Above ground and below grade storage and settling tables combined Above ground and below grade storage and settling tables combined

Above ground and below grade storage and settling - pollutant removal information

Above ground and below grade storage and settling - pollutant removal information
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Device	Primary mechanism	Secondary mechanism	Other mechanism	Proprietray/nonproprietray	Above ground/below grade	Pollutants removed
Pretreatment row on underground storage/filtration	Settling	Screening/straining	Infiltration (for volume loss)	Nonproprietary	Below grade	Sediment, total suspended solids
StormTech Isolator Row (see adjacent figure) [1]	Settling	Screening/straining	Infiltration (for volume loss)	Proprietary	Below grade	Sediment, total suspended solids (>110 µm)
Prinsco HydroStor Sediment Row	Above ground and below grade storage and settling	Screening/straining	Infiltration (for volume loss)	Proprietary	Below grade	Sediment, total suspended solids (>110µm)
Settling chamber/vault	Settling			Nonproprietary	Below grade	Sediment
Oil/water/grit separators	Settling	Screening/straining		Nonproprietary	Below grade	Trash and debris, floatables, oil and grease, coarse sediment, total suspended solids when placed off-line [2]; [3]
Hydro Dry Screen	Settling	Screening/straining	Buoyancy/skimming	Proprietary	Below grade	Total suspended solids, oils, gross debris, nutrients [4]
Suntree Nutrient Separating Baffle Box (NSBB)	Settling	Screening/straining	Buoyancy/Skimming; Biodegradation; Filtration (SkimBoss option)	Proprietray	Below grade	Total suspended solids, nutrients, organics, trash, litter, oils and grease [5]
Manhole Baffle Box	Settling	Screening/straining		Nonproprietary	Below grade	Sediment, suspended solids, trash, floatables [6]
Environment 21 StormPro	Settling			Proprietary	Below grade	Suspended solids, hydrocarbons, trash, floatables [7]
BaySeparator by BaySaver	Settling	Buoyancy/skimming		Proprietray	Below grade	Sediment, floatables, oil
Sump Manhole with SAFL Baffle	Settling	Screening/straining		Proprietray	Below grade	Sands and large silt sediment, total suspended solids
Prinsco Preserver Dissipator	Settling	na	na	Proprietary	Below ground	Sediment consisting of course silts and larger, TSS
Deep sump catch basin	Settling	Buoyancy/skimming		Nonproprietary	Below grade	Sediment, debris, trash, oil
Forebay/pre-settling basin for wet pond	Settling			Nonproprietray	Aboveground	Sediment

Above ground and below grade storage and settling - system design information

Above ground and below grade storage and settling - system design information
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Device	Drainage area	Entrance/exit velocity	Dimensions	Materials	Layout Recommendations (physical location, off-line placement)	Soils
Pretreatment row on underground storage/filtration	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	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 [8]	Two layers of woven geotextile, StormTech chamber, non-woven fabric if model has perforated side walls, gravel [9]	In-line, after a manhole with a high flow weir. System is ideal under parking lots and roadways and areas with tight footprints [10]	Ideally highly infiltrative to achieve volume reduction [11]
Prinsco HydroStor Sediment Row	Varies widely, units may be placed in parallel and series to accommodate	Rate varies per HydroStor chamber model.	Max length of row = 175 ft, but multiple rows may be used. Dimensions vary per HydroStor chamber model.	Two layers of woven geotextile, HydroStor chamber, non-woven fabric if model has perforated side walls, gravel	In-line, after a manhole with a high flow weir. System is ideal under parking lots, roadways, and areas with tight footprints.	Ideally highly infiltrative to achieve volume reduction
Settling chamber/vault	Can be sized to accommodate drainage area of downstream BMP [12]	Exit velocity to surface media filters should be non-erosive [13]	Recommended length to width ratio of 2:1
Oil/water/grit separators	<1 acre impervious cover [14]	1-3 ft/min or less [15]	Total wet storage = 400 cf per acre of contributing imp area, depth of permanent pool >4 ft [16]	Reinforced concrete	Off-line, ideal in urban areas with small lots and for retrofits [17]	No soil or terrain restrictions [18]
Hydro Dry Screen		Max Flow: 29-162 cfs, Treatment Flow: 11-80 cfs , 80% TSS removal: 1.8-16 cfs [19]	Five models: 4x8 ft to 12x20 ft ([20])		New construction or redevelopment sites, retrofit of storm drain lines, shallow installations with high groundwater or bedrock, installations requiring low headloss [21]
Suntree Nutrient Seprating Baffle Box (NSBB)		Maximum Treatment Flow Rate: 2-45 cfs [22]	4 ft x 2 ft x 2.7 ft - 24 ft x 12 ft x 9 ft [23]		Online [24]
Manhole Baffle Box	1-100 acres [25]		Typically 10-15 ft long x 6-8 ft high x 2 ft wider than pipe [26]	Concrete, fiberglass [27]	In-line or at the end of storm pipes, ideal for retrofitting existing pipes [28]
Environment 21 StormPro		0.5-8.6 cfs. Max loading for all models = 10.8 gpm/sq ft [Environment 21 StormPro]; [29]	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 [30]; [31]	Baffle wall: precast concrete or other approved rigid materials, Bypass pipe: rigid plastic [32]
BaySeparator by BaySaver	1.2-8 acres impervious area [33]	Treats maximum of 22 cfs [34]	5 standard sizes: manhole diameter 48-120 inches, 6-8 ft deep [35]	Concrete, HDPE, polyethylene [36]
Sump Manhole with SAFL Baffle	<10 acres [37]	Horizontal flow must be at least 3x flow from above [38]	Can be installed in sump structures w/ diameters of 3-10 ft and depths >= 3 ft [39]	Stainless steel [40]	New or existing sump manhole [41]
Prinsco Preserver Dissipator	Total impervious of <15 acres	Horizontal flow must be at least 3x flow from above	3' min. structure diameter, no max. structure dimensions, min. sump depth is 1.5x outlet pipe dia.	Stainless steel & HDPE	Inline. New or existing sump manhole. All parts retrofittable through 24" opening.
Deep sump catch basin	<0.25 acre impervious area	< 3 cfs [42]	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. [43]		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 [44]
Forebay/pre-settling	10 acres minimum to wet pond, portion feeding into forebay depends on number of tributaries to pond [45]	~0.2 cfs/acre drained	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; [46]	Bottom of forebay hardened using concrete, asphalt, or grouted riprap [47]	On-line, at each inlet contributing greater than 10% of the total design storm inflow to pond [48]	Underlying soils should be hydrologic group C or D, liner may be needed for A or B group soils. [49]

