West Virginia American Water on Tuesday began replacing all 16 of its water filters at its Elk River treatment plant, nearly four months after the chemical leak that contaminated water for about 300,000 residents in nine counties.
“Until this time, there was no way to be able to comfortably remove filters from service until our production volumes dropped to a more normal level,” water company spokeswoman Laura Jordan said.
An entire filter must be taken out of service for a week, causing other filters to take on extra work, Jordan said. The water company sees its highest flow rates in January and February.
While test results made public last week showed that trace amounts of MCHM were detected in treated water coming from the facility, the water company continues to say it is changing filters to address public concerns.
“I think it was not unexpected,” Jordan said of the results. “We were able to see from our own laboratory testing that levels were below 2 parts per billion, and 2 parts per billion is still 500 times below the CDC’s safety screening level.”
For weeks, state officials and the water company trumpeted the “non-detect” results from periodic tests that would detect and report chemical concentrations as low as 10 parts per billion and, starting in late-February, as low as 2 parts per billion.
Then, last week, after questions were raised by independent scientists investigating the leak’s impacts, West Virginia American revealed more-detailed test results that showed low levels of MCHM between 0.42 parts per billion and 0.60 parts per billion in water that had completed various stages of filtering and treatment. The testing did not find MCHM in raw water entering the plant or in settled water, but did detect the chemical in 10 of 14 filtered samples and in six of seven finished water samples.
When those results were made public, water company President Jeff McIntyre said, “It is not unexpected that MCHM effectively captured in filter material may show up in trace amounts in water leaving the plant.”
Just a week before that, though, McIntyre had told the Gazette that the plant’s filters “have not been impacted” by the chemical leak and were being changed only because of a public “perception” that they needed to be replaced.
In January, McIntyre told the state Bureau for Public Health that, given the low detection levels involved, “simple machine tolerance” would explain why treated water from the plant was showing MCHM levels greater than those in the raw Elk River water supply.
Also, McIntyre argued in a Jan. 24 letter to the state, comparing samples of raw and treated water taken at the same time do not account for the two hours of time it takes water to pass through the treatment plant. “Samples of finished water taken two hours after the raw sample in many cases, not all, report a lower number,” McIntyre said.
The water company still believes its filters are working properly, Jordan said Tuesday.
“From all of our own water quality testing, the carbon filters have still been performing exactly as they should be, and we still believe they have been containing, adsorbing the organic material of MCHM and all the other material this filter plant is purposed for filtering out of the Elk River,” Jordan said.
The company will replace only the activated carbon, Jordan said. Below the 26-inch layer of carbon, there are 4 inches of sand and 8 inches of gravel. Gravity filters the water through each layer and then it is passed through pipes to the last stages of treatment, Jordan said.
“That is the basically the finest particulates that have the ability to attract and adsorb organics like MCHM,” Jordan said of replacing only the carbon.
Two filters will be replaced each week, so the work should be finished by the end of May if all goes according to schedule, Jordan said. Calgon Carbon, a Pittsburgh-based company, is undertaking the work.
West Virginia American Water expects the replacement of all its filters to cost more than $1.1 million, Jordan said. Because only four filters are replaced annually, the company normally budgets that cost, Jordan said.
“The expenses that we’re incurring right now, it’s work that we’re doing regardless,” Jordan said. “I don’t know what we will try to seek recovery for at the Public Service Commission, and there’s no way for me to know what the Public Service Commission would allow recovery for.”
Staff writer Ken Ward Jr. contributed to this report.
Reach Rachel Molenda at firstname.lastname@example.org or 304-348-5102.