Using Grout to Stop I/I

For the past decade, a small company in central Ohio has created a business around the daunting task of assisting small communities with issues at their wastewater treatment plants. The largest objective, typically, is combating the inflow-and-infiltration (I/I) that overwhelms and plagues most of our nation’s municipalities.

This couldn’t be more evident in its most recent challenge in the Village of Ashley, Ohio, which called upon its services.

The population of the Village of Ashley is 1,400 people with approximately 540 homes connected to the sewer. Central Ohio Wastewater Services started in 2003, with a mission to investigate sources of water and remove I/I in the most cost-effective manner. “My father started the company after retiring from the state of Ohio for almost 33 years and he was a very good teacher in learning how to find I/I,” says owner TJ Howard.

The Village of Ashley project resulted in the Central Ohio Wastewater Services crews in finding significant I/I at the manholes. Crews found 17 manholes next to a creek in the woods that were 16 to 26 ft deep with a very high water table. In looking into the cost for replacement for all the manholes, the cost totaled approximately $300,000.

“The Village of Ashley did a (cured-in-place pipe) CIPP liner project in 2007, removing half the peak flow from 1 million gal/day to 500,000 gal/day at a plant that was designed for 190,000 gal/day,” Howard explains. “We found the infiltration was coming between the CIPP liner and the original pipe releasing at the manholes. The acting engineer at the time had heard of Source One Environmental (S1E) LLC and its product so we gave it a try. Since the start of the project, our average dry time flows have went from 60,000 gal/day to 30,000 gal/day and heavy rain fall events have fallen from 500,000 gal/day to 250,000 gal/day making the plant more efficient.”

The Village of Ashley has spent approximately $13,500 to rehabilitate the 17 manholes, compared to the $300,000 for replacement. The Village was so satisfied with the results that officials are starting more projects for the rest of the collection system using the same product to seal all the manholes.

“This methodology is a testimonial to the trenchless industry, and how companies such as S1E are continuing to assist contractors and communities who are in positions similar to this,” Howard says.

The Village of Ashley, Ohio

The Village of Ashley, Ohio, has spent approximately $13,500 to rehabilitate 17 manholes, compared to $300,000 for replacement.

Grouting and Trenchless

Grouting technology has been around for decades, and has evolved tremendously during that time. Grouting can be used in mainline applications, but also in vertical applications with the main purpose of soil stabilization. Typically, when a substrate is leaking, it is due to a defect, which is allowing the water that has settled through hydrostatic pressure to infiltrate into the structure. Water infiltrating into the structure is obviously a concern due to treatment costs, but there are also other, far more dangerous ramifications of a structure leaking underground.

Although there are many technologies that will address the defect and add structural integrity back to the substrate, the issue then lies in the void now surrounding the substrate from years of washout. The common, often overlooked issue is still there and a void above or beside a substrate can lead to unstable soil, in essence, causing a sinkhole. This is where grouting has become an effective, environmentally safe trenchless method.

It is important to understand that there are many different types of grout that all serve different purposes. Hydrophobic, hydrophilic, and acrylamide grouts are the most commonly used in the wastewater industry. It wasn’t until approximately 10 years ago that it was discovered that polyurethanes could also be used in the same fashion. Today, some of these different blends of urethanes are some of the most sought after chemicals used to isolate and stop leaks in virtually any type of substrate.

The product that Central Ohio Wastewater Services is referring to is called HyperFlex. HyperFlex is a pre-catalyzed, hydrophobic polyurethane that’s main purpose is for ground stabilization. Source One Environmental LLC, Davison, Mich., is the master distributor for SealGuard Inc. and markets this product to the wastewater industry. What impressed Howard was the product’s 20 to 1 reaction ratio, he says.

For decades, this product has been used in the mining industry to stabilize mine shafts and prevent them from leaking. It wasn’t until approximately 10 years ago that this product began to gain demand for stopping infiltration in underground substrates within the storm water and wastewater industries. S1E, which is owned by Fernco Inc., was created to provide cost-effective alternatives to conventional dig and replace methodologies.

“At this point in our history as a nation, the individual(s) faced with the challenging careers of maintaining our underground resources have their backs to the wall, unfortunately. Age does not discriminate, and this is evident when looking at our nation’s underground infrastructure as a whole. Conventional replacement of these precious resources is not realistic, so we have to find ways to extend the useful life of what we currently have in the ground. S1E is striving to develop new ideas and concepts every day to help the aforementioned individuals do just that,” says Jeff Urbanski, director of research and development with Source One Environmental LLC.

Central Ohio Wastewater Services

Central Ohio Wastewater Services used a low-pressure paint sprayer that was converted and fabricated to allow the contractor to inject the hydrophobic polyurethane grout at higher pressures out of 5-gal jugs.

After learning of the challenge that Central Ohio Wastewater Services was faced with, S1E recommended that a different type of delivery method be used to inject the single component, hydrophobic polyurethane into the substrates. An individual, regardless of strength, can only generate 5 to 7 psi of pressure by hand. Most of these types of grouts are put into a tube and injected by hand with a caulk gun. Because of the products’ chemical makeup, it reacts and “creams” much faster under high pressures, which keeps the product from washing out during installation. Therefore, a low pressure paint sprayer was converted and fabricated to allow Central Ohio Wastewater Services to inject the product at higher pressures out of 5-gal jugs.

At the very least, the Village of Ashley has saved hundreds of thousands of dollars in costs that would have been incurred through traditional replacement methodologies. As more and more communities begin to evaluate their respective collections systems, it goes without saying that the demand for these types of products is going to grow exponentially. It is up to the contractors, engineers, manufacturers, reps, and municipal officials to do their best to get involved in their local affiliations and network with each other in order to create more of these types of situations. The piece of mind that the individuals maintaining our underground assets should have is that the trenchless industry will continue to evolve and get better. After all, it is those individuals that have helped to create it by understanding that there are more efficient, cost-effective ways to solve problems.

Mike Moore is a business development manager at Source One Environmental LLC, Davison, Mich.
// ** Advertisement ** //