Feel the (sewage) heat!(sewer heat recovery)

Author:Query, Shawn
 
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Southeast False Creek in Vancouver, British Columbia, will be the site of the 2010 Olympic Village and a model neighborhood for sustainable urban planning. Once a bleak industrial scar on the city landscape, the neighborhood now has the potential to be one of the most sustainable communities in one of the greenest cities in the world.

Among the planned neighborhood features are native (and edible!) landscaping, urban agriculture and pedestrian- and bike-friendly pathways. Vancouver's City Council also voted last April for a newer technology called sewer heat recovery, which uses warm underground effluent to heat water and homes for the region. Unfortunately, while Vancouver earns points for recapturing energy from municipal sewage, that largely untreated waste is still discharged into open waters, releasing PCBs, heavy metals and other pollutants into surrounding ocean ecosystems.

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After a public debate between burning "biomass" from waste sawdust and the sewer heat recovery method, Vancouver residents voiced their preference for poo-powered heat, citing concerns over harmful emissions and transportation costs. "I think the perception in the community was that there would be this billowing smokestack emanating toxic fumes," says John Madden, a city planner.

Heat recovery passes raw sewage through a heat exchanger to capture its energy. Electric heat pumps boost the temperature from 50 degrees to 194 degrees Fahrenheit. Each unit of electricity the heat pumps use produces three units of heat energy.

The city expects to reduce greenhouse gas emissions by 50 percent or 6,000 tons annually by implementing the system. Though the wood-burning option had a better greenhouse gas rating, project manager of neighborhood utilities Chris Baber says community protest and time...

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