Filtration - pollutant removal information
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Device | Primary mechanism | Secondary mechanism | Other mechanism | Proprietray/nonproprietray | Above ground/below grade | Pollutants removed |
---|---|---|---|---|---|---|
Pretreatment vegetated filter strip (VFS) | Filtration | Screening/Straining | Settling | Nonproprietary | Above Ground | Sediment, organic matter, trace metals, nutrients, pesticides |
Level-Spreader - Vegetative Filter Strip System (LS-VFS) | Filtration | Screening/Straining | Settling | Nonproprietary | Above Ground | Sediment, organic matter, trace metals, nutrients, pesticides [1] |
Up-Flo Filter by Hydro International | Filtration | Settling | Screening/Straining | Proprietary | Underground | Sediment, heavy metals, oil, nutrients, floatables, trash [2] |
Storm Clean R catch basin filtration insert by CleanWay | Filtration | Screening/Straining | Proprietary | Underground | Trash and debris, sediment and total suspended solids, and oil (hydrocarbons and heavy metals depending on filter element options - Vermiculite media and MetalZorb media respectively) [3] | |
The StormBasin TM | Filtration | Proprietary | Underground | Sediment, trash, vegetation, nutrients, bacteria, oil, metals [4] | ||
Gravel filtration (e.g.,Filter socks, Rock Sox, gravel bags, gravel filter booms, etc.) | Filtration | Screening/Straining | Proprietary and Nonproprietary | Above Ground | Sediment, trash, organic matter | |
Filtration berm | Filtration | Nonproprietary | Above Ground | Sediment, trash, nutrients | ||
SiltSoxx R by Filtrexx | Filtration | Screening/Straining | Proprietary | Above Ground | Sediment, hydrocarbons, nutrients [5] | |
StormExx R by Filtrexx | Filtration | Screening/Straining | Proprietary | Underground | Sediment, bacteria, heavy metals, hydrocarbons, nutrients |
Filtration - system design information
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Device | Drainage area | Entrance/exit velocity | Drain down/detention time | Dimensions | Materials | Layout Recommendations (physical location, off-line placement) | Soils |
---|---|---|---|---|---|---|---|
Pretreatment vegetated filter strip (VFS) | < a few acres, max flow path 75-150 ft depending on perviousness, slope of drainage area <5% [6]; [7] | <1 ft/s, flow should be sheet flow and unconcentrated [8] | Maximum 72 hours [9] | VFS width (parallel to sheet flow) = 25-100 ft depending on vegetation, slope and drainage area soil [10]; [11] | Soil, grass [12] | Residential lawns, parking lots, part of riparian buffer [13] | Hydrologic Soil Groups A-D permitted, table for corresponding slopes [14] |
Level-Spreader - Vegetative Filter Strip System (LS-VFS) | < a few acres [15] | <=10cfs [16] | Maximum 72 hours [17] | LS width (parallel to sheet flow) = 10-100 ft, VFS width >= 30-50 ft [18] | Concrete, soil, grass [19] | Distance from surface waters: LS and VFS must be outside riparian buffer, LS must be outside stormwater setbacks [20] | VFS max slope = 8% [21] |
Up-Flo Filter | 0.66 acres impervious drainage area per filter module based on Nashville design storm [22] | 0.056 cfs per filter module (max number of modules 6-54) [23] | 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 [24] | |||
Storm Clean | Filtration flow rates (nominal/max)= 40/80 gpm, Strainer flow rate >= 100 gpm [25] | Filtration surface area (fabric elements) = 6.4 sq ft, Strainer surface area = 4.8 sq ft [26] | Stainless steel [27] | Can be fit into existing catch basin, curb inlet, drop inlet, or downspout [28] | |||
Gravel 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. [29] | Bags are high quality woven polymer material with high UV rating, gravel [30] | In front of or around existing catch basin inlets [31] | |||
Filtration berm | 1 cfs per 8 linear ft [32] | Berm height = 12-18 inches high with 3:1 side slopes, every 100-300 feet depending on slope [33] | Washed, well-graded gravel/rock ¾ to 3 inches in size with <5% fines [34] | Right-of-ways, traffic areas, construction sites [35] | No restriction | ||
SiltSoxx R by Filtrexx | Varies by application | Varies by application | Available in 5 in to 32 in diameter depending on application, up to 200 ft in length [36]; [37] | Filtrexx Media in Filtrexx Mesh [38] | Existing inlets, site perimeters, paved surfaces, compacted soils, exposed slopes [39] | Compacted or susceptible to erosion | |
StormExx R by Filtrexx | Same as catch basin | 15-40 gpm [40] | 15-gallon storage, fits any existing storm drain [41] | Stainless steel or HDPE, EnviroSoxx filtering media cartridge [42] | Existing inlet |
Filtration - system and component sizing
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Device | Land use | Downstream BMP (type) | Enhancement opportunity | Sizing calculations | Inlets/oulets | Flow diversion structures | Slopes |
---|---|---|---|---|---|---|---|
