The City of Prescott took the first step Tuesday in a yearlong process to improve the quality of the effluent (treated wastewater) coming out of the Airport Wastewater Treatment Plant.
In a unanimous vote, the Prescott City Council approved an Arizona Department of Environmental Quality (ADQ) “consent order” that requires the city to deal with the high levels of fluoride that have been detected in its treated sewage.
During all four quarters in 2012, the city’s effluent tested above the state’s fluoride standard of 4.0 milligrams pre liter. A city memo stated that the reported “exceedances” ranged from 5.1 milligrams per liter to a high of 9.4.
Testing from the first quarter of 2013 showed that the fluoride level was down to 2.5 mg/L, which is within the state standards.
A written statement that the city released on Friday attributed the fluoride problem to Pure Wafer, Inc., a plant located near the Prescott Airport that does silicon wafer recycling for the semi-conductor industry.
The plant reportedly uses hydrofluoric acid to scrub the wafers for recycling.
Prior to the approval of the consent order Tuesday, the council also approved an ordinance that implemented a new wastewater pretreatment program for industrial users.
Engineering Services Director Mark Nietupski led off the discussion on the consent order by telling the council: “With the prior action, you have taken a major step toward this.”
Basically, he said, the pretreatment ordinance would require the city’s five industries to take a number of steps to control their pollutant discharges.
In Pure Wafer’s case, Nietupski said city and company officials are still discussing how that will happen.
“We’re in a dialogue with Pure Wafer on a solution,” Nietupski said after the meeting.
Until those discussions are further along, Nietupski said it is too early to say what the steps might involve.
After the meeting, Jerry Winters, Pure Wafer’s director of U.S. operations, agreed that the two parties are working together to come to a resolution.
He explained that Pure Wafer (formerly Exsil, Inc.) entered a development agreement with the city in 1997 to locate in Prescott.
Noting that the de-velopment agreement “covers certain water and sewer elements,” Winters added that the city and Pure Wafer currently have some “interpretation differences” over what the development agreement requires.
Those differences pertain to “what the limits are and who’s responsible to deal with it,” Winters said.
The 17-page development agreement from March 1997 covers a number of issues relating to Exsil’s location in Prescott. The section on “wastewater discharge” touches on issues such as pretreatment, artificial recharge, and direct reuse, and it concludes with:
“In the event that developer discharges effluent of an inferior quality than is required by permit, and the city’s facilities are negatively impacted, developer shall be financially responsible for remediation of those facilities to the condition that existed prior to the discharge of the substandard effluent.”
Nietupski said the two sides have yet to determine the cost and who would be responsible. If the city were to incur any cost, he said, the expenditure would have to go back to the City Council for approval.
Prior to its vote on the consent order, the council heard from local resident Kathy Swenson, who questioned the large amount of water that Pure Wafer uses in its silicon wafer reclamation.
“It just doesn’t make sense that we ever allowed that to happen,” Swenson said of the 1997 agreement that brought Exsil to Prescott.
Council members responded that the council at the time saw a value in attracting the employer to Prescott.
Winters emphasized after the meeting that the levels of water were known when the city entered the development agreement with Exsil.
He added that Pure Wafer employs about 110 people and has an annual payroll of $5.7 million.
The consent order requires the city to submit monthly status reports to ADEQ over the coming year.
• April 14, 2016: 9th Circuit Doubts Validity of City’s Fluoride Rules
• Jan 10, 2016: Prescott vs. Pure Wafer Inc.
• April 17, 2014: Pure Wafer, Inc., Plaintiff v. City of Prescott et al., Defendants. Findings of Fact and Conclusions of Law and Permanent Injunction.
• Nov 28, 2013: Prescott hires outside law firm to fight Pure Wafer lawsuit
• Nov 22, 2013: Pure Wafer fluoride lawsuit
• Oct 2, 2013: Fluoride Rule in Prescott, Ariz., Spurs Lawsuit
• July 20, 2013: ADEQ fines Pure Wafer $120,000 for not having air quality permit
• July 19, 2013: Press release from Arizona Department of Environmental Quality