City Is Looking at Sewage Treatment as a Source of Energy.
New York Times, Tuesday February 8, 2010.

" New York City's sewage presents a daunting and costly challenge: it
creates foul odors and often contaminates waterways. But the city is now
casting its sewage treatment plants and the vast amounts of sludge,
methane gas and other byproducts of the wastewater produced by New
Yorkers, as an asset - specifically, as potential sources of renewable

For the city's Department of Environmental Protection, which is to issue
its strategy on Wednesday, it is a shift. Until now, the agency has mainly
played the role of water utility and environmental steward rather than
energy producer.

But like other cities around the country looking to reduce both the costs
of sewage treatment and disposal and the heat-trapping greenhouse gases
emitted in the process, New York is beginning to look at its waste as an
untapped resource.

Heating fuel can be extracted from sludge and butanol, an alternative fuel
to gasoline, from the algae generated by wastewater. Sewage treatment
plants could sell methane gas to provide power to homes. Such projects
represent a more sustainable long-term approach to managing a wastewater
treatment process that costs the city about $400 million annually, not
including capital investments.

New Yorkers currently produce some 1.3 billion gallons of wastewater
daily. The agency is seeking vendors to find uses for the resulting daily
yield of 1,200 tons of sludge, a residual that is currently sent to
landfills in Suffolk County, N.Y., and Virginia.

City officials, who hope to have a contract by 2013, said the solid could
be harvested for gases that produce clean energy and could be used in more
traditional ways, too, as fertilizer or as paving and building materials.

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.

Through a partnership with National Grid that is already in the works,
officials said, the Newtown Creek Wastewater Treatment Plant in Brooklyn
is expected to add enough methane gas to the city's natural gas network
next year to heat 2,500 homes.

City environmental officials said they were also seeking private partners
to develop a plant to produce both electricity and heat or steam near its
Wards Island Wastewater Treatment Plant; the power would heat the plant
and be sold to the market.

The agency is also studying proposals for solar and wind projects on
Staten Island, including one that would place solar panels on the
200,000-square-foot roof of the Port Richmond Wastewater Treatment Plant,
and another for a 1.5-megawatt wind turbine at the Oakwood Beach
Wastewater Treatment Plant."

Dr. Ann C. Wilkie                          Tel: (352)392-8699
Soil and Water Science Department          Fax: (352)392-7008
University of Florida-IFAS
P.O. Box 110960                         E-mail: [log in to unmask]
Gainesville, FL 32611-0960
Campus location: Environmental Microbiology Laboratory (Bldg. 246).
BioEnergy and Sustainable Technology Society