volume 1 - Halifax Regional Municipality

Halifax Water Integrated Resource Plan
Integrated Resource Plan Development and Evaluation
$600
30-Year NPV $Million
$500
$400
$300
$200
$100
$130
$333
$128
$283
$126
$196
$37 $33 $30
$86 $86 $86
Future Overflow
Compliance
Future WWTF
Compliance
Current Overflow
Compliance
Current WWTF
Compliance
$0
25-1 (A) 28-1 (B) 22-1 (C)
Figure 5.6
Wastewater System Compliance Timing
There is a 41% difference in the 30-Year NPV between C and A level of the future WWTF
compliance objective (Objective 4) which corresponds to implementation of HHSP
secondary treatment at 20 years and nutrient reduction at the 8 WWTFs (excluding BLT
which is currently under upgrade) at 10 years for A level and implementation of HHSP
facility upgrades and nutrient reduction at 30 years for C level. Otherwise, the impact of
compliance timing for the current WWTF compliance program (Objective 1) and current
overflow control program (Objective 3) is small, reflecting the relatively small
differences in timing (3 to 7 years for current WWTF and 5 to 15 years for current
overflow) and relatively small overall expenditures. Future overflow control (Objective
6) includes a number of projects (essentially the previously identified Enhanced
Overflow Control Program), which is fixed at 30 years for all plans.
Recent re-analysis of the risk categories associated with the HHSP facilities (the risk
category dictates the timing of upgrades), completed by the IRP team, using the WSER
procedures has indicated that all HHSP facilities are considered medium risk requiring
compliance by year 20 of the IRP. Accordingly, for purposes of the intermediate analysis
the Objective 4 HHSP upgrades are all with fixed timing with costs allocated to year 20
(2032) and additional O&M costs starting in year 21 (2033).
5.8.3 Initial Alternative Resource Plan Environmental and Public Health Impact Analysis
The initial plan analysis also included a high level examination of the environmental and
public health impact of the plan based on the timing of compliance of wastewater
projects, the level of control associated with wastewater compliance options (e.g.
Baseline versus Enhanced Overflow Control), and the WWTF compliance approach being
considered for nutrient reduction (Modified RWWFP versus RWWFP).
Revision: 2012-10-29 Integrated Resource Plan 67
October 31 2012 Page 100 of 272