Transcript Document

Water & Waste Dept.
Strategy to Control
CSOs in Winnipeg
Presentation To
April 27, 2005
Outline
Background
Existing System Response
Possible Control Options
Cost/Benefit Analysis
2003 CEC Recommendation
Conceptual CSO Mitigation Plan
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Background
5 Interceptor Sewer
systems
3 Pollution Control
Centres
79 CSO locations
231 Land drainage
outlet
101 to Red and
Assiniboine
2 Major Rivers
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NEWPCC
Wastewater Treatment
Plants
NEWPCC
SEWPCC
WEWPCC
374,000
160,000
86,000
160
50
27
302
59
32
WEWPCC
SEWPCC
Population Served
ADWF Recorded in
2002
ADWF Design
Capacities
ADWF = Average Dry Weather Flow (ML/d)
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Winnipeg’s Wastewater Sewers
Combined Sewers
Separate Sewers
Older parts of the City (pre 1960)
Approximately 30% of City has combined sewers
CSO – dilute mixture of sewage and land drainage
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Combined Sewers Exist Worldwide
Many European cities have combined sewers
control strategies being developed
In North America, about 850 communities
have combined sewers
e.g., Boston, Chicago, San Francisco
In Canada, cities include Halifax, Quebec City,
Montreal, Toronto, Edmonton, Vancouver
In Manitoba, portions of Winnipeg, Brandon
and Selkirk sewer systems have combined
sewers.
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Existing Systems Response
Model Requirements Were
Divided into 4 Main Systems
1 Land use / Run-off
Model
ICTS
ISTR
S) D
C
(
R
EWE
ED S
N
I
B
M
2
D CO
ATE
R
A
SEP WER
SE
RICT
DIST
Control Alternatives
Model
3
Interceptor / WPCC
Model
CS
WPC
CS
LDS
WWS
PRIM
tor
rcep
Inte acity
p
Ca
WF)
5xD
( 2.7
C
RY
NDA
SECO
ARY
nt
fflue
ted E
Trea
overflowed
intercepted
overflowed
intercepted
4
Receiving Stream
Model
River
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Receiving Stream Impacts
On average, CSOs occur 18 times per
recreation season (May 1 to Sept 30)
Overflows are wet weather driven
During dry weather, all sewage is intercepted and
conveyed to WPCCs for treatment
~ 1% of total annual sewage is lost to overflows
Effects of CSOs on River Quality relate to:
Microbiological water quality
Aesthetic quality (Visual)
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Predicted Fecal Coliform Levels for Representative Year, 1992
at North Perimeter Bridge (Worst Case Location)
100,000
Benefit of Effluent Disinfection
Benefit of Complete Sewer Separation
Fecal coliform density (organism s per 100m L)
Residual Land Drainage Impacts
10,000
1,000
GM 200
100
10
May
June
July
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August
September
9
ILLNESS RISK
CSO Advisory sub-committee concurred in
following:
CSO control will be costly and the benefits are
subjective
There are many reasons to consider CSO control
CSOs should not be considered a significant
public health issue …
CSO control is fundamentally a public policy and a
regulatory compliance issue.
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Control Methods
Several control options
possible:
Separation
End-of-pipe treatment
Storage and dewatering
Off-line tanks / Tunnels
In-line storage
Target of 4 overflows per season common
practice in USA
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Sewer Separation
Estimated at about $1.5+ Billion (no inflation)
Very disruptive to community
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End-of-Pipe Treatment
Vortex Solids Separator (VSS)
Very costly, large structure, requires land at outfalls
Requires chemicals, operational considerations
NOT recommended
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End-of-Pipe Treatment
Retention Treatment Basins (RTBs)
Very costly, large structure, requires land at outfalls
Requires chemicals, operational considerations
NOT recommended
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Off-line Storage Tanks
This will comprise large, near-surface tanks
located at the end of the combined sewer
trunks
This method is
used in:
Saginaw, Mich.
Toronto, Ont.
Sarnia, Ont.
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Deep Tunnels
Large tunnels could be used to store and convey
combined sewage to WPCCs for treatment
This method is used in:
Chicago, Ill.
