Halton Region wished to retrofit its decommissioned filter area at the Acton Wastewater Treatment Plant in Halton Hills, ON to create a new, sustainable administrative building designed with equity, diversity, and inclusion in mind. A growing municipality of about 600,000 in southern Ontario, the Region owns and operates seven wastewater treatment plants, as part of its responsibility to provide wastewater management services for the municipality.

Following the construction of a new stand-alone filter building at the Acton Wastewater Treatment Plant, the Region wished to retrofit the decommissioned filter building, repurposing the filter wing and combining it with the office wing to create a new administrative building. This adaptive reuse approach reduces the embodied carbon footprint by minimizing the need for new construction.

The Region engaged Associated Engineering to provide engineering services for the filter building retrofit and various plant upgrades. As the prime consultant, Associated’s scope of work includes critical elements such as the demolition of the existing process infrastructure, building mechanical services for the retrofitted space, and structural retrofit and backfilling of the existing filter tank, and repurposing of the space as offices.

In addition to the retrofit and facility upgrade, the Region wanted to implement energy-saving options to reduce the facility’s environmental impact. Funding is available for green initiatives to support this goal. Project Manager, Roy Gong, shares, “We proposed and reviewed several options with the Region, and completed a feasibility study to document the viability of potential approaches.”

Some of the green initiatives explored to reduce environmental impact included alternative heat sources, such as a hydronic heating system and geothermal heating. The team also investigated the benefits of upgrading the heating, ventilation, and air conditioning (HVAC) system.

Mechanical Designer, Yang An, says, “The existing HVAC system for the office area was old and outdated. We determined the most practical way to serve the retrofitted administrative building is to install roof-top units for conditioning the space. We proposed a new HVAC roof-top unit with better energy-efficiency. Variable air volume boxes are being installed for different rooms to tune the air flow and lower energy consumption when the space is unoccupied.”

During preliminary design, the Region requested that we incorporate Equity, Diversity, and Inclusion (EDI) concepts into our design, aligning with their new EDI policy. The EDI design concepts significantly altered the original design, in particular the changing rooms, locker rooms, and showers. Roy tells us, “Working closely with our architectural subconsultant, we developed solutions to minimize the impact on the overall design and re-work efforts. The Region acknowledged the scope of these changes and accommodated the additional work required.”

This collaborative approach demonstrated Associated’s commitment to delivering a design that meets Halton’s evolving needs and creates a more inclusive and equitable workspace

During detailed design, the Region asked our team to explore solar thermal wall installation, a technology used to capture and use solar energy to preheat the ventilation air for buildings. Yang explains, “Also known as a transpired solar collector, a solar thermal wall is a passive solar heating system designed to reduce the energy required for heating, especially in industrial and commercial buildings.” Our team’s investigations with a local supplier determined the feasibility of this option.

Currently, the team is working towards tender phase. The project team’s flexibility and agility in responding to the Region’s requested changes, combined with strong communication and a collaborative relationship between the Region, our subconsultants (Brown+Storey Architects and Eramosa Engineering), and our in-house team have created a successful teaming environment and the design of a sustainable workspace that fosters equity, diversity, and inclusion.

The post Retrofit of Acton Wastewater Treatment Plant creates sustainable office space that fosters equity, diversity, and inclusion first appeared on Associated Engineering.

re·li·a·bil·i·ty, /rəˌlīəˈbilədē/, noun, The quality of of performing consistently well.

re·sil·ience, /rəˈzilyəns/, noun, The capacity to recover quickly from difficulties; toughness.

When engineering for the built environment, Associated Engineering considers reliability and resilience for the systems we design. We include safety factors, stand-by and back-up process systems, alternative feeds, and back-up power to mitigate risks, such as climate change impacts. Adding redundancy to our systems is one way to achieve resilience, but redundancy has impacts, such as increased cost, maintenance, and embodied carbon. Designing for climate resiliency goes beyond ‘n+1’ and requires discussions with owners and operators. We need to think “outside of the box” and the facility we are designing.

Power Supply: Floods, snow, and fires can destroy critical infrastructure, leaving facilities without power for days, weeks, or longer. Fires may require the shutdown of natural-gas-powered systems. Adding a back-up power generator is a solution; however, we must consider the source of fuel for generators, the facility’s location, and the risks associated with fuel supply and transportation. Transportation routes can become blocked or damaged in flood events, blocking critical supplies. 

In the past, for cold climates, we have specified arctic-packages for outdoor generators. With the changing climate, we are experiencing +39°C temperatures in locations like Edmonton, Alberta, so we also need to consider high-temperature radiator and coolant systems so that we can operate up to +40°C. We also consider air conditioning in generator rooms. Care must be taken to consider the additional building electrical load which the generator has to power. And, the generator has to be sized to power the cooling for itself! 

Too hot to handle: In the past, when designing facilities in Canada, electrical designers didn’t worry too much about the ambient temperature; that was a consideration for the building mechanical designers. However, the Canadian Electrical Code for cable sizing is based on +30°C. Equipment that is rated for +30°C will need to be in a conditioned space.  Equipment that is rated for +40°C may also need to be in a conditioned space if there is a lot of heat accumulation in the area. 

We may need to consider multiple distribution systems and shedding power, because the equipment may get too hot or overload the generator. Maybe we need to design for full normal operation up to +30°C, only essential equipment from +30°C to +40°C, and for critical systems to operate when temperatures are over +40°C. 

Recovery: After fires and floods, we have faced questions such as, ‘How hot did the conduit get with the fire being so close?” or “Did the smoke enter the building and cover copper with soot?”  Considering potential fires, stickers can be applied to conduits; the stickers change colour if the outside temperature rises to +90°C. Then, operators and designers know the wires were compromised and need to be replaced. We can add smoke detectors in electrical rooms; if the alarms activate, we know there may be soot inside the room. However, smoke detectors are not precise, and don’t identify conduits drawing smoke directly into panels or motor control centres. After flooding, all affected electrical systems need to be replaced, which can be a significant cost to owners.

Engineers must consider future flood levels when designing new or renovating facilities. The changing climate creates impacts we must consider to reduce risks to facilities. Designers, owners, and operators need to have candid discussions so we can make informed decisions and develop reliable and resilient systems. 

About the Author:

Scott Friel, PE, P.Eng. is an Electrical Specialist in our Edmonton office. He has 24 years of experience in electrical systems design, electrical inspections, certification of hazardous location equipment, and commercial and industrial engineering studies. 

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