Changes

The OBC specifies a maximum rooftop retention time of 24 hours because standing water can lead to the proliferation of algae, bacteria, and mosquitoes. To avoid the rise of water quality issues, the City of Mississauga required that CVC install a separate CSA-compliant water recirculation system on the third floor (see Figure 2). This system draws rooftop rainwater through the recirculation line that is immediately upstream of the east modulating control valve. The following are the main treatment components found on the third floor:

The OBC specifies a maximum rooftop retention time of 24 hours because standing water can lead to the proliferation of algae, bacteria, and mosquitoes. To avoid the rise of water quality issues, the City of Mississauga required that CVC install a separate CSA-compliant water recirculation system on the third floor (see Figure 2). This system draws rooftop rainwater through the recirculation line that is immediately upstream of the east modulating control valve. The following are the main treatment components found on the third floor:

*"'Micron Filters:'" Remove any fine debris from the rainwater. This filtration is important for removing impurities, eliminating odours, and ensuring debris does not impede the efficacy of the ultra-violet treatment (UV) unit by blocking light. Two (2) filters are present, the first with a filter pore size of 20 μm and the second with a filter pore size of 5 μm – A pore size of 5 μm is required for CSA compliance.

*'''Micron Filters:''' Remove any fine debris from the rainwater. This filtration is important for removing impurities, eliminating odours, and ensuring debris does not impede the efficacy of the ultra-violet treatment (UV) unit by blocking light. Two (2) filters are present, the first with a filter pore size of 20 μm and the second with a filter pore size of 5 μm – A pore size of 5 μm is required for CSA compliance.

*"'UV Lamp:'" Disinfects rainwater by sterilizing bacteria and viruses with UV radiation. Note that UV disinfection does not have any residual effect that can be harmful to humans or aquatic life. A dosage of 40 mJ/cm2 is administered – This dosage is required for CSA-compliance.

*'''UV Lamp:''' Disinfects rainwater by sterilizing bacteria and viruses with UV radiation. Note that UV disinfection does not have any residual effect that can be harmful to humans or aquatic life. A dosage of 40 mJ/cm2 is administered – This dosage is required for CSA-compliance.

*"'Chlorine Pump:'" Provides a chlorine residual of 0.5 mg/L that can ensure that rainwater on the roof surface is protected from recontamination.

*'''Chlorine Pump:''' Provides a chlorine residual of 0.5 mg/L that can ensure that rainwater on the roof surface is protected from recontamination.

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.