kerbside programmes asked people to put paper, glass and cans into separate bins. But now the trend is toward co-mingled or “single stream” collection.
About 700 of America’s 10,000 kerbside programmes now use this approach, says Kate Krebs, executive director of America’s National Recycling Coalition.
But the switch can make people suspicious: if there is no longer any need to separate different materials, people may conclude that the waste is simply being buried or burned.
In fact, the switch towards single-stream collection is being driven by new technologies that can identify and sort the various materials with little or no human intervention. Single-stream collection makes it more convenient for householders to recycle, and means that more materials are diverted from the waste stream.
San Francisco, which changed from multi to single-stream collection a few years ago, now boasts a recycling rate of 69%—one of the highest in America. With the exception of garden and food waste, all the city’s kerbside recyclables are sorted in a 200,000-square-foot facility that combines machines with the manpower of 155 employees.
The process begins when a truck arrives and dumps its load of recyclables at one end of the building. The materials are then piled on to large conveyer belts that transport them to a manual sorting station.
There, workers sift through everything, taking out plastic bags, large pieces of cardboard and other items that could damage or obstruct the sorting machines.
Plastic bags are especially troublesome as they tend to get caught in the spinning-disk screens that send weightier materials, such as bottles and cans, down in one direction and the paper up in another.
Next, a magnet pulls out any ferrous metals, typically tin-plated or steel cans, while the non-ferrous metals, mostly aluminium cans, are ejected by eddy current.
As the aluminium cans are carried over this drum by a conveyer belt, the magnetic field from the rotor induces circulating electric currents, called eddy currents, within them.
This creates a secondary magnetic field around the cans that is repelled by the magnetic field of the rotor, literally ejecting the aluminium cans from the other waste materials.
Finally, the glass is separated by hand into clear, brown, amber and green glass. For each load, the entire sorting process from start to finish takes about an hour, says Bob Besso, Norcal’s recycling-programme manager for San Francisco.
The practice of shipping recyclables to China is controversial. Especially in Britain, politicians have voiced the concern that some of those exports may end up in landfills.
Many experts disagree. According to Pieter van Beukering, an economist who has studied the trade of waste paper to India and waste plastics to China: “as soon as somebody is paying for the material, you bet it will be recycled.”
In fact, Dr van Beukering argues that by importing waste materials, recycling firms in developing countries are able to build larger factories and achieve economies of scale, recycling materials more efficiently and at lower environmental cost.
He has witnessed as much in India, he says, where dozens of inefficient, polluting paper mills near Mumbai were transformed into a smaller number of far more productive and environmentally friendly factories within a few years.
The Chinese government has banned such practices, but migrant workers have spawned a mobile cottage industry that is difficult to wipe out, says Aya Yoshida, a researcher at Japan’s National Institute for Environmental Studies who has studied Chinese waste imports and recycling practices.
Because this type of industry operates largely under the radar, it is difficult to assess its overall impact. But it is clear that processing plastic and electronic waste in a crude manner releases toxic chemicals, harming people and the environment—the opposite of what recycling is supposed to achieve.
Far less controversial is the recycling of glass—except, that is, in places where there is no market for it. Britain, for example, is struggling with a mountain of green glass.
It is the largest importer of wine in the world, bringing in more than 1 billion litres every year, much of it in green glass bottles. But with only a tiny wine industry of its own, there is little demand for the resulting glass.
Instead what is needed is clear glass, which is turned into bottles for spirits, and often exported to other countries. As a result, says Andy Dawe, WRAP‘s glass-technology manager, Britain is in the “peculiar situation” of having more green glass than it has production capacity for.
Britain’s bottle-makers already use as much recycled green glass as they can in their furnaces to produce new bottles. So some of the surplus glass is down-cycled into construction aggregates or sand for filtration systems. But WRAP‘s own analysis reveals that the energy savings for both appear to be “marginal or even disadvantageous”.
Working with industry, WRAP has started a new programme called GlassRite Wine, in an effort to right the imbalance. Instead of being bottled at source, some wine is now imported in 24,000-litre containers and then bottled in Britain.
This may dismay some wine connoisseurs, but it solves two problems, says Mr Dawe: it reduces the amount of green glass that is imported and puts what is imported to good use. It can also cut shipping costs by up to 40%.
If done right, there is no doubt that recycling saves energy and raw materials, and reduces pollution. But as well as trying to recycle more, it is also important to try to recycle better. As technologies and materials evolve, there is room for improvement and cause for optimism. In the end, says Ms Krebs, “waste is really a design flaw.”
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