CEDAR CITY — The Cedar City Regional Wastewater Treatment Facility is working hard daily to remove inorganic waste like cellphones, towels and diamond rings from wastewater, prevent sewage backups and disinfect sewer water.

Wastewater superintendent Eric Bonzo is in charge of the 40-acre facility and collection system, which consists of all sewer lines, maintenance holes and lift stations within Cedar City, Enoch and parts of Iron County.

There are three lift stations in Cedar City and five in the county that pump wastewater to the plant but 95% of the water from Cedar City is gravity fed, Bonzo said.

It takes three to four hours to treat the wastewater flowing into the facility. Once treated and disinfected with chlorine, a local farm uses the effluent water for irrigation. Additionally, the facility uses disinfected water for cleaning and watering its lawns.

The Division relies on the supervisory control and data acquisition system to monitor the facility and alert staff to equipment failures and other potential issues. Networking devices in various facilities collect data and send it via fiber optic cables to the facility’s servers. Bonzo described it as the “heart of the plant.”

Councilmember Craig Isom said at an April Cedar City Council Meeting that he took a tour of the treatment facility and had a new appreciation of “something we take for granted.”

He continued to praise Bonzo’s work.

“There are superstars and then there are superstars,” Isom said. “Eric is one of the latter. I just cannot tell you how grateful (I am) for the way you run that operation.”

Bonzo said he credits his staff for the plant’s success.

“They’re great operators,” he said. “I mean, we’re recognized year after year by the state of Utah, the EPA, our permit writers as one of the cleanest wastewater treatment facilities in the state of Utah and one that was one of the most well maintained.”

Wastewater is microbiology

Key to the process is a colony of bacteria, Bonzo said, adding that the colony needs to be consistently monitored because changing weather, wastewater contents and other types of bacteria can affect its health and efficiency.

“Every day is a science project,” he said.

Wastewater is microbiology, Bonzo said. There are thousands of different types of bacteria at work in the plant breaking down organic materials in wastewater. The facility’s staff take samples and run tests to determine if the bacteria are getting enough, but not too much food to ensure the colony remains healthy.

“Keep those bugs happy because if they aren’t happy, you aren’t happy,” Bonzo said.

The colony is vulnerable to toxic substances, like gasoline, Bonzo said. A toxic substance made its way to the plant in 2018, killing the bacteria and halting facility processes for 43 days.

He said his biggest fear is having a toxic substance enter the plant again after an illegal dump. Once a colony is destroyed, staff must wait for the population to naturally rebuild itself.

2021 floods

There were nine rainstorms that affected the plant from mid-July to mid-August in 2021, Bonzo said, adding that the worst occurred in Enoch where the floods overflowed their sewer system and backed up into the community and citizens’ basements.

The Cedar City Collection crew and cleaning trucks from Brian Head, Enterprise and Salt Lake City were all dispatched to Enoch to help get the town back to normal.

After assisting Enoch, Bonzo said, he’d gone to the plant to prepare for oncoming storms. The city was inundated with floodwaters, causing maintenance manhole covers to pop out of the ground.

Power at the plant was down and the mechanical gate wouldn’t open, so Bonzo needed to go through the West gate. As he began inserting his key into the padlock, he said he saw a flash of light.

At the time, he said he thought the lightning had struck farther away, near the highway. But holding a chain and standing on a metal cattle guard, he had been electrocuted. He said he felt the shock move from his arm into his neck, which was sore for about three days.

“It was intense,” he said.

The plant was designed to process 4.8 million gallons a day and 11 million gallons at peak flow. Bonzo said he worries when the water flow reaches about 8 million gallons per day because then no wastewater is getting processed. At one point during the floods, the plant was pushing through over 20 million gallons per day, and due to the high volume, the facility’s primary goal was to move the water out.

Processing sludge

When Iron County was experiencing heavy flooding, large amounts of sediment entered the sewer system through maintenance hole openings that were approximately 3/4 of an inch in size. By September 2021, the Wastewater Division could see the floods’ full impact, Bonzo said, noting that it took five months to move the bulk of mud out of the facility. The process is still ongoing.

