Regular maintenance of a utility’s large-diameter pipe prevents emergency situations


U.S. Submergent Technologies crew cleaning large diameter pipe in Tampa, Florida
USST Crew cleaning large diameter pipe in Tampa, FL.

Water and wastewater collection and treatment processes are largely out of sight, out of mind. Our society often takes this infrastructure for granted and is largely unaware of what’s happening below their feet, even though every person in this country uses it every day at home or at work.

Large-diameter pipe (LDP) is generally treated the same way throughout our industry; we don’t see it regularly, so we assume it is functioning properly. LDP infrastructure is primarily only cleaned or rehabilitated when issues arise, such as overflows or collapse that force attention. Once an emergency situation arises, utilities typically scramble to solve a large and complicated issue that they are unprepared to handle, exacerbated by the fact that large-diameter pipe is difficult to clean under flow while in service.

Managing Flow in Large vs Small Diameter Pipe

Large-diameter pipe is generally described as 24-inches in diameter or larger. Typically, utility systems have regular maintenance plans for smaller pipe systems 18-inches or smaller that involve a vacuum-only approach. Because of the smaller size of the pipes, cleaning this infrastructure is routine and often managed by the utilities themselves.

Flow in smaller pipes is significantly less than flow in large diameter pipes and is usually managed with vacuum technology. As an example, the capacity of a 6-inch diameter pipe compared with a 60-inch diameter pipe is 100 times greater, even though the difference in diameter is only 10 times larger. This reality is often missed because LDP comprises less than 5% of a collection system. These larger flows create challenges because of the amount of water that must be managed and possibly bypassed, when cleaning is required.

To clean large pipe systems under these conditions is challenging. Bypass is expensive and may not be a viable option. But regular maintenance of these larger systems is crucial to the health and preservation of collection infrastructure both short and long term.

One of the main roadblocks to cleaning LDP is managing flow. A simple vacuum cannot handle this type of project. A vacuum will produce little to no productivity when attempting to utilize it under heavy flow, compared to utilizing it with smaller diameter pipe under significantly less flow. The bottom line is if there is too much water, vacuum technology may not be as productive as when there is less water present.  Historically, when LDP needs to be cleaned, the pipes are either bypassed or blocked, sometimes using inflated devices, to block the water from flowing into the section of pipe being cleaned. The cleaning is then accomplished using confined space entry.

USST technology, equipment and skilled crew can clean LDP under full flow, while in service, and remove significant amounts of material at a high production rate, without the need for bypass or diverting flow. As one of the only cleaning processes in the nation that can accomplish this task, we stand ready to assist utilities to restore their collection system capacity. You can read more about USST’s large diameter pipe capabilities here.

USST’s technology can help determine if your large diameter pipes need cleaning

Regular maintenance of a utility’s large-diameter pipe will prevent emergency situations as well as maintain the designed capacity. Let us show you how it works by signing up for our Eyes in the Pipe Webinar to learn more about the technology USST is introducing and how to get visibility into your utility’s collection system. Reserve your spot today.

Have questions? Call (844) 765-7866 or email

Cleaning Sand and Grit From Wastewater Treatment Structures In Operation


U.S. Submergent Technologies’ Combination3® Truck with extended boom removing sand and grit from Florida wastewater treatment facility while in operation
Combination Truck with extended boom at work removing sand and grit from Central FL facility.

Cleaning sand and grit from a digester at a wastewater treatment plant

A digester at a Central Florida Wastewater Treatment Plant was due for cleaning, having built up an accumulation of sand and grit. The structure was cleaned in operation with the aid of funding from Florida’s Sand & Grit Grant Assistance Program. See if your facility is eligible for similar funding by reading more about the program here .

Measuring 100-feet in diameter with approximately 18-feet high tank walls, the digester was cleaned using the versatile Combination Truck. Due to the size of the facility, the structure had to be cleaned while remaining in full operation. No bypass or shut down was necessary to remove the material and no confined space entry was required to complete the job due to the adaptive technology of USST’s equipment and skill of the crew members.

Led by USST Foreman Charles Harrington, the crew utilized the Combination Truck’s extended boom and downhole pump to remove sand and grit while navigating around coarse air diffusers found on the bottom of the tank.

“This kind of precision cleaning is difficult to accomplish while a structure remains in operation,” said Charles. “Our technology makes it possible to clean around diffusers without doing damage at a high rate of production.”

