Working toward cleaner water
Joel Danoy
Tracy Press
12/23/2011
One week remains for a public review period for the proposed Tracy Desalination and Green Energy Project, which will allow the water discharged into the Delta by city of Tracy to meet salt-level standards
According to Steve Bayley, deputy director of public works for Tracy, the state of California could begin enforcing a longstanding mandate that dictates municipalities discharging water into the Sacramento-San Joaquin Delta meet salinity standards. The city has been in noncompliance “for several years,” he said.
Since the Delta is a freshwater ecosystem, it can be disrupted if the salinity level of discharged water is too high. The agricultural industry in the Central Valley would also be affected, because water that is too salty will kill crop production and can’t be used to water livestock.
“It would have a devastating impact on the region’s crops,” Bayley said.
Fresh water from New Melones Reservoir, located near Jamestown in the Sierra Nevada foothills, is currently released into the Delta to balance the salinity level of the city’s effluent, he said. However, that practice could soon be eliminated if more fresh water is shipped from the region to Southern California, as the battle over the resource only seems to be intensifying.
With less fresh water to flush out the Delta, the state would then be required to enforce that salinity level requirements for discharge water, Bayley said.
The Tracy desalinization plant will process runoff water created at the Tracy Wastewater Treatment Plant. According to Bayley, the runoff being treated will be fed into a boiler and turned into steam. The steam is then transferred to a drying pan, where water is splashed on it to creating a cooling effect. Upon cooling, it exits the pan, basically as distilled water.
Designers have built a small-scale model of the machine at the wastewater treatment plant.
“The purpose of this is to show that it works, see what the salt content is like, see if any weird odors develop,” Bayley explained. “You just want to do a hands-on demonstration before building a facility to this magnitude.”
The plant’s heat source would come from biomass, such as walnut and almond shells, as well as other biomass materials collected in a 50-mile radius of the plant. Nearly 16.4 megawatt-hours of electricity will be created and sold to the local electrical grid, which could save rate payers about $400,000 annually, Bayley said.
This summer, the Musco Family Olive Co. opened its own one-of-a-kind biomass plant that uses olive pits as fuel. The 100,000-gallon-per-day plant processes salty wastewater created during olive manufacturing. The exhaust from the burning olive pits is scrubbed so well, it qualifies as the cleanest-burning biomass plant in the state.
Bayley said officials in Tracy saw the success and positive environmental impact of the plant — which opened earlier this year — and thought it could be duplicated by the city.
“They have a great thing going on over there,” he said. “We want to do that here, just on a larger scale.”
Once the review process is complete, Bayley said officials need to secure a power-purchase agreement to use the created electricity, secure further financing and then proceed with construction.
“Theoretically, the construction could start in less than a year,” he said. “Then it’s probably an 18-month construction time. So theoretically, it could be done in about two-and-a-half years without any delays or setbacks.”
