In a special meeting of the City and Borough Assembly on March 15, members finally moved ahead toward replacing Wrangell’s water treatment plant.
The outdated plant has had a number of production problems over the years, starting not long after its construction in 1999. Reliant on a combination of ozonation, roughing and slow-sand filtration before disinfection, high sedimentation from its two water reservoirs has made treatment a time consuming, inefficient process.
Poor filter performance has subsequently been impacting water quality and water costs, as well as falling behind elevated demand during the summer and winter seasons. In the summer of 2016 a combination of problems at the plant created an emergency shortage, disrupting local seafood production in the process.
Even before the emergency, the city has had replacement of the water plant on its radar. Since 2015 consultants CRW Engineering Group have been looking at alternative models better suited to Wrangell’s water supply and demand. A plant using dissolved air flotation (DAF) was recommended, a method which removes unwanted sediment and impurities from the water using bubbles and skimming. A miniature test plant was given a successful trial run in 2016, a contrast to the main plant’s coinciding production shortfall.
“When we started running it, it ended up producing far better water than our plant,” treatment plant manager Wayne McHolland attested at this month’s meeting. The finished product ranged between 92 and 94 percent in quality to ionized water, he recalled, as compared to the 70 to 80 percent range the plant currently puts out.
Public Works director Amber Al-Haddad noted Wrangell’s surface water supply is highly variable in sedimentation depending on the circumstances, but that the DAF package plant had done just as well under different conditions.
Participating by phone, assembly member Stephen Prysunka questioned the prospective plant’s increased capacity, which is about double what the current plant can produce. Given the reservoir’s currently low levels, he expressed concern other problems underlying Wrangell’s water production would not be addressed if the DAF project were pursued.
Costs for the DAF plant would run around $9.1 million, including $860,000 needed to improve the plant’s filters and water recapture. CRW’s cost estimates were brought down from an initial $13 million by making use of existing plant infrastructure.
To pay for this, the city has approached the Department of Agriculture for $3.82 million in loans and $3.16 million in grant monies, with another $2.5 million grant to be applied for through the Alaska Economic Development Administration. Remaining funds would come through the borough’s reserves and other, smaller grant sources.
If undertaken, Prysunka was worried the project would tie up funds possibly needed for other important problems, ranging from failing iron mains to metering household and small business water usage.
McHolland said the extra production capacity – up to 2,000 gallons a minute – would be an important redundancy feature for the plant, allowing it to catch up quickly during times of high usage.
“We just have to use what we need to make,” he said. “The biggest problem we have with this (current) plant is the delay in the treatment of water.”
Cost to improve the existing plant has been estimated at a considerably higher cost by CRW, with $3.87 million alone needed to get water storage capacity to a better level. Limited storage of treated water had been a crucial factor behind 2016s shortage. Another $10.9 million would go toward upgrading production itself.
Leaks within the water distribution system are another major area for concern, with little information yet as to the scope. During her presentation, Al-Haddad reported on average about 36 percent of Wrangell’s produced water is unaccounted for, based on production and sewage treatment figures from 2011 to 2017. Whether significant customer consumption or – more likely – leaks in the pipes themselves are to blame, she said it is hard to determine. A leak detection specialist arrived in Wrangell on Tuesday to assess its distribution system, and is expected to reach some educated conclusions by the week’s end.
Given the choice before them, other members of the assembly leaned toward moving ahead with the replacement plant. Time was one factor, David Powell mentioned, pointing out it would take possibly three years for a new plant to be operational.
“This has been taking way too long not to know what we’re doing,” he decided.
“How much more information do we need before making a decision?” Patty Gilbert asked, in agreement.
Looking ahead, new member Drew Larrabee saw the new DAF system as necessary just to meet current needs, not to mention allowing greater capacity for growth later. The city has been eyeing new mixed development at its former Institute property, service to which would be improbable with the current plant.
“Leak or no leak, we’re beyond capacity,” Larrabee said.
Roland Howell likewise saw the improvement in water quality as a deciding factor in his vote.
With two members participating remotely by phone, the assembly unanimously approved moving ahead with the new plant. Al-Haddad reported that, since that decision, the AEDA grant package has been submitted and the city is in its fund acquisition phase.
“Now we’re waiting to hear from them,” she said.
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