Industrial Wastewater Treatment Plant
(IWTP) Enhancement Project
Design Funding, Early Work, and
Long Lead Equipment Procurement
CIP C801234
Item No. 8k_supp
Meeting Date: August 11, 2026
Wash water and sediment from roadway, ramp,
& runway maintenance &cleaning
Industrial Stormwater
• Fuel storage & delivery areas
• Aircraft & airfield deicing and anti-icing
• Non-pollution generating sources
• Stormwater contaminated from buildings &
ground maintenance
Construction dewatering
Wash water from aircraft, vehicle, & equipment
Aircraft and other potable water system
flushing
Firefighting and fire suppression systems
Groundwater from fuel storage & delivery
areas
Industrial Wastewater System
Decant collection facility
Detention
• Three lagoons (80 million gallons storage)
Treatment Screening
• Mixing
• Flocculation
• Dissolved Air Flotation Units (Treat 4 to 7
million gallons per day)
Sediment disposal
(approximately 500 tons annually)
• Lagoon cleaning
• Decant collection
• Sludge collection
Permitted effluent discharges
(approximately 300 million gallons annually)
• National Pollutant Discharge Elimination
System (NPDES) Permit
• King County Industrial Waste Discharge
Permit
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Collection System
(approximately 300 acres)
Detention and Treatment
Effluent and Disposal
Project Purpose and Scope
Purpose:
The project will install a pre-treatment system and upgrade the existing systems to the IWTP to ensure
compliance with future King County Department of Natural Resources Industrial Waste Discharge permit
conditions.
Scope:
• Aerated Gravel Bed (AGB) treatment facility
• 5-Million-gallon storage tank
• Control system updates
• Building modifications and improvements
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Project Location
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Example Aerated Gravel Bed
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Project Budget & Schedule
• CIP: C801234
• Not to Exceed Budget: $280,782,000
• Previous Authorization: $20,135,000
• Current Request: $41,200,000
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• Key Schedule Milestones:
• 60% Design Complete: Q4 2026
• 90% Design Complete: Q2 2027
• MACC Determined: Q2 2027
• Early Work Released: Q2 2027
• 100% Design: Q4 2027
• Commission Construction Auth: Q4 2027
• Notice to Proceed: Q1 2028
• Substantial Completion: Q2 2031
We are here
Cone of Certainty
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Action Requested
1) Authorize full design and preparation of construction documents for the Industrial Wastewater
Treatment Plant Enhancements projects;
2) Procure long-lead items;
3) Authorize Port Construction Services to execute small works contracts and use Port crews for support
of construction;
4) Execute early work packages with Hoffman Construction;
5) Increase project authorization by $41,200,000 for a total project authorization of $61,335,000. The
total estimated Industrial Wastewater Treatment Plan Enhancements project cost is $280,782,000.
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Operated by the
Port of Seattle
FlySEA.o rg
Questions?