Some segments of Green Bay Water’s infrastructure are old — we’re talking 1882 old — but there is nothing yesteryear in the thinking of the utility’s leadership. 

“We like to think of ourselves as proactive,” says Brian Powell, general manager of Green Bay Water. “We are sometimes the first to try new technologies in Wisconsin. We’re open to new technology when it makes sense.”

A recent example of that state of mind was the repair last summer of 1,400 feet of 8-inch cast iron waterline along a street called Hazelwood Lane. The repair method: cured-in-place-pipe lining. It was the first-ever CIPP project for the utility.

Inasmuch as the cured-in-place technology has been around for 50 years, one might ask how a 2023 project in Green Bay squares with the idea of the water utility being progressive. The answer is contained in Powell’s statement about the utility employing such technologies “when it makes sense.”

The general manager says it was a matter of “finding the right project.” Factored into the search was the diameter of the pipe to be repaired, the condition of the street under which it runs, and the probable consequences of the pipe’s failure. The Hazelwood line checked all the boxes.

“It is a cast iron water main from the 1960s and had a leak history,” he says. “When it did leak, it would cause a lot of ground disturbance. So, it was problematic.” Furthermore, the pipe’s diameter was such that it didn’t need upsizing. It just needed sealing and strengthening against further leakage.

As for the condition of the street above it, Powell described Hazelwood as being “in pretty good shape and not going to be replaced any time soon. There’s a decent amount of life left in it.” The utility was even more reluctant to rip up the street because it was built of concrete and served a busy neighborhood in the area of Lambeau Field, home of the Green Bay Packers.  

So, the CIPP contract for Hazelwood Lane was let with FER-PAL Construction USA, which employed the ALTRA CIPP lining system. In due course, the liner was inserted in a Green Bay waterline for the first time. The project went well. “The contractor was easy to work with,” says Kristin Romanowicz, the utility’s engineering supervisor. “With our crew helping on four excavation pits, every part went as planned.”

Looking back on the inaugural project, Powell deems it a success. “It definitely was cheaper than a traditional repair. It was a very nonintrusive project, so traffic flowed along the street as normal. People had access to their properties as normal. And all of that’s a savings, too.”

The city is “brainstorming about where else we can use CIPP, but we don’t have anything set for the rest of this year,” says Romanowicz. The trenchless technology might be employed in places where digging is not a good option — such as railroad or river crossings, according to Powell. Otherwise, the same criteria will inform any decision to line another pipe.

“We’re tackling projects right now that need more immediate attention, but we’re definitely looking to use this technology in the future. We will be doing more lining.” 

DIVING IN

Lining pipe wasn’t Green Bay Water’s first foray into 21st-century pipe inspection and repair. That happened in 2010 when the city contracted with Pure Technologies, a Xylem brand, to assess 25 miles of the utility’s 36-inch main transmission line that runs from its filtering plant. Green Bay draws its water from Lake Michigan.

To accomplish the pipeline assessment, Pure Technologies utilized a proprietary robotic swimming device called PipeDiver. Because it’s engineered to float through a waterline on the moving water, it doesn’t interrupt the normal flow of water to customers.

The PipeDiver is sort of a prehistoric-looking, undulating three-segmented cylinder about eight feet long with a navigation head at the front and fins, or wands, projecting outward to keep it centered in a pipe. The device is available in three lengths to accommodate pipes of different diameters.  

The PipeDiver swam easily through the utility’s transmission line, which is a prestressed concrete cylinder pipe. Sensors particularly analyzed wire that keeps the pipe from being blown outward by high water pressure and otherwise evaluated the integrity of the pipe. Data from the device was transmitted to a computer and a report prepared.

The 2010 analysis was a success, the PipeDiver functioned perfectly and the report reassured utility engineers about the soundness of the line. A decade later, in 2021, Green Bay Water called for another assessment by the device. The second time, things didn’t go as swimmingly.

What happened is that the utility, in the interim, had experienced a catastrophic break in the transmission line. To strengthen the system at that point, interconnections between parallel lines were constructed and butterfly valves added upstream and downstream from the interconnecting pipe. One of these valves became an obstacle for PipeDiver.

“We thought the face of the valve was facing one way and it wasn’t. When PipeDiver encountered it, it got caught,” Powell says, a snag that occurred just seven miles into its 25-mile swim through the pipe. The device eventually had to be cut out.

The manufacturer might not have welcomed the hang-up, but Pure Technologies took the opportunity to rework PipeDiver. Modifications included shortening the device’s wands, so that it floated closer to the top of flowing water in the pipe instead of in the center of it. The higher float allowed it to clear the butterfly valve disc.

“They did a project in New Jersey to prove to us that they had fixed the problem,” Powell says. In 2022, the contractor crew returned to Green Bay and successfully floated PipeDiver the length of the transmission lines. This time, the PipeDiver also carried a camera, another level of inspection accomplished.

Powell recently conferred remotely with water utility engineers in San Antonio, who had a similar valve situation in a mainline. They wanted some reassurances about letting the PipeDiver dive. Powell reported to them on how the issue was resolved in Green Bay.

So, what did the successful 2022 PipeDiver analysis reveal about Green Bay Water’s mainlines? In a long and detailed report, the engineers learned that out of 8,000 pipes in the inspected line, only nine had wire breaks.  

“In other words, 0.12% of the pipes showed any stress,” Powell says. “I am told that, typically, 3 to 5% of pipes are revealed to be stressed, sometimes as high as 15%. We had so few pipes in poor condition that we elected to just go ahead and remove the nine bad ones.” Problems pinpointed and eliminated — thanks to the high-tech equipment.

EYES OPEN

The other tech marvel the utility has employed is called SmartBall, another Pure Technologies product. It is a round electronic package about the dimensions of a softball. Its electronics include a sensitive acoustic sensor that can pick up the sounds of leaks or of burbling gas pockets. Like the PipeDiver, it transmits its findings to system computers.

The device is housed in foam padding that resembles a Nerf Ball. Like the PipeDiver, it can be introduced to a water pipe with water running through it. The ball is pushed by the current, rolling along on the bottom of the pipe. “There is a range of velocities it can operate in. It was moving about 2 feet per second, which is within the range of the allowable velocity,” Powell says.

Most of the assessment work is done by the contractor, launching the ball via a long grapple and capturing and withdrawing the ball at the end of its run. The upshot of the SmartBall assessment? Three small leaks were discovered. It is success stories like these that keep Green Bay Water returning to new technology. 

The utility was introduced to the technologies the same way as other water and wastewater agencies. First, word of mouth talked up the devices. Presentations at trade shows sparked serious interest. Peers recommended this company or that, this product or that. Eventually, Green Bay Water engineers investigated on their own, going to Louisville, Kentucky, when city engineers there were in the midst of a pipeline assessment, and then to Houston for another evaluation. Persuaded, they scheduled an assessment in Green Bay, and the rest is history.

“There always are other technologies,” says Powell, who has been general manager just a few months but was operations manager, too, during a 20-year stint at Green Bay Water. “For now, we feel pretty good about SmartBall and PipeDiver, but we always keep our eyes and ears open.” 

The contracted assessment tests are “not cheap,” he says, “but doing them and finding problem areas before they truly fail is money well spent.”