Sunday, September 02, 2012

YOU ARE DRINKING WHAT?


With water in short supply across the country, it's time to take a serious look at recycling sewage


Almost 60% of the continental U.S. is now living through drought conditions, and half of all counties have been declared disaster areas. From coast to coast, cities and towns are placing restrictions on water consumption. With the nation so hot and dry and no end in sight, some are calling for a drastic solution: drinking our own wastewater—that is, what we usually flush down our toilets.
Not directly, of course. But drinking recycled wastewater is a relatively cheap and effective means of obtaining a lot of water. If all the wastewater dumped into waterways or the ocean were recycled instead, the U.S. would increase its water supply by as much as 27%, according to a report released earlier this year by the National Academy of Sciences. Nationally, that amounts to 12 billion gallons. (click below to read more)


The process for recycling wastewater is more rigorous than for "regular" tap water, with stronger filtration. As the NAS report noted, "With recent advances in technology and treatment design, potable reuse can reduce the concentration of chemical and microbial contaminants to levels comparable to or lower than those present in many drinking water supplies."
Recycled wastewater is also cheaper than other alternatives. Desalination—turning seawater into drinking water—sounds more palatable, but estimated costs can run one-half to two-thirds more than for a recycled wastewater facility. That is largely due to the amount of filtration required: Wastewater has roughly 1,000 parts per million of salt, but seawater has roughly 35,000 parts per million. Desalination is also, of course, limited to states near seawater.
But the idea of recycled wastewater still disturbs many people, which is why it hasn't caught on. Wade Miller, executive director of the Water ReUse Assocation, a national advocacy group, estimates that only 7% of municipalities across the country recycle wastewater—and that figure liberally interprets reuse, including water for agriculture and golf courses. Only a handful of communities actually drink recycled wastewater, Mr. Miller says, including El Paso, parts of Los Angeles County, and Orange County, Calif.
Where the programs exist, they are born out of desperation—which is precisely how the idea got its start.
It began in the tiny capsule of the Mercury rocket, on May 5, 1961, with Alan Shepard looking out his periscope viewer at the morning clouds. It was 15 minutes before his launch, before he was to become the first American sent into space, and he was nervous, according to "Moon Shot," the book that he later co-wrote. The launch director came on and told Mr. Shepard that there was an electrical glitch; the flight would have to wait.

Another problem emerged during the nearly 90-minute delay: "Man, I got to pee," Mr. Shepard told astronaut Gordon Cooper, who was in ground control. The flight was only supposed to last 15 minutes, and the rocket wasn't equipped with a toilet. Mr. Shepard was told to hold it.
"Gordo, I've got to relieve myself," Mr. Shepard said, getting angrier. "Tell 'em I'm going to let it go in my suit." But Mr. Shepard had electronic biosensors up and down his legs. Mr. Cooper said, "The medics say you'll short-circuit all their medical leads."
"Tell 'em to turn the power off," Mr. Shepard said.
And so the medical team did. A short while later, Mr. Shepard was launched into his suborbital flight, a brave, relieved man.
As space flights became longer, the problem of discarding waste persisted. Neil Armstrong walked the moon in diapers. It wasn't until the era of the International Space Station, with astronauts on six-month missions, that NASA engineers began to think creatively about waste. "We didn't think that we could resupply [the astronauts] with water up there," says Monsi Roman, a microbiologist at the Marshall Space Station, who has worked at NASA for 25 years. "And that's when we began to think about recycling urine for drinking purposes."
Urine consists of salt, water and contaminants, and on the space station today, the salt and contaminants are distilled and thrown away. The remaining water goes into a processor that burns away any lingering bacteria, and then iodine further cleans it. "It's a closed loop," Mr. Roman says—and an inspiration for wastewater treatment plants back on Earth.
Orange County's Groundwater Replenishment System, which opened in 2008, produces over 70 million gallons of water every day. It is modeled to a degree on NASA's space station breakthrough: The wastewater goes through a micro-filtration process and then reverse osmosis (in which chemicals, viruses and pharmaceuticals are removed) before being exposed to high-intensity ultraviolet light to destroy any lingering compounds. Over two-thirds of the county has been served by the recycled water system since it went online four years ago, says Michael Markus, the general manager of the Orange County Water District.
But it was a long time in coming. Mr. Markus and other water-district employees knew in the early 1990s that the county would soon face a water shortage—and they knew, too, that recycling wastewater would be as much a political challenge as an engineering one. So they hired consultants, polled the public and discovered common concerns. The water officials went to the 19 affected municipalities and gave presentations to their city councils. They then moved on to state and federal officials. Some 1,200 presentations and tours later, the recycled water began to flow from taps. "It tastes like distilled water," Mr. Markus says. "There's actually very little taste to it."
He believes that every municipality should follow Orange County's example. Because, he says, "you're wasting sewer water if you're not using it."

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