Paradigms
for the Anthropocene: An Example
The Social Good Summit included
concern that silos of traditional institutional mechanisms might hinder needed
progress toward sustainability. Sustainable cities will pose new puzzles to
solve for the water-energy-food nexus. Are solutions resilient, moving toward
zero waste, renewable?
A wastewater treatment plant produces
residuals from primary treatment of suspended solids and secondary treatment of
dissolved solids. Suspended solids settle out and dissolved solids become food
for microorganisms aided by oxygen pumped into the secondary treatment basins.
Clumps of such well-fed microorganisms then settle out as residuals. In the old
days, residuals might be loaded onto a barge at the riverside where the plant
was located and hauled out into the ocean for disposal. Now residuals may be
fed into a digester which produces biogas. This biogas can then become
electricity or compressed natural gas as
fuel for truck fleets.
For the United States nationally,
our over 3,000 wastewater treatment plants use about 3% of electricity
generated in the US, mostly for the motors that pump oxygen into secondary
treatment basins. Food waste is the largest segment of the solid waste stream
still going to landfill where it generates fugitive emissions of methane, a
more potent greenhouse gas than carbon dioxide. Adding food waste to the digesters
increases biogas generation which could then generate about 6% of the
electricity needed in the US. This would be an increase of 50% in electricity
generation from renewable fuels which is now at 12%. Huge.
Existing institutional arrangements
include solid waste management, wastewater treatment, and electric power
generation. This example combines these well established activities into one
operation which produces renewable, off-grid, resilient energy while reducing
methane emissions from landfills. If the grid goes down, the microorganisms
keep on eating! Resilient, sustainable solutions! Sustainable Cities
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