North Carolina’s New Era of Water Quality

With demand expected to exceed the capacity of the City of Gastonia's water treatment plant in 2019, the timeline for repairs to the system was critical.

Interior of the Gastonia Water Treatment Plant, depicting the 12 MGD membrane treatment process prior to distribution.
Interior of the Gastonia Water Treatment Plant, depicting the 12 MGD membrane treatment process prior to distribution.

Bringing surface water membrane technology to the Tar Heel State  

By Keith Garbrick

With 76,000 residents across 52 square miles, the City of Gastonia has grown 350-fold since its formative days as a railroad town supporting the textile industry with a steam-powered mill. And while it still intersects the Atlanta and Charlotte railroads, the city is home to a far more diversified economy than during its humble beginnings. As part of the Charlotte metropolitan area, Gastonia has experienced the region’s robust growth and economic development of the past two decades. In fact, the city’s 30-year projection suggests that by 2035 parts of the city will see population growth as high as 130 percent. 

Built in the 1920s, Gastonia’s Water Treatment Plant, initially designed to support a quiet mill town, was structurally failing and would soon no longer be able to produce enough clean water for its citizens. By 2009, two treatment trains out of an existing 10 had already been decommissioned due to structural concerns and demand was expected to exceed the capacity of the plant by 2019. The timeline was critical.

Initially, the city had engaged another engineering firm to study the plant and make a recommendation on how to solve this problem. The findings of this plan proposed building a completely new plant at a cost of $230 million and decommissioning the existing facility. After realizing it could not make this work due to budget constraints, Gastonia reached out to LaBella Associates to see if there was another way to solve this problem.

As a result, LaBella developed a four-phase approach to satisfy the city’s budget requirements. The first phase included a membrane treatment process that would provide a higher-level water quality at a capital cost equal to conventional treatment. This would increase plant capacity to 12 million gallons a day (MGD).

Conventional treatment uses sand and anthracite to filter and treat the water, while membrane technology is an ultimate barrier that filters out particulates, bacteria and viruses to ensure a higher-level water quality. While surface-level membrane technology is proven and accepted in other states, North Carolina had not permitted a single surface water membrane treatment facility anywhere in the state. This membrane filtering process has typically been more expensive to implement and raises costs for the customer, which is one of the reasons the state was behind in moving forward with this technology.

In order to make the plan work, LaBella and the city met periodically with stakeholders from the North Carolina Department of Environmental Quality (DEQ) to educate state regulators and provide a level of confidence in the team to successfully implement and move forward with the plan. This included site visits, presentations, and meetings with various membrane technology manufacturers to familiarize the state with the process and its benefits.

After nearly a year, the DEQ allowed the city to proceed and the state awarded the project the maximum single project loan of $35 million from the State Revolving Fund (SRF), funded by the Environmental Protection Agency (EPA).

Strainers filter large particles out of the influent to avoid damage to the membrane fibers.Strainers filter large particles out of the influent to avoid damage to the membrane fibers.In addition to this trailblazing effort, implementing the project took forethought and courage from the City of Gastonia for additional reasons. First, this was the single largest project the city had undertaken in its history. Second, the plant needed to remain operational while upgrades were made; this is equivalent to working on a car engine while it is running. As a result, it was imperative that the plant still continue to filter and treat water for local residents throughout the duration of design and construction.

LaBella’s technical expertise and knowledge of the plant and how it operates helped to make the improvements successful. The firm had been a trusted partner of the City of Gastonia for over 30 years and previous collaborations on the city’s critical infrastructure ensured a smooth process. During the three years of construction of Phase I of the Water Treatment Plant, there was never a violation of quality or capacity.

“LaBella has been a very positive force throughout the six-year-long, $65 million upgrade of the City of Gastonia’s Two Rivers Water Treatment Plant. This project is, by far, the largest project ever undertaken by the city and has been a daunting task for all of us,” said Ed Cross, division manager of water supply and treatment. “LaBella’s steady guidance and creative abilities have made the project so much better, each step of the way.”

Phase I of the plant was completed in 2019 and became the first in North Carolina to successfully implement surface water membrane technology. The result has been positive for the city, which has made itself a leader in driving the technology throughout the state. In addition, Two Rivers Utilities has been able to keep customers rates nearly the same while ensuring a higher quality of water. This new plant will set the standard of water treatment across the Tar Heel State. WW

About the Author: Keith Garbrick is the Southeast regional vice president at LaBella Associates in Charlotte, N.C. His 15 years of engineering experience have been dedicated to water treatment plant design, wastewater treatment plant design, and construction services for both public and private clients. His multi-faceted, end-to-end expertise, with roles ranging from designer to construction administration, allows him to successfully manage and permit large, complex projects.

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