West Columbia Plant Improves Water Treatment after the Flood
In West Columbia, Lake Murray is the source of water for 60,000 nearby residents. Before anyone can turn on their sink though, the water has to be treated for taste, cleaning, and safety. This past July, the treatment process ran into a problem: there was a contaminant present. It's called haloacetic acid, a carcinogenic, and it was above the legal limit of what the plant should be sending out to citizens. Cooper McKim has the story.
There are two key factors that explain the formation of haloacetic acids: chlorine and organic material. Chlorine is used for disinfection, and organic material is in the raw water. General Manager of the Joint Municipal Water and Sewer Commission, Jay Nicholson, puts it simply. He says "when the disinfectant hits the organic, the reaction occurs."
Tha’s how haloacetic acids, or HAAs, are formed. Nicholson says every surface water plant in the world that uses chlorine as a disinfectant will have some level of HAAs in their water. It’s common. The Lake Murray plant is used to that too, however, this is the first time the plant has experienced this kind of exceedance. Director of Planning, Engineering, and Water Plants, Mark Waller, knew exactly why it happened: October's historic flood last year.
"We were encouraging the city of West Columbia to make some changes so we could avoid this altogether."
The storm caused the level of organic matter in the water to skyrocket. During the storm, wind and water pushed innumerable leaves, plants, and waste into the lake. Soon enough, Waller says, "we had twice as much [organic material] as normal, we ended up producing more disinfection byproducts because we have to disinfect in order to kill viruses and bacteria... because that would make you sick right away."
The plant used more chlorine to combat the extra bacteria and organic material. Unfortunately, the side effect was a spike in HAA levels in the treated water. The plant's problem wasn’t that some foreign chemical had gotten in, but that their treatment process wasn’t working.
In May of this year, the state's Department of Health and Environmental Control came to sample the water. When the results came back, Nicholson says he was not surprised to find they had exceeded legal limits: "we were anticipating a problem if the plant had not changed its treatment technique... we were encouraging the city of West Columbia to make some changes so we could avoid this altogether."
DHEC’s results showed the plant was above the legal limit by 0.01 mg/l or 1 part per billion (ppb). The legal limit of 0.60 mg/l is set by the Safe Drinking Water Act.
This may not seem like much, but to Nicholson, it’s enough. He says "I don't care if its 1 part per billion or 200 ppb, it's not okay. We don't need to violate the maximum contaminant limit for safe drinking water."
Mark Waller says they began an alternative treatment plan in early July. The solution was simple - Waller says "we moved the feed point from the head of the plant to the top of the filters. We used to feed chlorine here, and now we moved it there." Basically, they stopped introducing chlorine where there was organic matter.
The next day, Waller reports HAA levels were cut in half.
The plant took this action, however, without a permit. Director of the Drinking Water Protection Division of DHEC, Doug Kinard, says they failed to follow proper administrative procedure, so they were placed under a consent order in punishment. Soon after, DHEC approved the new treatment process.
Kinard says he was never particularly worried about the effects of an HAA exceedance in the water. He explains the health risks come after a lifetime of exposure to high levels: "for a chronic contaminant, as long as the system addresses it and there is no prolonged year after year exposure, then there will not be any anticipated adverse health effects."
Lexington County Public Information Officer, Anna Huffman, says "the water was always safe for consumption."
Waller says he's just finishing up a master plan of improvements for the plant, no details of which are yet revealed. He says the expansion will likely occur in the next year or two, after having the plan approved through the state congress.
Waller says this plan will ensure what happened after October's flood, won't happen again: "let’s just put it to you this way, we're not gonna be surprised."