Drop Shaft /
Access Shaft
To
WPCC
Tunnel Storage
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In-line Storage
Large old trunk sewers
offer potential storage for
combined sewage during
smaller storms
Trunk Sewer
Relief sewers constructed for
basement flooding also
provide large volumes of
potential storage
Relief Sewer
7.55 ft
9.75 ft
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9.0 ft
17
Latent Storage
If these pipes are dewatered, storage could be
available for inline storage
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In-line Storage
In-Line storage involves retaining wet-weather flow in the pipe for
small rainstorms
The stored wastewater is dewatered at a controlled rate and sent to WPCC
If the rainstorm threatens basement flooding, all flow is released to river
Needs Local Testing
Sediment deposition
In-Line Storage
Odours
Minimize risk of
basement flooding
(reliability/liability)
Has been used
successfully in
other jurisdictions
To Interceptor
Inflatable
Dam
Cleveland and
Detroit
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CSO Control Benefits
With Effluent Disinfection
With
With
CSO
CSO
Separation
Control
200
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Long Term; Existing Interception Rate
56
52
N
Combined Sewer
Boundary
20a
69
30
20b
57
19
> 18 Overflows
32
23
11 to 18 Overflows
38
5 to 10 Overflows
70
44
29
1 to 4 Overflows
46
36
No Overflows
BFR in Place
60
18
39
1
41
35
8
9
5
7
22
34
11
43
12
17
37
16
4
27
13
28
31
15
33
42
54
25
26
40
21
3
6
72
24
68
14
COMBINED SEWER
DISTRICTS
55
2
10
BFR - Basement Flood Relief
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20a
20b
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
ALEXANDER
ARMSTRONG
ASH
ASSINIBOINE
AUBREY
BALTIMORE
BANNATYNE
BOYLE
CLIFTON
COCKBURN/CALROSSIE
COLONY
CORNISH
DESPINS
DONCASTER
DOUGLAS PARK
DUMOULIN
FERRY ROAD
HART
HAWTHORNE
JEFFERSON EAST
JEFFERSON WEST
JESSIE
LAVERENDRYE
LINDEN
MAGER
MARION
METCALFE
MISSION
MOORGATE
MUNROE
NEWTON
PARKSIDE
POLSON
RIVER
RIVERBEND
ROLAND
SELKIRK
STRATHMILLAN
ST. JOHN' S
SYNDICATE
TUXEDO
TYLEHURST
WOODHAVEN
61
51
sewrmap9
71
Average Annual Overflows ~ 18
Range: 7 - 30
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Proactive Program; Modified Interception Rate; Latent Storage
56
52
N
Combined Sewer
Boundary
20a
69
30
20b
57
19
> 18 Overflows
32
11 to 18 Overflows
23
38
70
44
5 to 10 Overflows
29
1 to 4 Overflows
46
36
60
No Overflows
18
39
1
41
35
8
9
5
7
22
34
11
43
12
17
37
16
4
27
13
28
31
15
33
54
25
42
26
40
21
3
6
72
24
68
14
COMBINED SEWER
DISTRICTS
55
2
10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20a
20b
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
ALEXANDER
ARMSTRONG
ASH
ASSINIBOINE
AUBREY
BALTIMORE
BANNATYNE
BOYLE
CLIFTON
COCKBURN/CALROSSIE
COLONY
CORNISH
DESPINS
DONCASTER
DOUGLAS PARK
DUMOULIN
FERRY ROAD
HART
HAWTHORNE
JEFFERSON EAST
JEFFERSON WEST
JESSIE
LAVERENDRYE
LINDEN
MAGER
MARION
METCALFE
MISSION
MOO RGATE
MUNROE
NEWTO N
PARKSIDE
POLSON
RIVER
RIVERBEND
ROLAND
SELKIRK
STRATHMILLAN
ST. JOHN' S
SYNDICATE
TUXEDO
TYLEHURST
WO ODHAVEN
61
51
s ewrmap14
71
Average Annual Overflows = 12.5
Range: 3 to 22
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Proactive Program; Modified Interception Rate; Raise Weirs to 40%
56
52
N
Combined Sewer
Boundary
20a
69
30
20b
57
19
> 18 Overflows
32
11 to 18 Overflows
23
38
70
44
5 to 10 Overflows
29
1 to 4 Overflows
46
36
60
No Overflows
18
39
1
41
35
8
9
5
7
22
34
11
43
12
17
37
16
4
27
13
28
31
15
33
54
25
42
26
40
21
3
6
72
24
68
14
COMBINED SEWER
DISTRICTS
55
2
10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20a
20b
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
ALEXANDER
ARMSTRONG
ASH
ASSINIBOINE
AUBREY
BALTIMORE
BANNATYNE
BOYLE
CLIFTON
COCKBURN/CALROSSIE
COLONY
CORNISH
DESPINS
DONCASTER
DOUGLAS PARK
DUMOULIN
FERRY ROAD
HART
HAWTHORNE
JEFFERSON EAST
JEFFERSON WEST
JESSIE
LAVERENDRYE
LINDEN
MAGER
MARION
METCALFE
MISSION
MOORGATE
MUNROE
NEWTON
PARKSIDE
POLSON
RIVER
RIVERBEND
ROLAND
SELKIRK
STRATHMILLAN
ST. JOHN' S
SYNDICATE
TUXEDO
TYLEHURST
WOODHAVEN
61
51
s ewrmap13
71
Average Annual Overflows = 10.5
