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Filtration Manufactured Treatment Devices (view source)
Revision as of 00:09, 7 February 2024
, 9 months agono edit summary
# '''Conditional Use Level Designation (CULD)''': These are technologies that should most likely and feasibly be able to meet stated performance goals, but the developer most conduct additional verification field testing (within a given time period) to achieve General Use Level designation.
# '''Conditional Use Level Designation (CULD)''': These are technologies that should most likely and feasibly be able to meet stated performance goals, but the developer most conduct additional verification field testing (within a given time period) to achieve General Use Level designation.
# '''Pilot Use Level Designation (PULD)''': Newly piloted and promising emerging technologies whose use is specific to a given project's field testing requirements. Requires further verification testing though.
# '''Pilot Use Level Designation (PULD)''': Newly piloted and promising emerging technologies whose use is specific to a given project's field testing requirements. Requires further verification testing though.
==Scaling==
Appropriate scaling ensures that performance results from the model tested and verified through [https://apps.ecology.wa.gov/publications/SummaryPages/1810038.html. TAPE] and/or [https://www.iso.org/obp/ui/#iso:std:iso:14034:ed-1:v1:en ISO 14034 ETV] can be confidently applied to other model sizes for the same MTD. Buyers should ensure to ask vendors to provide sizing data and calculations to confirm that the proposed unit is scaled appropriately. Verifications conducted in 2023 or later will include information on unit scaling in the publicly available verification statement.
The scaling rules, as stated in the [https://sustainabletechnologies.ca/app/uploads/2023/11/SETV-Filtration-MTDs-PAS-2023-11-07-English.pdf Canadian Procedure for Field Testing of Filtration MTDs]<ref>Toronto and Region Conservation Authority, 2023. Canadian Procedure for Field Testing of Stormwater Filtration Manufactured Treatment Devices: A Publicly Available Specification, Toronto, Ontario. https://sustainabletechnologies.ca/app/uploads/2023/11/SETV-Filtration-MTDs-PAS-2023-11-07-English.pdf</ref>, are as follows:
"''Scaling the tested filtration MTD to determine other model sizes and performance without completing additional testing is acceptable provided that:''
# '''''The depth, composition, bulk density and gradation of media remain constant. Nominal pore size of membrane based filters remain constant;'''''
# '''''The ratio of the system treatment flow rate to effective filtration treatment area (filter surface area) is the same or less than the tested filtration MTD;'''''
# '''''The ratio of effective sedimentation treatment area to effective filtration treatment area is the same or greater than the tested filtration MTD; and'''''
# '''''The ratio of wet volume to effective filtration treatment area is the same or greater than the tested filtration MTD'''''<br>
==Sizing==
Appropriate sizing of Filtration MTDs is more complex than for Oil-Grit Separators because of the wide variation in different filtration device designs. Assessing whether performance of Filtration MTDs meets performance objectives for the site based on verified testing reports will require the following information:
* Historical [[Understanding rainfall statistics|rainfall records]] (≤ 1 hour recording intervals, 15 minute preferred where available) from the nearest [[Climate Trends in Ontario|long term meteorologic station for months]] when temperatures are predominantly above 0°C. Data should be filtered to account for the initial abstraction factor, which represents an assumed loss occurring during the initial phases of a storm and ends when the total rainfall depth equals the abstraction factor (e.g. 2 mm);
* [[Drainage time|Site drainage area size]], impervious cover percentage and [[Runoff volume control targets|site runoff coefficient]] calculated based on pervious and impervious cover runoff coefficients relevant to the site drainage area (e.g. [[slope]], [[Texture|soil texture]]) and jurisdiction;
* Treatment objective (normally denominated as a removal efficiency for [[water quality]] parameters of concern, but some jurisdictions may use effluent concentrations either in addition or instead of removal efficiencies) and location in drainage system (i.e. stand alone or as [[pretreatment]] to other downstream BMPs); indicate whether upstream [[flow control]] is provided, and if so, the type (e.g. parking lot storage, roof storage, [[Flow through perforated pipe|pipe storage]]);
* Proposed model sizes and specifications (diameter or dimensions, internal sedimentation area, manufacturers recommended maintenance sediment storage depth, chamber depth, filter type and number, [[Bioretention: Filter media|media composition]] – if relevant);
* Verification test results (from field monitoring through TAPE or equivalent): lower 95th percent confidence interval of mean pollutant removal efficiency for each water quality parameter; upper 95th percent confidence interval of mean effluent concentration for each parameter; lowest measured bypass flow rate, head loss data, and other relevant operational parameters;
* 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).
==References==
==References==