good news for TSM! (more vitamins)

[www.scientificamerican.com]

"WICHITA FALLS, Texas—City officials began blending 5 million gallons a day of treated wastewater into their municipal water system this week, launching one of the biggest so-called direct reuse programs in the country.

While some residents in this city of about 105,000 are concerned about drinking water from a sewage treatment plant, city officials and business leaders say it was the only way to adapt to an unprecedented dry spell. The lakes that supply the city have dropped below 25 percent of their capacity.

It's just one of the hard choices facing the second-biggest U.S. state as it confronts a tightening drought, a population boom and the long-term effects of climate change. Voters approved $2 billion in a November election to fund water projects around the state, and other cities are considering the same direct reuse of wastewater as Wichita Falls.

Water officials in the Dallas-Fort Worth metropolitan area are considering a $3.4 billion plan to build a new reservoir, after efforts to import water from Oklahoma were shot down.

"We believe the rest of the state is watching what we're doing, and this may be a viable water source," Russell Schreiber, Wichita Falls' public works director, said in an interview. Once the drought breaks, Wichita Falls will return to sending its treated wastewater into local rivers and reservoirs, he said.

Another municipal water system in West Texas has been using recycled wastewater for more than a year. The Colorado River Municipal Water District has been piping treated effluent from a plant in Big Spring to a drinking-water plant that serves Big Spring, Snyder, Midland and Odessa, said John Grant, the district's general manager.

Victims of a 4-year drought
Other cities, including San Antonio and El Paso, use treated wastewater for irrigation but keep it out of their potable-water systems.

Water-quality officials at the Texas Commission on Environmental Quality asked Wichita Falls to do an extra round of tests of the system before approving it, and then only permitted it for six months. In an emailed statement, spokeswoman Andrea Morrow said the agency wants to take a measured approach.

"We recognize reuse is a viable option for the state of Texas as a new source, however it requires an innovative, engineered, site-specific treatment based on the source water used," she wrote.

Schreiber said his town turned to reused water out of necessity. In 2010, the lakes that supply the city were 97 percent full. Then the drought of 2011—the worst on record since the state started keeping records in the 1890s—brought temperatures above 100 degrees Fahrenheit for more than three months. And while other parts of the state got some relief in 2012 and 2013, the dry spell has never ended in Wichita Falls.

The city has been rationing water for more than 1,000 days. Lawn watering is banned, and residents are reusing water from bathtubs to flush their toilets.

The city has cut its water use from 40 million gallons on a typical July day to 12 million, Schreiber said. But it's still not enough.

"We don't have any other options—every supply lake within a 200-mile radius of us is in about the same shape as ours," Schreiber said.

Wichita Falls had one advantage when the drought hit—it had already built a rugged plant to treat water from a salty reservoir, Schreiber said.

To launch what it calls its "Direct Potable Reuse Project," the city pipes water 12 miles from its wastewater treatment plant to this treatment facility where it goes through microfiltration. A pump pulls water through a module filled with fibers that removes most of the impurities.

Then it is forced through a semi-permeable membrane that can remove dissolved salts and other contaminants. The process, called reverse osmosis, is used by the U.S. military, in ships and in the manufacture of silicon chips. The water then gets blended with lake water before going through the regular water treatment system.

A bargain, of sorts
At 60 cents per 1,000 gallons, it's far cheaper than any other source of water, Schreiber said.

He said there have been few complaints so far. A glass of the finished product, sampled at a downtown restaurant, tasted about average for West Texas.

Ronnie DeFord, who runs an antique store in downtown Wichita Falls, said he prefers to drink bottled water because it tastes better than city water. Using treated wastewater as a source of drinking water just adds to his general unease about water in general, he said.

"I can't understand why they didn't have a little foresight with this water situation," he said.

Katherine Smith, whose family-owned nursery has been in Wichita Falls more than 60 years, said she was initially angry with the city's response to the drought but eventually became a supporter of the reuse project.

Most cities in Texas draw their water from rivers and artificial lakes, which means they're generally drinking water that's been used upstream. Fort Worth and Dallas, for example, discharge their treated wastewater into the Trinity River, which supplies part of Houston.

The reuse program is no different, Smith said.

"It's something people have to get over because it's not anything new," she said. "Nobody's making any new water—it's all recycled.""