Wrightsville Beach received a second notice of violation last week from the N.C. Department of Environment and Natural Resources (DENR) due to levels of the disinfection byproduct trihalomethane (THM) exceeding the Environmental Protection Agency’s maximum contaminate level at two sampling sites in the town’s water system.
Town staff said they expected the March 2 violation because the violation was for a running average of samples taken during the fourth quarter of 2014.
THMs form when chlorine, a disinfecting agent, mixes with organic compounds such as bromine in the source water. They are suspected to be carcinogenic when consumed in large quantities over a long period of time.
Since town staff received the first violation for the third quarter of 2014, they say they have implemented a more effective method of flushing and circulating water through the pipes. The longer the water sits in the pipes, assistant public works director Steve Dellies said, the longer the chlorine mixes with the bromine and the more THMs form.
“Before, we used to just open the [fire hydrant] at the south end and just let water run through the system,” Dellis said during a March 11 phone interview. “What we do now is we start up by the Blockade Runner and we sequentially open all the fire hydrants as we go to the south end . . . and pull the water all the way down to the south end.”
The new flushing methods appear to be working, Dellies said. The first sample taken in January 2015 showed THM levels below the maximum contaminate level. If the second sample, taken March 10, shows similar results the water will be back in compliance for the first quarter of 2015.
Dellies said he expects the results back from the laboratory around March 27.
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