Range: 2.5 to 18
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Long Term; Modified Interception Rate; In-line Storage
56
52
N
Combined Sewer
Boundary
20a
69
30
20b
57
19
> 18 Overflows
32
11 to 18 Overflows
23
38
70
44
5 to 10 Overflows
29
1 to 4 Overflows
46
36
60
No Overflows
18
39
1
41
35
8
9
5
7
22
34
11
43
12
17
37
16
4
27
13
28
31
15
33
54
25
42
26
40
21
3
6
72
24
68
14
COMBINED SEWER
DISTRICTS
55
2
10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20a
20b
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
ALEXANDER
ARMSTRONG
ASH
ASSINIBOINE
AUBREY
BALTIMORE
BANNATYNE
BOYLE
CLIFTON
COCKBURN/CALROSSIE
COLONY
CORNISH
DESPINS
DONCASTER
DOUGLAS PARK
DUMOULIN
FERRY ROAD
HART
HAWTHORNE
JEFFERSON EAST
JEFFERSON WEST
JESSIE
LAVERENDRYE
LINDEN
MAGER
MARION
METCALFE
MISSION
MOORGATE
MUNROE
NEWTON
PARKSIDE
POLSON
RIVER
RIVERBEND
ROLAND
SELKIRK
STRATHMILLAN
ST. JOHN' S
SYNDICATE
TUXEDO
TYLEHURST
WOODHAVEN
61
51
s ewrmap15
71
Average Annual Overflows = 7
Range: 2 to 17
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Overview of Plan
Compliance with Fecal Coliforms Objective
100%
20%
Complete Sewer Separation
In-line Storage plus Distributed
Storage and Transfers
plus Off-Line Storage
40%
Available In-line Storage
60%
In-line Storage plus Distributed
Storage and Transfers
80%
Tunnel Storage (Zero overflows)
Minimum Compliance - Typical Year at North Perimeter Bridge
Disinfection at WPCCs
for Recreation Season (May 1 to Sept 30)
Percent Compliance with Objective
of 200 organisms/100mL for Different Control Scenarios
CSO Control Options
0%
$0
$100
$200
$300
$400
$500
$600
$700
$800
$900
$1,000
$1,100 $1,200
$1,300
$1,400
$1,500
Estimated Cost (Millions)
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Integration with Other Programs
Basement Flood Relief
Combined Sewer Renewal
Potential Opportunities
Oversizing of proposed relief pipes for storage
Allowance for localized separation
Cleaning of trunk sewers for storage
New Developments
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Cost/Benefit Trade-off
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2003 CEC Hearings
Clean Environment Commission (CEC) held public
hearings in January and April 2003, and recommended
Combined Sewer Overflow Reduction
7. The City directed to shorten the timeframe to complete its CSO plan a 20 to
25 year period.
8. The City directed to reduce CSOs by instrumenting outfalls, adjusting
weirs, accelerating combined sewer replacement, advancing the pilot
project …within two years.
Public Notification System
9. The City directed to develop and implement a notification system to inform
the public whenever there is a release of raw sewage to the local Rivers …
Provincial Implementation (to be confirmed)
Accept City plan to reduce overflows to 4/year on average
Complete CSO plan by 2030
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Public Notification & Information
Keep our rivers clean!
What goes into the sewer
can end up in our rivers.
Responsible at source
control
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Long-term Goal: 4 Overflows/year
Captial costs
Plan Components
Master CSO Implementation Plan
Raise Weirs
Inflatable Dam Pilot Testing
Sewer SCADA System
Integration with Basement Flooding Relief
Access available system storage
Develop additional storage to achieve 4 o/fs
Estimated Capital Cost
APEGM - CSO Strategy
2003 $ (Million)
Adjusted to Year of
Implementation
$
4.0
$
1.6
$
2.7
$ 11.1
$ 28.0
$ 54.0
$ 196.0
$
$
$
$
$
$
$
4.0
1.6
2.8
11.8
32.9
65.8
297.9
$ 297.4
$
416.9
Timeframe
2005 - 7
2005 - 8
2005 - 8
2005 - 9
2004 - 17
2008 - 17
2018 - 30
30
Winnipeg's CSO Control Plan
City’s current CSO control plan reflects many
important considerations:
2003 CEC Hearings recommendations
Manitoba conservation guidance and priorities
Consistency with prevailing international practice
Understanding of benefits and costs
Fiscal responsibility and environmental stewardship
Initiation of near-term actions to reduce CSOs
Confirmation of long-range control program
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