Pretreatment system design information - all devices

Pretreatment system design information - all devices. NOTE: we have not maintained the links in these tables. If you want to find a link, go to this page, which is more likely to have updated links.
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Device	Primary mechanism	Drainage area	Entrance velocity	Dimensions	Materials	Layout Recommendations (physical location, off-line placement)	Soils
Vortechs TM by Contech	Hydrodynamic separation	<10 acres, recommended <5 acres with <1-acre impervious cover1, 2	1.6-25 cfs3	9 standard sizes: 9 ft x 3 ft to 18 ft x 12 ft3		Small footprints of predesigned models are suitable for urban areas and as a retrofit to existing networks. Can be online or off-line.3, 4
Continuous Deflective Separation (CDS) R by Contech	Hydrodynamic separation	<10 acres, recommended <5 acres with <1-acre impervious cover5, 6	Inline up to 6 cfs, offline precast modules 3-62 cfs, offline cast in place up to 300 cfs7, 8	16 models: 3-10 ft diameter8		Small footprints of predesigned models are suitable for urban areas and as a retrofit to existing networks9
Downstream Defender TM H.I.L. Technology	Hydrodynamic separation	<10 acres, recommended <5 acres with <1-acre impervious cover10, 11	1.6-24 cfs for 50% removal of 100-micron particles, peak flow rate 3-38 cfs12	Predesigned manhole sizes: 4-12 ft in diameter, custom: up to 40 ft in diameter; Depth: 3.33 - 9.42 ft13, 14		Small footprints of predesigned models are suitable for urban areas and as a retrofit to existing networks15
First Defense R by Hydro International	Hydrodynamic separation		0.85-6.0 cfs for 50% TSS Removal16	Six models: Diameter= 3-8 ft, Depth = 3.75-8 ft16		At point of entry into drainage line, sites constrained by space, topography, or drainage profiles, and retrofit installations16
Stormceptor R by Imbrium or Rinker Materials	Varies from 1 acre to 150 acres depending on model, common in-line models can treat 0.55-6.7 acres impervious cover17, 18		8 prefabricated in-line models, 1 48-in diameter inlet model, large-scale MAX model18		Small footprints of predesigned models are suitable for urban areas and as a retrofit to existing networks. Extended Oil Storage and Oil and Sand Removal Systems available for hot spot areas. Can be inlet or in-line, single or in series19, 20
Barracuda by BaySaver	Hydrodynamic separation	Recommended <5 acres with <1-acre impervious cover21	50% TSS removal: 1.25 cfs, Maximum: 6.25 cfs22	6 manhole models: 36-120 in diameters22		Small footprints of predesigned models are suitable for urban areas and as a retrofit to existing networks
Dual Vortex Separator by OldCastle	Hydrodynamic separation		0.56 – 9 cfs23	Multiple sizes for both square manhole and square grated inlet models: 36 in to 144 in diameter24		Small footprints of predesigned models are suitable for urban areas and as a retrofit to existing networks. Can be online or offline24
SciClone TM by BioClean	Hydrodynamic separation		WQ flow rate = 0.7-6.3 cfs25	Twelve models: 3-14 ft diameter, storage capacity 11-231 cu ft26		Small footprints of predesigned models are suitable for urban areas and as a retrofit to existing networks27
Rain Guardian - Bunker	Screening and straining		Up to 6.11 cfs [1]	Standard exterior dimensions = 51.25 in L x 20 in W x 15.75 in H, Designed for garden standard ponding depth of 9 in or 12 in [2]	95% recycled plastic lumber [3]	Residential bioretention (rain gardens) [4]
Rain Guardian - Turret	Screening and straining		Up to 3.45 cfs [5]	46 in by 50 in base, 19.5 in total height, designed for garden standard ponding depth of 12 in [6]	Reinforced concrete base, fiberglass grate [7]	Parking lot rain gardens and high traffic areas [8]
Rain Guardian - Foxhole	Screening and straining			2 ft 11 in W x 1 ft 7 in H x As Long as Needed in 3 ft increments [9]	Reinforced concrete base, fiberglass grate [10]	Under walkways, paths and roads into a rain garden [11]
Riprap check dams	Screening and straining	<10 acres [12]		4-5 ft wide at the bottom, 1.5 to 2 ft wide at the top, 1.5 to 2 ft high, side slopes no steeper than 2:1 [13]	Riprap, coarse aggregate facing uphill side, mixture of rock sizes, nonwoven geotextile below [14]	Small open channels (not streams or rivers) with channel slopes >10% [15]	Areas conducive to erosion (sandy/silty) [16]
