On Friday, Sept. 10 an “upset” occurred at the Star Valley sewage treatment plant, causing partially treated sludge to spill into Houston Creek.
“What happened is something was flushed down the sewer in Houston Creek Landing probably that caused the plant to go crazy,” said Jake Garrett, manager of the wastewater division with Gila County.
He said whatever was flushed caused the bacteria treating the sewage to go out of balance. Currently, officials believe motor oil was the cause.
“Nothing should go down the drain that wouldn’t go in your mouth,” said Garrett.
The sludge has left a black layer of mud and oil along a stretch of Houston Creek near the Houston Creek RV Resort off Moonlight Drive.
“You’ll see along the creek a half mile long black deposited material, which is the sludge that came out because of the upset. It’s made up of partially treated sewage,” said Garrett.
The Arizona Department of Environmental Quality is working with Pivotal Wastewater, the company that owns the Houston Creek Landing Wastewater Treatment Plant (WWTP).
“Upsets are operating conditions at any WWTP that result in inefficient or incomplete treatment of wastewater and can occur from time to time if a plant has problems with a biological treatment or a mechanical issue,” said Caroline E. Oppleman, ADEQ communications director.
ADEQ received a complaint from a resident on Sept. 1 after they noticed the color of the stream “was off.” They submitted a complaint to ADEQ on Sept. 7. ADEQ sent a field inspector on Sept. 8, who confirmed sewage sludge in the creek.
“A number of factors may have contributed to the upset. The WWTP reported that there was an accumulation of partially treated sewage sludge in the secondary clarifier (part of the treatment process) which then led to the discharge of that material into the creek. Since that time, the WWTP has resolved the upset and pumped out the secondary clarifier to prevent further release,” Oppleman said.
The release was stopped on Sept. 10.
The company hired Kary Environmental Services to spray an emergency liquid spill control to clean up the spill. Work started on Sept. 16.
Cleanup could take 30 to 60 days, according to the company on its website.
Oppleman said it is difficult to estimate how much waste was released.
Garrett calls the material a biological disinfectant that “eats all the bad stuff.”
A contractor has applied an organic, biodegradable, cleanup solution called Micro-Blaze Emergency Liquid Spill Control.
“This solution is a form of bioremediation that will digest organic materials in soil and water and control odors,” Oppleman said. “This is an important step that needs to be taken to protect public health as part of the cleanup process. Since this solution is biological in nature, it takes seven days to treat the area. After seven days, the WWTP contractor will return to remove any remaining solid or sludge material for proper disposal, monitor the progress of the ongoing bioremediation, and take any necessary additional action.”
Currently, the material has caused a white foam to form at the end of the pipe the treatment plant uses for the treated water to exit.
The day treatment/remediation started, the water ran clear, while frogs and dragonflies continued about their business in the slow-moving tiny trickle of the creek.
Awareness of the emergency has rolled out slowly.
On Sept. 10, residents of Star Valley received a message from the county’s emergency communications program Everbridge that said, “Wastewater in Houston Creek in Star Valley,” but not much else.
Then on Thursday, Sept. 16, the Citizens Emergency Response Team (CERT) received a request for help from the Gila County Health and Emergency Management Department to knock on doors to warn residents about the health risk of going into the creek. Sheriff Adam Shepherd offered the posse to help knock on doors as well.
The message, “avoid all contact with water and stream bed in this area ... untreated wastewater and deposited sludge can harm. These wastewater overflows carry pathogens, bacteria and other compounds that pose a risk to public health and the environment.”
“Out of an abundance of caution, residents, including pets, should stay away from Houston Creek from Rainbow Drive to the end of Moonlight Drive (south of Sprague Drive) until the cleanup work is completed and follow guidance on signs posted in the area and at creek access points because partially treated sewage sludge may contain harmful pathogens, bacteria and other compounds,” Oppleman said.
Residents should avoid all contact with water and the creek bed in this area and not swim, drink, wade or walk in the creek bed while notices are posted.
Garrett understands the biological disinfectant will separate out the solids and allow crews to remove them. ADEQ will then monitor and test the creek until levels clear and residents can continue to enjoy the area.
The county will send out a message on Everbridge when remediation efforts have concluded and the water tests clean. Garrett suggests looking on the Pivotal website for updates as well.
The spill might concern those with a well, as many in Star Valley have.
“Many of those wells are uphill from the spill,” said Garrett.
He does caution well owners to test their wells every year, “because of what was done in the past” in Star Valley.
“In the current regulations for wastewater positions, a separation of 100 feet is required,” he said. “In the old days there were only 50 feet separations required,” Garrett said.
The plant returned to normal function Friday.
ADEQ and Gila County officials are available to answer questions from community members on the ADEQ Hotline at 602-771-1440.
Jake Garrett, manager, Gila County Environmental Health Division, can be reached at 928-701-1669 (mobile).