Microwave toilets

Updated September 19, 2009

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New for October 2009! Now that the Cold War is over, microwave toilet research has been fully declassified. Just kidding, this crap(per) was meant to be a commercial product!

There are several patent examples of using microwave energy to incinerate waste, this one is US Patent 5,276,924, Method and Apparatus for Disposing of Body Wastes. In many places there is no access to water for sanitation, and there is a real need for toilets that can render "substances" safe. Beyond the outhouse and latrine technologies (thanks to the French language for providing soldiers a name for an important hole in the ground), there have been commercially successful non-water systems in two categories: composting, and electrical incineration of wastes.

Composting toilets boast that the waste can be used as a nutrient-rich fertilizer. In practice, you can start a garden without buying any seeds, if your diet is rich in raw vegetables. Just sprinkle the compost in the yard and watch tomato plants spontaneously spout. We're not sure we'd eat a tomato whose seeds passed through a random family member...

Electrical toilets, affectionately known as turd-burners, have at least a psychological advantage, as the waste is cooked enough to kill any organisms in it. Here, microwave technology seems to be misplaced. Sure, you can cook stuff quickly with microwaves, but a lot depends on the dielectric properties of the material. In the referenced patent, you have to drop in some absorbing material (find 17 in the sketch) to dry the waste (think "cat litter". The patent mentions that the absorbing material can be collected and reused. We'd hate to have to argue over who's chore that going to be.

This might sound sacrilegious, but were inclined to think that a simple resistive heating element (like a toaster) is a better idea than trying to use microwave energy in this application. A heating element would provide better system efficiency, because none of the power would be wasted in a high-voltage power supply.

Many people think that microwave heating has some magical property where it is much more efficient than a mere heating element. Not true! A small heating element on a stove can burn 1200 watts, if you craked it on high. But you usually leave it on