Willamette Water Treatment Plant, Wilsonville, OR, USA
Key Data:
Raw water intake
450,000m³/day
Water treatment capacity
57,000m³/day
Treatment expansion capacity
265,000m³/day
Back-up storage
42,000m³
Population served
12,000
Seasonal water demand
7,500m³/day (winter); 22,000m³/day (summer)
Main plant elements
Screening; enhanced sedimentation; ozonation; dual media filtration; secondary disinfection (chlorine)
Filter layers
Granular activated carbon (2m) and sand (0.3m)
Total site footprint
10 acres (4ha)
Project cost
$43.8 million
Treated Water Quality:
Microbial contaminants
Nil detected (Coliform, Faecal Coliform, Giardia Cryptosporidium)
Turbidity
0.03 to 0.09 turbidity units
Nutrients (nitrate + nitrite)
0.3ppm to 0.8ppm
Inorganic chemicals
Arsenic - <0.1ppb; barium - 4ppb to 7ppb; other regulated inorganics - nil; VOCs - nil; synthetic organic chemicals - nil
Disinfection by-products
Bromate - nil; total trihalomethanes - 10ppb to 24ppb; total haloacetic acids - 3ppb to 7ppb
Project Timeline:
Project commencement
January 2000
Clearwell hydrostatic testing
May 2001
Operation commenced
April 2002
NorthWest Construction Excellence Award
2002
ASLA Award for Merit
2004
Key Players:
Plant owners
City of Wilsonville
Operators
US Filter Operating Services
Main contractors
Montgomery Watson Harza
Architect
Miller Hull Partnership
Landscaping
Murase Associates
Other contractors / suppliers
Slayden Construction; Natt McDougall Co.; Tigard Electric; Landtech Solutions; US Filter