Digester cleaned by U.S. Submergent Technologies at Central Florida wastewater treatment facility
Central FL digester.

Efficient sand and grit removal freed up capacity at this wastewater treatment facility

Approximately 39-tons of sand and grit was removed from the digester and disposed of at an offsite facility. Spent biosolids lingering at the bottom of the tank were also removed, emulsified, and returned to the tank for treatment and/or processing, thereby freeing up additional capacity.

Need a structure cleaned quickly or have a facility that must remain online?  USST is well-equipped to perform sand and grit removal from both wet or dry conditions, while in operation, and can do so at a higher production rate than most vacuum trucks.  Give one of our representatives a call for a free site assessment at (844) 765-7866 or email to learn more.

6 Things You Didn’t Know About Florida’s Sand & Grit Grant Program

As you may or may not be aware, Florida has funding available through a grant assistance program for qualifying utilities to remove sand and grit from their facilities. We’ve got answers to some of the most frequently asked questions about the Sand & Grit Grant Program below.

Paint-filter dry sand removed from a structure while in operation.
Paint-filter dry sand removed from a structure while in operation.

When did the program start?

The program began in 2014 and is administered by the Florida Department of Environmental Protection (FDEP) developed to assist wastewater treatment plants in the removal of sand and grit to increase capacity, reduce energy use, and improve effluent quality.

How do I qualify?

Your facility must be a public utility with an average annual daily flow of 3MGD or under, and a portion of the plant must remain online during removal.

What is the process?

A simple, 1-page information sheet must be filled out; once it has been submitted to the FDEP, they begin to draft the grant agreement.

How much funding can I receive?

If eligible, your facility will be reimbursed 50-100%. There is no limit to the amount of funding your facility can receive through the grant program.

How many structures can I get funding for?

As many as needed that qualify. There is no limitation to the number of structures you can clean under the grant program as long as all qualifications are met.

How soon can I get reimbursed?

Typically within 30-days of invoice submittal to FDEP.

Have more questions? Reach out to one of our knowledgeable representatives to learn how this program can potentially benefit your facility by calling (941) 404-3405 or emailing

Stormwater Box Culvert Cleaned in Both Wet and Dry Conditions


 USST's Combination3® Truck
USST’s Combination Truck

After experiencing a series of overflows in a residential area, a West Florida city was looking to clean up a severely blocked stormwater box culvert.  Due to a fluctuating tide schedule creating a surcharged environment, the stormwater structure was cleaned in both wet (high tide) and dry (low tide) conditions.

Paul Stephenson, one of USST’s experienced Foremen (read more about Paul here!), led the USST crew on the project, cleaning more than 300-feet. 

“Having our Combination Truck allowed us to get everything done in one go,” said Paul. “We used a number of setups to remove material with one truck, including the vacuum, downhole pump and jetter, depending on whether the tide was in or out and the resulting conditions in the structure.”

The USST crew utilized the downhole pump and jetter when water was present in the structure to remove sand and grit and switched to vacuum to remove remaining material during dry conditions. In total, 12-yards were removed and disposed of at an offsite city facility.  Lawn chairs, wood, and yard waste were some of the larger debris removed from the structure.

Debris removed from Stormwater Box Culvert.
Debris removed from Stormwater Box Culvert.

There was minimal intrusion into the surrounding neighborhood during the project due to the closed loop cleaning system of the Combination technology, which meant less odor and noise for nearby residences.

“This was one of the more challenging projects I have had the privilege of leading,” said Paul. “We were fortunate to have the technology necessary to be able to react to situations as they arose and accomplish this job efficiently.”

Reach out to one of our Project Advisors to learn more about USST’s specialties in removing material from hard-to-reach environments.  Call (844) 765-7866 or email us at

60-Yards of Tough Rag Material Removed from Splitter Boxes


Rag material removed from splitter box structure.
Rag material removed from splitter box structure.

Access issues had prevented two splitter box structures at a South Florida wastewater treatment facility from being thoroughly cleaned in years.  A large amount of accumulated rag material had built up over time, and the structure was experiencing significantly reduced capacity.

The two structures in question consisted of an Auxiliary Secondary Clarifier Distribution Chamber with dimensions estimated at 30-feet by 45-feet as well as a Secondary Clarifier Distribution Chamber measuring approximately 40-feet by 40-feet.  These two structures function as splitter boxes for a secondary clarifier at the facility and serve to split flow from the clarifiers to oxidation tanks.

