No one knows when normal sewage treatment will be possible at the West Point regional wastewater-treatment plant in Seattle, which was severely disabled in a catastrophic flood Feb. 9
It’s going to be a long road back to recovery for the crippled West Point wastewater-treatment plant in Seattle.
A workhorse of the regional wastewater-treatment system, the plant is estimated to have sustained at least $25 million in damage in a flood Feb. 9 and cannot presently function properly.
Recovery of the plant remains in very early stages. Damage had never occurred at the plant at such a scale. It has taken Hurricane Sandy or Katrina-scale damage to produce similar wreckage elsewhere in the country.
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- Sewage backup keeps residents out of South Park homes — for weeks (Feb. 24)
- Officials say damage to sewage plant in Discovery Park is catastrophic (Feb. 16)
- Millions of gallons of wastewater dumping into Puget Sound after heavy rainfall (Feb. 9)
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“We do not ever want to see this type of event to occur again,” said King County Councilwoman Jeanne Kohl-Welles, chairman of the Regional Water Quality Committee, which held a hearing on the plant Wednesday. The committee includes city- and county-council members, as well as local sewer-commission officials charged with overseeing the Seattle and King County wastewater system.
Committee members had lots of questions about what caused the flood, and how long it would be before the plant is operating again. But they got few answers.
King County wastewater managers promised a forensic review but said the key task is to get the plant running right.
Rod Dembowski, a Metropolitan King County Council member on the committee, pressed hard for a date when the plant would be back in working order, but county wastewater managers said they could not commit to a date.
“It is in my view an environmental catastrophe,” Dembowski said. “We are not meeting permit. We have no prognosis almost a month later when we get the plant back. We are owed a better explanation of what happened. It is still quite murky.”
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Normally, wastewater is screened for trash, the grit is removed, and the effluent cleaned in primary treatment by settling until it is about 60 percent clean of solids. Then it is discharged to secondary treatment, where beneficial microorganisms feed on the remaining material.
The effluent is next disinfected, dechlorinated and discharged at 90 to 95 percent clean before it is returned to Puget Sound. That’s better than the 85 percent clean required by the county’s permit for operating West Point from the state Department of Ecology.
But meeting that permit requirement is far from possible now at the damaged plant.
Primary treatment is substandard, and secondary treatment is unavailable. The latter system is intact, but it is offline to protect microorganisms from ingesting influent too dirty for them from the damaged primary-treatment system.
“If we undermine the biology, we will have a bigger problem then,” Mark Isaacson, director of the wastewater division, told the committee.
Since the flood at West Point, wastewater treatment is limited to screening out trash and grit, very minimal settling out of solids, disinfection and dechlorination.
Scum and solids usually removed from the wastewater in primary treatment now remain, with solid removal rates only in 30 percent ranges, a far cry from what the permit requires. The effluent is disinfected and dechlorinated before it is discharged to the Sound.
The plant also can only manage about half its usual capacity, raising the likelihood of emergency bypasses of totally untreated wastewater during the wet weather months. So far nearly 300 million gallons of raw sewage and stormwater have been bypassed from the plant because it is so damaged.
Cleaning and repairs have been continuous at the plant since the flood, the cause of which is still under investigation. What is known so far is that pumps taking effluent from the plant failed during a power disruption, as sewage kept pouring into the plant at maximum flow due to a rainstorm.
Primary-treatment tanks were soon swamped, and stormwater and sewage cascaded downstairs, flooding underground tunnels full of equipment up to 15 feet deep before an emergency gate finally automatically triggered. That shunted the incoming untreated wastewater to Puget Sound.
Plant cleaning is largely complete, including a mile’s worth of the tunnels, which have been steam-sanitized and Sheetrock walls removed.
Necessary repairs are extensive, with 124 electric motors, 124 pumps and 200 electrical motor-control centers damaged, along with 125 electrical panels, 25 electrical transformers, 125 electrical-control stations, more than 2,000 light fixtures, more than 1,200 outlets and switches, more than 125 instruments and three-equipment control systems.
Even with people working around the clock, most of the damage remains to be repaired or equipment replaced.
On Monday, the council passed legislation waiving competitive-bidding requirements to help speed fixes to the plant.
Kohl-Welles called for an extensive review of the plant and its operations. An independent outside expert panel also may be tasked to review what went wrong. Committee members questioned whether staff training manuals were up to date, and why it took so long to close the emergency gate.
“It’s never one thing,” Dembowski said. “It had to be a series of events.”