HUMBOLDT — Things turned sour in Humboldt Thursday when an underwater examination of raw water intake procedures revealed a proliferation of zebra mussels as well as malfunctioning equipment.
About 10 years ago the mechanism that controls a valve on one of two Neosho River intakes malfunctioned. On Thursday city officials had a hired diver from Gardner take a look — feel, actually, since the murky water prevented him from seeing past the port in his helmet — as to what was holding things up.
Within an hour diver Chris Smith asked for tools to try to free the frozen shut valve. No luck.
Second piece of bad news: He also found the second sluice valve didn’t budge when its control wheel was turned. It was frozen open.
“Not what we wanted to hear, but better than not knowing,” City Administrator Cole Herder lamented.
After a mechanical trick or two were tried to open one valve and close the other, Herder resigned himself to the inevitable — the valves, as well as control shafts and gears, will have to be replaced.
When that will occur, he doesn’t know. Engineers from Kramer Consulting, Topeka, were on hand to confer. They will help with acquiring valves and other equipment to put the intake system back to 100 percent. (Kramer Consulting designed Humboldt’s water plant, including intake system, that went on line in 1981.)
If that weren’t enough for one day, Smith also scraped a double handful of zebra mussels attached to one of the dysfunctional control rods.
“They’re a huge problem,” Herder said, one so severe that the minute the mussels were retrieved they were doused in bleach. “That kills then,” said Steve Doleshal, another diver from Utility Diving Services.
So dreaded is the spread of the mussels that after tools used in the dive came from the water, they were sprayed with liquid bleach to prevent any minute organism from growing and being transported to another job site.
Concern is twofold. The mussels can cover screens placed over intakes and slow or practically stop inflow. Also, they can find their way into a pipeline — Humboldt’s is a quarter of a mile long — that carries raw water to the processing plant. No indication of feeder pipeline infestation has been found — yet.
Elsewhere that has occurred, said Jake Fault, another diver.
At Osage City, an 11-mile transport pipe was so clogged with the mussels water volume dropped off to the point city officials thought the line had developed an extreme leak.
Keith Nickel, plant supervisor, said 120,000 gallons were pumped to the plant twice a day — noon and midnight — for processing, so far with no noticeable glitches.
Now it’s a waiting game with the intake valve problems — to determine what is needed and find a time to correct the problems.
THE DIVERS were in town for a second project, to remove a small tree with limbs protruding above the water line jammed along the north and west sides of the 40-foot intake silo. The tree arrived during high water a few months ago. The concrete silo, with a foot-thick wall, has an outside diameter of 10 feet. Atop is a small building containing controls.
