A Better View of the Future

A proactive approach to inspection and maintenance helps a small Colorado utility cut inflow & infiltration and sanitary sewer overflows.

A Better View of the Future

Bill Wolf (left) and Gary Link lower a camera tractor through a manhole to a sewer line for video inspection.

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Frequent sanitary sewer overflows once plagued the city of Fruita, Colorado. As is often the case, one of the many factors contributing to the problem was inflow and infiltration.

But those chronic SSO issues are a thing of the past. The city has not had an incident in over a decade. It’s largely thanks to an ambitious staff of three, who take a proactive approach to maintaining the entire 74-mile collections system in the western Colorado city.

“We run into challenges, but I think we do a great job considering the amount of staff we have,” says John Carrillo, wastewater collections crew leader for the city’s Public Works Department.

Fruita implemented a systematic cleaning and inspection cycle in 2002. Carrillo and two others spend the majority of their time maintaining the collections system. The cleaning and inspection program has gradually evolved and is paying dividends for Fruita. Beyond simply eliminating SSOs, the program has helped the city better manage funds and prepare for the future.

“We’re able to actually look at the conditions of our system, compare it against road overlay work and try to schedule work so we can do all the repairs at the same time,” Carrillo says. “We’re not 100 percent there yet, but we’re moving in that direction of being more responsible to the citizens with the decisions we’re making about road and utility maintenance.”

New approach

Fruita has a population of 12,881 with a projected growth rate of 2.5 percent per year over the next 30 years. The collections system serving that population is a combination of new and old. About 86 percent of the 74 miles of sewer line is PVC. Older clay tile makes up about 9 percent of the system. Concrete accounts for 3 percent, 1 percent is sliplined, and another 1 percent is Orangeburg. Fruita maintains that system with an annual operating budget of $360,000, about a quarter of the entire Public Works operations budget.

Carrillo has worked for the city for 10 years, and for the past seven, he has focused on the collections system, overseeing maintenance for eight lift stations, as well as the administrative side of collections. Two other Collections Division employees assist him. Gary Link handles the cleaning work with a Vactor 2100. A smaller unit, a Vactor 2103, is used as a backup and also for working in more restrictive areas of the city. Bill Wulff inspects pipes using a RapidView IBAK North America system with two tractors and three cameras capable of handling pipe from 4 to 48 inches in diameter.

“Prior to 2002, the city only had one outdated jetter truck without a vacuum system,” Carrillo says. “There was about one SSO a month on average at that time, and there was no way of removing anything from the collections system. They were just pushing debris down the line from manhole to manhole.”

So, the city purchased a Vactor 2100 and immediately went full-bore into a cleaning program. 

“At that point, between two and four full loads of sludge and grit were coming out of the collections system daily,” Carrillo says. “As this progressed, we were able to start identifying problem areas of the city. For example, if we started to pull out mud in a line, it usually pointed to a broken or collapsed section of pipe.”

Problem areas were cataloged in handwritten reports. The crew began targeting I&I problem areas through reports from the Vactor operator and tracking of flow conditions in manholes throughout the city. A year into the cleaning program, Fruita added the inspection component with the purchase of a camera van retrofitted with CUES equipment. That aided in more clearly defining the exact sources of I&I and fixing the problems, which mostly center around the oldest parts of the system, Carrillo says. Early on, Fruita identified storm drain inlet connections into the system and took care of them immediately.

System upgrades

The main I&I culprit for Fruita, though, is groundwater from the irrigation season that runs March to October. Again, it’s the oldest parts of the system with clay tile and Orangeburg pipe that are largely affected, so the inspection program has helped identify the areas in greatest need of repair or replacement.

“What we see is the irrigation water follows the existing trench and service lines, which leads to I&I along with mineral deposits near service taps and jointed segments,” Carrillo says. “In the extreme cases, we utilize a cutting attachment on our Vactor to remove deposits. The city does implement a watering schedule for the citizens, but overall during the irrigation season, soils become hydrated and the areas of our collections system with poor ratings collect the excess water.”

