Energy from Human Dung

gigacannon · Posted: Tue May 16, 2006 9:56 am Post subject: Re: Energy from Human Dung

Humans mainly eat simple sugars, so there's not much carbon left in human dung. Cows, on the other hand, eat grass, which is mainly composed of cellulose. Cellulose is broken down by bacteria in the cows' stomachs, and it's this that leads to so much of the methane produced.

This isn't as good an answer as I'd like. I'd better go research it.

Caoimhan · Intermediate Crude Joined: May 10, 2005 Posts: 562

Isn't this a biofuel thread? Waste is biomass.

grabby · Light Sweet Crude Joined: Nov 08, 2005 Posts: 1328

I think more appropriately we could say

Biomass = waste.

More accurate.
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nethawk · Posted: Fri May 19, 2006 10:12 pm Post subject: Re: Energy from Human Dung

Waste-to-Energy of course cannot completely meet the world's demands for energy, but that doesn't mean that it shouldn't be used. WTE for sewage make perfect sense, especially on large treatment plants. The Hyperion Treatment Plant which serves Los Angeles generates over half of its internal needs via the digestors, offsetting millions of dollars worth of electricity bills per year, and saving the natural gas that would been used to make that electricity.

The treatment plant in my town processes about 3 million gallons per day, but they currently flare the methane during summer and use it for heating during the winter. With all of the housing units that are being added and former septic-tank areas that are being connected to the treatment plant, methane production may make a generator feasable. Electricity prices are unlikely to influence it, as the local utility (PPL) uses local coal for 60% of its energy, nuclear for 30%, and hydro for most of the remainer. Very little oil and gas (which is good).

Digestor gas should AT LEAST be used for heating when it is needed, and it would be nice to see digestors installed at the large commercial (factory) farms which currently pump manure into lagoons and waste its energy value and usually fertilizer value as well. They could burn the methane in IC engines, generate electricity for on-farm needs, sell the remainder to the grid, and use the waste heat from the engines to heat the animal barns during winter.

It makes no sense to throw that energy away.