Hey Mr. Green:
What about recyclable plastic food tubs? I use hot water and detergent to get them ready to recycle, and I'm feeling guiltier and guiltier. Since I don't use many, that's a lot of heating water just for one item. Surely that's worse than putting them in landfill to break down over the decades?
—Karen, in Malvern, UK
Have you considered addressing this crisis of conscience simply by using cold water? It works for me.
But in any case, don’t worry even if you do use hot water. It would still be quite worthwhile to recycle these containers provided you don’t dump too much hot water in them. Consider, for example a typical food container like a one-quart yogurt tub made of #5 plastic, aka polypropylene. It requires around 1,500 British thermal units just to make the plastic resin for this container, according to calculations based on a recent energy study by the American Chemical Council. By contrast, you only need about a fifth as much energy to heat a quart of water to 140 degrees with a tank water heater (and less with an “on-demand” heater). So unless you’re using more than a whole gallon of really hot water for that one measly container, you can get by with a lot less energy than it takes to make a new one. Plus, when plastic makers use recycled plastic, it can cut their energy use almost in half because they don’t have to concoct the stuff from scratch. So even if you do use a gallon of water, there would still be a net savings of energy. (Similar levels of energy conservation also result from recycling other types of plastic.)
The energy needed to make detergent should even less of source of remorse unless you’re slathering it on like a gourmand deploying gravy. Most dishwashing energy, whether by hand or machine, is dedicated to heating the water. For example, if you use a dishwashing machine, the detergent’s contribution to the device’s total energy use is less than 10% of the amount that goes to heating its water and powering its motor.
By the way, scientific studies have revealed that mechanical dishwashers use less energy and water than hand-washers of china and flatware and recyclable plastic. While it hurts terribly to see man go up against the machine and lose—like when the great chess master Gary Kasparov challenged IBM’s Deep Blue computer and went down to defeat—my own overactive environmental conscience forces me to present this discovery.