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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.
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