In the quest for alternative sources of energy, domestic wastewater-human sewage-is becoming an electricity magnet for researchers. In particular, gases and other waste products extracted from the wastewater treatment processes are being studied as means to generate electricity--by inclusion in fuel cells, by turning generators, etc. The objective is not confined to powering a treatment plant, but extends to adding electricity to the grid.
Even the mere flow in sewers is being looked at for production of hydro power. One inventor has come up with the idea of placing a small generator in a house sewer pipe. When a toilet is flushed, electricity would be generated to light the house or television set. However, such a concept may be practicable only during television commercial breaks or Super Bowl half time.
One researcher has estimated that one gallon of wastewater contains enough energy to light up a 100 watt bulb for 5 minutes. Unfortunately, federal law will prohibit production of 100 watt light bulbs after 2011.
Waste to energy is not a new idea. In the frontier west. pioneer homesteaders heated and cooked by burning buffalo chips. I recall a grade school science experiment by which electricity was produced from a potato. Now that the federal government wants to prohibit or limit the serving of potatoes in government subsidized school lunch programs, perhaps potatoes could be used to generate electricity for the grid instead of the griddle.
Using wastewater as an energy source perhaps should be tempered by some reality. It takes energy to build and operate a wastewater treatment plant and tributary sewer mains. Perhaps a more efficient wastewater energy source is the old fashioned outhouse. It requires minimal energy to build. While it does not generate electricity, it also does not use electricity. By saving electricity, it reduces demand on the grid. Has technology gone full circle?
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