Changes

=='''Station 1 – Roof Surface'''==

=='''Station 1 – Roof Surface'''==

By utilizing the roof of Building A for storage, CVC’s head office gains the ability to capture an additional 40,000 L of rainwater. A structural load assessment conducted by WSP Canada concluded that an average depth of 130 mm of rainwater could safely be supported by Building A’s roof assembly. Since Building A’s roof is gently sloping, this corresponds to a depth of 75 mm at the parapet (roof edge) and 250 mm at the roof drains (lowest point). Rainwater can be held on the roof for up to six (6) days. Whether rainwater is retained on the building’s roof or drained into the basement for treatment is determined by the modulating control valves on the building’s third floor.

By utilizing the roof of Building A for storage, CVC’s head office gains the ability to capture an additional 40,000 L of rainwater. A structural load assessment conducted by WSP Canada concluded that an average depth of 130 mm of rainwater could safely be supported by Building A’s roof assembly. Since Building A’s roof is gently sloping, this corresponds to a depth of 75 mm at the parapet (roof edge) and 250 mm at the roof drains (lowest point). Rainwater can be held on the roof for up to six (6) days. Whether rainwater is retained on the building’s roof or drained into the basement for treatment is determined by the modulating control valves on the building’s third floor.

=='''Station 2 – Modulating Control Valves'''==

=='''Station 2 – Modulating Control Valves'''==

The key mechanisms for the SBR’s ability to hold water are the modulating control valves installed on the third floor. Whereas typical flat roof buildings allow rainwater to passively drain from their roofs without rainwater retention, the SBR roof drains are configured with valves that stop drainage from occurring. These valves allow water to pond on the roof up to a safe maximum depth, determined by the height of the overflow pipes, which is an average of 130 mm in the case of the SBR. Water that is held back by these valves is passed through the SBR’s first CSA-compliant treatment system via a suction line that is installed immediately upstream of the east modulating control valve.

The key mechanisms for the SBR’s ability to hold water are the modulating control valves installed on the third floor. Whereas typical flat roof buildings allow rainwater to passively drain from their roofs without rainwater retention, the SBR roof drains are configured with valves that stop drainage from occurring. These valves allow water to pond on the roof up to a safe maximum depth, determined by the height of the overflow pipes, which is an average of 130 mm in the case of the SBR. Water that is held back by these valves is passed through the SBR’s first CSA-compliant treatment system via a suction line that is installed immediately upstream of the east modulating control valve.

=='''Station 3 – Third-Floor Treatment System'''==

=='''Station 3 – Third-Floor Treatment System'''==

The OBC requires that flat roofs do not allow rainwater to pond beyond a maximum depth 150 mm. Furthermore, the OBC demands that rainwater is drained within 24 hours. In order to maximize the benefits of rainwater capture, CVC sought exemptions from these restrictive clauses of the OBC. The City of Mississauga granted both of these exemptions, under a set of conditions.  

The OBC requires that flat roofs do not allow rainwater to pond beyond a maximum depth 150 mm. Furthermore, the OBC demands that rainwater is drained within 24 hours. In order to maximize the benefits of rainwater capture, CVC sought exemptions from these restrictive clauses of the OBC. The City of Mississauga granted both of these exemptions, under a set of conditions.  

It is important to note that chlorination only occurs when the roof water’s chlorine residual drops below 0.5 mg/L, at which water is passed through a chlorination unit and directed back to the filters. This recirculation system was not included in the original SBR design, but its inclusion will ensure that the ponding of water on the roof does not present any water quality and human health concerns. CVC has engaged Toronto Metropolitan University (TMU) to research the water quality of the SBR (among other research areas). Hopefully, this research will demonstrate that rooftop treatment is not required and that treatment before final distribution is sufficient.

It is important to note that chlorination only occurs when the roof water’s chlorine residual drops below 0.5 mg/L, at which water is passed through a chlorination unit and directed back to the filters. This recirculation system was not included in the original SBR design, but its inclusion will ensure that the ponding of water on the roof does not present any water quality and human health concerns. CVC has engaged Toronto Metropolitan University (TMU) to research the water quality of the SBR (among other research areas). Hopefully, this research will demonstrate that rooftop treatment is not required and that treatment before final distribution is sufficient.

=='''Station 4 – Base Cistern and Treatment System'''==

=='''Station 4 – Base Cistern and Treatment System'''==

When rainwater is drained from the roof surface into the basement, it is collected by a rainwater cistern (CVC’s old, passive system). Water from this cistern can be pumped through the SBR’s second CSA-compliant treatment system. The following are the main treatment components of this basement system:

When rainwater is drained from the roof surface into the basement, it is collected by a rainwater cistern (CVC’s old, passive system). Water from this cistern can be pumped through the SBR’s second CSA-compliant treatment system. The following are the main treatment components of this basement system:

Once treatment is complete, the rainwater is added to Building A’s greywater line for use in the building’s toilets. Currently, rainwater is only planned for use in toilets, but greywater use could be expanded to irrigation applications at a later phase. Although CVC would have no need for it, there is potential for rainwater to be reused for industrial uses, like vehicle washing and industrial processes. Upgrading the treatment systems could also make rainwater reusable as potable water.

Once treatment is complete, the rainwater is added to Building A’s greywater line for use in the building’s toilets. Currently, rainwater is only planned for use in toilets, but greywater use could be expanded to irrigation applications at a later phase. Although CVC would have no need for it, there is potential for rainwater to be reused for industrial uses, like vehicle washing and industrial processes. Upgrading the treatment systems could also make rainwater reusable as potable water.

=='''Station 5 – Programmable Logic Controller'''==

=='''Station 5 – Programmable Logic Controller'''==