Protect & Perform

Extending Wastewater System Service Life with Polymer-Based Coatings

Written by AMPP | May 20, 2025 4:00:00 PM

Underground wastewater systems are often out of sight, but they’re rarely out of mind. If corrosion takes hold, municipalities face public safety risks, emergency repair costs, and potential environmental disaster. The American Society of Civil Engineers (ASCE) 2025 Wastewater Report found the average number of collection system failures is on the rise, and municipalities are looking for proactive ways to maintain these vital systems. As reported in a recent CoatingsPro magazine article, polymer-based coatings and linings are an effective way to protect and extend the service life of wastewater systems. Here’s how polymer systems work.

Why use polymer-based corrosion protection? 

Wastewater systems are subject to aggressive chemical and moisture exposure, especially the underground components. Organic waste breakdown creates hydrogen sulfide (H₂S), sulfuric acid, and other corrosive byproducts. The concrete and steel substrates used in wastewater systems must withstand the threat of chemical and microbial-induced corrosion from these byproducts.

Polymer systems are flexible, durable, and able to form a long-lasting protective barrier between the substrate and the highly corrosive organic waste transported through wastewater systems. For an effective result, choose an appropriate polymer product and ensure it is applied correctly.  

 

Types of polymer-based coatings and liners 

Depending on the substrate, exposure conditions, and chemical load of the wastewater, there are a few polymer types to choose from:

  • Epoxy Coatings: Known for strong adhesion, chemical resistance, and durability, epoxies are a workhorse for infrastructure protection—especially when paired with proper surface preparation.
  • Polyurethane Coatings: Superior flexibility and resistance to mechanical impact and chemical degradation, often used in transitional zones or areas prone to substrate movement.
  • Polyurea Liners: Valued for fast cure times, moisture tolerance, and elongation properties, polyureas are ideal for large surface areas and fast-paced maintenance projects.
  • Calcium Aluminate Cement Liners: In new construction, products like SewperCoat or Sewper Liner offer biogenic corrosion resistance, which can protect concrete before it degrades.
 
Considerations when applying polymer systems 

When properly applied, polymer systems go beyond corrosion prevention. They also reduce long-term maintenance costs, extend service life, and minimize downtime by helping to prevent system failures. Consider these factors when applying a polymer-based coating or lining:

  • Chemical Load: Know what the structure will be exposed to—concentration, temperature, and frequency matter. Chose a product that can handle the load.
  • Surface Preparation: Successful adhesion begins with substrate cleaning, profiling, and moisture control. Closely follow manufacturer recommendations.
  • Cure Time and Downtime: Quick return-to-service may be critical, especially for high-traffic or high-flow assets, but allow enough time for full curing.
  • Application Conditions: Temperature, humidity, and ventilation all affect how a coating behaves in the field. Be aware of extra cure time and number of coats needed.
  • Regulatory Requirements: Products must meet local environmental and health standards, particularly regarding VOC limits or wastewater treatment compatibility.

Whether specifying polymer coatings for a municipal contract, applying protective systems in the field, or inspecting linings on aging infrastructure, AMPP offers courses, certifications, and best practices designed to deliver reliable wastewater system protection.

Are you an AMPP member? You have access to the expanded content library, including Standards, conference proceedings, and journal articles. Search “polymer coatings” to read more about these systems!

 
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