Finding the Faults: How Leak Detection Advancements Can Help You Quantify I&I

Finding the Faults: How Leak Detection Advancements Can Help You Quantify I&I

After a recent trial run, Hillsborough County, Florida, is now committed to using newer technologies like focused electrode leak location by Electro Scan (pictured) and the SL-RAT by InfoSense as part of its I&I program.

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As the leader of a large and rapidly growing water/wastewater utility, Richard Cummings needs to make sure I&I issues are identified accurately and efficiently, and he needs to make sure those issues are unquestionably solved the first time he has a crew on site.

In this endeavor, he largely credits embracing emerging technologies that can give him quantifiable data about leaks and help take human error out of the equation wherever possible.

Cummings is the director of Hillsborough County, Florida’s Field Maintenance Services Division, which offers sewer/water services to about 200,000 customers. When he first started working at the utility in 2001, it was a little more than half the size it is now. Since 2013, he says the rate of growth has been “off the chain.”

“Hillsborough County is like many in the state of Florida. It started out as an entity and over the years it acquired a lot of different franchises,” he says. “A lot of the people in the franchises weren’t taking care of their systems the way they needed to. They were run down. Some of them hadn’t even had basic maintenance to sewers and waterlines.”

As Hillborough took over these franchises, it found a lot of the pump stations were overrun, and there were some significant I&I problems. As a result, the division typically spends $2 million to $3 million on a sliplining contract every couple years, and it has ramped up its CCTV and pipe cleaning efforts as well. “Even right now, to comply with Environmental Protection Agency requirements and the Department of Environmental Protection, they really would like for us to go through all of our collections system at least once every five years.”

Adopting new technologies

The true game changer for Hillsborough County, according to Cummings, has been the adoption of technologies like Electro Scan’s focused electrode leak location (FELL) and the SL-RAT by InfoSense.

He says the utility first started using the SL-RAT, an acoustic inspection tool used to screen for blockages in small-diameter gravity sewers. Cummings praised its cost-effectiveness and efficiency in sewer assessments. It allows the utility to dispatch its CCTV and cleaning trucks more purposefully. “It’s very useful and we can get a lot of territory covered. The guys can go through literally like 7,000 feet per week.”

Later, after using CCTV to tackle a lengthy project at one of its worst basins — the River Oaks basin in the western portion of the county — Cummings decided to give FELL technology a test run for possible use in the future.

“With FELL technology, we did a small segment of a couple of runs two or three years ago,” he says. “It really opened our eyes up as far as what was happening.”

Since that initial test, the county has continued to use FELL to inspect its sewer system, and it has found a lot of leaks. “The main benefit I see is quantifying the leak — that’s the deal.”

Instead of relying on human operators to use cameras and MACP/PACP coding to identify and report leaks, the utility started getting its data via Bluetooth using Electro Scan’s included software, which offers detailed reports about individual leak intensities, even estimating their contribution to I&I in gallons per minute.

“Before, it was up to the human being to decide whether it’s this much of a leak, or this much, or this much. We like FELL technology because it puts a quantitative number on that. It tells the intensity of the leak and puts a number against it using a mathematical formula.”

And it finds a lot of defects, according to Cummings, the most significant of which almost always end up being at the lateral connections in his experience. “You can go manhole by manhole run, and you can see exactly by looking at it, it quantifies it. FELL is looking for leaks that make a difference — it shows an intensity. When you’re looking through these charts, you can see how many feet they are apart, and typically what you see is that these leaks are at a lateral almost all the time.”

A multiple-use case

Identifying sources of I&I is only half the battle, though. Cummings says he wants to start using Electro Scan’s FELL technology to verify the integrity of those lateral connection repairs.

“We’ll decide we have a leaky pipe, and we’ll go in and slipline that and we’ll grout around where the laterals connect,” he says. “That’s fine, except for, that grout is clear, so it looks like clear jelly. So when you grout it, I can’t tell how much you put in there and I can’t tell if you stopped the leak or not. What we’re finding out now is that if you use FELL technology before, and then you slipline, you can also use FELL technology afterward to make sure that they grouted the laterals correctly.”

Cummings says he likes the added assurance a program like that could provide. “Because many times I think I’ve fixed the problem and I turn around and it’s leaking again. I sliplined it — so what? Did I stop the leakage rate? I have to be in there at the same time of year to test it when I’m talking about groundwater levels. With FELL, it doesn’t matter.”

Hillsborough crews prepare to run an Electro Scan electrode through a pipe in a residential neighborhood to inspect the system for leaks.
Hillsborough crews prepare to run an Electro Scan electrode through a pipe in a residential neighborhood to inspect the system for leaks.

How it works

To use FELL technology, Hillsborough’s crews first pound a conductor rod into the ground. Then, they use an electrode attached to a jet hose that pulls along a column of water. “Every joint it passes over is covered by water, and if water can get in, then the electricity can get out the same way,” Cummings says. “So if there’s a leaky joint and water could get into that joint, using this water, the electrical current squeezes through that crack and travels through the ground and the circuit is connected when it goes to that ground rod. The FELL technology can see the strength of that signal and the duration and tell you how much of a leak rate it is.”

It’s a technology that complements more traditional CCTV work. If there’s an obvious leak, Cummings says he wants to get a look at it with a camera. But for the less obvious leaks, which often accompany I&I programs, he says FELL is a solid technology. “Electro Scan tells you where the leak is,” he says. “And that’s worth a lot of money, because if you take care of that leak once, you’re saving money every month from now on. You’re not pouring water in the system.”

Keeping up on technological advancements and showing a willingness to give emerging technology a chance has proven beneficial for many utilities, including Hillsborough County’s Field Maintenance Services Division.

“A lot of this technology used to be pie-in-the-sky stuff 20 or 30 years ago,” Cummings says. “Things are going to change so much in the next 15 or 20 years, it’s going to be unrecognizable.” 


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