Manhole rehabilitation is a crucial process that revitalizes aging sewer systems, utilizing specialized manhole rehabilitation equipment to restore structural integrity without the need for costly replacements. By employing innovative methods like cured-in-place liners and polymer coatings, we can efficiently address corrosion and leaks while minimizing disruption to daily operations. This proactive approach not only extends the lifespan of manholes but also safeguards public health and the environment, making it an essential practice for municipalities and industries alike.

What is Manhole Rehabilitation?

Manhole rehabilitation is the process of restoring aging manholes and reinforcing the structure to avoid needing to fully replace the manhole. While replacement may be the only option for manholes that are damaged beyond repair, sewer manhole rehabilitation is ideal for situations in which the manhole can be restored through trenchless methods.

Types of Manhole Rehabilitation

– Cured in Place Manhole (CIPM)

A cured in place manhole (CIPM) liner is a felt tube that relies on resin in its core to tightly secure the manhole as the tube is inflated and the catyzed resin hardens. CIPM works well for traditional cylindrical manholes but typically requires larger crews and more equipment to get the job done than other trenchless rehabilitation methods.

– Geopolymer Manhole Linings

Geopolymer linings are cement-based and act as a glue, coating the manhole and forming a seal to support the structure. Geopolymer linings are effective in corrosive environments and provide a structural enhancement to the host structure.

– Cementitious Liners

Cementitious liners are a relatively low-cost and easy-to-apply solution typically cementitious manhole linings are applied during a low-pressure spraying process. They aren’t ideal for corrosive environments, but recent improvements have led to better protection against infiltration, lengthening the manhole’s lifespan.

– Manhole Grouting with Chemical Injections

Manhole grouting is a good option for cracked or leaking structures and involves applying gel within the manhole to seal and waterproof the cracks and/or construction joints and seams to effectively prevent inflow and infiltration. Grouting is preferred for sealing manhole structures subject to leaking but is not recommended for infrastructures that are structurally failing, as a more comprehensive approach is required for advanced deterioration.

– Monoform™ Manhole Rehabilitation Solutions

While HK Solutions Group offers solutions across the spectrum of available trenchless rehabilitation methods, we have found some projects require outside the box thinking. This is why our trademarked Monoform™ and Monoform Plus ™ manhole lining solutions innovative answers to the most challenging manhole issues. Whether sewer structures are located in a strenuous environment (such as areas of extreme heat or highly corrosive areas) or have simply deteriorated over time, one of our Monoform™ solutions will ensure the lasting integrity of your infrastructure. In fact, our Monoform™ solutions have the equivalent lifespan of a full manhole replacement without the unnecessary expense and interruption to your day-to-day operations.

–Monoform™

The original Monoform™ is a 100% structural solution enhancing sewer systems without the need for excavation.

–Monoform PLUS™

Monoform PLUS™ combines the trusted Monoform™ solution with a high density polyethylene (HDPE) Agru corrosion protection barrier. These two technologies combine for a 100% structural and 100% corrosion resistant remedy in corrosive geographies or facilities working frequently with chemicals. HDPE manhole linings are durable and last longer than traditional manhole structures that deteriorate rapidly from high H2S

The Benefits of Sewer Manhole Rehabilitation

Commercial properties, industrial facilities, and municipalities can benefit from manhole rehabilitation. Trenchless manhole rehabilitation products and methods can revitalize existing infrastructure, prevent disasters, and restore the integrity of the system for years to come.

-Extends Lifespan

Manhole lining systems protect the substrate from daily wear and tear as well as chemical attacks, corrosion, and other damage, extending the lifespan of the manhole regardless of shape, condition, or material.

-Solves & Prevents Inflow & Infiltration Issues

Damaged manholes are vulnerable to inflow and infiltration issues caused by excess water from storms or the ground seeping through holes or cracks in the manhole system. If left unaddressed, these issues lower the capacity of the sewer system, increase operational costs, and damage the infrastructure. Protective linings, in conjunction with chemical grouts, solve existing inflow and infiltration issues as well as prevent the development of future challenges.

-Prevents Corrosion

Corrosion caused by hydrogen sulfide (H2S), microbes, or environmental conditions damages the structure of concrete manholes or the mortar joints of brick manholes. Over time, this corrosion leads to serious deterioration of the manhole infrastructure. Installing an anti-corrosive manhole rehabilitation product prevents or slows the development of corrosion in the structure.

-Increases Cost Savings

Replacing a manhole is expensive not only the initial digging but also the rebuilding that follows. Alternatively, a manhole rehabilitation project provides significant cost savings because there is no digging, building, or downtime required.

-Reduces Downtime

Manhole replacement requires facilities and municipalities to halt operations while crews and their equipment work. The manhole rehabilitation process, on the other hand, does not require any digging and does not disrupt daily operations. In most cases, sewer manhole rehabilitation crews can finish the job in 12 hours or less.

The Process of Manhole Rehabilitations: 3 Common Applications

There are many technologies that can assist with sewer manhole rehabilitation without the need for additional excavation. Products like cured-in-place (CIPM) manhole liners, cementitious lining systems, and polymer coating and lining systems help stop leakage, prevent corrosion, enhance the structure, and extend the service life of the manhole.

1.Cured-in-Place Manhole (CIPM) Liners

CIPM liners are tubes made of a variety of resins and other materials that are inserted into the manhole and inflated until it is tightly secured to the interior. As the tube is inflated, the resin hardens and provides strong, long-term chemical resistance.

The use of a CIPM liner requires that the manhole is large enough for the inflated tube to fit into. If the manhole chimney is not wide enough, it may need to be removed so the CIPM liner can be placed into the widest part of the pipe. Additionally, the bottom of the manhole must be designed with a seal that will ensure nothing gets between the liner and the substrate while it is being inflated.

Installing CIPM liners often requires more equipment and larger crews than other manhole rehabilitation methods. However, they can be an effective and affordable option for rehabilitating traditional, cylindrical manholes.

2.Cementitious Lining Systems

Cementitious mortar lining systems are specially formulated to provide a permanent seal on the interior of the manhole corridor. They are applied with a low pressure spray or a trowel and can be installed quickly, with less downtime.

These liners act as a protective shield and are often reinforced with fibers to provide extra crack resistance and tensile strength. Unfortunately, their chemical resistance is not as strong as polymer-based lining systems, so they are not ideal for corrosive environments.

3.Polymer Coating & Lining Systems

Polymer coating and lining systems include products made from epoxies or polyurethanes. These systems are applied by hand with a trowel or via a pressure sprayer and are designed to protect the structure of the manhole from corrosion, chemical attacks, wear and tear, and impacts.

When polymer liners are installed correctly, they provide protection and support the structure for years. If the manhole is already corroded, use cementitious mortar liners to build the manhole back to its original shape. Then, after the polyurethane or epoxy liner is applied to the interior of the manhole corridor, it fully seals to the substrate. The result is an impermeable, durable, chemically resistant, anti-corrosive, environmentally safe shield that cures quickly and provides long-term protection.

Conclusion

Manhole rehabilitation is vital for maintaining urban infrastructure. By leveraging advanced rehabilitation equipment and techniques, we can effectively enhance the durability and functionality of sewer systems, ensuring they meet the demands of modern cities. This approach not only saves costs and reduces downtime but also contributes to sustainable community development, protecting our essential resources for future generations.

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