Coordinating Large-Scale Water Reclamation Facility (WRF) Design, Expansion and Rehabilitation

The Challenge: Expanding and Rehabilitating Sioux Falls’ Largest Water Reclamation Facility 

When you’re spending $215 million on an industrial construction project that’s meant to last 20 years or more, there’s little room for error. You need to get everything right from the outset – and ensure everyone is on the same page.

Close communication was a necessity across the board as contractors worked to expand and rehabilitate the 23-acre regional water reclamation facility (WRF) and collection system for the City or Sioux Falls, South Dakota. But collaboration carried an especially important weight for the coatings work that would need to be done to protect the facility’s new assets from an early demise.

Coordination among the project team of the City of Sioux Falls, McCarthy Building Companies, MVP Painting and Sherwin-Williams Protective & Marine led to a successful outcome for the newly expanded and rehabilitated Sioux Falls Regional Water Reclamation Plant. These efforts to ensure the proper specification, application and testing of long-term protective coating solutions will help the city better serve the water needs of its growing population for the next 20 years and beyond. They also helped the project earn top honors as the 2025 Sherwin-Williams Wastewater Impact Award winner.

The Solution: Collaboration and Communication for Long-Term WRF Coating Success

The WRF development project is the largest endeavor taken in the city’s history, marking a major expansion of the facility to meet the region’s needs for the next two decades. It’s also the first major development for the Sioux Falls Regional Water Reclamation Plant since it was built in the 1980s. The project will increase the facility’s daily treatment capacity by 43% from 21 to 30 million gallons. This capacity will support an additional 100,000 customers, matching the region’s projected growth to nearly 300,000 residents by 2036.

The entire project includes constructing a headworks building where wastewater enters the facility, installing new generators, upgrading the electrical system, adding three aeration basins and four final clarifier pools, and by adding more storage tanks to expand the facility’s chlorine treatment areas.

To achieve 20-plus years of performance, those new assets not only needed to be constructed and installed properly, but they also needed to be protected with robust coating and lining systems that would minimize wear and maintenance needs. Specifying the right materials for those applications is where the project team’s collaboration started – well before any construction broke ground. Early outreach from Sherwin-Williams Protective & Marine to the City of Sioux Falls prior to the public bid encouraged engineers to consider the company’s coating solutions for the project specification.

“It was highly important for us to get the coating selections right so we could protect this major infrastructure investment over the long term,” said Mark Perry, Wastewater Superintendent for the City of Sioux Falls. “That meant relying on the expertise of our contracting providers, as well as some key suppliers to understand the range of options that were available and which ones would perform the best for each application.”

Sherwin-Williams worked with the City and Grandview, Missouri-based MVP Painting to refine specifications for the various assets that would need to be coated and lined. Everyone focused on longevity at first, while also considering budgetary options, before preparing specifications designed to maximize asset life in all cases. That included opting for especially robust systems for some exterior piping that faces aggressive exposures.

Construction Manager at Risk (CMAR) McCarthy was then responsible for ensuring those specifications were followed after the construction company built various assets. Such oversight is usually managed directly with the industrial painting contractor, but the use of some unfamiliar materials for the project prompted McCarthy and MVP Painting to work closely with Sherwin-Williams throughout the project to overcome any learning curves and ensure quality coating applications.

“There’s usually a longer loop from us to the coatings supplier, but the nuances of this project welcomed the opportunity to open direct lines of communication – and that made all the difference,” said Michael Korus, Project Manager for McCarthy. “This collaboration allowed us to hone best application practices with MVP Painting and have timely conversations with Sherwin-Williams at critical decision points, helping the entire scope move quicker.”

WRF Expansion: Optimizing Coating Performance for New Clarifiers 

The coating needs for the plant’s four new final clarifier pools are a prime example of how communication and collaboration among the project team helped the City realize a longer-term protective solution. During initial specification discussions, the team considered using a coal tar epoxy for the clarifiers’ sludge troughs. While a viable solution, coal tar would likely not hold up long against the corrosive nature of the solids and contaminants collected in the troughs.

As an alternative, Sherwin-Williams proposed a three-coat system that would ensure durability by building protection one layer at a time to deliver significantly greater resistance to chemical and corrosive attacks than a coal tar application.

