Swampscott and Lynn are still contemplating the next steps on the ultraviolet (UV) pilot program at King’s Beach.  

“From our experience this summer, we’ve seen that to truly answer those questions we have to know more from an engineering perspective what a UV solution would entail,” said Lynn Mayor Jared Nicholson.  “Based on what we learned this summer, the team has some thoughts on how that could potentially be smaller than originally envisioned, and how to build it into the culvert which would have a much less intrusive presence above ground, on the street.”

About 35 people were present at the city of Lynn and town of Swampscott’s King’s Beach Town Hall event on Wednesday, October 22. The official report on the King’s Beach UV pilot program concluded that the technology “effectively treats day-to-day dry weather stormwater flows from the Lynn and Swampscott culverts.” While there is no specific plans for the location of a future UV system, State Rep. Jennifer Armini (D–Essex) said there’s a possibility of the program even running underground. Nicholson also added that it was known before the start that a future permanent UV program would not be on the Humphrey Street location.

“This is great information, great data that we got,” said Swampscott Town Administrator Nick Connors, who added that Director of the Department of Public Works and former interim administrator Gino Cresta will present in front of the Select Board.

Water quality issues at King’s Beach date back nearly a century, when Stacey’s Brook, which flows into the beach, was converted into a combined sewer and stormwater system serving both Lynn and Swampscott. Issues have persisted since 1891, and until this year, King’s Beach ranked as the second-most polluted beach in Massachusetts.

In 1985, Lynn invested $65 million into a wastewater treatment facility and worked to ensure no sewer-to-storm drain connections continued to empty into King’s Beach. Similarly, Swampscott has moved with its source elimination work, with the projected investment of $10 million over several years to repair and line sewer mains and service laterals to prevent sewage from entering the storm drains and emptying into Stacey’s Brook culvert.

Installed on June 2, the UV project uses ultraviolet light to kill bacteria in stormwater before it reaches the ocean, aiming to provide a cleaner beach for Swampscott and Lynn residents. The project wrapped up a bit early, on Monday, August 18.

Liz Smith, who worked with the data, said that a key to the project was that everyone came together to not only clean the water but also work for better outcomes for the overall community

Nicholson added that the collaboration has allowed for “real progress.”

The UV pilot project was in operation for 59 days, approximately two months. It was designed to operate continuously during both dry and wet weather conditions throughout the summer, with the exception of large rainfall events. For rainfall events greater than a quarter of an inch, the system was designed to remain on but it would not be able to treat all flows. 

The report notes that the “effectiveness of the UV system is reduced during wet weather events, particularly in the first 24 hours, due to increased turbidity in the flow.”

The filtration system treated flows up to approximately 5 million gallons per day. 

Since June 20, water treated through the UV system has consistently tested at or below 10 colony-forming units per 100 milliliters (cfu/100 ml), except on June 28, July 24, and July 26. The Massachusetts Department of Public Health specifies that safe waters have at or under 104 bacterial organisms cfu/100 ml.

Meanwhile, untreated water flowing from the Stacey’s Brook culverts in Lynn and Swampscott have often been above 104 cfu. The majority of the Massachusetts Department of Health’s weekly testing has shown the water quality as acceptable throughout the summer.

In-house testing for the pilot program was conducted daily at five locations, gathering data on untreated stormwater from Lynn and Swampscott individually, the combined flow before and after UV treatment, and ocean water approximately three feet deep near Swampscott’s access ramp.

The number of exceedances for the bacteria threshold was only eight days, compared to 33 days in 2024, 43 days in 2023, 31 days in 2022, and 23 days in 2021. 

This is also a big difference when compared to the inches of rain, which typically raises bacteria count. According to data from the Beverly Regional Airport Station analyzed by the Swampscott Tides, 2025 saw 7.14 inches of rain in June, July and August. During the same time period there was 6.15 inches in 2024, 14.62 inches in 2023, 4.45 inches in 2022, and 13.23 inches in 2021. 

This means in 2025, there were 1.12 days of exceedances per inch of rain. In 2024, the number was higher at 5.36 days per inch, and 2022 was also recorded higher at 6.97 days per inch. 2023, at 2.94 exceedances per inch, and 2021, at 1.74 days per inch of rain, were more on par with this year’s results, even without a UV pilot project in place.

A study will need to take place, while there is also discussion for a potential temporary program again next summer. Funding sources and power from National Grid would be needed for the latter. 

“If we were to do a site selection now, we wouldn’t know how big it would need to be,” Nicholson said. 

Residents living near the site of last summer’s pilot program complained that the study was conducted without informing them of a future location or sharing any concrete details about upcoming plans. Nicholson pushed back that “without the answers to those questions” around specific data information “we wouldn’t know the answers.”

Jeff Chelgren spoke out against the potential for a second iteration of the program, stating that he and his husband Stephen Harrington were “prisoners in our own home” over the summer.

“There were some poor decisions made about the equipment,” Chelgren said. “We are opposed to anything else going on there.”

Around 25 years ago, Chelgren planted a yew bonsai tree, along with rocks and other vegetation, on a traffic island at the corner of Humphrey Street and Lynn Shore Drive. After maintaining the spot himself, Chelgren removed the entire installation in August and returned the space to Swampscott due to his displeasure with the UV project.

A group of Swampscott and Lynn residents, including Chelgren and Harrington, filed a legal notice citing noise concerns from the joint UV treatment project. The group alleges the pilot program violated noise limits, citing a commissioned study that recorded noise levels between 61 and 65 dB, “far in excess of the allowance of 10 dB above” ambient noise, as permitted by the Department of Environmental Protection.

The study did not note noise outside of the fact “blankets were affixed to all fencing that surrounded noise-making equipment.” Instead the results focused on tidal, wet weather and ocean impacts as operational performance-related issues.

It was confirmed during the forum that “some spot checking” was done around the generator for the sound.

“You can’t inflict this on a neighborhood and then turn your back on the neighborhood,” Chelgren said at the forum.