Tuesday, June 27, 2006


I am in love with the Discovery Channel. It is something I will just have to work on. Recently, the show Dirty Jobs has caused me to consider something I never thought I would: What is the best use for table leavings?

A few weeks ago Mike Rowe introduced us to a gentleman in Las Vegas who has come up with an innovative way to run his ranch. Well, I say ranch, but I guess its really a farm. Really what it is is some kind of pig factory. I think it is getting difficult to tell the difference between a farm and a factory. Anyway, whatever words you use this guy grows pigs. Naturally if you grow livestock you need feed. I assume that typically feed is one of the more expensive things you have to provide for you animals. He's solved this in a fairly interesting way.

Have you been to Vegas? To a Vegas buffet? Do you wonder what happens to the food at the buffet that doesn't get eaten? Really with all the buffets and even with all the visitors, when I lived in Vegas I was always under the impression that an awful lot of food must wind up in the dumpster. Turns out there are people making good use of the waste. This guy goes to get the leftovers from the casinos, hauls it off to the farm in the desert, filters out all of the non food waste and turns it into hog feed. The process is filthy, and I guess this is the only way we find out about it because it very much was a dirty job.

The scale we're looking at here is fairly small, and they didn't say so, but I got the feeling that we were only looking at the leavings from a couple of hotels. But the thought is sound, and actually it seems that the grade of food the animals got was probably better than standard animal feed, since hours before it was people feed - fairly high end people feed at that.

But animal feed is only the beginning. Someone else has thought of a somewhat larger scale way to deal with food waste. Another dirty job as it turns out and so another segment on the same show. The city of San Francisco has created what for lack of better terminology is a giant mechanical digestive track. They do the same kind of sorting process - although here it was interesting to see that cardboard cartons are just as much food as food is, but they did sort out other things: palettes, phones, cutlery and the like.

They take the food material that is left and make farts. Farts to power generators.

You know the kids joke "save gas, fart in a jar?" They've taken it to heart, and seriously, and made it work.

The food matter is run through a pulverizer and then is trucked to a chemical vat - the "stomach" where they produce vast volumes of methane gas, something we all do on a somewhat smaller scale. That gas is then burned for energy. They didn't talk about that part of the operation but I assume we're talking about boilers for turbine generators. What they showed as about a semi trailer full of waste food apparently can power 1000 homes for one day.

Actually, I am not sure how good an energy source that figure turns out to be. But, it must pay for itself, and it is by far better than rotting away in a landfill. Where I grew up there was a landfill we used to drive by every now and then. At night you could actually see blue flames burning from pipes they'd sunk into the ground. They were burning off the naturally occurring methane before it built up and exploded.

Using table scraps to power methane generators is a fairly interesting application. But is it better than using the food for, you know, food? I guess I am fairly at a loss to decide whether electrical power or animal feed is a better outcome here. Really, the other dimension to the whole discussion is whether either use is good when there are so many people who don't have enough to eat. One would think that before we come up with innovative ways to use waste food we ought to try to minimize the actual amount of waste food. Banana peels and apple cores are one thing, but at least in the Vegas instance of this discussion a goodly amount of what was being used was actually wasted food, rather than food waste.

So I guess based on that I vote for methane since that seemed to use a wider range of material, some of which nobody would ever eat for food.

Interesting stuff though. Food for thought, if you will.


Peg said...

I'm so excited you wrote about this. And if I had more than 30 seconds to do so, I'd have more to say. But I'll limit myself to this:

On a household level we can compost our food waste. It's clean and safe and eliminates I think it's 1/3 of household landfill garbage.

And, you're right, the fact that we waste all this food on a daily basis is another subject entirely.

I wonder if this show will be out on DVD?

David said...

THat of course assumes you don't live in an apartment building.

Not sure I would want a compost closet.

Peg said...

I read an article in the NYT about how lots of people do just that; they have a small bucket in the closet or under the sink. But if you do it indoors it's recommended that you use worms so the material breaks down more quickly, so it doesn't smell. "Eeeew" factor aside, it's pretty nifty.