USST Crew at work at South Florida facility.
USST Crew at work at South Florida facility.

“A drain down was necessary to evaluate and perform maintenance on the structures,” said Michael Kisling, USST Foreman on the project, “but once the water level was lowered, it was clear that the estimated 6-to-8 feet of rag and debris material was going to be difficult to remove.”

The top level of the structures had been cleaned over the years, but rag material had built up due to the depth and position of the debris.  The USST crew developed a crane attachment to be used with the Combination Truck’s extendable boom to reach and remove the difficult material.  Without the innovation of the crew and technology, the quantities of material would not have been possible to access. 60-yards of rag material in total was removed from the site, including other debris such as pipes and even a full-sized metal handrail.

Metal debris removed from structure.
Metal debris and rag material removed from structure.

“It was a surprise every time we pulled the crane out of the structures,” said Michael. “We never knew what we were going to find next!  I’m proud of the way our crew handled the tough project and the creative way our crew solved the problem.”

If you find yourself with an issue that seems unsolvable, give us a call, we love a challenge!  Contact us by calling (844) 765-7866 or email with any questions you may have or share a comment below.

Shout Out to Critical Workers in the Wastewater Field


Eric Pace, Paul Del Favero, & Charles Harrington from the USST Family
Eric Pace, Paul Del Favero, & Charles Harrington from the USST Family

As we navigate this unprecedented situation together, we want to recognize the essential work being done by our customers, suppliers, business partners, and so many others working to keep vital infrastructure flowing.  The work you’re performing in the wastewater and water sectors is critical to maintaining quality of life for our communities throughout this pandemic and beyond.

While social distancing has required temporary measures to limit physical interactions, it doesn’t change the passion and respect we share for the work we do as industry friends.

Join us in cheering on our fellow wastewater and
water co-workers.

Leave a positive message, a note of encouragement, recognize anyone you know who has gone above and beyond, or simply drop a line letting us know how you’re coping in the comments below.  We’ll share the shout outs on social and in our next newsletter.

We are committed to staying positive, as well as practicing the highest health and safety standards throughout these circumstances, and we’d genuinely like to hear how you’re doing.

From all of us at USST, we appreciate your role more than ever, respect the critical work you are performing, and are happy to contribute wherever most helpful.


The USST Team

Deep Wet Well Cleaning, 40-Foot Vertical Pull to Debris Box


USST’s Combination Truck

Sand, grit, and other wastewater residuals had accumulated over time in a West Florida lift station, reducing its overall capacity.  As part of a larger rehabilitation and improvement plan, the City of Tampa’s San Carlos Pump Station required cleaning and had a buildup of material deep in the wet well that needed to be removed.  Due to the challenging depth of the material, previous companies had been unable to reach the material with conventional vacuums and equipment.

A buildup of material in a wet well such as this has the potential to cause several issues, including increased pump run times and wear and tear on equipment.  A drain-down and confined space entry was necessary in order to efficiently access the wet well. 

The Combination Truck’s powerful vacuum was used to remove sand, grit, sludge, and rags at approximately 37-feet depth from the bottom of the wet well to slab/grade elevation, without any issues.  USST’s vacuum is powered by a blower capable of delivering nearly double the CFM of a standard vacuum truck, allowing the crew to remove large amounts of wastewater residuals and complete the job quickly and on schedule.  In total, 12-cubic yards were removed from the structure, ready for offsite disposal.

USST’s Combination Trucks are more than just a simple vac truck.  Equipped with powerful vacuum, downhole pump, jetter, and extended-reach boom, they have the ability to clean in wet or dry conditions in up to eight different setups without bringing multiple pieces of equipment to the jobsite.

“Lift stations in particular are one of the structures we can clean very efficiently in a variety of ways,” said Denver Stutler, USST CEO.  “We can remove material quickly and safely at an increased rate in almost any situation.”

Have a lift station that needs attention?  The Combination Truck makes restoring lift station capacity easier than you think.  Call one of our knowledgeable representatives for a free quote or to ask any questions you may have at (844) 765-7866 or email and check out our video to learn more about the Combination technology

What types of structures does U.S. Submergent Technologies clean? 

