Solano District Wins Award for THM Reduction

The Association of California Water Agencies (ACWA) on May 22 presented the Clair A. Hill Award to Solano Irrigation District for its Total Trihalomethane Reduction System.

The award was presented to the district during the annual ACWA Spring Conference & Exhibition, where water officials gathered for programs and panel discussions on a variety of key issues.

The district was selected from among four finalists to receive the award.

"Solano Irrigation District is an outstanding example of a local agency implementing creative solutions to manage California's water resources," ACWA President Glen Peterson said. "Solano's project has captured national attention for its ability to dramatically reduce disinfectant byproducts in response to more stringent water quality standards."

Using a recirculating pump, district staff developed an aeration process designed to reduce total trihalomethanes, a byproduct formed when disinfectants react with organic material in water. The pump draws water from the bottom of a water tank and discharges it into the atmosphere using a spray nozzle above the water surface. Total THMs have been reduced from 120 parts per billion to 36.4 parts per billion, a 70 percent reduction.

Since it became operational in November 2006, water agencies across the country, including the U.S. Navy, have called or visited to find out how they can model their own systems after Solano's. With a total investment of less than $5,000 for research, implementation, and operating costs, the district's solution is both practical and cost effective.

The district has the honor of awarding a $5,000 scholarship to a deserving student in the name of Clair A. Hill, founder of the consulting engineering firm CH2M Hill.

Other finalists for this year's award were:

  • Central Basin Municipal Water District for "Water Wanderings: A Journey Through California's Water," a hands-on water education program for students.
  • The city of Oxnard, for its Brackish Water Desalter, a component of its Groundwater Recovery Enhancement and Treatment Program.
  • The city of Riverside, for its John. W. North Water Treatment Plant, which completely eliminated the agency's reliance on imported water.

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