Tom Weton, director of public works, inspects one of the two ozone-producing machines at Wrangell's water treatment facility. The machine is the one that has been failing and staff fear the other machine will start failing, as both are running beyond their manufacturer-recommended lifespan.
The lower reservoir supplies Wrangell with its water. If pumps from the reservoir fail, the borough's water treatment staff don't have a way to bypass the lower reservoir to draw directly from the upper reservoir.
Wrangell's water supply has its troubles.
From the source reservoirs to the end users, the system for filtering and delivering water to businesses and residences needs some major overhauls -and they won't be cheap.
The problems, officials say, start at the top at the lower reservoir and dam, which send water into the treatment plant where it goes through multiple phases of filtration and then is piped to customers.
At an assembly meeting on Sept. 14, Public Works Director Tom Wetor presented a report detailing the problems with the filtration system. He also presented potential solutions along with treatment plant manager Wayne McHolland, who has worked at the plant since 2002.
To Assemblymember Patty Gilbert, the problem is five-fold.
"The challenges are, No. 1, picking the correct water treatment system; the second is coordinating with federal agencies and grants to build this; the third problem is the reservoir, the incoming water; the fourth is the distribution, we have metal pipes that are degrading; the fifth is the end user wasting water," Gilbert said.
"Meanwhile, we have to maintain the plant and upgrade the plant. It's a huge multidimensional problem."
According to Wetor, if the delivery system from the lower reservoir and dam to the treatment plant fails, there is no way to bypass that and pull water from the upper reservoir.
"The state has identified them as some of the worst dams in the state and needing some repairs," Wetor said. "A full, comprehensive repair of that system, we're talking about probably $50 million. We are in the process of trying to do some smaller projects because we don't have $50 million, but we are in the process of doing an upper dam bypass project where we can draw water off the upper reservoir."
At the treatment plant, one of the steps in the filtration process involves producing ozone, which bubbles up in the water and oxidizes iron, manganese and sulfur to form metal oxides that can then be filtered out. One of those two ozone-generating machines, along with the compressors that help them function, are beginning to fail.
"The compressors are just getting old, they're getting near their useful lifespan," Wetor said. The lifespan is about 20 years and 150,000 hours. Currently, the compressors are at 22 years and 150,697 hours and counting. "That, along with possibly several other reasons, are contributing to our ozone generators not producing the ozone that they're specified for."
The generators are producing about half the ozone they should, Wetor said, possibly due to the compressors being too small, cooling issues, and other problems they haven't been able to identify. One of the ozone generators fails on a regular basis.
McHolland fears what is happening with the failing machine will happen with the machine that is still operating properly.
Another issue faced at the plant is the roughing filter, which helps capture more particulate matter before feeding water into the slow sand filter. A finer-grain media was originally used for the filter, but the flow capabilities weren't meeting the demand of consumers. Instead of a finer-grain media, a gravel-sized media was put in place. That led to more contaminants making it through to the slow sand filters.
Wetor said the highest contaminant levels are seen from August to November.
"Our source water is basically surface water. It comes out of a muskeg," he said. "Late in the summer, after everything blooms and dies off and washes away, it ends up in our water. When the organic loading is so high, for the last five years or so, we've struggled to keep up."
The water quality in spring is "as good as you're going to find anywhere," Wetor said.
The delivery system to homes and businesses is failing too in some areas. Some of the ductile iron pipes should last 40 to 50 years, and Wetor said some are only lasting about 20, possibly due to acidic soil or electrolysis, leading to corrosion.
"The city has been chipping away at replacing that stuff," Wetor said. "Everything is being replaced by ... high-density polyethylene, basically a really heavy-duty plastic pipe."
Then there is the treatment plant itself. Between 2017 and 2019, the borough received commitments for $9 million in federal funding toward building a new treatment plant. Due to various delays, that cost could be as high as $12 million now, Wetor said. If so, further funding would be needed. The borough is getting an updated estimate.
The project would involve replacing the plant's sand filtration system with a more efficient flotation system that binds pollutants and other material to air bubbles, which rise to the surface for removal.
Until a complete overhaul at the treatment plant, the recommendation from public works is to replace the ozone-making system for $445,000.
Water department reserves are currently at $490,000.
"There is no one smoking gun, that's the issue here," Borough Manager Lisa Von Bargen said at the Sept. 14 assembly meeting. "Obviously, if we had unlimited funds, we could take the all-in approach."
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