Eliminating Combined Sewer Overflows from Vancouver’s ... · • System performance &...
Transcript of Eliminating Combined Sewer Overflows from Vancouver’s ... · • System performance &...
Eliminating Combined Sewer Overflows from
Vancouver’s Waterways Brian Crowe, P.Eng.
Director of Water, Sewers & District Energy City of Vancouver
April 16, 2014
Vancouver’s Strategy to Eliminate CSOs
• How a combined sewer system operates
• System performance & vulnerabilities
• Separation mandate – Progress and current pace
• Strategy – Public side separation through lifecycle replacement – Additional strategies/emerging best practices
• Benefits and Opportunities
Stanley Park 2011
Primary Driver - Environmental Improvement
Strategy to Eliminate CSOs: Timely Reconstruction of the Sewer System
Transitioning from a
combined system (sewage and runoff in one
pipe) to a separated system (sewage in one pipe, runoff
in another pipe)
Combined Sewer Overflows
Combined Sewage to
Treatment Plant
Stormwater & Runoff
Combined Sewage Overflow
Capacity Limits at Treatment Plant or in Sewer Interceptors
Sanitary Sewage
Construction of the English Bay Interceptor Sewer – 1930’s
Progress in eliminating untreated sewage discharges in Metro Vancouver
Current CSO Locations
Combined Sewer Overflows During Storms
Additional Vulnerabilities of Combined System
• Storm-induced overland flooding • Combined-sewage backups into
buildings • Sensitivity to climate change
impacts
LWMP (Provincial Regulation) commits us to:
• Eliminate CSOs by 2050
• Separate combined sewers
at an average rate of 1% annually
Vancouver’s Commitment to Eliminate CSOs
Progress at Eliminating Overflows
05000
1000015000200002500030000
Discharge Volume
(million L)
1990 2000 2010 2020 2030 2040 2050
CSO Reductions
Projected Separation – about 60% complete by 2020
Infrastructure Lifecycle Management
Collapsing Sewer Main
Infiltration
Theoretical Lifecycle Replacement Projection (Why 2050?)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0
50
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200
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Mai
n Se
wer
Sys
tem
Sep
arat
ion
Mai
n Se
wer
Rec
onst
ruct
ion
(km
)
Required Main Sewer Reconstruction by Decade
Required main sewer reconstruction based on life cycle analyses
1% Replacement Rate of Main Sewer System (km)
Main sewer system separated
Tools - Construction Strategies
• Disconnecting roof leaders
• Private property separation
• Green roofs • Rainwater harvesting • Permeable pavement • Rain gardens • On-site storage, etc.
Additional strategies – Integrated Stormwater Management
Signs of Progress!
Future State – Fully Separated Homes – Rainwater & Sewage as Resources
Sewage as a Resource (Energy Recovery)
Thank You
Thank You