volume 1 - Halifax Regional Municipality

Halifax Water Integrated Resource Plan
Integrated Resource Plan Development and Evaluation
Consideration should also be given the timing of other major WWTF upgrades and
expansions. They include:
• There are about 25 plus current compliance WWTF projects programmed in the
early part of the IRP to approximately 2018.
• Under the RWWFP, the expansion of the Herring Cove WWTF will be required to
accommodate future growth between 2031 and 2036 and the expansion of the
Dartmouth WWTF would be required between 2021 and 2026.
• The WSER will require upgrade of all three HHSP WWTFs to secondary treatment
within 20 years (by 2032).
• The Aerotech WWTF will require expansion between 2031 and 2036.
In consideration of the benefits of nutrient control, particularly on the smaller receiving
waters, and the schedule of expansions and upgrades in the later planning period, a 10-
year or 10 plus year timing for nutrient control seems reasonable. Hence, the A level
plans (38-4 and 40-4) were given further consideration.
The Enhanced Overflow Control Program has an additional 30-year NPV of $71 million
when compared to the Baseline plan in the RWWFP. The implementation timing in this
case has been fixed at 30 years. Figure 5.9 presents the annual average volumes of
overflow associated with the Baseline and Enhanced Overflow Control alternatives. As
can be seen, the annual overflow volume is reduced by over half. As importantly, the
Enhanced Overflow Control Program provides additional control at 19 outfalls not
addressed through the RWWFP.
Annual Overflow Volume (m 3 )
20,000,000
15,000,000
10,000,000
5,000,000
0
Baseline
Growth No
Control
RWWFP
Baseline
Enhanced
Overflow
Control +
RWWFP
Figure 5.9
Enhanced Overflow Control Program Annual Volume
Consequently, Plan 40-4 with B level (5 year WWTF and 10 year overflow
implementation) current wastewater compliance, A level future wastewater nutrient
compliance (10 year implementation), the Enhanced level of future overflow control (30
year implementation) and the composite asset renewal program is the Recommended
IRP.
Revision: 2012-10-29 Integrated Resource Plan 75
October 31 2012 Page 108 of 272