Various factors can cause wastewater structures to develop sizable cracks, through which waste will escape by exfiltration. Groundwater will also enter the wastewater system through infiltration. Cracks can develop in deteriorating concrete wastewater infrastructure for many reasons, including earth movements or daily and seasonal temperature fluctuations that cause expansion and contraction, such as freeze-thaw. Harsh chemicals that treat wastewater can deteriorate the concrete, as can be exposed to hydrogen sulfide gas, a form of sulfuric acid found in sewers created by anaerobic organisms. Leaks, cracks, and damage to coating systems are the greatest of challenges in facility maintenance and new construction and trigger severe financial fines. Since the EPA regulates municipal wastewater management, concrete cracks or leaks that lead to wastewater exfiltration can put the municipality in breach of a judicial consent decree.
If the EPA finds that a municipality has an old leaking sewer system, putting them on a consent decree can mean that they don't get federal tax money until the issue is fixed. A cement material is commonly used to repair wastewater-related sewer leaks. But this process has drawbacks, as does the use of other coating materials. Many experts have transitioned to an advanced polyurea system for concrete repairs in wastewater infrastructure from municipal manholes and lift stations to clarifiers, sumps, and trenches.
Hydrogen sulfide gas eats through at the cement in sewer concrete, so it may only have a lifespan of just a few years. Because much lower elongation properties limit epoxies, they crack and don't bridge cracks well. Polyurethanes have more elongation but nothing like polyureas.
ArmorThane's polyurea coatings are proving ideal for wastewater infrastructure rehabilitation by delivering strong, flexible, abrasion- and chemical-resistant waterproofing that bridges existing cracks. ArmorThane's polyurea system can be installed and used in many temperatures, set and cure rapidly as well as minimize downtime. The spray-applied waterproof coating is a durable protective seamless liner that stops leaks and strengthens the integrity of the entire structure. It produces superior physical properties such as elongation up to 400%, extreme hardness, and high tensile strength to create a perfect industrial liner that protects, strengthens, and waterproofs the infrastructure.
Characteristics of Polyurea
Several polyurea's characteristics help extend wastewater infrastructure longevity and limit wastewater exfiltration and groundwater infiltration.
Since polyurea systems provide superior elongation, it bridges cracks up to 0.125. With tensile strength much higher than traditional materials, it has a lower permeability for better waterproofing. Its chemical resistance and impact, abrasion are excellent, so it resists hydrogen sulfide.
Instead of years between the reapplication of cementitious coatings, the polyurea coating will provide cost-effective decades of durability and protection.
With effective crack repair and surface preparation, the polyurea coating will be a thick film applied directly to the concrete structure.
The polyurea's capacity to set and cure quickly also minimizes wastewater treatment plant or infrastructure downtime. This can result in tens of thousands of dollars in savings per hour, all while avoiding days of service delay.
Wider Temperature Range
While traditional coatings such as epoxies, cementitious, and polyurethanes will prematurely fail if not installed under a limited range of temperatures, ArmorThane's polyurea is designed for application and use -40 to 350 °F. It will endure decades of freeze-thaw cycling and wide fluctuations of temperature and humidity.
Typically, clarifier maintenance teams need high-pressure power washers for hours to clean waste from concrete surfaces. Since the polyurea gives waterproofing and has a cleanable surface, crews can hose down the clarifier to wash it. This can cut essential weekly clarifier cleaning by two-thirds.
For wastewater-related rehabilitation, polyurea is a preferred coating for any application that demands crack bridging, longevity, chemical, and temperature resistance, as well as a quick turnaround.
For more information on protective coatings, sign up for a free subscription to ArmorThane's mailing list, a digital publication covering this industry's technologies and best practices.