For the first time, a Glendale research team testing methods for stripping chromium 6 from groundwater has released an estimate for how much it will cost long term — putting the tab at up to $27 million over 20 years.
The costs will be a key consideration for the California Department of Public Health, which plans to use the more than 10 years of research carried out by Glendale Water & Power to set a new maximum contaminant level for cancer-causing hexavalent chromium.
In doing so, state officials must consider the costs and technical feasibility.
“The costs are something new. It’s the first time they’ve seen that,” said Leighton Fong, a civil engineer and project manager for the research.
Although the state Department of Public Health has reviewed the report, they would not comment on the initial cost estimates because they had not completed a cost benefit analysis, spokesman Ronald Owens said.
Last year, state officials set a public health goal for chromium 6 contamination of .02 parts per billion — far below the current limit of 50 parts per billion. By law, state officials must get the final limit — planned to be released by July 2015 — as close to the public health goal as economically feasible.
Glendale and other San Fernando cities have been grappling with water contamination caused decades ago by the aerospace manufacturing industry. The city distributes water with chromium levels of 5 parts per billion or less by blending contaminated groundwater with more expensive, but clean, water from the Metropolitan Water District of Southern California.
Reducing the chromium to 1 part per billion can be achieved through a variety of methods, but they are estimated to cost millions of dollars and each have their own drawbacks, according to the city’s first interim report about its research released in May.
The research alone — funded by a variety of grants and a group of companies responsible for the contamination — is expected to cost $8.8 million by the end of next year.
One removal method applied to a “large” system — one that can handle a population of 10,001 to 100,000 — could cost $27 million to install, operate and maintain over 20 years, according to the report.
A “medium” system for a population of 3,301 to 10,000 would cost about a third as much.
That method uses resin to strip chromium, but it has side effects, such as formaldehyde and uranium byproducts. It costs about $70,000 to drain the formaldehyde from the process, Fong said.
“You’re just trading one contaminant for another,” he said. “That’s not a good strategy.”
The researchers have started testing other resins without uranium and formaldehyde issues and plan to include that analysis in a final report slated for late 2013.
The resin has been the most successful at getting close to the public health goal. Another technology, which uses iron to reduce the chromium and then filter it out, has brought the contamination level down to 3 parts per billion.
The water could be filtered again through a membrane with very small pores to get down to 1 part per billion, but that extra step would add to the cost, Fong said.
An analysis of using an iron-based material resembling green table salt to filter out the chromium will be included in next year’s report — although officials have already discovered that the process can be hampered by water with high concentrations of minerals.