Energy happens: NYC seeks sewage power

Clean energy from some of the filthiest stuff on Earth? New York City combines sewage treatment and renewable power generation.
Written by Melissa Mahony, Contributor

New York City offers a variety of smells. Soon, one of them —that of methane—may tell another tale of New Yorkers' resourcefulness. The Department of Environmental Protection announced plans this week to heat homes and some of its facilities via sewage.

Millions of people living on or around a tiny island produce a lot of sewage. A lot. Enough for 6,000 miles of sewer pipes. New Yorkers generate about 1.3 billion gallons of wastewater everyday.

Digesters at water treatment plants separate the liquids and solids. In case you were wondering, each year a person makes, on average, 66 pounds of "sludge." And that's what it weighs dried.

Speaking of sludge, or biosolids, the DEP says NYC produces 1,200 tons of it daily.  The anaerobic breakdown of the excrement produces large amounts of methane. This currently goes to waste in landfills. The city used to dump biosolids into the ocean (lucky ocean!) until 1988 when the practice was banned.

New York Times reports:

The biggest potential source of energy, officials said, is the methane gas from sewage treatment plants’ digesters. About half of the methane produced by the city’s plants is already used to meet about 20 percent of the energy demands of the city’s 14 sewage plants, whose electric bills run to a total of about $50 million a year. Now the city wants to market the other half, which is burned off and wasted.

The DEP hopes to develop 30 to 50 megawatts of clean energy supply at its facilities through wind, water, sun and sewage. One site for such gas-to-grid projects is Brooklyn's Newtown Creek Wastewater Treatment Plant, the city's largest such facility. Partnering with National Grid, the plant could be heating 2,500 homes by next year.

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Image: Flickr/DistortedSmile

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