Pretreatment vegetated filter strip (VFS) | Often not suitable for in ultra-urban settings where space is limited or areas with high pollutant loading [43] | Infiltration, Retention [44] | No | Depends on slope and imperviousness of drainage area: See MPCA table entitled “Guidelines for filter strip pre-treatment sizing” | Outflow 2-3 inches above filter strip [45] | May include pervious berm or check dam, which should have an outlet pipe or overflow weir [46] | 2-6% depending on soil, 0% perpendicular to flow [47] |
Level-Spreader - Vegetative Filter Strip System (LS-VFS) | Often not suitable for in ultra-urban settings where space is limited or areas with high pollutant loading [48] | Infiltration, Retention [49] | No | LS length: 10 ft/cfs, VFS sized for a 1 in/hr storm (larger flows bypassed) | Outflow 2-3 inches above filter strip [50] | May include flow bypass, forebay and/or blind swale, and underdrain [51] | Depth at inlet = 3 ft, depth before outlet = 1 ft |
Up-Flo Filter | Suited to industrial sites, locations contributing to wetlands/protected regions or area requiring high level of treatment [52] | Yes | See manufacturer’s sizing tool (requires registration) | Can accept 15 in or 24 in pipes [53] | Bypass siphon, sump, filter module, outlet module [54] | ||
Storm Clean | Underground Injection Controls (UIC), swales, detention/ retention ponds, infiltration trenches [55] | Yes | Sized to rectangular or round catch basin, adaptive design available for larger catch basins [56]; [57]; [58] | Bypass port, strainer, filter element [59] | |||
Gravel filtration | Areas with high erosion concern such as construction sites. | No | Each gravel bag can be adjusted to meet specific flow, sediment, or filtration requirements. [60] | ||||
Filtration berm | Residential, Commercial, Industrial, Retrofit, Highway/Road, limited Ultra-Urban [61] | No | 8 linear feet per 1 cfs based on 10-yr, 24-hr design storm [62] | Size outlets for 24-hour drawdown time [63] | Suitable for most steep surface slopes [64] | ||
SiltSoxx R by Filtrexx | Construction, Residential, Commercial | No restriction | Yes | Flow-based, see time to overflow at different flow rates (1-7.5 gpm/linear ft) for each size in Table 1 | Slope up to 1:1 grade [65] | ||
StormExx | No restriction | Yes | One-size fits all with modification supports [66] | Treated water outlet from cartridge = 2 in diameter | Bypass structure |
Filtration - installation and maintenance recommendations
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Device | Installation notes | Frequency of inspections | Maintenance checklist (link) | Permitted on private land/ Maintenance agreement recommended | Practices for minimizing sediment and trash buildup | Practices for minimizing washout | Cost considerations (equipment needed and man hours) |
---|---|---|---|---|---|---|---|
Pretreatment vegetated filter strip (VFS | Construction sequence | Quarterly and after every 1 in storm event for first two years, then biannually [67] | Sediment removed at least biannually of when buildup exceeds 2 inches in depth [68] | Appropriate vegetation and landscaping maintenance; See Appendix [69] | Generally $100-$1400 per acre [70] | ||
Level-Spreader - Vegetative Filter Strip System (LS-VFS) | Construction notes | Quarterly and after every 1 in storm event for first two years, then biannually [71] | Sediment removed at least biannually of when buildup exceeds 2 inches in depth [72] | Appropriate vegetation and landscaping maintenance; See Appendix [73] | Generally $100-$1400 per acre [74] | ||
Up-Flo Filter | Every 6 months for first year of operation, then site specific. Floatables, sediment, media, and drain down filter each need to be inspected [75] | Inspection and maintenance checklist | Sediment removal at least once per year or once sediment depth is 16 inches [76] | Routine maintenance for manhole unit takes about 1 hour [77] | |||
Storm Clean | One-person installation [78] | Monthly [79] | Maintenance instructions | When visual inspection or water sampling show degradation. MetalZorb is non-hazardous and does not require special waste handling [80] | Vactor truck or large shop vac; One person [81] | ||
Gravel filtration | After each rainfall | Remove sediment from behind bag as needed | |||||
Filtration berm | Construction sequence | After each rainfall [82] | Maintenance considerations | Routinely remove accumulated trash and debris [83] | Appropriate vegetation and landscaping maintenance (eg. mowing and level gradient restoration); See Appendix [84] | Depends on height, length, width, and location of berm [85] | |
SiltSoxx R by Filtrexx | Installation instructions | Within 24 hours after rainfall event [86] | Maintenance instructions | Sediment removal from upslope side when accumulation has reached ½ the effective height of the Soxx [87] | |||
StormExx | Installation notes | Every 90 days, frequent drive through inspection during leaf-fall and after storm events [88] | Costs for one year of service and maintenance may be added to proposal [89] | Quarterly general service, fall cleaning and cartridge replacement [90] |
This page was last edited on 13 April 2020, at 18:00.
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