As a cautionary measure, Ascension Parish officials are disinfecting water lines in a west bank parish water district that had brain-eating amoeba elsewhere on its system this summer.

The disinfection, known as a chlorine burn, is not being required by state regulators but is being done as a proactive step, parish officials said Wednesday.

“We are doing that burn because we feel that something is needed to ensure we deliver the best potable water to the people on the west bank (of Ascension),” said Ken Dawson, the parish government’s chief administrative officer.

The state Department of Health and Hospitals did order Ascension Consolidated Utilities District No. 1 to do a chlorine burn on a different section of the water system in late July after the amoeba was found there. DHH gave the all-clear Oct. 29 after tests were negative.

A chlorine burn involves boosting chlorine levels over a 60-day period to a level known to kill the amoeba, Naegleria fowleri, and bio-film, known to provide a place for the amoeba to live.

The section affected by the second chlorine burn on the ACUD system has about 500 customers, including people in the community of Lemannville and the Ascension Parish Prison and its roughly 500 inmates.

ACUD does not produce its own water but buys it from other systems. As a result, ACUD, which serves the outskirts of Donaldsonville, has two halves: one supplied by Assumption Parish and the other by St. James Parish. The amoeba was found in late July on the Assumption side, which serves Modeste and Smoke Bend.

Dawson said chlorine levels continue to remain in good shape since that first burn and the Assumption side has resumed normal operations.

The St. James side also has had problems with low chlorine levels, and parish officials had been seeking a DHH permit for the equipment to do a chlorine burn on the St. James side before the amoeba was found on the Assumption side.

Dawson said the parish has since received DHH’s approval. Chlorine levels, what is known as the “residual,” reached the required level about two weeks ago so the 60-day clock for the burn could start. Dawson estimated the burn should continue through early January.

“In the cooler months, you have less biological activity (in water lines) and so we expect those residuals to really do well,” he said.

Follow David J. Mitchell on Twitter @NewsieDave.