Filter change at W.Va. American Water plant more than half done
From the time it is sucked out of the Elk River, mixed with coagulants, pumped through clarifiers, “sludge blankets” and carbon filters, and then treated with chlorine, fluoride and corrosion inhibitors before finally being stored in a 4.5 million gallon “clearwell,” a drop of water has spent about two hours in West Virginia American Water’s treatment plant, on Court Street in Charleston.
Those carbon filters have been the object of much attention since the Jan. 9 chemical leak that contaminated the company’s Kanawha Valley treatment plant and, by extension, the tap water of 300,000 people in the area.
As of this week, the company is more than halfway done with changing out its 16 filters.
It takes about four days to change each one and another couple days for test results to come back before a changed filter can be put back online.
The company began changing the filters, two at a time, on April 1, and expects to be done around the first week of June.
West Virginia American consistently has said it was not necessary to change the filters and that the company is doing so only to improve public perception of the water after the Freedom Industries leak on Jan. 9.
The company has collected treated water samples every four hours and tested them at REIC Laboratory, in Beaver, since shortly after the leak. Since late February, every one of those samples has shown a “nondetect” level of the leaked coal-cleaning chemical Crude MCHM at a detection level of 2 parts per billion.
In late March, though, samples collected by the West Virginia Testing Assessment Project, or WVTAP, a team of independent experts hired by the Tomblin administration, showed “trace amounts” of the chemical in treated water coming out of the plant.
Those samples were sent to a different lab, Eurofins Lancaster Laboratories, in Pennsylvania, that has a more precise level of detection. That lab can detect MCHM at levels as low as 0.38 parts per billion. The late March samples showed levels between 0.42 and 0.60 parts per billion, just above the lab’s detection limit but far below the controversial 1-part-per-million screening level recommended by the U.S. Centers for Disease Control and Prevention.
West Virginia American has changed eight of its filters and is in the process of changing numbers nine and 10. Water was sampled from each of the eight removed filters and tested at the Eurofins lab before the new filters were put back in use.
All of those samples returned “non-detect” levels at 0.38 parts per billion, water company spokeswoman Laura Jordan said.
Andrew Whelton, co-leader of WVTAP, said changing the filters increased his confidence that a source of MCHM was being removed.
“Water treatment plant filters were identified as a source of MCHM by WVTAP and then confirmed by follow-up sampling by West Virginia American Water,” Whelton said. “Clearly, not detecting MCHM in treatment plant water above 0.38 parts per billion is a good sign.”
West Virginia American and its parent company, American Water Works, have been sued dozens of times for their role in the water crisis. American Water, which just announced a first-quarter profit of about $68 million, has said it views those lawsuits as a “risk factor” for its future.
Changing out 16 filters in the Charleston plant will cost about $1.1 million.
The filters are not a cartridge or a screen, like you might see in a refrigerator water dispenser or a Brita pitcher. They are huge cement tanks, more than 20 feet deep. They are filled with a layer of gravel, then a layer of sand and then topped with a layer of granulated activated carbon.
In each tank the layer of carbon is 26 inches thick and weighs about 55,000 pounds. The carbon looks like jet-black coffee grounds.
It takes two days to suck the carbon out of each tank, using vacuum hoses, into tankers that truck it away. Each filter has enough carbon to fill five tanker trucks.
Then, tankers from Calgon Carbon, a Pittsburgh-based company, come with new carbon. The carbon is mixed on site with water and is hosed back into the filters.
In normal circumstances, West Virginia American changes each filter about once every four years. Usually, the used carbon is regenerated — it is heated to 1,700 degrees Fahrenheit and then mixed with new carbon so it can be reused in filters. However, the carbon from these filters will be reused only for industrial purposes, not water filtration, Jordan said.
All of the carbon used in the plant’s new filters will be unused, virgin carbon.
The carbon filters come near the end of a treatment process that begins on the bank of the Elk River, where raw water is sucked in through the plant’s lone intake.
Coagulants, chemicals that make mud and dirt particles stick together in bigger clumps, are added to the raw water. It’s then sent to a hydraulic mixing chamber, and what emerges is cloudy brown water.
That water gets sent to one of four clarifiers — giant, open-topped cylindrical tanks — that Jordan describes as the “workhorses of the treatment process.”
Each clarifier can hold about 750,000 gallons of water. The water is forced up through a “sludge blanket,” a type of filter that removes any solids, usually mud and dirt, in the water.
Water emerges from the clarifiers crystal clear and, most often, Jordan said, already drinkable.
It is then piped to the carbon filters, which, Jordan said, mostly address taste and odor issues. It travels through the carbon, sand and gravel layers of the filters before being treated with chlorine, fluoride and corrosion inhibitors, which help keep water from corroding your pipes.
Finally, the water is stored in the plant’s “clearwell,” a 4.5-million-gallon underground storage site beneath the big green lawn that borders Court Street.
From there, it is pumped to customers in nine counties, at an average rate of about 26 million gallons per day.
In case of emergencies, the company has on hand hundreds of extra pounds of powdered activated carbon. If there’s a contamination, the company can dump the powdered carbon into the filtration process. Ideally, any contaminants stick to the carbon and are then filtered out as they travel through the plant. West Virginia American used its extra powdered activated carbon on the day of the chemical leak. It wasn’t sufficient.
Staff writer Ken Ward Jr. contributed to this report.
Reach David Gutman at firstname.lastname@example.org or 304-348-5119.