Human waste proposed as source of natural gas
Scott Simpson, Vancouver Sun
Published: Tuesday, July 22, 2008

Terasen Gas customers on the North Shore could soon be firing up
their furnaces and hot-water heaters with natural gas collected as
a byproduct in the processing of human waste.

A $1.1-million project involving Terasen, Metro Vancouver and
QuestAir Technologies proposes to capture and purify "biogas" from
operations at the Lions Gate sewage treatment plant and pump it
into a nearby Terasen distribution pipe for use by the gas
utility's customers.

It will be the first time in B.C. that energy from human waste is
captured and used in this fashion, and it's fairly novel on a
global scale as well -- although processes using gas from
landfills and agricultural waste are well established.

Last week, the project received a $366,000 grant from British
Columbia's Innovative Clean Energy (ICE) fund.

As with natural gas that is conventionally pumped from underground
deposits, the gas produced at Lions Gate will be almost pure
methane. It's an odourless, clean-burning heat energy source.

Gas producers typically add trace amounts of another gas,
mercaptan, which smells like rotten eggs, so that it can be
detected in the event of a leak.

The Lions Gate gas is produced in the "digestion" of sewage, a
mechanical process that separates solid from liquid waste at the
regional treatment facility in West Vancouver.

Some of the gas produced in this process is already being burned
as heat to support waste digestion, but Lions Gate produces more
than it can use.

The excess gas has traditionally been flared, or burned off, into
the atmosphere through an open flame.

"As times change and technologies change, no one wants to be
flaring gas," said Stan Woods, a senior engineer with Metro
Vancouver. "So there is a real opportunity, and it worked out well
for Terasen in the sense that there is a gas pipeline nearby."

The gas will be processed to remove impurities using technology
from Burnaby-based QuestAir, and pressurized for insertion into a
nearby Terasen gas-delivery pipe.

Terasen expects the project will yield enough gas to meet the
energy demands of 100 homes.

The Lions Gate project could be in operation as early as July 2009
and Terasen hopes to learn enough to develop a larger-scale
operation in future, such as harvesting methane from agriculture
waste.

Terasen communications manager Joyce Wagenaar said the project
will last at least 10 years and represents "a significant
demonstration and learning opportunity" for the gas utility.

"We feel that biogas has the potential to be a cost-effective,
clean energy source and we need to explore that," Wagenaar said in
an interview.

"Metro Vancouver has other [waste water treatment] plants so if
this pilot is successful there is potential there."

Wagenaar said Terasen is particularly interested in a recent study
by BC BioProducts Association, which identified substantial
potential for biogas produced from agricultural waste in the
Fraser Valley.

"That could produce enough gas to serve 25,000 homes, so we are
really looking at biogas, and depending on the success of this
project, would explore other opportunities across the province."

http://www.canada.com/vancouversun/story.html?id=47e363c0-1b3b-4a5b-81b5-ae45ea0a9853

--
Kyle J. Fricker
Chemical Engineering
University of Florida