When the inspection program was first implemented, the city was making a move to a Microsoft Access database system to log every maintenance event or callout that occurred in the city, and the CCTV inspections became a part of that initiative. As problem areas were identified, funding was allocated to do spot repairs or minor capital projects. But all the inspections were on DVDs stored in filing cabinets.

“They were fairly well-organized, but imagine 1,000 DVDs and you need to find a specific line. You’re pulling out every DVD trying to find it,” Carrillo says. 

When the camera van was scheduled for replacement in 2012, Fruita made a technological upgrade. The city tested out equipment from several vendors and settled on a RapidView IBAK North America system using PipeLogix software.

“We were able to get away from DVDs and actually export the entire video inspection along with graphic reporting to a separate server,” Carrillo says. “Now anyone working for the city can get into our server file and see all the lines that have been inspected.”

A simple scoring system on a 1 to 5 scale (bad to good) was established, taking into account the length of a pipe, its material, and its condition. A score was tied into every event in the database, and that information was used alongside the city’s GIS and mapping system to create a more easily navigable format for identifying problem areas and prioritizing work.

“We can pull up a utility map of the collections system, click on a line and see all the attributes of that line,” Carrillo says. “And then there’s a hyperlink you can select to see the actual video inspection, the score and any reports. There’s also a secondary map that just has the numerical scores of the entire system and color coordinates our troubled areas. Once we started moving this way, we were able to start coordinating these inspections with other planned projects like road overlays and other utility repairs. That has really turned into a big win-win for us.”

Small but mighty

Growing the cleaning and inspection program has not been without its challenges. One is maintaining such a proactive approach with a small staff, Carrillo says. 

“Some months are greater than others, but we really like to maintain a two-year schedule for cleaning and a three-year schedule for inspection,” Carrillo says. “If we’re a mile short, it’s not the end of the world, but we try to stay as close as possible to that schedule.” 

Keeping that schedule means cleaning about 35 miles of sewer line every year and inspecting about 25 miles. Carrillo says Link and Wulff each keep their own schedule. On a typical day, they’ll come in, prep their equipment, and go out in the field for eight hours. The Vactor will take about two loads to the treatment plant, and anywhere from five to 25 inspections will be done, depending on the area and the length of the line. The next day, before heading out again, Link will enter all the previous day’s events into the database — every line that was cleaned and any additional notes. After four full days of inspections, Wulff will usually spend a day exporting everything from the camera into the database, adding notes and scoring each line on the 1 to 5 scale. Any immediate concerns are dealt with along the way.

More for the money

Fruita is currently replacing about a quarter-mile of pipe a year, an amount Carrillo says is acceptable considering the capital funds available, but he’d like to do more.

“You can’t raise rates all the time,” he says.

But Carrillo adds that his advice to other small utilities is to look at it all with a long-term view. “The biggest thing to remember is that everything costs money, but in the large spectrum, you need to determine the long-term savings over the cost today,” he says. 

For example, the money put into regularly cleaning and inspecting the system has cut down on Fruita’s lift station maintenance in the long term. Carrillo says there used to be up to 10 maintenance callouts a month on average because of debris, rags and grease coming into the lift stations. Now the city sometimes goes months without a single lift station issue, and when there is a problem, it’s typically a power outage or a mechanical or electrical failure — not anything collections system-related.

Treatment costs have also gone down.

“Our overall treatment cost has reduced 5 cents per 1,000 gallons, which was $16,000 to $18,000 per year in 2016 and 2017. We have seen an increase of 42.7 mg/L COD, showing that the reduction of I&I is working by concentrations increasing at the treatment plant,” Carrillo says. “By resolving problems with I&I, it allows us to continue with repairs and upgrades to our existing system without having to build ‘new’ conditions to expand capacity. Projects we’ve completed have allowed 140 homes to be tied into our system over the last three years without having to increase capacity. That is a huge win for our department to be able to keep up with the growth of our community.

“You don’t have to blow your budget, but if you’re able to do something to reduce maintenance costs and treatment costs and increase the capacity of the collections system without actually expanding the system, that’s worthwhile. You’ll be money ahead in the end. The long-term investment in infrastructure always needs to be in the back of your head.”


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