Latest Research Produces a Chlorine-friendly RO SystemThe problem of separating salt from water has long been solved by forcing the water through a polyamide membrane in a process called reverse osmosis (RO). However, the water can't be disinfected with chlorine because it degrades polyamid material. Now, researchers at Virginia Tech have created a new polymer membrane for RO that will not be degraded by chlorine.
“Our RO materials grew out of our work on proton-exchange membrane (PEM) materials used in fuel cells,” says Virginia Tech professor James McGrath. “The polymer structure is similar, but PEM materials are treated with a dilute acid, and the RO materials are treated with a salt to put them in the neutral form.”
Last year, McGrath's group received funding from the Office of Naval Research (ONR) to develop an RO material that would not break down from chlorine. “We have suggested for some time that PEM materials could be used, so our students quickly began sending sample materials for testing to Benny Freeman, chemical engineer at the University of Texas. Within a year, we had a successful material. “People have been doing RO for 40 years, but not with this new material,” McGrath notes.
The ONR has expanded the project to add Don Baird, professor of chemical engineering at Virginia Tech, to fabricate the membrane. “The material we created and evaluated in the first year was relatively thick,” McGrath explains. “To be competitive, it has to be a thin film, so the water can pass through quickly - 10 times to 100 times thinner than our present samples. That is not trivial, but we think we know how to do it.”
The Virginia Tech research group has created an asymmetric membrane. Imagine rigid foam with a thin membrane skin. The separation takes place at the skin and the water passes quickly through the foam's large pores. Without the foam, the skin or film layer is not strong enough to withstand the pressure of RO.
McGrath now is looking for companies to work with to produce the new material. He also is working on a different process to separate ethanol from water. “We think we can make membranes to do that, too,” he claims.
Quickie Legislative ReportHere we offer theReader's Digest-version of our usual “Legislative Update” department, compiled by the versatile and talented Caroline Mims.
Safe Water Goal Lowered -The U.S. Environmental Protection Agency (EPA) water officials are backing away from a 2008 target of having 95 percent of people who served by community water systems receive water that meets all health-based standards. They propose to replace what they termed the ideal of 95 percent by 2008 with a more realistic level of 91 percent by 2011.
Abandoned Mine Bill -The Senate Environment and Public Works Committee recently approved legislation that would encourage third-party good Samaritans to clean-up abandoned hard-rock mines by granting them liability protections under several environmental statutes, including the Clean Water Act. No action has been taken on similar legislation in the House, and the legislation is not expected to be enacted by Congress this year.
In Washington State -In order to meet legislative requirements adopted in April 2005 and also remain consistent with the state law governing construction and maintenance of wells, the Washington Department of Ecology is updating the licensing requirements for well contractors and operators. Specific rule amendments will address the process and criteria for evaluation of continuing education classes, conducting annual performance reviews on those counties delegated to inspect wells, establishing new categories of licenses for drillers that meet specific requirements and adjusting current licensing fees.
Perchlorate Standard -California is proposing a perchlorate standard of 6 micrograms/L under a rule that also provides variances for economically distressed communities. The rule proposed by the California Department of Health Services would require community and non-transient/non-community systems to conduct an initial year-long round of monitoring for perchlorate in source waters. Systems that do not detect perchlorate then would monitor annually on a reduced schedule, while those that exceed the maximum contaminant level (MCL) would monitor quarterly until four consecutive samples comply. The rule would set a method detection limit of 4 MCL for perchlorate.
Underground Aquifers -The New Mexico Aquifer Assessment Act of 2006 will instruct the U.S. Geological Survey, in collaboration with the state of New Mexico, to undertake a ground water resources study that will help to better understand the nature and extent of New Mexico's resources and provide the necessary information to identify potential new sources of water and know the limitations of what is available.
Great Lakes Plan on Hold -Congress appears likely to adjourn this year without adopting a $20 billion restoration plan to slow the escalating environmental degradation of the Great Lakes.
Needs Some WorkDerelict water well drilling rig near Estancia, N.M. Photo courtesy oflaphroaig.uhnet.net.
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