Re the recent post about the
prospect of using compost to create biofuels, an EPA award-winning example in
Seattle was reported last April, in relevant part (see comment that
Executive Ron Sims announced that the county will bring about 2 million
gallons of homegrown biodiesel to King County to power Metro
another case of the county turning waste into a resource," Sims said in a
statement. "This time biosolids from our local wastewater treatment process
are being used to grow canola that will be refined into biodiesel to power our
local transit system. This ultimate act of recycling shows how far we've come
in developing new approaches to creating energy independence while reducing
our carbon footprint."
are retrieved from two King County wastewater treatment plants and
transported to Sunnyside to fertilize canola.
(are) very high in nutrients. I know that in Eastern Washington the biosolids
are used to improve soils and fertilize a lot of different crops," said Annie
Kolb-Nelson, the Media Relations Planner for King County Wastewater Treatment
Division. It's "fecal matter, basically."
crop is a test of a hypothesis by University of Washington scientists in 2003.
County teamed up with
Natural Selection Farms of Sunnyside. Soon some of the annual 115,000 tons of
biosolids were put to use by other area farmers as well.
crushed into oil by a seed-crushing facility in Sunnyside, then shipped to
Imperium Renewables for processing into biodiesel. The biofuel will be enough
to run all Metro diesel-powered buses on a 20 percent mix of biodiesel and
ultra-low sulfur diesel for nearly a year.
The “fecal matter”
comment is not exactly accurate: in fact, biosolids across the
U.S. contains a significant
portion of food waste that begins its route via a food waste disposer (aka
garbage disposal; common in most U.S. homes), traveling through
underground sewers (no trucks) to wastewater treatment plants for processing
into compost-quality biosolids, often via AD and with energy capture.
After all, food waste is similar to human waste: @ 70% water, with a
slightly higher ratio of C:N than human waste, which is helpful in most
wastewater treatment processes, and enriches the quality of biosolids.
All in all, an important aspect of recycling that shouldn’t be overlooked by
those focused on managing solid waste.
For an interesting
essay on the historical and contemporary recycling of human waste, read
“Wasteland” in the current issue of Harper’s.