TRENTON, N.J. — Trenton Water Works (TWW) has hired nationally recognized water-quality expert Dr. Mark LeChevallier to conduct an independent review of the utility’s water distribution system, water-quality practices, and ongoing work to reduce the risk of Legionella bacteria.
The review will help TWW identify additional steps it can take to protect water quality as drinking water moves from the treatment plant through hundreds of miles of water mains, storage facilities, and other infrastructure before reaching customers.
“Protecting water quality does not end when water leaves the treatment plant,” said Sean Semple, Director of the city’s Department of Water and Sewer, which operates Trenton Water Works. “We have taken significant steps to strengthen water quality throughout our distribution system, and we want to build on that progress. Dr. LeChevallier brings decades of experience and an independent perspective that will help us evaluate the work already underway and identify additional opportunities to further strengthen our water-quality practices.”
Dr. LeChevallier is principal and manager of Dr. Water Consulting LLC and previously worked for American Water before retiring in 2018. He holds bachelor’s and master’s degrees in microbiology from Oregon State University and a Ph.D. in microbiology from Montana State University.
He has authored more than 300 research papers and has received numerous awards for his contributions to the science of water treatment. Dr. LeChevallier has served on the Water Science and Technology Board of the National Academies of Sciences, Engineering, and Medicine and the U.S. Environmental Protection Agency’s Science Advisory Board. He also served on a National Academies committee that studied Legionella management in water systems. He is a fellow of the American Academy of Microbiology and the National Academy of Engineering.
What Dr. LeChevallier Will Review
Dr. LeChevallier’s work will focus on six areas:
* Water Distribution System: Review how water moves through TWW’s distribution system, including chlorine levels, how long water remains in the system, storage-tank operations, water pressure, and flushing practices.
* Microbial Risk: Review TWW’s existing water-quality and microbiological data to identify conditions that could encourage bacterial growth and determine whether additional monitoring or testing is needed.
* Legionella Management: Conduct a detailed review of TWW’s Legionella management program, including how and where TWW samples for Legionella and how the utility communicates with large water customers about managing water quality inside their buildings.
* Regulatory and Technical Review: Provide technical advice on reports and other information submitted to state regulators, corrective-action plans, audit responses, public communications, and briefings for TWW leadership.
* Procedures and Monitoring: Review procedures used by TWW employees for water-quality monitoring, Legionella sampling, distribution-system assessments, and related field work.
* Communication and Stakeholder Engagement: Help TWW communicate technical water-quality information to regulators, public-health agencies, large water customers and other stakeholders.
What TWW Is Already Doing
TWW has taken several steps to reduce conditions that can contribute to the growth of Legionella and other bacteria and to improve water quality throughout its distribution system.
A major part of that effort is TWW’s Low Velocity Water Main Flushing Program, an operational method developed in cooperation with state and federal agencies to help maintain targeted chlorine residuals and keep water moving throughout the distribution system. Under the program, TWW strategically opens selected fire hydrants in different parts of its service area and keeps water flowing at a low rate. This moves older water out of the system and brings in water with higher chlorine residuals, particularly in areas where water may not circulate as quickly. Keeping the flow low also reduces the chance of disturbing sediment in water mains.
TWW has expanded the use of automatic and manual flushing equipment to support this work. Automatic flushing devices can be programmed to release water at selected locations and intervals, while manual flushing allows crews to target specific areas based on water-quality conditions, operational needs, and sampling results.
The utility has also increased the number of water-quality sampling stations throughout its distribution system, providing additional locations to monitor chlorine residuals and other water-quality conditions across the five municipalities TWW serves.
TWW has also implemented enhanced management of the nearly 100-million-gallon Pennington Avenue Reservoir, where treated water is rechlorinated before entering the distribution system. Rechlorination helps maintain an adequate disinfectant residual as water moves through the distribution system to customers.
At the water filtration plant, TWW has rehabilitated chlorine contact basins to improve disinfection. The utility also cleans, disinfects, and inspects its finished-water storage tanks as part of its ongoing water-quality program.
TWW’s efforts also include public education and outreach. In previous years, the utility has produced and distributed bilingual educational materials about Legionella, including information developed by state and federal public-health and environmental agencies.
“Clear communication is an important part of protecting public health,” said Michael Walker, TWW’s Chief of Communications and Public Outreach. “Our ratepayers and service-area residents should understand what Legionella is, what TWW is doing to reduce the risk, and what they can do to help protect water quality in their homes and buildings. We will continue to provide reliable, understandable information and be transparent about the work we are doing.”
Major investments in TWW’s treatment, storage, and distribution infrastructure are supporting these operational improvements through its 10-Year $763 Million Capital Improvement Plan.
One of the largest projects will replace the open Pennington Avenue Reservoir with enclosed finished-water storage and a new central pumping station. TWW is also rehabilitating water mains and making other improvements designed to strengthen water quality and system reliability.
Dr. LeChevallier’s independent review will build on these efforts and help TWW determine whether to implement additional monitoring, operational changes, or other actions.
Understanding Legionella
Legionella is a bacterium that occurs naturally in freshwater. Under certain conditions, it can grow in water systems and cause Legionnaires’ disease, a serious type of pneumonia.
People generally become sick by breathing tiny droplets of water containing Legionella. The disease is not typically spread by simply drinking water.
Legionella can grow when water sits for long periods, warms up, or lacks enough disinfectant. That is why water utilities closely monitor chlorine levels, water age, storage, and circulation.
Legionella can also grow inside the plumbing systems of large buildings, including hospitals, nursing homes, hotels, apartment buildings, and other facilities with complex plumbing systems. Building owners and managers therefore also play an important role in maintaining water quality after water enters their properties.
Legionella Is a National Challenge
Legionella is not unique to Trenton or New Jersey. Water utilities, building owners, and public health agencies nationwide work to manage the risk.
One of the largest U.S. outbreaks occurred in New York City in 2015, when 138 cases of Legionnaires’ disease and 16 deaths were linked to a cooling tower in the South Bronx. The outbreak involved a building cooling system rather than New York City’s drinking-water distribution system, illustrating that Legionella can develop in different types of human-made water systems.
Legionella remains an important national public health issue, underscoring the need for water utilities and building owners to understand and manage the conditions that can allow the bacteria to grow.
“TWW is taking a proactive approach,” Semple said. “We want to use the best available science, learn from experiences in water systems and communities across the country, and continue improving how we manage water quality throughout our system.”
TWW provides drinking water to approximately 217,000 people through approximately 63,000 metered connections in Trenton, Hamilton Township, Ewing Township, Lawrence Township, and Hopewell Township.
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