Garbage contains not only valuable raw materials; it also contains energy, which can be reclaimed in a number of ways. The oldest process is capturing the methane given off by rotting organic materials, and this has been used by small European farmers for some time. A British farmer recently claimed to run his car on methane extracted from pig manure. Smallscale production is simple, but needs considerable amounts of manure or other organic matersal.
Now an Arizona company, NRG Inc., will recover methaneÑthe chief ingredient of natural gas by sinking wells into garbage land fills. Under contract with Los Angeles County, it will drill three 125ft wells into the Palos Verdes garbage dump, expecting to recover 700,000 cubic feet of methane a day, after removing about the same amount of carbon dioxide from the extracted gas. NRG hopes eventually to recover 10 million cu.ft. of methane per day from this one dump; and it estimates there are 1,000 more such igh yield dumps in the US.
Burning garbage at power plants is more efficient not only energetically (plastics burn, but do not rot) Ñbut also for recovering raw materials, which are extracted from the shredded garbage directly, or sometimes from the residual ashes. Refuse power plants have rapidly proliferated in Europe in the last few years, and some 40 large plants are now in operation there. In the US, Wheelabrator Frye Inc. is now building such a plant near Saugus, Mass., which will by 1975 dispose of 1,000 tons of garbage a day, meeting clean air emission standards; it will produce steam for a power plant to be built by General Electric, which is hoping for a power output of up to 3.5 MW. Wheelabrator estimates that the 200 million tons of garbage collected annually in the US could be converted to 1,400 MW of electric power.
A third way of reclaiming energy from refuse is to process it into fuel by pyrolysis, or heating in an oxygen free atmosphere. Several US companies are now developing this technology. For example, Union Carbide has a pilot project for turning refuse into fuel gas in New York, and Occidental Petroleum has a garbage to oil project underway in California.
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Vol. 1, No. 5
Newsletter: Access to Energy Newsletter Archive Volume: Volume 1 Issue/No.: Vol. 1, No. 5 Date: January 01, 1974 11:41 AM (For actual publication date see newsletter.) Title: Guilty of Profit
Copyright © 2004 - Access to Energy Newsletter Archive
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