Facts of the Matter
Lots of energy flushed down the toilet
Recycling is the rule rather than the exception in natural ecosystems, as the decomposers such as bacteria and fungi break down organic waste. They use whatever energy remains in the carbon compounds and release nutrients back into the system.
We are a problem as consumers because we create large amounts of waste and then overload the system by storing our waste in landfills. There the decomposers use the energy and release carbon dioxide and methane into the atmosphere.
People are discovering that garbage is useful stuff. For decades cities like Honolulu have burned trash to generate electricity. But there are other waste products that have remained untapped until recently. Honolulu dedicated in October a waste-water treatment facility that turns sewage sludge into 25 tons of methane and fertilizer per day.
This is a big step but only one of several approaches to using the vast pool of sewage into which we all contribute.
Our aversion to human excrement is strong, and it is based upon both a genetic component that recognizes the variety of pathogens contained therein, but also a psychological component that arises from enculturation.
In London, treated solid sewage is burned to generate electricity.
Estimates vary, but some say that 20 percent of the world's energy needs could be met by burning solids extracted from sewage.
A major advancement in converting waste to energy is that of Changing World Technologies. Their patented Thermal Conversion Process is the first commercially viable method of converting organic waste into oil.
Their Renewable Environmental Solutions subsidiary can convert 250 tons per day of leftovers from commercial turkey production into 20 thousand gallons of diesel fuel and fertilizer.
Brian S. Appel, CWT chairman and CEO, says, "Utilizing above-ground waste streams to create a renewable, environmentally sound domestic source of energy is one of our most promising options for breaking our virtual bondage to oil imports."
The process mimics the natural geologic activity that converts organic material into petroleum. It is carbon neutral and provides a solution for solid-waste management while creating a renewable source of energy with no toxic emissions.
Another company, Enertech Environmental, has received about $57 million in venture capital to develop five plants that will convert sewage sludge using a technology they call "SlurryCarb." This process applies heat and pressure to produce a solid, high-carbon material that can replace coal to supply energy.
Although the U.S. is far from energy self-reliance, the U.S. population creates roughly 5 million tons of sewage sludge annually, and agriculture produces more than 6 billion tons of solid waste. If all of that were converted into energy, it could easily meet the current demand of 4 billion barrels of oil that the country imports each year.
Of course it will be a long time, if ever, before all of our waste will be converted into energy, but even one-fourth of it would go far toward meeting our energy demands while also reducing our carbon footprint.
Richard Brill, professor of science at Honolulu Community College, teaches earth and physical science and investigates life and the universe. E-mail questions and comments to firstname.lastname@example.org