Percent P Removed Via Non-Volume Reduction Treatment

Percent P Removed Via Non-Volume Reduction Treatment.

Caution: NOTE: These percentages apply to the non-volume reduction portion of stormwater runoff. The volume reduction portion of stormwater runoff receives 100 percent credit for particulate and dissolved phosphorus.

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	Particulate P		Dissolved P
	Current in MIDS calculator	Proposed	Current in MIDS calculator	Proposed
No underdrain	0%	0%	0%	0%
Elevated underdrain	45%	Is soil P content tested to be < 30 mg/kg per Mehlich III (or equivalent) test? If yes, 40% If no, 0%	0%	Is soil P content tested to be < 30 mg/kg per Mehlich III (or equivalent) test? If no, 0% If yes, is there at least 2 feet of soil above the elevated underdrain? If yes, 20% credit, If no, credit = 0.2*x Where x = (soil depth above elevated underdrain) /2 feet Additional credit for approved P-sorbing soil amendments = 40 percent if one of the following conditions aapplies. 5% by volume elemental iron filings above IWS or elevated underdrain Minimum 5% by volume sorptive media above IWS or elevated underdrain Minimum 5% by weight water treatment residuals (WTR) to a depth of at least 10 cm (1/3 foot) Other P sorptive amendments with supporting third party research results showing P reduction for at least 20 year lifespan, P credit commensurate with research results
Underdrain at the bottom	45%	Is soil P content tested to be < 306 mg/kg per Mehlich III (or equivalent) test? If yes, 40% If no, 0%	0%	Is soil P content tested to be < 30 mg/kg per Mehlich III (or equivalent) test? If yes, 20% If no, 0% Additional credit for approved P-sorbing soil amendments = 40 percent if one of the following conditions applies. 5% by volume elemental iron filings above IWS or elevated underdrain Minimum 5% by volume sorptive media above IWS or elevated underdrain Minimum 5% by weight water treatment residuals (WTR) to a depth of at least 10 cm (1/3 foot) Other P sorptive amendments with supporting third party research results showing P reduction for at least 20 year lifespan, P credit commensurate with research results
Internal Water Storage (IWS)	Not in calculator	Is soil P content tested to be < 30 mg/kg per Mehlich III (or equivalent) test? If yes, 40% If no, 0%	Not in calculator	Is soil P content tested to be < 30 mg/kg per Mehlich III (or equivalent) test? If yes, 20% If no, 0% Additional credit for approved P-sorbing soil amendments = 40 percent if one of the following conditions applies. 5% by volume elemental iron filings above IWS or elevated underdrain Minimum 5% by volume sorptive media above IWS or elevated underdrain Minimum 5% by weight water treatment residuals (WTR) to a depth of at least 10 cm (1/3 foot) Other P sorptive amendments with supporting third party research results showing P reduction for at least 20 year lifespan, P credit commensurate with research results