Archaebacteria are significant to humans in several ways. In the future, methane bacteria may be used on a large scale to furnish energy for engine fuels and for heating, cooking, and light, since the methane gas they produce can be used to replace the methane in natural gas. Methane has an octane number of 130 and has been used as a motor fuel in Italy for over 40 years. It is clean, nonpolluting, safe, nontoxic, and prolongs the life of automobile engines, also making them easier to start. The methane is given off by the bacteria as they "digest" organic wastes in the absence of oxygen. Nine kilograms (20 pounds) of horse manure or 4.5 kilograms (10 pounds) of pig manure fed daily into a methane digester will produce all the gas needed for the average American adult's cooking needs. Considerably less green plant material is required to produce the same amount of methane.
The digester basically consists of an airtight drum connected by a pipe to a storage tank with a means of drawing off the sludge left after the gas has been produced (Fig. 17.15). The sludge itself makes an excellent fertilizer, although many sludges that originate from municipal and large-scale agricultural plants carry with them toxic levels of metals.
France had over 1,000 methane plants in operation by the mid-1950s, and in India, where cows produce over 812 million metric tons (800 million tons) of manure per year, many villages satisfy their fuel needs with manure-fed methane gas digesters. They are now being employed on a
Figure 17.15 An integrated organic digester operation for the production of methane gas. Reprinted from Producing Your Own Power (c) 1974 by Rodale Press, Inc. Permission granted by Rodale Press, Inc., Emmaus, PA, 18049.
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small scale in rural areas in the United States. Methane is the primary source of hydrogen in the commercial production of ammonia.
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Acai, Maqui And Many Other Popular Berries That Will Change Your Life And Health. Berries have been demonstrated to be some of the healthiest foods on the planet. Each month or so it seems fresh research is being brought out and new berries are being exposed and analyzed for their health giving attributes.