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Wastewater at the Grass Valley treatment plant off Freeman Lane contains residential, commercial, industrial and road wastes.
Ultraviolet radiation will replace polluting chlorine to treat water going into Wolf Creek from Grass Valley’s sewage treatment plant starting next year.
The more complex chlorine process will be scuttled in favor of intense blue lights zapping bacteria at the treatment plant.
“It’s like having a large tanning booth out there,” Mayor Mark Johnson joked at Tuesday’s City Council meeting after being updated on the plans.
Using ultraviolet light to rid wastewater of bacteria is just the next step state officials want more local governments to take on, said Norm Benton, the treatment facility’s lead plant operator.
“It’s nice. it’s just expensive,” Benton said.
Ultraviolet radiation will cost the city an estimated $7 million to install. It’s generally a more expensive cleaning process because it uses much more energy, Benton said. But it’s also an easier process, he added.
Chlorine requires the wastewater to sit for “an hour or so” to allow the cleaning to take place, Benton said. To neutralize potential cancer-causing agents for fish in the creek, the water is then treated with sulfur dioxide — another toxic chemical.
New treatment standards come at a continually quicker and more expensive pace, Benton said.
“It used to be they’d stick us with these upgrades every 10 to 15 years,” Benton said, referring to state and federal standards. “It’s every three years now.”
<b>Mine waste treated</b>
That’s hardly the only challenge Benton and his colleagues face at the wastewater treatment plant.
The plant, which opened in 1949, has been treating nearly half a million gallons of water a day from a nearby abandoned mine for the last several years, Benton said. The mine water contains iron and manganese, he said.
Treatment of the mine water has cost the city $1.5 million so far. It has become the subject of a multiyear lawsuit between the Denver-based Newmont Mining Corp., which owns the mine shaft, and the city. Grass Valley wants Newmont to reimburse the city for treating the water coming out of an abandoned mine shaft, but Newmont says it’s not responsible. The suit is set for trial in federal court in Sacramento this September.
The mine water and all other water from municipal, residential, industrial and commercial sources will continue to be treated with chlorine at least until March 2008.
Grass Valley officials are seeking an extension of the early 2008 deadline for the ultraviolet radiation upgrade. In the meantime, city officials are asking for help from the California’s revolving loan fund to cover costs.
Whenever the upgrade work starts, it could take about nine months to finish, Benton said.
But what’s good for the fish of Wolf Creek won’t be applied to water for the residents of Grass Valley — at least for now. The city hasn’t yet been asked to make the same treatment upgrade for drinking water.
<i>To contact Staff Writer Greg Moberly, e-mail gregm@theunion.com or call 477-4234.</i>
The more complex chlorine process will be scuttled in favor of intense blue lights zapping bacteria at the treatment plant.
“It’s like having a large tanning booth out there,” Mayor Mark Johnson joked at Tuesday’s City Council meeting after being updated on the plans.
Using ultraviolet light to rid wastewater of bacteria is just the next step state officials want more local governments to take on, said Norm Benton, the treatment facility’s lead plant operator.
“It’s nice. it’s just expensive,” Benton said.
Ultraviolet radiation will cost the city an estimated $7 million to install. It’s generally a more expensive cleaning process because it uses much more energy, Benton said. But it’s also an easier process, he added.
Chlorine requires the wastewater to sit for “an hour or so” to allow the cleaning to take place, Benton said. To neutralize potential cancer-causing agents for fish in the creek, the water is then treated with sulfur dioxide — another toxic chemical.
New treatment standards come at a continually quicker and more expensive pace, Benton said.
“It used to be they’d stick us with these upgrades every 10 to 15 years,” Benton said, referring to state and federal standards. “It’s every three years now.”
<b>Mine waste treated</b>
That’s hardly the only challenge Benton and his colleagues face at the wastewater treatment plant.
The plant, which opened in 1949, has been treating nearly half a million gallons of water a day from a nearby abandoned mine for the last several years, Benton said. The mine water contains iron and manganese, he said.
Treatment of the mine water has cost the city $1.5 million so far. It has become the subject of a multiyear lawsuit between the Denver-based Newmont Mining Corp., which owns the mine shaft, and the city. Grass Valley wants Newmont to reimburse the city for treating the water coming out of an abandoned mine shaft, but Newmont says it’s not responsible. The suit is set for trial in federal court in Sacramento this September.
The mine water and all other water from municipal, residential, industrial and commercial sources will continue to be treated with chlorine at least until March 2008.
Grass Valley officials are seeking an extension of the early 2008 deadline for the ultraviolet radiation upgrade. In the meantime, city officials are asking for help from the California’s revolving loan fund to cover costs.
Whenever the upgrade work starts, it could take about nine months to finish, Benton said.
But what’s good for the fish of Wolf Creek won’t be applied to water for the residents of Grass Valley — at least for now. The city hasn’t yet been asked to make the same treatment upgrade for drinking water.
<i>To contact Staff Writer Greg Moberly, e-mail gregm@theunion.com or call 477-4234.</i>
