Halifax Harbour Cleanup Inc. - Halifax Regional Municipality

Issues 31
17. The Panel recommends that a monitoring
and public reportlng instrument be established
by the provincial and federal governments,
involving other interested parties,
which will address the ways in which Harbour
conditions are improving as a result of
the Project, controls-at-source programs and
other initiatives.
4.5 ENERGY CONSERVATION
Energy conservation is a fundamental component of the Project
and its goal of sustainable development, and it should be
incorporated as a specific element in the Project’s Environmental
Management Plan.
To achieve sustainable development from the standpoint of
energy consumption, a careful audit of all energy uses and
demands should be undertaken for all aspects of the Project,
and alternatives chosen to minimize energy use when
appropriate.
There are ‘two main areas where energy can be conserved:
• energy required to produce and assemble materials used in
the initial construction of the Project (embodied energy)
• energy required for the ongoing operation and management
of the Project
HHCI took advantage of a number of design and operating
options that have potential for energy conservation, including
. selection of a sea-level site, to reduce energy costs from
pumping to higher land elevations
• ventilation design
• use of heat exchangers at the STP, to recapture waste heat
for interior space heating and other operations
. minimizing hydraulic losses in the collection and outfall/diffuser
systems
• use of fixed-speed pumps to maximize energy/maintenance
efficiencies
• minimizing the number of pumping stations for the collection
system
• use of OFS process, which captures and uses some of its
by-product as a fuel source for sludge drying
• use of cistern and freshwater pond for landscape irrigation
on artificial island
It remains unclear whether the initial siting criteria for selecting
a sea-level site to reduce pumping (energy) costs is being
met, given the W-metre lift required at the headworks of the
STP from the intake tunnel.
The Panel did not hear from many participants about energy
implications for the Project, with the exception of some comments
regarding energy demand for the OFS process and the
main pumping station at the STP. Nevertheless, the Panel
believes that energy conservation is fundamental to the Project’s
ability to meet the goal of sustainable development.
While HHCI has taken steps to reduce operating energy,
cleariy the first priority for a project of this magnitude, it also
makes sense to look at options that will minimize the initial
energy investment (embodied energy). It is an accepted fact
that construction materials such as cement, concrete, aluminum
and steel have high energy requirements for production
relative to some other materials, such as wood and many
plastics. While it may not be feasible or appropriate to eliminate
the use of concrete in many project components (tunnel
liners, foundations, basic STP infrastructure, etc.), it is appropriate
to examine ways in which these high-embodied-energy
materials and fabrication processes can be held to a minimum.
Alternative designs, reduced capacities and value engineering
audits are ways in which embodied energy can be
optimized.
Another area deserving attention is transportation, which also
consumes extensive amounts of energy, especially the transport
of fill, spoils, construction material and equipment, and
personnel.
The Panel concludes that conservation of energy, including
embodied energy, is important for all aspects of the Project:
construction, operation, maintenance and replacement cycles.
It is noted that while the Quality and Value Engineering Audit
Report prepared for HHCI evaluated some Project components
from an energy and economic standpoint, it did not
address other aspects of sustainability; nor did it address
operating energy consumption for all Project components or
embodied energy.
18. The Panel recommends that HHCI commission
an independent energy audit to evaluate
and make recommendations on both embodied
and operating energy consumption, with
tiimo;2+tive of minimizing overall energy
.
19. The Panel recommends that HHCI examine
the alternatives presented in the Quality and
Value Engineering Audit in light of their energy
demands, relative to existing Project design
components, as one of the criteria for
selecting final design solutions.
4.6 THE COLLECTION SYSTEM
4.6.1 introduction
At the present time, 39 municipal outfalls along the waterfronts
of Halifax and Dartmouth, and overflows from 4 pump
ing stations discharge raw, untreated sewage from Halifax,
Dartmouth and the County of Halifax into Halifax Harbour (see
Figure 1).
The proposed system will intercept and consolidate most of
this sewage, transporting it to the regional treatment plant.