“Careful selection of the protective system for the sludge troughs proved to be a major win for the plant on two fronts,” said Korus. “First, the facility has a more robust system that will last longer and require less maintenance over time. Plus, they saved on application costs, as applying coal tar is more labor intensive than building up the three-coat system.”

The specified system began with a cementitious resurfacing coating, Dura-Plate® 2300, that MVP Painting applicators troweled onto the prepared surface of the sludge troughs (Figure 1). The material fills in any voids and bugholes in the concrete prior to adding the additional coats to promote adhesion of those layers to the sludge troughs’ concrete surfaces.

Applicators next sprayed an intermediate coat of Dura-Plate® 235 at about 5 to 8 mils dry film thickness (DFT) onto all the sludge trough surfaces (Figure 2). This modified epoxy phenalkamine provides exceptional performance in corrosive environments and is formulated specifically for immersion and atmospheric service like what the troughs experience.

Collaboration and communication entered the picture again during the Dura-Plate 235 applications, as the hot summer weather began to interfere with applications. Technical service representatives from Sherwin-Williams visited the site to help MVP Painting overcome extreme outgassing releases that were occurring as the concrete heated up. This outgassing could interfere with coatings adhesion, so the team arrived at a plan to constantly monitor the environment and the substrate temperature. This led to applicators chasing the shade and avoiding spraying when temperatures were too high to ensure proper adhesion. Sherwin-Williams also assisted with dialing in the plural-component spray equipment to ensure material temperatures and spray pressures were correct.

“This project represented the most help I’ve ever had from a paint supplier,” said Dallas Cox, Project Manager for MVP Painting. “Sherwin-Williams really made the job flow smoothly and helped to resolve all the issues. I don’t see that very often.”

For the topcoat, applicators sprayed a deep blue coat of Poly-Cote™ 115 over the entire intermediate layer (Figure 3). This flexible polyurethane coating has optimal build properties, which allowed applicators to achieve a film build of 80 to 150 mils in a single pass. Its flexibility allows for expansion and contraction as the exterior sludge troughs weather temperature fluctuations and atmospheric exposures. In fact, the complete coating system resists effects from weather, extreme temperature shifts and ultraviolet exposure.

“The City naturally wanted the coatings to last,” said Cox. “Coal tar would have been more of temporary solution that required frequent maintenance. The chosen system is designed for the long term by plugging up voids with the resurfacer, really sealing up the concrete with the intermediate epoxy build and protecting everything below with the flexible topcoat.”

For quality control, the project team carefully inspected all work, ensuring coatings were built to the required DFT by testing in process applications using wet film gauges (Figure 4) and then following up with holiday spark testing to ensure complete coverage and ultrasonic testing to confirm the final DFT of all coatings met specifications.

WRF Expansion: Preparing New Pipes for Long-Term Service 

The facility’s various exterior pipes also required coatings to protect against corrosion in the damp, exposed environments in which they operate. Specifiers had the option of using multiple different coating systems for these spaces and ultimately opted for a robust, chemical-resistant polysiloxane system that would prioritize longevity. This high-performance system was particularly important for the piping installed above the three new aeration basins that treat wastewater with microbes, as they’re located directly over contaminant-filled water that releases hydrogen sulfide gases and salts. As those corrosive materials contact the pipes, they can damage weaker coatings, leading to failure of the protective film and ultimately corrosion.

Consulting with Sherwin-Williams, the specification team opted to use Sher-Loxane® 800 as the topcoat for the pipes (Figure 5). The polysiloxane coating combines the properties of both a high-performance epoxy and a polyurethane to enable the durability of the former and the flexibility of the latter in the same application. The combined properties enable effective long-term corrosion control and weatherability. The coating’s high gloss retention and excellent UV resistance were also important qualifying factors in its selection for the basins.

“With long-term performance and minimal maintenance being a primary goal, we wanted to use something higher end than a typical urethane,” said Perry. “Because the polysiloxane coatings are protecting the pipes, we shouldn’t have to touch them for a decade or more – even with their close proximity and exposure to corrosive substances.”

