Item No. 8k_supp
Meeting Date: August 11, 2026

Industrial Wastewater Treatment Plant
(IWTP) Enhancement Project
Design Funding, Early Work, and
Long Lead Equipment Procurement
CIP C801234

Industrial Wastewater System
Collection System

(approximately 300 acres)
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

Detention and Treatment
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)

Effluent and Disposal
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

Firefighting and fire suppression systems
Groundwater from fuel storage & delivery
areas
2

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

3

Project Location

4

Example Aerated Gravel Bed

5

Project Budget & Schedule
• CIP: C801234

• Key Schedule Milestones:

• Not to Exceed Budget: $280,782,000

• 60% Design Complete:

Q4 2026

• Previous Authorization: $20,135,000

• 90% Design Complete:

Q2 2027

• Current Request: $41,200,000

• 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

6

Cone of Certainty

We are here

7

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.

8

Questions?

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