A Manhole Rehabilitation Solution for Concrete Corrosion Repair

August 18, 2021

Monoform PLUS manhole rehab project.

HK Solutions Group offers industrial and municipal services to companies across the Midwest. We often provide our industrial customers with solutions like hydroblasting, industrial vacuum services, tank cleaning, dry ice blasting and other industrial cleaning services.

HK is also a trusted manhole rehabilitation contractor, working with municipalities across the US to restore and fortify manholes and other sanitary system structures. Recently, our team had the privilege of tackling a tough manhole rehabilitation project that truly showcased our industrial expertise.

An Industrial Manhole Rehabilitation Challenge

One of our long-standing industrial services customers came to us looking for help with a tricky situation — a deteriorating manhole located in the middle of their chemical processing facility. They came to us with a common question: Can damaged concrete manholes be repaired without tearing up existing infrastructure?

Concrete repair is possible for concrete structures that are cracked, corroded or otherwise damaged. Concrete patches, liners and other techniques may be used to restore deteriorating structures, but some scenarios require specialized treatment. Projects involving high heat, high acidity and complex infrastructure may need innovative solutions.

Multiple factors made this a difficult manhole rehabilitation project, but HK was up for the challenge.

Monoform PLUS manhole rehabilitation project.

Aging Facility and Structures

This facility, located near Topeka, Kansas, was built in the 1950s and was more than sixty years old at the time of this project. The manhole was lined with acid bricks. Although these bricks are specially designed to resist chemical and thermal corrosion, they were deteriorating after decades of wear and exposure to strong chemicals.

Significant Chemical Corrosion

The manhole was part of a process-water discharge system with high sulfuric acid content. Sulfuric acid has a very low pH and is very corrosive. The chemical corrosion was causing significant infiltration and inflow issues.

Extreme Heat

The wastewater in the system was around 140°F — too hot for traditional manhole rehab techniques such as a spray-on manhole lining. Any rehab solution would need to be resistant to both the corrosive properties of acidic chemicals and high temperatures.

Complex Infrastructure

Because of this manhole’s location in the facility, it would be extremely costly and difficult to replace. Excavation to dig up and replace the manhole was not an option, as it would have required:

  • Shutting down the plant for several days
  • Moving huge and expensive pieces of industrial equipment
  • Working around existing plumbing, electrical wiring, fiber optics and other subsurface infrastructure
  • Carefully working near dangerous explosive and caustic chemicals

Complicated industrial facility infrastructure

The business owners knew they needed to repair or replace this manhole in order to continue the plant’s operations successfully, but they simply couldn’t figure out a safe, affordable and viable manhole rehabilitation option. Even our team was stumped initially as we searched for a viable manhole rehabilitation option for concrete corrosion repair that could also withstand such high temperatures, but it wasn’t long before we had the perfect solution.

Monoform +™ For Manhole Rehabilitation

In 2021, HK Solutions Group established a fabrication and distributorship for AGRU Lining Systems and developed our Monoform PLUS™ manhole lining solution. Monoform +™ is a 100% structural and 100% corrosion-resistant manhole rehabilitation option that doesn’t require excavation. It is also extremely durable when exposed to high temperatures. These features made Monoform PLUS™ the perfect option for restoring the Topeka-area chemical plant’s deteriorating manhole.

Durability and Longevity for Lasting Manhole Rehab

The Monoform™ installation process involves inserting an ABS plastic interior forming system into the existing manhole structure and pouring ready mixed concrete to create a restored structure. Monoform PLUS™ takes this to the next level by integrating the Agru Sure Grip™ High Density Polyethylene (HDPE) liner.

100% Corrosion-Resistant To Hold Up Against both Corrosive and Caustic Chemicals

Manhole lining solution for a number of structural manhole.

Monoform PLUS™ is our preferred manhole lining solution for a number of structural manhole rehabilitation situations. AGRU HDPE liners are particularly effective for restoring manholes with sulfuric acid or hydrogen sulfide corrosion.

Withstands Extreme Temperatures

In addition to its corrosion resistant properties, HDPE can withstand very high temperatures — up to 180°F. Other manhole linings aren’t compatible with extreme temperatures, but Monoform PLUS™ can take the heat.

Fast and Cost-Effective Installation

Our quick and efficient Monoform PLUS™ installation process is another thing that sets HK Solutions Group apart from other manhole rehabilitation contractors. Because Monoform™ is a trenchless technique, we don’t need to do any excavation, and we don’t need to worry about replacing or relocating subsurface infrastructure.

Achieving Exceptional Concrete Corrosion Repair Results

Our team of manhole rehab technicians spent a total of 24-48 hours onsite for this project. We performed the Monoform PLUS™ manhole restoration process without disrupting the facility’s operations. Additionally, the Monoform PLUS™ manhole rehabilitation solution cost the customer only a fraction of what they would have paid for a traditional manhole replacement — not to mention the cost savings of keeping the plant operating the whole time and maintaining the current infrastructure. They are very pleased with the results and are planning to use the Monoform PLUS™ process for future manhole repair needs.

A Manhole Rehabilitation Solution With Diverse Applications

Monoform PLUS™ is suitable for a wide range of industrial and municipal applications. HK Solutions often uses Monoform PLUS™ to rehabilitate municipal sanitary sewer system manholes and eliminate manhole leaking — both infiltration and exfiltration.

What causes the corrosion in concrete sewers?

Sanitary system manholes in certain areas experience hydrogen sulfide concrete corrosion due to acidic groundwater. Hydrogen sulfide corrosion in city sewers is very similar to the sulfuric acid corrosion seen in chemical plants and other industrial facilities.

Why is hydrogen sulfide objectionable in a sanitary drainage system?

High levels of hydrogen sulfide in sanitary sewers can cause concrete corrosion over time. Corroded sewer pipes, manholes and other structures make the whole sewer system vulnerable to pipe collapses, leaks, infiltration, root invasion and other serious issues.

Monoform PLUS™ is a suitable solution for a variety of municipal and industrial situations where traditional manhole rehabilitation techniques may be impossible or ineffective.

Partner with HK Solutions Group

Our expertise and innovation help us tackle the toughest jobs. Contact HK Solutions Group to learn more about our industrial services and our manhole repair and rehabilitation services.

HK Solutions Group isn’t just an industrial services and manhole rehabilitation contractor. We serve customers across the US with various industrial and municipal services, including pipeline inspections, pipeline rehabilitation, waste handling and more. Explore our diverse range of services, and call us to learn more: 515-283-0500.

photo of Wayne Turner
Wayne Turner

Wayne joined the HK Solutions Group team in 2020 upon the acquisition of his AGRU HDPE liner supply and fabrication business, Turner Lining Company. Along with his business savvy, Wayne brings 45 years of innovative experience in the precast industry to the team. Backed by Wayne’s extensive expertise, HK Solutions Group created Monoform PLUS to provide superior service for municipalities with long-lasting manhole rehabilitation technology able to withstand highly corrosive conditions.

Learn More About Wayne