U.S. Submergent Technologies cleans sand, grit, and other debris out of wet environments. We’re well known for our success in wastewater treatment facilities, but our Combination technology gives us the ability to clean the hard-to-reach places in a variety of submerged conditions. 

Our innovative jetter and combined vacuum and downhole system enables the rapid removal of accumulated solids from wet infrastructure while it remains in operation. U.S. Submergent Technologies (USST) is able to restore capacity in numerous industries and other systems that can benefit from being cleaned while in service, with no bypass.  


USST Crew performing pipework in Tampa, Florida

Large-diameter pipe systems can become clogged with sand or debris, causing blockage, reducing flow capacity, and causing potential upstream flooding. Over time, sand seeps into collection systems through cracks and seams, constricting pipe flow once it begins to accumulate.

Other unwanted debris, both naturally occurring and manmade (litter), makes its way into pipe systems, adding to the problem and obstructing flow. Other unwanted debris, both naturally occurring and manmade (litter), makes its way into pipe systems, adding to the problem and obstructing flow. Since we are unable to see the accumulated material, the problem often goes unnoticed. When this impacts a lift station, energy costs can rise significantly as well as wear and tear on equipment.

If capacity isn’t restored, a blocked pipe could potentially cause flooding and water damage in the surrounding areas, as well as impeding overall flow. USST removed 32-tons of sand from a stormwater pipe in Miami-Dade county under surcharged conditions. With USST’s technology, our crews can clear blockages in submerged or surcharged conditions without the need to bypass flow and without resorting to confined space entry.  

Examples of pipe systems USST has the ability to clean appear below:

  • Gravity/Sanitary Sewer Collection Pipes
  • Outfall Pipes
  • Siphons
  • Stormwater Systems, including box culverts and baffle boxes


USST’s Combination Truck reaching into aeration tank to perform cleaning with no shutdown needed.

There are many types of tank structures used in a variety of ways in wastewater treatment systems, and they can all experience reduced capacity from the gradual accumulation of sand, grit, FOGs, rag material, vegetation, and more. Buildups of these types of material leads to increased energy costs and reduces overall plant efficiency.

With the assistance of USST’s patented equipment and process, our crews can tackle the toughest of issues, often while the system or structure remains in full operation in submerged conditions. We provide facilities the option to maintain a regular maintenance schedule instead of performing costly repairs or replacing expensive infrastructure.

Combination Truck extended boom removing material from oxidation tank while in operation in Mount Dora, Florida.

USST can clean the following, but not limited to, structures:

  • Aeration Basin
  • Anoxic Tank
  • Backwash Basin
  • Clarifier
  • Chlorine Contact Chamber
  • Digester
  • Effluent Channel
  • Equalization Basin
  • Grit Chamber
  • Gypsum Pond
  • Headworks
  • Influent Channel
  • Lagoon
  • Methane Tank
  • Oxidation Ditch
  • Package Plant
  • Ponds
  • Reject Pond
  • Sand Filter
  • Sediment Trap
  • Sludge Tank
  • Splitter Box
  • Storage Tank
  • Surge Chamber
  • Trickling Filter

Lift Stations

USST Crew with Combination Truck at work on lift station in North Florida.

Lift or pump stations are an integral part of the wastewater collection system. They transport wastewater from lower to higher elevations and are often equipped with one to three pumps for redundancy. Lift stations tend to accumulate sand and grit due to unwanted inflow and infiltration (I&I) issues during periods of high flow (e.g., heavy rain or high tourist traffic) which can clog the system. The more sand in a wet well, the more frequently the pumps must start and stop due to reduced cycle times. A facility may only have one operating pump, putting undue stress on the already limited capacity of the structure.

Performing regular lift station maintenance reduces the risk of sanitary sewer overflow (SSO), where untreated wastewater is discharged from a sewer into the environment before reaching a wastewater treatment facility. SSO can have extremely negative consequences for the environment and population in the areas surrounding the overflowing wet well.

With USST’s Combination truck and patented GritGone Process®, our crews can clean lift stations with one piece of equipment and quickly switch between cleaning modes to solve most access issues. The jetter has the ability to clean the structure, and the vacuum removes material such as fats, oils and greases. The truck’s downhole pump removes sand and grit from the wet well while the lift or pump station remains in full operation at full capacity, without the need for confined space entry. 

  • Lift or Pump Stations
  • Wet Wells

Why is grit buildup a problem for wastewater treatment facilities?

