In Stockholm, a new system was introduced with great fanfare a few years back. The old trash chutes in private homes were modified by the addition of a plastic partition wall to accept only newspaper (right) or paper (left). Kitchen waste went into the new pneumatic chute on the bottom floor. Everything else (glass, plastics) went into the boxes on the street, except for those things that went into the 'environment cottage' in the yard. Proud banners with a grand sunrise proclaimed: "Recycling: for your children’s and their children’s future!"

A seemingly perfect solution—except for the fact that the street-side collectors tended to overflow. They attracted rats and posed a fire hazard. The plastic separator of the chute system often suffered damage as bundles of newspapers fell along it for fourteen stories, mixing up the paper types. The pneumatic chute only worked with the neatly biodegradable paper bags delivered by the project, not the 'ecofriendly' paper bags from the store. The mess in the environmental cottage first led to its temporary closure, and when enough junk begun to pile up around it, to hiring a man to guard it during very restricted 'open' hours.

When criticized, those involved in the project defended it strongly, arguing that even if it did not fully work, it got people thinking about their trash and that it would hopefully teach them to behave more green. That is no excuse for bad garbage handling or inefficient recycling. Sooty factory smoke might also get people thinking about the environment more than filtered smoke, but clearly the latter is more beneficial.

Recycling easily becomes a route to symbolic absolution—all that time spent sorting garbage somehow counteracts the sins of consumerism. The fact that the recycling program produces significant health hazards, overflows the neighborhood with trash whenever there is a holiday, and does not, in actuality, help the environment, becomes irrelevant. Only unbelievers, critics would say, think about such crass things.

'Single stream' recycling does not require you to be ecologically conscious. The machines do the work for you.

'Multi-stream' programs like this one, which ask consumers to put paper, glass, and cans into separate bins, have seldom been financially self-sustaining because the costs of collecting, transporting, and sorting materials generally exceed the revenues generated by selling the recyclables. Government subsidies are needed to keep the programs afloat.

Not surprisingly, then, the old-fashioned garbage bin is making a return. 'Single stream,' the hot topic in waste collection today, means one collection container for all types of recyclables, separate from all non-recyclable trash.

Single stream recycling means less work for consumers. Rather than laboriously separating all substances in the home (with people making costly mistakes) and taking up excessive space on the sidewalk, separation can increasingly be done at the processing plant. Materials are separated and processed and sold on end-markets. The waste separation has been improved by the adoption of new sorting technologies. Paper and plastic items are spread out on a conveyor belt in a single layer, and then spectroscopic sorters identify each type of material by its wavelength in the infra-red spectrum. When illuminated by a halogen lamp, each type of material reflects a unique combination of wavelengths in the infra-red spectrum that can be identified with an accuracy of up to 98 percent.

The biggest expense in recycling is the collection cost, so single stream makes recycling more feasible. It improves recycling rates, saves time and money, and achieves the vision expressed by Bruce Sterling: "Make the things do the Green thinking." With high energy costs, improved recycling will benefit industry. Compared to using new materials, recycling aluminum can reduce industry’s energy consumption by 95 percent, 70 percent for plastics, 60 percent for steel, 40 percent for paper, and 30 percent for glass.

Single stream programs are starting to catch on in the United States, with San Francisco shifting to single stream collection. San Francisco now boasts a recycling rate of 69 percent—one of the highest in America. Single stream programs might also benefit developing countries by importing waste. Indian companies in Mumbai were able to build large sorting facilities and achieve economies of scale with better efficiency and lower environmental costs.

Despite the benefits, opposition against single stream is considerable. The greatest resistance to technologically driven changes might come for ideological reasons. Multi-stream recycling requires that people are enthusiastic and involved, otherwise it will not work. Anything that forces people to change their habits or spend extra time, money, or energy will fail unless it is rigidly enforced. In Sweden, Germany, and the United Kingdom, for example, extreme methods such as spy cameras and "trash spies" were used to monitor recycling.

Single stream does not require you to be ecologically conscious; the machines do the work for you.

Waldemar Ingdahl directs Swedish Eudoxa, a think tank focused on emerging technology.

Image credit: photo by flickr user Bombardier.