Operations at Wildcat Wastewater Treatment Plant hit a temporary hiccup earlier this month due to a malfunction at SCA Tissue’s Flagstaff facility. The company’s in-house water treatment system malfunctioned, causing an increase in the inert fibers and inorganic materials like sand, clay and carbonates in the plant’s wastewater. At their highest, the levels of suspended solids were nearly four times the limits of the city permit of 1,200 milligrams per liter.
SCA noticed the problem on Jan. 4 and notified the city the same day because its wastewater is discharged into the municipal sewer system. Human health or safety impacts weren’t a concern because water treated at Wildcat wasn’t being fed back into the city’s reclaimed wastewater system at that time, Flagstaff Utilities Director Brad Hill wrote in an email. The city’s other treatment plant, Rio de Flag, was not affected. High levels of suspended solids are a problem, though, because they hamper the plant’s ability to effectively treat wastewater. Hill also wrote that, in general, a high concentration of solids in water could pose a health concern, but it all depends on what those compounds are.
Within four days of noticing its wastewater problem, SCA had identified the root cause — unclumped solids that were floating in the water — and implemented new procedures to correct the issue and prevent it from happening again, company spokeswoman Susan Michini wrote in an email. New operating procedures call for halting production if the release of total suspended solids is trending to a level close to the city permit’s limit.
In Arizona, SCA makes paper towel and tissue products to be used in places like office buildings, schools and restaurants. Statewide, the company uses 72,000 tons of recycled paper each year, which is turned into pulp and made into new products.
Onsite wastewater treatment is required to handle the sand, clay and carbonate residues that are left over from the de-inking process necessary to turn recycled paper into pulp, Michini wrote. All of SCA’s North American mills pre-treat their wastewater to minimize the load on water treatment plants downstream, the company said. After getting notification from SCA that solids weren’t properly settling out of its wastewater, the city issued a violation notice to the company for exceeding the industrial discharge limit for total suspended solids. The notice gave SCA 24 hours to stop discharging its industrial wastewater into the city’s sewer system, which the company did. It also temporarily shut down production.
SCA was then required to submit a detailed report describing the cause, location, volume, concentration, time and dates of the discharge, as well as improvements the company had made to its treatment processes to bring it back into compliance. In that report, SCA also mentioned it would provide weekly reports tracking levels of suspended solids in its wastewater until the city says it should stop.
For its part, the city will not be doing any additional monitoring of the company beyond the twice-a-year sampling outlined in its permit, Hill wrote. Once SCA’s wastewater dropped to within the range of its permit on Jan. 8, it took Wildcat about two days to process the surge of solids in the water, Hill wrote. Wildcat was not discharging treated effluent into the city’s reclaimed wastewater system when the SCA violation occurred due to seasonal low demand for reclaimed wastewater. It has only been discharging water into the Rio de Flag, Hill wrote.