Our wastewater collection and treatment systems remove the biological waste in our water by design. However, other waste — debris such as sand and grit — accumulates in collection and treatment infrastructure, but their systems are not designed to remove this type of material. This type of debris accumulates because most of the wastewater infrastructure is below the earth’s surface. Collection systems are comprised of pipe segments that have joints, seams, gaps, and cracks, which are exacerbated as the pipes shift over time. These gaps allow sand to enter the pipe. 

The Damage Done by Grit

Sand and grit, unmanaged, can wreak havoc on the treatment process by reducing the operating capacity of the system. Sand and grit cause abnormal wear and tear on pumps and other mechanical components. Hydraulically speaking, sand and grit can adversely affect operational aspects of the collection and treatment system including full or partial plugging of outlets and/or pump suctions.

The Risks of Grit and Sand Accumulation

Determining whether or not there is an issue is the real challenge. Pipes are below ground while tanks are made of concrete or steel and are not transparent. Accumulated sand and grit sits at the bottom of these structures, reducing valuable capacity, until issues such as overflows make it clear that immediate attention is needed.

Equipment failure is a problem for wastewater facilities because it often takes a significant amount of time to repair or replace the equipment in question, resulting in the system running at reduced capacity or having to figure out a bypass solution. In smaller facilities, there may not be an option to divert or bypass flow, leaving them in a critical situation that requires a quick resolution.

A Solution to Unwanted Grit and Sand

Often, the first solution to restoring critical capacity is to build new infrastructure. This option is costly, and municipalities must spend a great deal of time to navigate a lengthy approval process, financing, design, and finally, constructing new infrastructure.

Instead, facilities can save money and ensure optimum capacity by scheduling regular maintenance to manage sand and grit accumulation. U.S. Submergent Technologies’ Combination Truck and GritGone Process® make it possible to remove grit from pipes, tanks and lift stations without shutting down the facility or requiring bypass pumping. USST can also remove material in submerged or surcharged conditions and reduce or eliminate the need for confined space entry.

Removal of material can reduce energy demands and allow structures to return to their design capacity. Regular maintenance to remove accumulated grit is a much less costly solution than rebuilding infrastructure or replacing entire pipe systems.

Call a USST Project Advisor to learn more about how we remove material from hard-to-reach environments. Talk to us at (844) 958-1207 or email us at

Tackling Tough Lime Removal in BTU Structure


Lime buildup prior to removal in outer ring of BTU.
Lime buildup prior to removal in outer ring of BTU.

A large Biological Treatment Unit (BTU) at an East Florida wastewater facility was experiencing reduced capacity and due for maintenance.  Measuring 113-feet by 130-feet and consisting of three concentric rings with a center pier effluent chamber, the cleaning of the tank was part of a plan to remove tough lime material that had accumulated over time.

Lime is typically used for precipitating impurities, adjusting pH levels, and odor control.  In the case of this BTU, the lime was not intended to be introduced into the system and was taking up valuable capacity.  The sludgy, clay-like consistence of lime material can prove challenging during removal and was an issue that had previously been unsolvable by others.

Led by Foreman Michael Kisling, USST crew arrived with the Combination Truck prepared to tackle the challenge.  In order to effectively remove large quantities of lime, sand, and grit material from the BTU, a drain down was necessary. 

USST's Combination3® Truck at work on BTU in East Florida.
USST’s Combination Truck at work on BTU in East Florida.

USST crew utilized the Combination Truck’s powerful vacuum to first clean the structure’s outer rings, moving on to the center pier effluent chamber, removing an estimated 9-feet of material.  Combination Truck’s vacuum is powered by a blower capable of delivering nearly double the CFM of a standard vacuum truck, allowing the crew to remove large amounts of wastewater residuals and complete the job quickly.

“I’m proud of the performance of both our crew and equipment on this project,” said Denver Stutler, USST CEO.  “Being able to reach and remove what others can’t is our specialty, and we welcome the challenges.”

Overview of East Florida facility's BTU structure.
Overview of East Florida facility’s BTU structure.

In total, an estimated 45-tons of lime, sand and grit material were cleaned from the outer rings while 15-tons were removed from the effluent chamber and disposed of offsite.

USST can build a plan to remove material from both wet or dry conditions in a variety of hard-to-reach environments from tanks, pipes, lift stations, and more.  Give one of our project advisors a call for a free site assessment at (844) 765-7866 or email