A "rain garden" is shown in a residential area of Puyallup, Wash., Tuesday, Oct. 18, 2011. Puyallup has installed more than 50 rain gardens to soak up rain and stormwater runoff as a strategy to keep rainwater from washing pollutants into rivers and Puget Sound. Retrieved from: www.seattlepi.com
“SEATTLE (AP) — The city of Puyallup has installed dozens of neighborhood rain gardens to prevent rain from washing pollutants into nearby waterways. Mount Vernon used a type of asphalt that allows rainwater to seep into the ground when it built a new walkway. And Seattle has used roofs planted with vegetation to reduce runoff.
Washington cities and counties have occasionally turned to eco-friendly strategies to keep rain from carrying grease, metals and other toxic pollutants into rivers, lakes and Puget Sound. But low-impact methods, such as using vegetation and cisterns to slow runoff, may soon be a requirement every time someone builds a new development or redevelops property in Western Washington.
State environmental regulators released draft rules Wednesday that spell out exactly how governments should incorporate the strategies to control polluted runoff that can harm fish and water quality.
The draft rules attempt to strike a balance between tackling stormwater pollution while recognizing that local governments are strapped for resources, Ecology Director Ted Sturdevant said Wednesday.
The state was ordered to consider greener strategies by the state Pollution Control Hearings Board after environmentalists sued. The board mandated low-impact methods for the most populous areas in Western Washington. The board also said the state needed to do more to ensure low-impact methods were used in smaller cities in the region.”
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Retrieved from: green tech media
“Amy Childress, a professor at the University of Nevada Reno, and a group of researchers are experimenting with a method that essentially harnesses the hidden power of waste streams to turn sea or swamp water into something you could possibly drink.
“In theory, it could offset 50 percent of the energy required in reverse osmosis (RO) desalination, she said. The fifty percent figure is just in theory, she added for further emphasis, but any progress in reducing the power consumed in desalination would be welcome. Energy — which is used to pressurize water so that an RO membrane will fleece the salt and other impurities — can account for around two thirds of the operating cost of the desal plant, according to general industry estimates.
“The UNR concept works as follows. A standard RO plant for converting seawater into fresh water would be erected. It would function like a standard plant. Next to it would be a pressure retarded osmosis (PRO) plant. In this plant, lightly- to moderately-fouled water like sewer water would be directed to a reservoir. At one end of the reservoir would be an RO membrane. On the other side of the membrane would be an extremely salty solution. It could be the brine discharge from the principle RO plant.
“Nature, and water, seek an equilibrium, so the lightly salted water would push itself through the membrane to the briny side in a vain effort to achieve saline equilibrium. The flow of water to the briny side would create pressure. Think of what happens when you eat salty food and get the sudden urge to drink water. You get bloated and distended. Same thing happens here.”
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