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Getting people to recycle isn’t always easy. The bottled beverages we buy at the supermarket often require a small deposit that we can get back by recycling the bottle, but often, we just don’t.

Researchers from the University of British Columbia tested the idea of giving people returning bottles a small chance of winning a big cash prize instead of a 10-cent deposit return. The result was that people recycled 47% more bottles.

Changing how we reward recycling made a big difference. When given a choice between a guaranteed return and a possible large reward, many chose the lottery option. When people were randomly assigned to one type of reward or the other, those in the lottery group brought in almost three bottles for every two returned by the other group.

This isn’t a new idea. Norway has a recycling lottery, and their bottle return rate is close to 100 percent. The way it works there is there are reverse vending machines in grocery stores all over the country. The revenues generated by the machines is split in four ways: 34.5% of the gross revenue goes to the Red Cross; 35% goes to the people who bring in their bottles in the form of winnings in the lottery; 9.75% goes to the stores for managing the machines and the lottery; and 10.75% goes to the operating company of the Recycling Lottery.

The Canadian experiments demonstrate that a recycling lottery could be effective in more places than Norway. However, it shouldn’t completely replace the guaranteed refund option, since some people depend on it for income.

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How lottery-style bottle returns could transform recycling

Photo, posted July 9, 2011, courtesy of Mr.TinMD via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Engineers at MIT have created a superabsorbent material that can soak up significant amounts of moisture from the air, even in desert-like conditions.

The material is a transparent, rubbery substance made from hydrogel, which is a naturally absorbent material that is already widely used in disposable diapers. The MIT researchers enhanced the absorbency of hydrogel by infusing it with lithium chloride, which is a type of salt that is a powerful desiccant.

They found that they could infuse hydrogel with more salt than was possible in previous studies. Earlier studies soaked hydrogels in salty water and waited 24 to 48 hours for the salt to infuse into the gels. Not much salt ended up in the gels and the material’s ability to absorb water vapor didn’t change much. In contrast, the MIT researchers let the hydrogels soak up the salt for 30 days and found that far more salt was absorbed into the gel. The result was that the salt-laden gel could then absorb and retain unprecedented amounts of moisture, even under very dry conditions.

Under very dry conditions of 30% relative humidity, the gels captured 1.79 grams of water per gram of material. Deserts at night have those levels of relative humidity, so the material is capable of generating water in the desert.

The new material can be made quickly and at large scale. It could be used as a passive water harvester, particularly in desert and drought-prone regions. It could continuously absorb water vapor from the air which could then be condensed into drinking water. The material could also be used in air conditioners as an energy-saving, dehumidifying element.

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This salty gel could harvest water from desert air

Photo, posted July 26, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A recycling lottery

Getting people to recycle isn’t always easy. The bottled beverages we buy at the supermarket often require a small deposit that we can get back by recycling the bottle, but often, we just don’t.

Web Links

Harvesting Water From The Air | Earth Wise

Engineers at MIT have created a superabsorbent material that can soak up significant amounts of moisture from the air, even in desert-like conditions.

Web Links