Wattles	Screening and straining	Not available, although perhaps similar to silt fence <0.25 acre		Two sizes: 9 in diameter x 25 ft long and 12 in diameter x 20 ft long, wooden stakes through wattle into soil every 3-4 ft [17]	Straw, tubular UV-stabilized black synthetic netting, 18-24 in wooden stakes [18]	Newly constructed or disturbed slopes [19]
Hydro Screen	Screening and straining	Depends on model/application	Outfall screen can handle up to 1,000 cfs [20]	Depends on model/application	Stainless steel	Downspouts, detention ponds, private property/roofs, curbs, parking lots, farms [21]
Pretreatment row on underground storage/filtration	Above ground and below grade storage and settling	Varies widely, units may be placed in parallel and series to accommodate		Varies. Limiting factor is site footprint available.	Rigid chamber, gravel	In-line, ideal under parking lots and areas with tight footprints	Ideally highly infiltrative to achieve volume reduction
StormTech Isolator Row	Above ground and below grade storage and settling	Varies widely, units may be placed in parallel and series to accommodate	See flow Table 2	Max length of row = 175 ft, but multiple rows may be used, see dimensions table for models SC-310, SC-310-3, SC-780, MC-3500 and MC-4500 [22]	Two layers of woven geotextile, StormTech chamber, non-woven fabric if model has perforated side walls, gravel [23]	In-line, after a manhole with a high flow weir. System is ideal under parking lots and roadways and areas with tight footprints [24]	Ideally highly infiltrative to achieve volume reduction [25]
Settling chamber/vault	Above ground and below grade storage and settling	Can be sized to accommodate drainage area of downstream BMP [26]	Exit velocity to surface media filters should be non-erosive [27]	Recommended length to width ratio of 2:1
Oil/water/grit separators	Above ground and below grade storage and settling	<1 acre impervious cover [28]	1-3 ft/min or less [29]	Total wet storage = 400 cf per acre of contributing imp area, depth of permanent pool >4 ft [30]	Reinforced concrete	Off-line, ideal in urban areas with small lots and for retrofits [31]	No soil or terrain restrictions [32]
Hydro Dry Screen	Above ground and below grade storage and settling		Max Flow: 29-162 cfs, Treatment Flow: 11-80 cfs , 80% TSS removal: 1.8-16 cfs [33]	Five models: 4x8 ft to 12x20 ft (see Table 1) [34]		New construction or redevelopment sites, retrofit of storm drain lines, shallow installations with high groundwater or bedrock, installations requiring low headloss [35]
Suntree Nutrient Seprating Baffle Box (NSBB)	Above ground and below grade storage and settling		Maximum Treatment Flow Rate: 2-45 cfs [36]	4 ft x 2 ft x 2.7 ft - 24 ft x 12 ft x 9 ft [37]		Online [38]
Manhole Baffle Box	Above ground and below grade storage and settling	1-100 acres [39]		Typically 10-15 ft long x 6-8 ft high x 2 ft wider than pipe [40]	Concrete, fiberglass [41]	In-line or at the end of storm pipes, ideal for retrofitting existing pipes [42]
Environment 21 StormPro	Above ground and below grade storage and settling		0.5-8.6 cfs. Max loading for all models = 10.8 gpm/sq ft [43]; [44]	11 models. The 5 models in the StormPro V series range from 4 ft x 8 ft x 2.5+ ft to 10 ft x 20 ft x 5+ ft [45]; [46]	Baffle wall: precast concrete or other approved rigid materials, Bypass pipe: rigid plastic [47]
BaySeparator by BaySaver	Above ground and below grade storage and settling	1.2-8 acres impervious area [48]	Treats maximum of 22 cfs [49]	5 standard sizes: manhole diameter 48-120 inches, 6-8 ft deep [50]	Concrete, HDPE, polyethylene [51]
Sump Manhole with SAFL Baffle	Above ground and below grade storage and settling	<10 acres [52]	Horizontal flow must be at least 3x flow from above [53]	Can be installed in sump structures w/ diameters of 3-10 ft and depths >= 3 ft [54]	Stainless steel [55]	New or existing sump manhole [56]
Deep sump catch basin	Above ground and below grade storage and settling	<0.25 acre impervious area	< 3 cfs [57]	Diameter of outlet pipe = D: diameter of catch basin = 4D, sump depth >= 4D, top of outlet pipe 1.5 D below bottom of inlet. Minimum sump depth = 4 ft. [58]		Off-line system. May not be used in place of oil/grit separator or sand filter in areas with potential to generate high concentrations of oil and grease such as high-use parking lots, gas stations, and vehicle storage areas [59]
