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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Suite 1000, Portland, OR 97204

Design Data

Columbia Boulevard Wastewater Treatment Plant

Design Data

 

Service population: 614,000  
     
Number of employees: 90  
     
Design flow: Primary Secondary
Average    
dry weather capacity: 120 mgd 100 mgd
     
Peak    
wet weather capacity: 300 mgd 160 mgd
     
Average daily flow: 73 mgd  
     
Peak flow: 280 mgd (max-wet season)   
     
Annual operating cost: $13,900,000  
     
Unit Number Type/Size
     
Pumps and Headworks    
Influent pump 6 Centrifugal
Bar screen 5 5/8-inch clearance
Grit basin 6

24-foot diameter,

mechanically induced vortex

     
Primary Section    
Settling tanks    
   Dry weather 1,400,000 gal. (each) 
   Wet weather  1,015,186 gal. (each) 
     
Secondary Section    
Aerator 8 1,825,500 gal. (each)
Final clarifier 8 1,460,938 gal. (each)
     
Effluent Pumps    
Wet weather 3 62,500 gpm (each)
Dry weather  62,500 gpm (each) 
Outfall line:    
   Gravity   87-inch, 2.3 miles
   Pressurized   72-inch, 1.52 miles
     
Digestion    
D-1, D-2 secondary digestion 2 1,323,960 gal. (each)
D-3 blend tank 1 1,323,960 gal.
D-4 gas storage 1 1,323,960 gal.
D-5,6,7,8, 9 & 10 primary digestion 6 2,393,960 gal. (each)
     
Biosolids    
Belt press 4 60 dry tons produced per day
Sludge output concentration   20% solids