Wednesday, November 30, 2016
JACKSON Lead appearing in Jackson’s water in 2015 resulted from a faulty lime-feed system at O.B. Curtis Water Treatment Plant, as well as shifting water chemistries, an expert consultant told the Jackson City Council Tuesday. That problem, he added, is now repaired.
The council hired Philip Gibson of Trilogy Engineering Services in April to study the City’s corrosion-control system after the State of Mississippi set off a local panic when it announced in January 2016 that lead had turned up in tap water in several local households six months before.
On Tuesday, Gibson retraced the steps leading up to the corrosion-control study, including the City’s repeated switches between well water and surface water, like in 2015 after a water-main break in south Jackson.
This surface-water system and the well system had different kinds of chemical make-ups, including stronger “oxidants” in the well system, Gibson said.
“So, and right after that because of some issues at the O.B. Curtis plant with the high-service pump, the well system was put back on service,” Gibson said. “So when that water chemistry was changed, that kind of caused the lead that could be in the water or inside the pipes … to kind of destabilize, which led to the exceedances in the June 2015 samples. “
The other reason for the lead in the water, Gibson said, was the system that feeds lime into the water at the plants.
For some years, the lime-feed system at the O.B. Curtis plant improperly fed the alkaline-stabilizing material into the water system, leading to leaching lead from the pipes themselves, Gibson said.
“Also, the O.B. Curtis plant was producing water that was real low pH because of the line-feed system that they had,” Gibson said.
“We went out and looked at both the pH system at both the O.B. Curtis and the J.H. Fewell plant. Doing that, we found problems with the lime-feed system. There was a certain valve that got stopped up on the system.” The plant operators then thought the system thought was feeding into it, although it wasn’t.
Since meeting with the operational staff, Gibson said he believes the lime-feed system could have been operating inefficiently for years before the 2015 test showed lead in the drinking water.
“And it had occurred slowly over eight or nine years, and they didn’t realize,” Gibson told the Jackson Free Press after the meeting.
The problem with the metering pump that fed the system is now repaired, he said.
“Working with the operational and maintenance staff over at O.B. Curtis as well as J.H. Fewell, we have that system working back as it was originally designed,” Gibson said.
The consultant described the lime-feed system in O.B. Curtis as like pumping chemicals through a garden hose. “They were having to change those out at least three or four times a week if not more. And now they are having to change them out once a month,” Gibson said.
“So the system is operating like it’s supposed to be operating.”
Trilogy’s contract expired after six months, and cost the City more than $400,000 for the state-mandated study. Gibson said that he would continue to study the different combinations of chemicals, including lime replacements like soda ash, and would include that research as a part of the study. Gibson said Trilogy would continue to work with the city in the coming months.
Jarriot Smash, interim director of the public works department, said now that Trilogy and the department have determined the problems, the City will focus on the lime-delivery system, while continuing to explore more options for controlling the alkalinity and pH.
“Now we know, and we keep vigilantly watching,” Smash said. “You get it right and make sure it stays right.”
Email city reporter Tim Summers Jr. at [email protected]. Read more about Jackson’s lead problem at jfp.ms/jxnwater.