Bonzo said close to 500 metric tons of dirt and mud had mixed with the estimated 800 metric tons of sludge the plant typically processes. Due to contamination, the plant had to process, dehydrate and haul the sludge to the landfill.

The process was slowed by the onset of autumn when the weather made drying the sludge more difficult. Only about 15% of the sludge cake is solid and the rest is water, Bonzo said. Because the landfill charges by weight, the plant allows the sludge to become fully dehydrated before carrying it out.

The Division will prepare for future floods by placing sandbags over maintenance holes to prevent dirt and water from entering the sewer system. However, Bonzo noted that there are over 4,000 maintenance holes in Cedar City alone and the Division cannot cover them all.

Additionally, the plant recently installed a grit removal channel, which is approximately 15 feet deep and allows sediment to settle before it enters the plant, Bonzo said. Once settled, mud, dirt and rocks can be removed and hauled away.

Maintaining the system

Bonzo said that 20 years ago, the water department maintained the sewer lines when necessary, and 20-30 sewer backups were reported in Cedar City homes every year.

Currently, the wastewater division regularly maintains the system, cleaning and videoing sewer lines every four years, a task that is required by Utah every seven years.

Routine inspection and maintenance allow the Division to monitor for pipe failures and other repairs and create a prioritized list of what repairs must be completed each year. Bonzo said Cedar City had just one major sewer backup in the last six to seven years.

A couple of years ago, there was a sewer backup at the Iron County Jail. He said his crew was able to break the blockage and remove toothbrushes, toothpaste containers and an estimated 2,000 AA batteries.

The pretreatment crew subsequently worked with Iron County to install a pretreatment grinder to avoid future blockages, Bonzo said, adding that when the new jail is built, the pretreatment program is planning to do extensive work there as well.

The primary causes of sewer backups are grease and flushable wipes, he said, noting that despite the name, flushable wipes do not break down and cause millions of dollars’ worth of sewer backups.

According to a wastewater update posted on Cedar City’s website, personal and disinfectant wipes are made from cloth-like materials that can accumulate in the sewer system as they don’t break down like toilet paper. When used with low-flow appliances, flushable wipes can become dry and clump together, becoming “hard like a rock,” and causing additional problems, such as clogging mechanical sewer lift stations.

The Pretreatment Program coordinator Peter Sury said the program regulates all commercial-industrial facilities, such as automotive businesses, mortuaries, restaurants and car washes in Cedar City and Enoch, as well as other places in Iron County. The program also works with various state departments and issues environmental permits.

Bonzo said the Division’s pretreatment technician Kurt Raffield inspects the city’s more than 237 food establishments four times a year. He tests the grease and oil separators, which filter out oil and grease from the water entering the sewer system.

“We used to have a lot of grease problems in our collection system,” Bonzo said. “But by the due diligence of our pretreatment department, our collections department, everything pays off.”

Citizens should avoid putting anything in the toilet that isn’t toilet paper or “what a person does in the toilet,” Bonzo said. Additionally, he said individuals should avoid putting oil, grease or eggshells down sink drains or in garbage disposals. Eggshells are abrasive and can create problems for pumps and other equipment.

“It’s not a garbage can,” he said.

Bonzo said an operator at the plant called him to the screenings building, where everything larger than a cigarette butt is removed from wastewater. A 14-inch, rubber car tire was stuck in the machinery. He said someone must have lifted a maintenance hole cover near a 36-inch trunk line flowing into the facility and dropped it in because it wouldn’t have fit through a smaller pipe.

A variety of unusual items have been filtered at the Wastewater Treatment Plant, including diamond rings, bath towels, matchbox cars, bouncy balls, cash and cellphones, Bonzo said.

“I’ll give you a little quote I learned a long time ago: ‘Wastewater is the only science in the world that has no control of what comes in but we must have a defined output.’ We have no control what comes into this plant,” he said.

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