volume 1 - Halifax Regional Municipality

Halifax Water Integrated Resource Plan
Integrated Resource Plan Drivers and Objectives
As indicated in Section 3, 10 of 14 WWTFs are not currently compliant with their NSE
Permit to Operate and require upgrades. Details of compliance status can be found in
Volume 3 Appendix B –Wastewater Treatment System Review. A number of projects
are included in the Five-Year Capital Plan that address the required upgrades. Additional
projects were identified through the preparation of the IRP and have been included for
consideration in the alternative plans.
Additional wastewater treatment improvements will also be needed to meet the
recently promulgated Canadian Wastewater Systems Effluent Regulations (WSER) 23 . The
proposed regulations are intended to phase out the release of untreated and
undertreated wastewater. The regulations will apply to wastewater systems that treat,
or are designed to treat, an average daily volume of at least 100 cubic metres per day
(m 3 /d). The national performances standards that wastewater systems will be expected
to meet are shown in Table 4.2.
Table 4.2
Proposed National Performance Standards
Parameter
Carbonaceous Biochemical Oxygen Demand (CBOD)
Suspended Solids (TSS)
Total Residual Chlorine (TRC)
Concentration
Average ≤ 25 mg/L
Average ≤ 25 mg/L
Average ≤ 0.02 mg/L
Un-ionized ammonia as N at 15˚C ± 1˚C
Maximum < 1.25 mg/L
The average concentrations shown in Table 4.2 are typically achievable with a secondary
level of treatment. The WSER also requires that wastewater treatment facility effluents
must not be acutely lethal.
Some Halifax Water WWTFs will need to be upgraded to meet the WSER. Halifax Water
has recently completed a risk assessment of its Halifax Harbour Solutions WWTFs
indicating that under the WSER all three facilities will be required to upgrade to full
secondary treatment within 20 years (by 2032).
The Province of Nova Scotia has indicated that it will implement WSER requirements
under its jurisdiction through conditions attached to approvals issued by Nova Scotia
Environment.
In addition to the current compliance and future WSER requirements, a review of the
Halifax Water WWTFs indicates that 10 WWTFs (see Table 4.3) discharge to receiving
waters with limited assimilative capacity. Discussions with NSE have indicated that
advanced nitrogen and/or phosphorus removal potentially to the limit of technology
(LOT) will be required for these facilities at some point in the future. Halifax Water has
already implemented more conventional nutrient removal at four facilities including
23 Wastewater Systems Effluent Regulations, Canada Gazette, Vol. 146 No. 15, June 2012
Revision: 2012-10-29 Integrated Resource Plan 35
October 31 2012 Page 68 of 272