How a Rialto water plant may make environmental clean-up history
Day and night, tiny microbes are working to clean up perchlorate and nitrates from contaminated groundwater in the Colton-Rialto water basin.
After years of testing in coordination with state water officials, Rialto’s West Valley Water District will, likely on Wednesday or Thursday make environmental clean-up history by shipping the water directly to customers from a $23 million specialized treatment plant at its headquarters, 855 W. Base Line Rd.
The plant has the capacity to provide the water needs for about 16,000 of West Valley’s 66,000 customers. The district serves the communities of Bloomington, Colton, Fontana, Rialto, parts of unincorporated areas in San Bernardino, and a portion of Jurupa Valley in Riverside County.
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“Other locations are using the same technology, but they are discharging the output of the plant to groundwater or surface water, said Matthew Litchfield, interim general manager.
“This is a harbinger of what is to come,” said Todd S. Webster, a regional vice president of Texas-based Envirogen Technologies Inc., which designed and built the plant.
Fluidized Bed Reactors, which is what the biological treatment plant is, are used for removal of perchlorate and other chemicals elsewhere in California, and other states including Arizona, Nevada, Texas and New Jersey, Webster said.
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The $23 million dollar treatment plant was paid for largely with grant funding including:
• $10 million from the Proposition 84, the Safe Drinking Water, Water Quality and Supply, Flood Control, River and Coastal Protection Bond Act of 2006.
• $2.6 million from the Santa Ana Regional Water Quality Control Board Cleanup and Abatement Account Fund.
• $3 million from the state Water Resources Control Board.
The perchlorate plume is from a military, industrial and agricultural legacy that was discovered in the Rialto-Colton groundwater basin in 1997, according to U.S. Geological Survey studies.
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Perchlorate is rich in oxygen, and for that quality is used as a component of solid rocket fuels, flares, fireworks and explosives, a USGS report says.
In 1998, West Valley and the city of Rialto shut down several wells due to perchlorate detection.
“Some time ago, the leadership of West Valley made a decision to try and solve the perchlorate problem and not to make attorneys wealthy,” said Dr. Clifford O. Young, Sr., president of the West Valley Water District.
In 2005, the West Valley district installed ion exchange systems on some wells with low concentrations of perchlorate. This uses a resin to pull out pollution.
For higher contamination levels, another approach was needed and the district elected to pursue using perchlorate-eating microbes.
A small pilot project was developed and successfully tested before moving onto building the full-scale version, which began in 2011. The final permit for the plant was granted on May 17.
“The state of California was involved with us every step of the way,” Webster said.
Here’s a simplified view of how the system works:
Naturally occurring microbes are placed into giant cylindrical tanks and fed acetic acid, a strong form of vinegar, which helps them grow and multiply.
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Water from the polluted wells is introduced at the bottom of the tanks and forced upward through a medium containing the bacteria.
At first, the bacteria withdraw the oxygen from the water, although some of the free oxygen was removed at an earlier stage on the grounds of the plant, said Sergio Granda, chief water treatment plant operator.
Once the microbes have drawn out available oxygen from the water, they go after the oxygen in the water’s nitrates.
Then the bacteria attack the perchlorate, pulling out the oxygen, and destroying it as far as being a public health threat, Granda said.
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Minus the harmful nitrate and perchlorate, the water moves to a final treatment modeled after West Valley’s Oliver P. Roemer Water Filtration Facility — which currently ships water directly to consumers, Webster said.
That way, employees would have a familiarity with the operations of the final filtration and chloration, he said.
The water feeding West Valley’s giant twin FBRs has had perchlorate readings in the several hundred parts per billion range, while the state drinking water standard allows no more than 6 parts per billion, Webster said.
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Ingestion of perchlorate can affect iodine uptake by the human thyroid and thyroidal hormone production needed for normal growth and development, scientists say.
Fluidized Bed Reactors are good ways to treat high levels of pollution, Webster said. The other method uses expensive resins and loses its effectiveness quickly with high pollution levels.
Those resins do not destroy the perchlorate; they bind with it to remove it from the water.
Afterward, the resins need to be regenerated or burned.
Although the up-front capital costs are higher with FBR’s, the operational costs are lower, he said.
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A paper co-authored by Webster found, in one case, ion-echange was about seven times more expensive than a bio-reactor.
Operational cost for the West bio-reactor are estimated to be $900,000 annually.
And there is no risk of the perchlorate being reintroduced into the water system with FBRs, Webster said.
It’s eliminated.