Applicators applied Sher-Loxane 800 over a primer coat of Epo-Phen™ FF, which is a flake-filled, anti-corrosive epoxy phenolic novolac coating. They first blasted pipes to an SSPC SP-10 Near-White Metal Blast Cleaning level to remove all contaminants before applying the primer at 3.5 to 4.5 mils DFT and then adding the polysiloxane topcoat at 4 to 6 mils DFT. The primer features flakes of micaceous iron oxide (MIO), which stack up like plates in the coating film to prevent an easy path for water to penetrate the coating film. With this protection working underneath the high-gloss topcoat, a significant barrier exists between the exterior surface of the pipes and their steel substrates.

MVP Painting applicators also lined the concrete aeration basins themselves with Dura-Plate® 6100, a high-build, 100% solids epoxy coating (Figure 6). This step created a barrier between the corrosive basin contents and the concrete substrate, protecting that surface from severe wear to enable long-term operation.

WRF Rehabilitation and Maintenance: Setting up for the Long Haul 

The overall coatings project also included some rehabilitation work in the plant’s original headworks building. Applicators from MVP Painting performed surface preparation on a variety of filters, pipes and other equipment, being careful to contain any debris. Next, they applied Macropoxy® 646 in a single, high-build coat to restore corrosion protection on those assets. The fast-drying polyamide epoxy mastic was handy for the maintenance painting, as it can be applied directly to marginally prepared steel surfaces.

The Results: A Durable, Cost-Effective Water Reclamation System for Decades to Come 

With a price tag of $215 million and funding coming from a grant from the American Rescue Plan Act and a low-interest loan from the U.S. Environmental Protection Agency via a state revolving fund program, the City of Sioux Falls served as good stewards for those funds. Collaborating with the project team and involving all parties in the specification discussions led to selecting a variety of coating systems that promote longevity of service and will minimize maintenance needs for many years. These cost-effective decisions are sure to pay off over the next 20-plus years.

“Going into a project of this size, you don’t always realize how important the coatings are in the whole grand scheme of things,” said Korus. “But they can really make or break the long-term performance of assets and affect their future maintenance cycles. We’re glad we made time to meet with Sherwin-Williams and bring them into the fold.”

ABOUT THE AUTHORS

Tyler Day has over 15 years of expertise in the paints and coatings industry, including six years with Sherwin-Williams Protective & Marine. As a current Project Development Manager, he supports a diverse range of industries, including Infrastructure, Manufacturing & Processing, Energy, Freight Rail and Marine. Tyler is an AMPP Level 1 Certified Coating Inspector, underscoring his commitment to quality and industry standards. Contact: Tyler.Day@sherwin.com

Casey Holter is a seasoned coatings professional with over 22 years of industry experience, including six years dedicated to Sherwin-Williams Protective & Marine, specializing in Water Infrastructure. Currently serving as an Asset Protection Manager, Casey brings deep expertise from his prior roles in store operations and multi-segment support, where he spent 16 years supporting a wide range of customer needs. He is an AMPP Level 1 Certified Coating Inspector. Contact: Casey.L.Holter@sherwin.com

Figure 1. Applicators trowelled a coat of the cementitious resurfacing coating Dura-Plate® 2300 (shown behind the applicator) onto sludge troughs for the facility’s new clarifiers before spraying the intermediate coat (shown).

Figure 2. An intermediate coat of Dura-Plate® 235 sprayed onto all the sludge trough surfaces sealed up the concrete to prevent water infiltration and protect the substrate from wear.

Figure 3. A deep blue topcoat application of Poly-Cote™ 115 in the sludge troughs allows for expansion and contraction due to temperature fluctuations.

Figure 4. Applicators used wet film gauges during spray applications to ensure the coatings were built to the required film build.

Figure 5. Piping associated with the facility’s aeration basins received a two-coat protective system featuring a flake-filled, anti-corrosive epoxy phenolic as the primer and a high-performance polysiloxane as the topcoat for long-term corrosion control, gloss retention and weatherability.

Figure 6. The specification team opted for a more durable polysiloxane coating system instead of a urethane system for piping above the facility’s aeration basins due to the pipes’ exposure to hydrogen sulfide gases and salts.