All of the wastewater that
students produce at Merry Lea’s future collegiate facility will
be treated onsite by an ecological engine. An ecological engine is a
sewage treatment plant that looks and smells like a greenhouse. It operates
without harsh chemicals or expensive equipment. Merry Lea’s ecological
engine will be showcased behind a glass wall in the center of the south
side of the academic building so that students and visitors can study
it. Its tanks will fit in about 1,000 sq. feet and process up to 6,500
gallons per day.
Ecological engines were developed by John Todd of the University of
Vermont and are now in use cleaning up everything from municipal sewage
to candy factory wastes. They work by mimicking nature. Water flows
through a series of tanks containing microorganisms, snails, small fish,
algae and more complex plants, becoming progressively cleaner.
In an ecological engine,
wastewater is not waste: it is food for something else. Each tank is
a balanced ecosystem and food chain, with a variety of species keeping
each other in check. In a typical ecological engine, the food chain
begins with bacteria that consume suspended organic matter and break
down ammonia into nitrates. Algae and duckweed consume the nitrates;
snails and zooplankton eat the algae and fish eat the zooplankton. Plenty
of light and supplemental aeration make the cleansing process quicker
and more compact than it would be in the natural world. The purified
water can then be recycled for washing, flushing toilets or irrigation.
To learn more about ecological engines, go to
www.oceanarks.org.
