A sewer main broke early Monday morning, necessitating a temporary shutdown
of nearby pump stations and causing an overflow of untreated water into Inner Harbor.
The main line connecting town to the sewage treatment plant ruptured near the
Sea Level Seafoods processing facility at 1204 Zimovia Highway. City crews responded to the scene, shutting down pump stations near the Public Works Department building and City Park in order to repair the break.
Eighty-five percent of Wrangell households are connected to the municipal
sewage system, and the broken section of line connects the business district and
surrounding neighborhoods with the treatment plant. Working to
repair the line, a crew had the section repaired and operable by around 11 a.m.
As a result of the pumps’ shutdown, a considerable amount of sewage water – estimated at around 20,000
gallons, or one percent
of the town’s daily sewage volume – overflowed into the nearby harbor. The station at the park did not experience any overflow.
The city notified the state Department of Environmental Conservation and Environmental Protection Agency about the release, as required by law. On Tuesday EPA had issued a response, deciding Wrangell would not need to conduct any
ambient water quality testing of the harbor because its basin
was sufficiently flushed through tidal action so doesn’t pose a contamination risk. The city will be required to file an incident report with the agency.
The break happened
amid an ongoing state of water conservation for Wrangell, after its reserve tanks for treated water ran disconcertingly low in mid-July. A state of
disaster was declared by Mayor
David Jack, and emergency measures taken to reduce use of the resource.
The supply problem has been a long-standing one, as the slow sand filtration method Wrangell’s system employs is ill suited to its
water supply, which comes from a pair of open reservoirs and tends to be silty. Sedimentation builds up on the filters more quickly than expected, necessitating more frequent clearings – a process which takes time, reduces outflow and wastes pretreated water.
The Borough Assembly has taken up the issue, discussing a number of possible fixes and temporary solutions at an emergency meeting July 19. Replacing the sand in the filters would likely help,
which hasn’t been done since the system was installed nearly two decades ago. That approach would be expensive,
as the city estimates the cost to do so could run into the $500,000 range.
Other efficiencies are being looked into, such as adding additional backflow storage to save water during filter changings, as well as taking
on a temporary system to treat water during next year’s busy summer season. Modifications to the plant’s roughing filters are already set to
be made, with most materials by now on hand to make the fix. Once everything is ready, Public Works has estimated it would take two days to make the adjustment.
“It’s something we’re going to continue moving forward on,” said Wrangell manager Jeff Jabusch. “We’re looking at all kind of different things.”
In the near future, he said Public Works may send staff to Craig to inspect its treatment plant, which also utilizes slow sand filtration.
A more long-term fix
would be to replace Wrangell’s system entirely, an
option already underway. Last summer the Assembly awarded CRW Engineering Group with a contract to undertake a
pilot study to test out a better suited filtration system.
An engineer arrived last month to initiate the scheduled study, and has been able to
answer some questions the city has had about its current
system during the ongoing crisis.
For the present, residents and businesses are advised to continue saving water, reducing personal use where
possible and refraining from washing boats and vehicles.
Two of the largest users of treated water, processors Trident Seafoods and Sea
Level Seafoods, have already made changes at their plants
to reduce demand by about
half, by substituting seawater for city water during some processes.
“I think that helped,” Jabusch said. The reserve tanks are currently full, and
once through the busy
fishing month of August demand should slacken.
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