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A Successful History of a Divided Wet Well Solution

Brian Casey, P.E. – Carollo Engineers Shawn Clark, P.E. – APSCO LLC Richard Johnson – City of Albany Chip Ullstad – Carollo Engineers

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Presentation Agenda

•  Project background •  Influent pump station design modifications •  Pump station physical modeling •  Construction of pump station modifications •  Pump station cleaning •  Maintenance and operation results •  Lessons learned

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Project goals included regulatory requirements and design preferences

•  Improve system reliability •  Reduce SSOs by 2012 •  Increase capacity from 29 to 68 mgd without

compromising dry weather flows •  Maintain free water surface below crown of

influent pipe •  Address maintenance issues

–  Low flow + wide wet well = solids accumulation

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The wet well layout was large and inefficient, particularly for low flows

Influent Flow

Low flow pumps High flow pumps

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The trash rack protected pumps but caused maintenance issues

Ground surface

Trash rack

72” influent pipe

Shallow slope does not direct solids to pumps

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Existing pumps had extended shafts to the motor floor only

Ground floor

Motor floor

Pump floor