The city of Flagstaff has reported that the Wildcat Hill Wastewater Treatment Plant exceeded its permitted E. coli bacteria levels in June.
The city released the news about the E. coli Wednesday afternoon and said it has already notified the Arizona Department of Environmental Quality.
According to the press release, the Wildcat permit limit for E. coli is 15 colony forming units /100 milliliters.
On June 12-14, the maximum for E. coli tested at Wildcat was 231 CFU. According to the city, the wastewater was not sent into the reclaimed distribution system.
On June 16-17, the maximum for E. coli tested at Wildcat was 129 CFU. This water was treated with chlorine, which disinfects the E. coli, before it was sent into the reclaimed wastewater system.
Since those dates, the plant equipment has been cleaned and the plant has not exceeded its E. coli levels. As a measure of comparison, ADEQ has established the maximum E. coli concentration for full body contact at 235 CFU and partial body contact of 575 CFU. The city has notified ADEQ and has addressed external and internal issues that resulted in the exceeded levels.
During the same time, the plant was having problems with cloudy water. It is unknown if the two are related.
An investigation into the cause determined that a local manufacturing company had been discharging wastewater into the city’s sewer system that affected Wildcat’s ability to treat effectively. The city and the manufacturing plant are collaborating to prevent it from happening again.
— Sun staff report