An infinitely renewable energy source: waste

Although the concept is hotly debated, sooner or later the world will run out of oil. It will take longer to run out of coal, but that, too, is not a renewable resource. Trees are renewable resources, but of course they have far more important uses than burning them for energy. We usually think of solar, wind, and geothermal power as renewable, but the US, anyway, produces so much garbage, sewage, and other waste that it raises the danger of running out of landfill space. Let's turn all that waste to energy.

Most waste disposal in the US happens either in landfills or incinerators, and no one particularly likes either one of them. In Greensboro, North Carolina, for example, residents of the area around the landfill finally succeeded in getting it closed to anything but construction rubble. The landfill was there before any of the houses, but in the days of segregation, blacks could not purchase property anywhere else. Now, the city must haul trash to a landfill in another county, which costs millions of dollars a year more than operating its own landfill.

Landfills themselves are non-renewable resources. They must have certain geological characteristics, which do not exist everywhere. One difference between an old-fashioned garbage dump and a modern landfill is that each day's trash must be covered with a layer of dirt to control odor and vermin. That means that it fills to capacity sooner. Meanwhile, because landfills also require a liner and the garbage in it is not exposed to air, lettuce that was just beginning to rot when it was thrown out years ago has not decomposed any more in the landfill.

So far, I have considered only household trash. Wastewater treatment plants take in raw sewage and return clean water to lakes and streams. Think of all the leftover solid sludge!  Industry produces its own waste. Waste from poultry and meat producers includes manure, which too often winds up on open-air lagoons, and billions of pounds of feathers.

There are lots of ways to turn our wastes from a problem to a resource. Here are just a few, some of which are becoming commonplace in other industrialized countries:

• Make the garbage and all those feathers into biodiesel. Use that to replace petroleum-based diesel. Of course, many other agricultural wastes can also become biodiesel. Households would have to keep "wet" garbage separate from "dry" garbage, as was normal as recently as 50 years ago.
• Turn household wastes into energy. The heat released by incinerating garbage works just as well as coal for boiling water, which is the normal way to generate electricity. It can also activate thermo-photovoltaic cells to generate additional electricity.
• Turn sewage sludge into ethanol. That will have the added benefit of turning corn back into a food source instead of a particularly costly and inefficient fuel source.
• Scientists are also exploring ways to make electricity from sludge.

There are so many ways to extract energy from waste (including waste heat from running appliances!) that there is no excuse to keep importing fossil fuels. American society needs to get past the increasingly mindless debates over global warming, climate change, where to drill to increase domestic oil supplies, and what kind of taxes to pay in order to make a transition to more environmentally friendly fuels. We need to get on with the urgent business of using our garbage problem to solve our fuel problem, regardless of whether we prefer Al Gore's rhetoric or Sarah Palin's.