Comparative BMP phosphorus removal

General summary of comparative BMP phosphorus removal performance^a,e,f
Link to this table

BMP Group	BMP Design Variation	Average TP Removal Rate (%)b	Maximum TP Removal Rate (%)c	Average Soluble P Removal Rate (%)dg
Bioretention	Underdrain	see Phosphorus credits for bioretention systems with an underdrain	see Phosphorus credits for bioretention systems with an underdrain	see Phosphorus credits for bioretention systems with an underdrain
	Infiltration	100 for infiltrated portion 0 for non-infiltrated portion	100 for infiltrated portion 0 for non-infiltrated portion	100 for infiltrated portion 0 for non-infiltrated portion
Filtration	Media Filter	50	55	0
	Vegetative Filters (dry)	50	55	0
	Wet Swale	0	35	0
Infiltrationf,i	Infiltration Trench	100 for infiltrated portion 0 for non-infiltrated portion	100 for infiltrated portion 0 for non-infiltrated portion	100 for infiltrated portion 0 for non-infiltrated portion
	Infiltration Basin	100 for infiltrated portion 0 for non-infiltrated portion	100 for infiltrated portion 0 for non-infiltrated portion	100 for infiltrated portion 0 for non-infiltrated portion
Stormwater Ponds	Wet Pond	50	75	0
	Multiple Pond	60	75	0
Stormwater Wetlands	Shallow Wetland	40	45	0
	Pond/Wetland			0

^a Removal rates shown in table are a composite of five sources: ASCE/EPA International BMP Database; Caraco (CWP), 2001; MDE, 2000; Winer (CWP), 2000; and Issue Paper D P8 modeling
^b Average removal efficiency expected under MPCA Construction General Permit sizing requirements
^c Upper limit on phosphorus removal with increased sizing and design features, based on national review
^d Average rate of soluble phosphorus removal in literature
^e See also Calculating stormwater volume and pollutant reductions and credits
^f Note that the performance numbers apply only to that portion of total flow actually being treated; it does not include any runoff that by-passes the BMP
^g Note that soluble P can transfer from surface water to ground water, but this column refers only to surface water
^h Note that 100% is assumed for all infiltration, but only for that portion of the flow fully treated in theinfiltration facility; by-passed runoff or runoff diverted via underdrain does not receive this level of treatment

Caution: Removal rates shown here are composite averages intended solely for use in comparing performance between BMP designs and for use in calculating load reduction in site-based TP models. They have been adapted, rounded and slightly discounted from statistical values published in BMP performance databases.