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Hemphill Water Treatment Plant Retrofit

Hemphill Water Treatment Plant Retrofit. Powering the Next Century of Clean Water

Background: A Legacy of Service Since 1893

The Hemphill Water Treatment Plant, named after former Atlanta Mayor W.A. Hemphill (1891–1892), has been a cornerstone of the city’s water infrastructure since 1893. It remains one of the most critical facilities in the region, supplying 65% of Atlanta’s drinking water with a capacity of 136 million gallons per day, including the water supply to Atlanta Hartsfield International Airport. 

The original main inlet piping to the reservoir installed in 1893 is still in use and is a testament to the plant’s enduring legacy. Stress on the water system dramatically increased due to the rise in population and ongoing commercial and industrial expansion. This growth, combined with aging infrastructure and capacity restraints, made modernization a top priority in 2025.


The Challenge: Aging Infrastructure and Capacity Constraints

The plant’s aging infrastructure was unreliable and inadequate, which was compromising treatment quality and failing to keep up with growing demand. The plant’s 40+ year-old electrical system had also become a liability. The outdated switchgear posed a safety concern with more downtime needed for maintenance as well as operational concerns related to reliability.  

A comprehensive electrical infrastructure upgrade was essential to restore system reliability, safety, and capacity and to prepare for more growth in the Atlanta area. A major challenge for improving the electrical system was to maintain service levels during the switchgear transition, which meant the existing switchgear had to be replaced in stages. In many applications, the entire new switchgear can be installed, with cable crossover as allowed for power transition. At this site, the existing gear blocked the space needed for both stages of the new switchgear, adding complexity to the overall application.


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The Solution: Phased Retrofit with OEM Switchgear Partner

To address these challenges, Application Engineers from nVent teamed up with a major switchgear OEM partner to design a solution for a complex, time-staged retrofit of a new medium voltage switchgear solution.  Utilizing the OEM’s dedicated team as the way to package the switchgear inside an e-house solution, the team collaborated with the city’s engineering and contractor teams to deliver an integrated nVent TRACHTE solution.


Key Upgrades (Application Notes):

  • Arc-resistant switchgear was installed with inherent pressure-relieving plenums and arc chutes to safely manage risks associated with fault conditions in medium voltage electrical equipment. This enhanced safety provides operators with better working conditions and less risk associated with potential arc faults.
  • An integrated e-house solution was designed to fit the existing pad and electrical feeders. This unique solution was pre-engineered to allow the existing switchgear to be removed in stages, with the e-house solution positioned over existing feeders for those sections being retrofitted.
  • The offset-split building allowed for the stage-one retrofit to be fully functional as a standalone solution for half the bus and feeders, with stage-two installed at a later date, mating up the two sections of the e-house for a complete solution.
  • The scope included in the stage-one building section included the DC system for control power of the new switchgear, the HVAC units for that section plus the HVAC power and thermostat.
  • Trachte’s Application Engineer worked closely with the City, Engineer of Record, and the switchgear OEM, designing a solution that allowed the contractor to demo half the existing gear and install one section of the building. This provided a building section with fully operational switchgear, an appropriate aisle space in front of the gear and all support equipment required for safe operation.
  • Stage-two of the installation involves the final demo of the existing switchgear and connecting the second half of the Trachte building to the stage-one section, plus all field connections by the contractor.


Conclusion: Building for the Next 100 Years

nVent was at the forefront of a team of professionals assembled to provide a modern solution to a complex problem, amplified by limited space and the critical nature of maintaining operations. The diverse experience the nVent team can bring to each application was exemplified on this project, with challenges presented at each step of the project. 

This project further demonstrates how application-focused engineering and collaborative planning can modernize legacy infrastructure without compromising service continuity. While split-building shipments are often driven by logistics, this project required a phased approach to successfully integrate the new system with existing infrastructure and transportation restrictions. 

We delivered a solution that aligned with the City’s vision for sustainable, resilient infrastructure for the future of Atlanta. The Hemphill WTP is now equipped to meet Atlanta’s high-volume water demands for decades to come with improved quality, safety, reliability, and operational efficiency.