Management of the sewer system in Johnson County, Kansas, is no guessing game.

Johnson County Wastewater is employing a data-based tool that enables the agency to identify and prioritize critical maintenance and repairs and to maximize the life of the pipes in its collections system. Called the Collection System Asset Management Plan, or CSAMP, the tool assimilates data collected by the division’s CCTV units and delivers weekly assessments of sewer conditions, identifying critical needs, assessing risks, and assigning next actions. If a pipe needs to be repaired or replaced, CSAMP recommends the most effective solution.

Initiated in 2014, the program is now in its fifth year and has already produced significant savings. “We’re able to minimize risks and thereby minimize costs,” says Patrick Beane, P.E., Johnson County Wastewater asset manager. “The more data we collect, the better we are (at doing our job).”

The Johnson County system

The Johnson County Wastewater collections and treatment system serves more than 400,000 residents who live in 16 bedroom communities southwest of Kansas City. The system includes seven treatment plants, which together process about 50 mgd, and over 2,250 miles of gravity sewer lines, including 42 miles of force main and 32 pumping stations. There are no combined sewers.

The collections system consists of a mixture of pipe sizes and materials, some dating back to the early 1940s when the county chose to build its own sewer system instead of sending wastewater to Kansas City. The network developed rapidly, matching the residential growth in the area following World War II. The first treatment plant was built in 1949 and was run by one employee hired in 1947. The current Johnson County Wastewater employs 215 people. The Johnson County Wastewater collections staff numbers 53 people, and nearly all of the maintenance and operation of the collections system is done in-house.

The sewer lines primarily consist of smaller 8-, 10-, and 12-inch pipe that includes clay, PVC, and ductile iron. The larger-diameter interceptors are a mix of reinforced concrete, iron and fiberglass pipes. The system has 55,000 manholes, approximately half of which are older brick construction.

Johnson County Wastewater uses a pair of Vactor jet/vac combo trucks and five additional Vactor cleaning trucks to keep the lines clear and operational. Inspection is accomplished with a recently upgraded fleet of four Envirosight CCTV units that televise about 150 miles a year.

“Our goal is to maximize our cleaning capacity, which is up to 485 miles a year — or about 20 percent of the entire system,” says Joe Barnes, project manager. “We try to clean from top to bottom, pulling the material toward us.”

The crew operates on a two/four/eight-year cycle, cleaning the highest risk pipes every two years, which are primarily the oldest clay pipes. The four-year cycle includes a mix of clay and other types of pipes, and the eight-year lines are generally the newest pipes. That has replaced an old three/five/seven schedule that Barnes says, “had a lot of peaks and valleys in the amount of pipe that needed to be cleaned each year.

“Some of our pipes are lined,” he adds, and they require special attention.

The wide variety of pipe sizes and materials represents the biggest challenge for the Johnson County Wastewater collections crew.

“We have to have a variety of cleaning nozzle sizes on hand, in order to match up to the pipe size,” Barnes says.

The clay pipes require a special effort. “They normally have a 50-year anticipated life, and we’re trying to get them inspected at or before 80 percent of that — 40 years,” Barnes says. Upgrading the smaller 6-inch lines to 8-inch is another challenge.

As with most sewer systems, infiltration and inflow can be an issue. “We address I&I all the time,” Barnes says. “We keep attacking it as our lines get older.”

CSAMP to the rescue

Faced with such a far-flung sewer system, and the variety of pipe ages, sizes, and materials of construction, the CSAMP has been a godsend for Johnson County Wastewater.

It was developed five years ago by the agency in conjunction with its engineering consultant, HDR. The program pulls together all the maintenance, repair, and replacement needs; prioritizes the needs based on criticality of the required work; and recommends appropriate next actions for each pipe. It features a decision-logic algorithm that matches the agency’s business logic and renewal strategies.

At the heart of the CSAMP is the data that resides on the agency’s Lucity enterprise asset management software. It’s updated on a weekly basis from the department’s collected CCTV data. The pipe condition data are uploaded, the model runs over the weekend, and it reports assess risk ratings and what actions are required. Data are coordinated with the agency’s computerized maintenance management system and GIS mapping systems.

“During the development of the CSAMP in workshops with HDR, we developed a needs list of 131 initiatives,” Beane says. “We met with all of the different groups that would be impacted to refine the approach and develop the implementation plan for those improvement initiatives. We said, ‘Here’s what we need to achieve.’ It was hard work by everybody.

