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Credits apply only to the water being treated by a device. The applicable treatment volume must be determined using one of the [https://stormwater.pca.state.mn.us/index.php?title=TP_and_TSS_credits_and_guidance_for_manufactured_treatment_devices_(mtds)#Calculating_annual_volume_treated methods described here]. | Credits apply only to the water being treated by a device. The applicable treatment volume must be determined using one of the [https://stormwater.pca.state.mn.us/index.php?title=TP_and_TSS_credits_and_guidance_for_manufactured_treatment_devices_(mtds)#Calculating_annual_volume_treated methods described here]. | ||
− | The Tier 1 credit equals the TAPE-approved credits. Tier 2 | + | The Tier 1 credit equals the TAPE-approved credits. Tier 2 credit was determined by analyzing water quality data collected at ZigZag, Oregon. The site consisted of transportation land use with 0.063 acres of impervious draining to the device. The system contained one 18-inch StormFilter |
cartridge with PhosphoSorb media operating at a specific flow rate 1.67 gpm/ft<sup>2</sup> or 12.5 gpm per 18-inch tall cartridge. | cartridge with PhosphoSorb media operating at a specific flow rate 1.67 gpm/ft<sup>2</sup> or 12.5 gpm per 18-inch tall cartridge. | ||
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*95% lower confidence limit TSS removal (all data) - 84.8% | *95% lower confidence limit TSS removal (all data) - 84.8% | ||
TAPE means and medians represent values meeting TAPE criteria for TP (inflow concentrations of 0.1 to 0.5 mg/L) and TSS (inflow concentrations greater than 20 mg/L). Of the 22 samples, TAPE medians and means represent 16 samples for TP and 17 samples for TSS. | TAPE means and medians represent values meeting TAPE criteria for TP (inflow concentrations of 0.1 to 0.5 mg/L) and TSS (inflow concentrations greater than 20 mg/L). Of the 22 samples, TAPE medians and means represent 16 samples for TP and 17 samples for TSS. | ||
+ | |||
+ | The Tier 3 credit of 70% is based on the following. | ||
+ | *PP removal of 60%, assuming PP is 75% of TP and TSS removal is 80% (80% * 75% = 60%) | ||
+ | *DP removal is 40%. Assuming DP is 25% of TP, the DP credit is (40% * 25%) equals 10% | ||
+ | *TP removal is PP removal plus DP removal equals 60% + 10% = 70% | ||
+ | *DP removal is based on testing of the phosphosorb media, which contains expanded aluminum ([https://www.researchgate.net/publication/276965524_Orthophosphate_Adsorption_Equilibrium_and_Breakthrough_on_Filtration_Media_for_Storm-Water_Runoff_Treatment Ma et al., 2011]). | ||
===Inspection, operation, and maintenance=== | ===Inspection, operation, and maintenance=== |
Contech's StormFilter using PhosphoSorb Media is an engineered bioretention system designed to filter pollutants from stormwater runoff. It is classified as a manufactured treatment device (mtd).
This page provides information on pollutant removal credits for StormFilter using PhosphoSorb Media, links to supporting information, and links to information on system design, inspection, operation, and maintenance.
When conditions described in this section are met, applicable Contech StormFilter using PhosphoSorb Media systems are approved for the following removals for total suspended solids (TSS) and total phosphorus (TP).
For more information on credits, see TP and TSS credits and guidance for manufactured treatment devices (mtds)
For a discussion of StormFilter configurations, link here.
To receive the full credit, StormFilter systems must comply with the following conditions.
Additional information is provided in Washington State Department of Ecology's report GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS) AND PHOSPHORUS TREATMENT For CONTECH Engineered Solutions Stormwater Management StormFilter® with PhosphoSorb® media. Note that some information in this report is specific to Washington State and not applicable to Minnesota.
Credits apply only to the water being treated by a device. The applicable treatment volume must be determined using one of the methods described here.
The Tier 1 credit equals the TAPE-approved credits. Tier 2 credit was determined by analyzing water quality data collected at ZigZag, Oregon. The site consisted of transportation land use with 0.063 acres of impervious draining to the device. The system contained one 18-inch StormFilter cartridge with PhosphoSorb media operating at a specific flow rate 1.67 gpm/ft2 or 12.5 gpm per 18-inch tall cartridge.
MPCA compiled data from Appendix D of the report The Stormwater Management StormFilter® PhosphoSorb® at a Specific Flow Rate of 1.67 gpm/ft2 General Use Level Designation Technical Evaluation Report. Below are summary statistics for the device.
TAPE means and medians represent values meeting TAPE criteria for TP (inflow concentrations of 0.1 to 0.5 mg/L) and TSS (inflow concentrations greater than 20 mg/L). Of the 22 samples, TAPE medians and means represent 16 samples for TP and 17 samples for TSS.
The Tier 3 credit of 70% is based on the following.
Meet the conditions specified for [ the appropriate TP and/or TSS credit].
Meet the following conditions, unless conditions for [ the appropriate TP and/or TSS credit] are more stringent.