Transcript Municipal Class Environmental Assessment

Municipal Class
Environmental Assessment
Expansion of Omemee Wastewater
Capacity
Presented to City of Kawartha Lakes
Kevin Warner, P.Geo and John Desbiens, P.Eng
Existing Omemee WPCP
• 2 sewage lagoons with spray irrigation
disposal, rated capacity of 608 m3/day
• Average sewage flow in 2009: 828 m3/day
• Spray irrigation only permitted April to
December
• Winter storage capacity of sewage lagoons is
inadequate for current flows, required
emergency discharges to Pigeon River.
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Class Environmental
Assessment Process
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
The EA Process - Simplified
• Identify and document needs
• Present alternatives
• Assess the technical and financial merit of each
alternative
• Select the preferred alternative
• Submit application and supporting technical
documents for review and approval
• Include local stakeholders through the entire process
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Class EA Addendum
• The purpose of the addendum study was to assess
alternative solutions that were noted to have been
neglected in the previous Class EA.
• Additional alternative solutions included five on-site
treatment and disposal options.
• Still considered the 2007 recommended pipeline
connections to the Lindsay WPCP and WTP.
• The Provincial Policy Statement notes that it prefers
all future growth should be serviced by municipal
water and wastewater systems.
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Calculation of
Wastewater Flows
Aspect
Units
2011
2021
2031
1,350
1,804
2,143
L/cap./day
450
450
450
Available Greenfield Land Available for
Development
ha
49.3
44.4
40.7
Estimated Developed Land Area
ha
Existing
4.9
3.7
Infiltration of Water into Collection System
m3/day
220.5
332
414
Precipitation Surplus to Sewage Lagoons
m3/day
76
76
76
m3/day
904
1,219
1,455
L/cap./day
669
676
679
Population
Assumed Resident Sewage Flow Contribution
Total Sewage
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Alternative Solutions
• Wastewater Pipeline to Lindsay WPCP
• Additional Sewage Lagoon
• Increased Spray Irrigation Disposal
• Subsurface Disposal
• Engineered Wetlands w/ Subsurface Disposal
• Combined On-Site Disposal
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Assessment Matrix
Alternative Solution
Natural
Environment
Social
Environment
Economic
Environment
Cultural
Heritage
Environment
Pipeline Connection
Minimal
Minimal
High
Intermediate to
High
Additional Sewage
Lagoon
Minimal
Low
Intermediate
Low
Increased Spray Irrigation
Low
Low
Intermediate
Low
Subsurface Disposal
Low
Minimal
Low
Low
Engineered Wetlands
Minimal
Minimal
Intermediate
Low
Low
Low
Low
Low
Combined Spray Irrigation
and Subsurface Disposal
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Financial Costs
Alternative Solution
2021 Flows
Pipeline to Lindsay WPCP
$17,900,000
Additional Sewage Lagoon
$2,600,000
2031 Flows
Spray Irrigation
$147,000
$186,000
$224,000
Subsurface Disposal
$616,000
$792,500
$969,000
Engineered Wetlands
$1,890,000
$2,530,000
$3,010,000
$530,000
$690,000
$850,000
Combination Subsurface
Disposal with Spray Irrigation
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2011 Flows
December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Preferred Solution
• Large subsurface disposal system
(LSSDS)
– similar to current spray irrigation, with
infiltration of effluent into soil
– Modular growth (add capacity as required)
– Most economically effective solution
– Minimal to low impact to all environments
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Alternative Design Concepts
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Impact Assessment
• No change in land-use with on-site disposal
• Subsurface system would be designed for
BOD and TSS (30 mg/L each)
• Current effluent quality from sewage lagoons
is generally below 15 mg/L for BOD and 10
mg/L for TSS.
• Nitrate concentration in GW predicted to be
0.74 mg/L at property boundary.
• No residential wells downgradient of disposal
field.
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Water Supply
• Residents use private wells (80%) + 2 municipal wells (20%)
• All wells are sourced from one of two aquifers:
– Sand /gravel aquifer and bedrock contact aquifer
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Potential Water Demands
Parameter
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Unit
2011
2021
2031
Estimated Population
persons
1,359
1,804
2,143
Estimated Water Demand
m3/day
611.6
811.8
964.4
Projected Water Demand Increase
m3/day
0
200.3
352.8
Well
Units
Daily Average
Water Demand
Well 1
m3/day
30.1
198.72
168.7
Well 2
m3/day
16.0
262.1
246.1
Total
m3/day
46.1
460.82
414.7
December 14, 2010
Rated Capacity of Reserve Capacity
Municipal Wells of Municipal Wells
Class EA Addendum for Omemee Wastewater Capacity Expansion
Class EA Conclusions
• Large subsurface disposal system found to have low
impact to surrounding environment.
• Economical solution, modular growth.
• LSSDS location has sandy soils and deep water
table.
• Current lagoon effluent quality is below tertiary
concentrations; not anticipated to strengthen
• Nitrate concentrations calculated well below MOE
Reasonable Use Criteria limit of 2.5 mg/L.
• Water supply – projected growth could be serviced by
existing municipal supply wells or additional
municipal supply wells. Expansion of the municipal
water supply should be assessed in future study.
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion
Class EA Next Steps
• City to review ESR Addendum
• Submit draft ESR to MOE for review and approval
• Issue Notice of Completion
• 30 day comment period
• Submit detailed design to MOE for approval
• Implementation of approved system
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December 14, 2010
Class EA Addendum for Omemee Wastewater Capacity Expansion