Vancouver, which will host the 2010 Olympic Games, is instituting green measures like sewer heat recovery.© AP Photo/Jonathan Hayward
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.
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 constraints led officials to sewer heat recovery instead. He says only three other facilities in the world capture heat from raw sewage, two in Oslo, Norway and one in Tokyo.
While the heat recovery technology will significantly reduce greenhouse emissions, the raw sewage will eventually go to a plant on Iona Island, where it will receive only primary treatment. The sewage will be filtered for solids and partially broken down biologically, removing 50 percent of the harmful chemicals, pharmaceuticals and industrial waste. The leftovers, alas, will be discharged directly into the Georgia Strait.
Christianne Wilhelmson is program coordinator for the Georgia Strait Alliance, a group advocating for the health of the waterway. "I think what they’re proposing is great in and of itself, and it’s a way to produce energy with a renewable resource," she says. "However, it’s only one small part of how we should be managing our sewage."
Wilhelmson says Vancouver should be upgrading to secondary treatment, which would filter out approximately 90 percent of the in-gredients that hinder marine organisms" abilities to reproduce and fight off disease. Although Wilhelmson says more action should be taken on the tail end of the sewage pipe, she says resource recovery sets a good example for sustainability.
"When you talk to communities about cost and resource recovery, people are really grabbing onto it," she says. "I am hopeful that more communities will take interest."