Twenty years later, PWWSD 18 plant still keeping water clean
Twenty years ago, construction work began on a new water treatment plant that, under the auspices of Public Wholesale Water Supply District 18, was designed to treat water from Banner Creek Reservoir west of Holton for use by water customers in both the city and Jackson County Rural Water District 3.
Since its completion about a year later, the water plant has seen only a few operational changes, the most significant being a switch from its original membrane filtration system to a more traditional sand filtration system, according to Holton Water and Sewer Superintendent Dennis Ashcraft, who also oversees daily operations at the PWWSD 18 plant southwest of Holton.
And even though changing state and federal rules and regulations regarding water treatment plants continue to force changes in the way things are done, Ashcraft said PWWSD 18 continues to keep up with those changes and provide the best water to the more than 3,500 served by the district in both Holton and RWD 3.
“We’re always in contact with the guys from the city and RWD 3,” he said. “We’re sending them some of the best results when they inquire into what’s going on.”
PWWSD 18 was formed in 1997 to improve water service to Holton and RWD 3 utilizing water from the recently-completed Banner Creek Reservoir after the area had experienced significant drought and water supply issues. One such drought was affecting the city of Holton when plans for the new district’s water treatment plant were finalized.
At that time, much of the city’s water supply came from Prairie Lake, which had gotten down to six feet below normal pool level, and Holton city officials had placed residents under water use restrictions while looking at possible actions to remedy the drought situation.
Holton and PWWSD 18 officials approved the placement of a raw water line from the reservoir to the city’s water treatment plant as a temporary measure until the PWWSD 18 treatment plant was built.
“We designed it and installed it so that we could disinfect the water and turn the line into a water main so that we could still utilize it later,” Ashcraft said.
The line carried water from the reservoir to the city’s treatment plant while the PWWSD 18 treatment plant was being built at a cost of more than $6 million. That plant, it was noted, was designed to be a state-of-the-art facility, utilizing a membrane filtration system designed to treat two million gallons of water per day, with a maximum daily treatment capacity of three million gallons.
The plant also involved a Claricone clarifier system with the ability to handle wide swings in raw water turbidity, utilized a “sludge blanket” that provided an efficient use of chemicals, had no “moving parts” and was cost-competitive compared with other types of clarifiers.
“The thing with the membrane filters, back when we built this plant, was that the regulations from the Kansas Department of Health and Environment and the Environmental Protection Agency were changing rapidly,” Ashcraft said. “Everybody was saying, ‘How do I get on the other side of the curve?’ Everybody thought the answer was membranes.”
The membrane filtration system was included in the plant’s original design for its ability to reduce the risk of water customers consuming such contaminants as E. coli, fecal coliform and trace nitrates that affect the body’s use of oxygen. But over time, district officials learned that the membrane system was difficult to maintain and not as reliable in colder temperatures.
“They were just expensive to operate, and the manpower needed to operate them was phenomenal,” Ashcraft said. “Any way you slice it, the membranes were just not a good fit.”
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