June 30, 2026

Advancing Stormwater Innovation with PerkFilter & NEST in Nashville, Tennessee

Advancing Stormwater Innovation with PerkFilter & NEST in Nashville, Tennessee

At a Waffle House location in Nashville, Tennessee, PerkFilter™ is doing more than managing stormwater; it is helping validate the future of stormwater treatment technology.

 

Project Overview

Oldcastle Infrastructure’s PerkFilter system is an underground stormwater treatment system designed to improve water quality by removing pollutants from runoff before it enters local waterways. Using engineered, media-filled filtration cartridges, the system captures key contaminants such as total suspended solids (TSS), phosphorus, and nitrogen. Widely used in commercial and municipal applications, it offers a compact, high-performance solution that is also simple to maintain and service.

Originally installed approximately six years ago as a fully operational system, the site has since been leveraged as a monitored test location as part of the NEST (New Stormwater Technologies) program. Through this initiative, Oldcastle Infrastructure is collecting performance data to support increased regulatory approval and broader adoption of the technology.

 

Background: The NEST Program

The NEST program is a North Carolina-based initiative designed to establish a formal, state-recognized pathway for approving stormwater treatment devices through verified field performance.

Each product must be monitored at two sites:

  • One site within North Carolina
  • A second site either within North Carolina or outside the state, provided rainfall patterns and soil conditions are similar

Since PerkFilter is not yet approved in North Carolina, there are no existing installations available for monitoring. Establishing a new test site within the state is a difficult and time-consuming process. It requires a project designer willing to specify an unapproved system, construction coordination and completion, and sufficient time for the site to stabilize before monitoring can begin.

To accelerate testing, Oldcastle selected an existing installation in Nashville, where monitoring could begin immediately under comparable environmental conditions. This allows the team to efficiently meet program requirements while collecting reliable, real-world data from a typical, operational system that treats actual stormwater runoff which is much more complex than synthetic stormwater formulated in a laboratory.

 

Challenge

To support PerkFilter’s inclusion in the NEST program, Oldcastle Infrastructure needed to capture reliable, defensible pollutant removal data under real operating conditions while maintaining standard system performance.

The selected monitoring site also needed to:

  • Reflect environmental conditions similar to North Carolina
  • Provide adequate space for an array of monitoring equipment
  • Operate as an active commercial property

The Nashville Waffle House site introduced additional complexity due to its high traffic and continuous operations, requiring maintenance activities to be carefully executed with minimal disruption.

 

Solution

Oldcastle addressed these challenges by leveraging the existing PerkFilter system in Nashville, which provided runoff with appropriate pollutants and pollutant concentrations, suitable environmental conditions, and immediate readiness for monitoring.

To prepare the system, a standard maintenance cycle was completed in late 2024, followed by ongoing monitoring. The maintenance process included:

  • Removal of spent filtration cartridges
  • Inspection and cleaning of the structure
  • Replacement with new, media-filled cartridges

Maintenance was completed efficiently with careful planning to ensure safety and minimize disruption to site operations.

This project reinforces that PerkFilter systems are designed for straightforward, efficient maintenance. With basic training, a wide range of qualified contractors can perform routine service, making it a practical and scalable solution for utilities and site owners.

 

Our Service & Maintenance Approach

While Oldcastle Infrastructure maintenance team provides expert service and support, PerkFilter systems are intentionally designed to be easy to maintain without specialized or limited providers.

Routine maintenance activities such as cartridge replacement, inspection, and cleaning can be completed quickly and safely by trained crews, helping customers avoid operational complexity and reduce long-term maintenance concerns.

This ease of service is a key consideration for engineers and owners selecting stormwater treatment solutions since it helps control long-term operational costs.

 

Service & Maintenance

A key component of Oldcastle Infrastructure’s service offering highlighted in this project is the PerkFilter cartridge exchange program, which introduces a more sustainable and cost-effective approach to system maintenance. Rather than replacing spent filter cartridges with entirely new units, used cartridges are emptied, collected, cleaned, refurbished, and returned to inventory. The refurbishing process involves removing and disposing of spent media, cleaning and repairing the structural components, and sending the renewed units to manufacturing facilities where they are refilled with new media. This allows the cartridges to be reused without compromising performance.

The program provides clear benefits for both Oldcastle Infrastructure and its customers. Contractors can receive refurbished cartridges at a reduced cost or receive credits toward future purchases, while Oldcastle Infrastructure reduces its reliance on new raw materials. Already established in the western United States, this program is now being implemented in the eastern region, supporting a more circular lifecycle model for stormwater treatment products and reinforcing the company’s commitment to sustainability.

 

About PerkFilter

PerkFilter is an underground stormwater treatment system designed to improve water quality by removing pollutants from runoff before it enters local waterways. Using engineered, media-filled filtration cartridges, the system captures key contaminants such as total suspended solids (TSS), nitrogen, and phosphorus, which are pollutants that can negatively impact rivers, lakes, and downstream drinking water supplies if left untreated.

Commonly used in commercial and municipal applications, PerkFilter is well-suited for sites with limited space while still meeting stringent regulatory requirements. Engineers and specifiers choose PerkFilter for its competitive capital cost, proven performance, ability to deliver measurable, field-validated results, and easy and cost-effective maintenance.

Its role in programs like NEST further reinforces its reliability, demonstrating effectiveness while offering a maintainable, long-term solution supported by ongoing service and cartridge exchange programs.

 

Impact

The PerkFilter delivers impact across multiple dimensions, combining regulatory advancement, environmental benefits, operational excellence, and sustainability. Through ongoing monitoring, the testing at the Nashville site is generating the data required to support NEST approval, helping position PerkFilter as a validated, trusted solution for engineers and regulators.

At the same time, the system continues to improve water quality by removing pollutants from stormwater runoff, supporting broader environmental goals. The successful execution of maintenance activities in a high-traffic commercial setting demonstrates Oldcastle Infrastructure’s ability to deliver efficient, low-disruption service, while the exchange program reduces material waste and extends the lifecycle of system components.

Together, these outcomes highlight the value of integrating performance validation, service expertise, and sustainability into a single project.

 

Conclusion

This project illustrates how Oldcastle Infrastructure is advancing stormwater management through a combination of innovation, field validation, and operational expertise. By leveraging an existing system for performance monitoring, maintaining it through a highly coordinated service effort, and incorporating sustainable practices through the exchange program, Oldcastle Infrastructure has created a model for how stormwater solutions can deliver both immediate and long-term value.

As programs like NEST continue to shape the future of stormwater regulation, solutions that combine proven performance, ease of maintenance, and real-world validation will play a critical role in driving adoption.

 

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