Forebay/pre-settling	Above ground and below grade storage and settling	10 acres minimum to wet pond, portion feeding into forebay depends on number of tributaries to pond [60]	~0.2 cfs/acre drained [61]	Volume > 10% of water quality volume, depth = 3-6 ft, surface area = 10% of pond permanent pool surface area or 0.1% of drainage area, Tear shaped (inlet at narrow end) w/ avg length to width ratio = 3:1, side slope = 3:1 or flatter [62]; [63]	Bottom of forebay hardened using concrete, asphalt, or grouted riprap [64]	On-line, at each inlet contributing greater than 10% of the total design storm inflow to pond [65]	Underlying soils should be hydrologic group C or D, liner may be needed for A or B group soils. [66]
Pretreatment vegetated filter strip (VFS)	Filtration	< a few acres, max flow path 75-150 ft depending on perviousness, slope of drainage area <5% [67]; [68]	<1 ft/s, flow should be sheet flow and unconcentrated [69]	VFS width (parallel to sheet flow) = 25-100 ft depending on vegetation, slope and drainage area soil [70]; [71]	Soil, grass [72]	Residential lawns, parking lots, part of riparian buffer [73]	Hydrologic Soil Groups A-D permitted, table for corresponding slopes [74]
Filtration	Level-Spreader - Vegetative Filter Strip System (LS-VFS)	< a few acres [75]	<=10cfs [76]	LS width (parallel to sheet flow) = 10-100 ft, VFS width >= 30-50 ft [77]	Concrete, soil, grass [78]	Distance from surface waters: LS and VFS must be outside riparian buffer, LS must be outside stormwater setbacks [79]	VFS max slope = 8% [80]
Up-Flo Filter	Filtration	0.66 acres impervious drainage area per filter module based on Nashville design storm [81]	0.056 cfs per filter module (max number of modules 6-54) [82]	Round manhole: 4 ft diameter, 7.5 ft high Rectangular vaults: 6 ft x 8 ft x 6.5 ft to 15 ft x 13 ft x 6.5 ft		Roads, carparks, commercial properties, airports, offline and online treatment of existing storm drains [83]
Storm Clean	Filtration		Filtration flow rates (nominal/max)= 40/80 gpm, Strainer flow rate >= 100 gpm [84]	Filtration surface area (fabric elements) = 6.4 sq ft, Strainer surface area = 4.8 sq ft [85]	Stainless steel [86]	Can be fit into existing catch basin, curb inlet, drop inlet, or downspout [87]
Gravel filtration	Filtration	Same as inlet gravel bags are placed around		Varies by need. For example, one version available comes in 11x48, 11x96, and 19x28 inch bags. [88]	Bags are high quality woven polymer material with high UV rating, gravel [89]	In front of or around existing catch basin inlets [90]
Filtration berm	Filtration		1 cfs per 8 linear ft [91]	Berm height = 12-18 inches high with 3:1 side slopes, every 100-300 feet depending on slope [92]	Washed, well-graded gravel/rock ¾ to 3 inches in size with <5% fines [93]	Right-of-ways, traffic areas, construction sites [94]	No restriction
SiltSoxx R by Filtrexx	Filtration	Varies by application	Varies by application	Available in 5 in to 32 in diameter depending on application, up to 200 ft in length [95]; [96]	Filtrexx Media in Filtrexx Mesh [97]	Existing inlets, site perimeters, paved surfaces, compacted soils, exposed slopes [98]	Compacted or susceptible to erosion
StormExx R by Filtrexx	Filtration	Same as catch basin	15-40 gpm [99]	15-gallon storage, fits any existing storm drain [100]	Stainless steel or HDPE, EnviroSoxx filtering media cartridge [101]	Existing inlet
SNOUT	Screening/Straining	Same as catch basin	Same as catch basin	Variety of sizes and shapes fit most rectangular and round manholes [102]		Existing manholes and sumped catch basins (sump depth must be >36 inches or 2.5 x outlet pipe diameter [103]
Eliminator	Screening/Straining	Same as catch basin	Up to 2 cfs if Elimo-Filter used [104]	8, 10, 12, 15, and 18-inch sizes	High Density Polyethylene	Existing manholes and sumped catch basins
Floatable boom	Buoyancy/Skimming			Float height = 2-8 inches, Skirt/curtain = 8-16 ft, Section length 25-100 ft [105]	Blocks of expanded polystyrene, PVC	Calm to medium current water bodies downstream of nearshore construction zones, dredging, demolition [106]
Hood	Buoyancy/Skimming	Same as catch basin