For municipal wastewater personnel looking to address Inflow and Infiltration (I&I) issues related to manhole repairs, there are several effective DIY solutions and approaches to mitigate these problems. Inflow refers to the surface water entering the sewer system, while infiltration refers to groundwater entering through cracks and joints in the system. Both contribute to excess flow in the system, leading to potential overflows, increased treatment costs, system wear and potential regulatory issues.
Here’s a breakdown of some DIY repair options:
1. Manhole Sealing and Grouting
- Seal Cracks and Joints: The most common cause of I&I in manholes is cracks or failed joints. Sealing these with high-quality, durable, cementitious, epoxy or polyurethane-based sealants can prevent both water infiltration and the introduction of surface water.
- Stop Minor Leaks: Minor leaks in concrete or brick manholes can be effectively stopped using a rapid set hydraulic cement, often referred to as a water plug. Sauereisen F-180 Instaplug.
- Grouting: Use a hydrophobic grout or injection grout to fill cracks, voids, or gaps around manhole joints. This method is often effective for manholes with significant infiltration problems. The grout is injected under pressure into the affected areas, expands rapidly, sealing them effectively. Sauereisen’s F370 Hydroactive Polyurethane Grout.
2. Manhole Chimney Seal Installation
Chimney Seals: Install an elastomeric or polymer seal around the riser section of the manhole, where the manhole lid meets the frame and over the grade ring if present. These seals help prevent rainwater from entering the sewer system via the manhole and also help reduce infiltration from groundwater. Sauereisen, easy to apply F-88 Manhole ChimneySeal.
- Adjustable Frames and Covers: Over time, manhole frames and covers can become misaligned or corroded. Replace or adjust them with newer, more reliable models that have tight-fitting gaskets or elastomeric seals to prevent surface water from entering.
- Gasket Systems for Joint Protection: Installing flexible rubber gaskets at the joints of manhole rings or between the manhole base and riser sections can effectively block water infiltration from groundwater and rain. These systems are usually simple to install and can be done by municipal crews with basic tools.
3. Easy to Apply Coatings
- Polymer or Cementitious Coatings: Applying polymer coating to the interior surface of the manhole can protect against both infiltration and structural deterioration from corrosion, which often contributes to I & I. Sauereisen SewerGard 210 Epoxies.
- Cementitious coatings that provide a negative side water barrier based on crystalline technology are often used for their durability and effectiveness in reducing water penetration. Sauereisen F-190 H2OPruf.
- Portland-based and calcium aluminate-based cementitious linings are also effective in stopping I & I and restoring structural integrity to concrete and brick manholes. Sauereisen F-121 RestoKrete Substrate Resurfacer and F-170 SewerSeal.
4. Inspection and Monitoring
- Regular Inspection: Using CCTV inspection tools, workers can locate specific sources of I&I. After identifying the problem areas, targeted repairs can be made. This is an essential part of any ongoing I&I mitigation strategy.
- Flow Monitoring: Install flow monitoring equipment to help assess the effectiveness of repairs and identify future I&I problems.
5. Preventative Maintenance
- Routine Cleaning and Maintenance: Regularly clean the manholes and ensure they remain clear of debris and root intrusion, which can exacerbate I&I issues.
- Checking for Surface Water Entry Points: Inspect the area surrounding the manhole for signs of surface water runoff entering the system. Installing or repairing proper drainage around manhole structures can significantly reduce inflow.
By implementing these solutions, municipal personnel can take proactive steps to manage and reduce I&I, thus extending the life of the wastewater system, reducing treatment costs and improving overall system performance. It’s always a good idea to follow best practices and safety guidelines when performing these repairs, especially in high-risk areas.
Sauereisen offers Engineered Solutions for Municipal Wastewater.
Protect your valuable infrastructure with the engineered systems that last. At Sauereisen, we draw upon over 126 years of industry experience to produce high-quality corrosion resistant products for municipal wastewater. Contact us at www.sauereisen.com or call Sauereisen at +1 (412) 963.0303 today — the first step toward long-term protection. We’ll help you find the right solution.