Canadian Consulting Engineer

Carbon sequestration may contaminate drinking water, says AWWA

August 18, 2008
By Canadian Consulting Engineer

Governments and the oil industry, including Canada's oil sands companies, are hoping that geological carbon sequest...

Governments and the oil industry, including Canada’s oil sands companies, are hoping that geological carbon sequestration is an answer to some of their environmental problems. The technology involves collecting carbon dioxide emissions from oil production and injecting the gas into deep underground geological formations and aquifers. Because the C02 is stored in the geological formations, the greenhouse gas wouldn’t be emitted into the atmosphere.
Canada is investing heavily in studies to find out whether the technology is feasible here and consulting engineering companies are helping to carry out the studies. A large eight-year, $80-million study project is going on in southeast Saskatchewan, where carbon dioxide from a Dakota synfuel plant is being injected underground at Encana’s Weyburn and Apache’s Midale oil fields.
However, the American Water Works Association is extremely concerned about the possible impacts of the technology and spoke out at a U.S. Congressional hearing on July 24.
An AWWA spokesperson, Don Broussard, spoke before the U.S. House of Representatives Energy and Commerce Subcommittee on Environment and Hazardous materials.
AWWA says that Broussard’s testimony: “raised serious concerns about the potential effect this unproven technology may have on our nation’s underground sources of drinking water.”
Broussard continued: “Our overarching concern regarding geologic carbon sequestration is the potential contamination of underground sources of drinking water and other unintended — and possibly harmful consequences.”
AWWA says that GCS [geological carbon sequestration] “threatens safe water supplies because contaminants released during the power generation process could be absorbed into previously-pristine aquifers during sequestration, rendering them unusable as a drinking water resource. GCS has not yet been proven through study and research, and many experts have raised concerns about the ability to safely contain carbon dioxide once it has been pumped underground.”
Broussard noted that “Water chemistry in an underground setting is complex. …We need to consider how geological carbon sequestration could potentially release iron, manganese, arsenic, mercury, and possibly other inorganic substances into groundwater surrounding the injection zone.”
AWWA urged the U.S. Congress not to deploy carbon sequestration until further studies were done, and to seek alternative geo-engineering approaches to destroying or immobilizing carbon dioxide.


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