Changes

* Design TSS runoff concentration for the site or jurisdiction  

* Design TSS runoff concentration for the site or jurisdiction  

As with OGS, the Rational Method can be employed to estimate flow rates discharged to the MTD for the site in question based on historical rainfall records and the selected recording interval (≤1 hour, 15 minute preferred where available).  These flow rates are in turn used to calculate hydraulic and sediment mass loading to the selected Filtration MTD model (TRCA, 2023)<ref>TRCA. 2023. Guidance on the Use and Application of Results from Verified Laboratory and Field Testing for Stormwater Manufactured Treatment Devices. A Publicly Available Specification Prepared by: Toronto and Region Conservation Authority and Supported by: The Standards Council of Canada. June, 2023. Accessed: https://sustainabletechnologies.ca/app/uploads/2023/07/SETV-Guidance-PAS-2023-07-27-English.pdf</ref>. In general, sizing should ensure that at least 90% of the annual runoff volume during an average year is treated (i.e. does not exceed the system treatment flow rate as defined in Table 2 below).

As with OGS, the Rational Method can be employed to estimate flow rates discharged to the MTD for the site in question based on historical rainfall records and the selected recording interval (≤1 hour, 15 minute preferred where available).  These flow rates are in turn used to calculate hydraulic and sediment mass loading to the selected Filtration MTD model (TRCA, 2023)<ref>TRCA. 2023. Guidance on the Use and Application of Results from Verified Laboratory and Field Testing for Stormwater Manufactured Treatment Devices. A Publicly Available Specification Prepared by: Toronto and Region Conservation Authority and Supported by: The Standards Council of Canada. June, 2023. Accessed: https://sustainabletechnologies.ca/app/uploads/2023/07/SETV-Guidance-PAS-2023-07-27-English.pdf</ref>. In general, sizing should ensure that at least 90% of the annual runoff volume during an average year is treated (i.e. does not exceed the system treatment flow rate as defined in Table 2 below).<br>

 

[[File:CSETV.JPG|450px|thumb|The Canadian Stormwater Environmental Technology Verification project encompasses three deliverables: 1) & 2) Two separate Canadian Publicly Available Specifications for Testing and Verification of Oil and Grit Separators and Filtration Manufactured Treatment Devices. 3) A Canadian Publicly Available Specification for Guidance on how stormwater technology testing and verification procedures should be applied and how performance results should be interpreted and factored into approvals and procurement decisions.]]<br>

[[File:CSETV.JPG|450px|thumb|The Canadian Stormwater Environmental Technology Verification project encompasses three deliverables: 1) & 2) Two separate Canadian Publicly Available Specifications for Testing and Verification of Oil and Grit Separators and Filtration Manufactured Treatment Devices. 3) A Canadian Publicly Available Specification for Guidance on how stormwater technology testing and verification procedures should be applied and how performance results should be interpreted and factored into approvals and procurement decisions.]]<br>

|The maintenance sediment storage depth/volume represents the storage depth/volume available for sedimentation either on top of the media filter or within the chamber housing the filter cartridges and pretreatment chamber(s) (if applicable), as recommended by the manufacturer and confirmed through field testing.  The sump depth is constant across different unit sizes, but the sump volume increases in relation to the effective filtration area, as per the scaling rule noted above.

|The maintenance sediment storage depth/volume represents the storage depth/volume available for sedimentation either on top of the media filter or within the chamber housing the filter cartridges and pretreatment chamber(s) (if applicable), as recommended by the manufacturer and confirmed through field testing.  The sump depth is constant across different unit sizes, but the sump volume increases in relation to the effective filtration area, as per the scaling rule noted above.

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The recommended maintenance frequency must adhere to the findings in the field test report or be shown through detailed design calculations to meet the approval agency maintenance interval requirements, with a buffer of safety added for uncertainties in site specific sediment, gross solids and debris loads.  MTD inspections may need to be more frequent at sites where the site runoff quality is likely to lead to faster clogging of system filtration components than was observed in the field test.  Some runoff quality parameters that may enhance [[clogging]] potential relative to the field test results may include the presence of a larger mass of finer particles (silts and clays), higher organic matter content or hydrocarbon loading, and higher bacterial loads, which can enhance the development of biofilms.

The recommended maintenance frequency must adhere to the findings in the field test report or be shown through detailed design calculations to meet the approval agency maintenance interval requirements, with a buffer of safety added for uncertainties in site specific sediment, gross solids and debris loads.  MTD inspections may need to be more frequent at sites where the site runoff quality is likely to lead to faster clogging of system filtration components than was observed in the field test.  Some runoff quality parameters that may enhance [[clogging]] potential relative to the field test results may include the presence of a larger mass of finer particles (silts and clays), higher organic matter content or hydrocarbon loading, and higher bacterial loads, which can enhance the development of biofilms.