“Obviously,” Beane continues, “we couldn’t do all of these at once.” But by continuing to inspect the sewers, identifying critical needs, assessing risks, and recommending next actions, the CSAMP has accomplished a lot in the last five years — a period Beane calls a “journey.”

“Our CSAMP is not unique. All utilities from Fort Worth (Texas) to Kansas City face similar challenges,” he notes. “It’s based on our system and our specific needs. It’s a never-ending continuous improvement program of determining how we get better at what we’re doing.”

He points to a number of specific accomplishments: “It’s helped us develop a long-term plan and shored up our capital improvements program. It prioritizes and details what we’re asking of our ratepayers. We try not to overburden them through our requests for repairs.”

The CSAMP also helps in the agency’s communications with its board by identifying and justifying critical projects. Furthermore, it has helped Johnson County Wastewater modify cleaning schedules, minimize failures, track specific performance indicators, and transfer knowledge to new employees (see sidebar).

Prior to adopting the CSAMP, Johnson County Wastewater had only completed inspections on approximately 20 percent of its sewer system, concentrating on likely high-risk areas. The program has also allowed Johnson County Wastewater to validate it was in full compliance with its line cleaning risk management guidelines in 2014. And it tracks compliance each year.

Repair and replace

The CSAMP’s ability to identify and recommend specific repairs and replacements may be its most valuable feature. By analyzing thousands of observations on a weekly basis, it recommends repairs or replacements where needed, as well as the criticality of the project.

“Based on the defect and the seriousness of it, we can determine what type of repair a pipe needs — a pipe patch short liner, a full CIPP liner, or opencut excavation,” Barnes says. “Is it a small hole, or a crack, or a defect that could lead to total collapse?”

He says patches are applied by Johnson County Wastewater staff to 5-foot sections having just one defect. His team uses trailer-mounted Trelleborg Pipe Seals liner systems to make the repairs. CIPP is also the primary repair option for longer sections of pipe. The current contractor is SAK Construction. “We bid out a five-year contact for pipe rehabilitation and typically get good pricing,” Beane says.

When a pipe wall is deformed or missing and the pipe is losing capacity, the opencut method may be called for.

Much of the repair work is done in-house, but outside firms are used when the work is too deep for Johnson County Wastewater equipment or when access to the damaged section is difficult.

The data collected through the line cleaning efforts are equally vital. “We are able to generate consistent findings on sludge, roots, what kind of material we are dealing with, and if we are on the right cleaning schedule,” Barnes says. “We don’t want to waste resources and possibly degrade the pipe by cleaning it unnecessarily.”

In other cases, the program reveals a sound pipe and puts it in a monitoring-only status.

That’s important in the overall objective of the CSAMP at Johnson County Wastewater. “We want to maximize the life of our assets, especially our old clay pipe,” Beane says. “With CSAMP, we’ve found out it’s actually in better shape than we expected. If we had TV tapes from 10 or 20 year ago, we’d have even better understanding of the risk in our system.”

Even so, Beane says the program has helped Johnson County Wastewater save money in contracted cleaning and CCTV expenses.

In the end, it’s all about cost. “When we started, we had a worst-case budgetary backlog of some $400 million,” Beane says. “But we’ve actually been spending between $5 and $7 million a year by not doing work except when it is needed. Eventually we’ll have to renew or replace all our pipes, but not all at once.

“By having data to understand our conditions and the rate they are deteriorating, we have a high level of confidence in what we need to be spending.”

Transferring knowledge

Training may not have been part of the initial plan, but the Collection System Asset Management Plan in place at Johnson County (Kansas) Wastewater has proved to be an excellent method for educating new employees on the ins and outs of the sewer system.

“It’s a big benefit,” says Patrick Beane, P.E., asset manager. “We have a starting point. We can bring new people up to speed.”

Beane says new hires can review the documentation on emergency, cleaning, and inspection procedures produced by the CSAMP and readily see and understand departmental procedures and priorities.

“They can see how we clean and whom to notify in certain situations.”

The system knowledge helps in turn with the agency’s public outreach. “These are the employees out in the field, in the trucks, in contact with the public,” Beane says. “They know and understand the system.”

That helps them explain field activities to property owners, Beane says, “most of whom never even think about the sewer system.”