"Blended" water on its way "Blended" water on its way (February 03, 2006)

First new treatment plant and pipeline in 30 years
by Carol Bogart

People in Pleasanton whose drinking water and water for household use is purchased from the Zone 7 Water Agency could soon experience less hardness in that water thanks to a new treatment plant.

The plant, which began construction in March 2005 in the Altamont pass area in unincorporated eastern Alameda County, will be the first new treatment plant serving the Tri-Valley since Zone 7 built the Del Valle Water Treatment Plant in 1975. Raw surface water that originates in the Sacramento-San Joaquin Delta will be treated at the new plant, blended with groundwater from wells, then delivered to Pleasanton, Livermore and Dublin.

Surface water, the agency reports, is softer than groundwater. Softer water makes soap easier to "suds" and can be less damaging to plumbing from such things as magnesium and calcium deposits, which can affect corrosion.

Some in Pleasanton say the water tastes bad, depending on the season. Zone 7 manager of Environmental and Public Affairs Karla Nemeth said, "The fact that the water is blended won't improve the earthy-musty taste and odor issues associated with surface water." She explains that those issues typically show up during warm summer months when algae blooms in "source (surface) water" in the Delta itself and in the South Bay Aqueduct. She said the natural organic breakdown of the blooms produces the taste and odor.

"What will improve that is our design and selection of a treatment process for the new plant that will be more effective at removing taste and odor-causing compounds from surface water than (the process) now available at our other treatment plants," she said. Zone 7 plans to upgrade the other plants at a future date. The disinfectant Zone 7 uses to remove potentially illness-causing bacteria and viruses from drinking water is chloramine. Chloramine combines chlorine with ammonia. Nemeth said chloramine is used year-'round in place of chlorine alone, which had been used for years until scientists discovered that the chemical reaction between chlorine and decaying organic material such as algae or dead leaves can create trihalomethanes.

Exposure through drinking water to trihalomethanes can cause breast cancer, according to the EPA. In response to state and federal regulations for trihalomethanes, Zone 7 switched to chloramine treatment in 1990, Nemeth said, adding that other Bay Area water agencies switched to chloramine for water treatment throughout the 1990s. Nemeth said chloramine treatment vs chlorine equals safer water. For Argonne National Laboratory's fact sheet regarding chloramine water treatment, visit www.ead.anl.gov/pub/doc/cyanide.pdf .

Anticipating regional population growth and increased demand for water, Nemeth said Zone 7 will be able to expand the plant to its full capacity--up to 42 million gallons per day. The pipeline will be roughly 11 miles long and will deliver the treated water from the plant to Zone 7’s existing distribution pipeline near Vasco and Kitty Hawk Roads in Livermore. For those interested in following the water plant project's progress, Zone 7 has established an informational website: www.altamontproject.com. The scheduled completion date is 2009.

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