File photo of Brita water pitchers
Pipes carrying sediment crisscross the Mississippi River where the U.S. Army Corps of Engineers is building an underwater sill with that mud that should slow the flow of saltwater up the Mississippi River south of New Orleans on Tuesday, September 26, 2023. (Photo by Chris Granger | The Times-Picayune | NOLA.com) Ultra Violet Filters
File photo of Brita water pitchers
Pipes carrying sediment crisscross the Mississippi River where the U.S. Army Corps of Engineers is building an underwater sill with that mud that should slow the flow of saltwater up the Mississippi River south of New Orleans on Tuesday, September 26, 2023. (Photo by Chris Granger | The Times-Picayune | NOLA.com)
Filters that can help purify water quickly are ubiquitous, and you might be wondering if a typical pitcher, tap or whole-home filtration system can help keep salt out of your drinking water.
Alas, as a wedge of salt creeps up the Mississippi River, desalinating water is too tall an order for the average residential filter to handle.
Still, some systems are advertised as doing just that. But the cost and effectiveness varies.
These work through reverse osmosis, where a semipermeable membrane separates salt from water, according to Scientific American. The systems work with a variety of membranes, only some of which can handle the pressure and filtration of seawater.
Thomas Bruley, who works with water purification as a site manager for a Florida electricity company, said that the average reverse osmosis system is meant to filter only freshwater.
Bruley suggested that anyone looking at reverse osmosis as a brackish or seawater filtration option discuss their options with local manufacturers. These companies can test the water and make sure the membrane is the right fit.
"A lot of these smaller units are kind of trapped between what it can and can't do," he said.
Still, reverse osmosis is the only way to remove man-made chemicals called PFAS that have been linked to health hazards. Some systems can also remove lead, in addition to bacteria commonly found in water.
"If you're worried about any contaminants or anything else in the water, it's just another safeguard," said Bob Thomas, Loyola University professor and chair of environmental communications.
Another way to remove salt from seawater is to boil it — a process known as thermal distillation — but that requires capturing the desalinated water that's turned into vapor.
Distilled water can be made with thermal distillation systems in homes, too. Ones that distill eight gallons of water a day run about $1,200.
"You can buy thermal distillation, but you're moving a lot of other things out of the water that you need," Thomas said. "You can go buy distilled water at the grocery, but for me, it doesn't pass the taste test."
Most home options — from Brita pitchers to PUR faucet filters to whole-house filtration systems — use carbon as a sponge to soak up some contaminants and make the water smell and taste better.
But the salt in water is too small to get trapped by those filters.
Unless installing a desalination reverse osmosis water filter or distillation system is in the cards for your home, you'll likely have to buy water from the store.
Editor's Note: This report has been updated to include further details about retail reverse osmosis systems.
Email Gabriella Killett at GKillett@TheAdvocate.com or follow her on Twitter, @GEKillett.
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