Above ground and below grade storage and settling - system and component sizing

Above ground and below grade storage and settling - system and component sizing
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Device	Land use	Downstream BMP (type)	Enhancement opportunity	Sizing calculations	Inlets/oulets	Flow diversion structures
StormTech Isolator Row	Residential, Urban, Commercial	StormTech detention/ infiltration arc storage chambers [50]	Yes	Volume-based for sites with good infiltrative soils, or more commonly rate-based using a water quality flow <= 2.5 gpm/sq ft of bottom area using two layers of woven geotextile, see Table 2. See design tool from manufacturer (does not require registration). [51]		Manhole with overflow weir before pretreatment row
Prinsco HydroStor Sediment Row	Residential, Urban, Commercial	HydroStor detention/infiltration storage chambers	Yes	Volume-based for sites with good infiltrative soils, or more commonly rate-based using a water quality flow <=2.5 gpm/sq ft of bottom area using two layers of woven geotextile.		Manhole with overflow weir before pretreatment row
Settling chamber/vault	Urban, Construction, Agricultural [52]	Infiltration, Media Filtration [53]; [54]	No	Volume equivalent to at least 25% of water quality volume, surface area calculated from flow and particle settling velocity [55]		Overflow weir at end of chamber
Oil/water/grit separators	Ultra-high density, Industrial, Commercial [56]		Yes	Size device to pass 2-year 24-hour storm without interference and then provide bypass for larger storms [57]	8-inch diameter minimum [58]	Inlet chamber (sediment trapping), oil separation/storage chamber, inverted elbow pipe to bypass chamber [59]; [60]
Hydro Dry Screen	Residential, Commercial		Yes	Rate-based, 80% TSS removal based on 25 gpm/sq ft settling area, treatment flow rate based on 150 gpm/sq ft settling area. Download the manufacturer’s sizing tool here (requires registration)	Max pipe diameter = 30-60 in [61]	Vertical screen weir [62]
Suntree Nutrient Separating Baffle Box (NSBB)		Rainwater harvesting, Wet or dry detention [63]	Yes	Q = ciA (runoff coeff. * intensity * area), then see Table 1 (NJCAT) [64]	See tables for inlet and outlet placement depending on manhole and pipe diameters	Three chambers/stages [65]
Manhole Baffle Box			Yes		Precast boxes: can be used for pipes up to 48 in diameter, up to 60 in if cast in place [66]	Weir height = 3 ft, set at same level as pipe invert [67]
Environment 21 StormPro			No	Rate-based sizing	Model V510: inlet/outlet diameter = 15 in diameter [68]	Baffle wall, bypass pipe [69]
BaySeparator by BaySaver			Yes	Rate-based sizing		Surface skimming weir, flow to and from offline manhole storage [70]
Sump Manhole with SAFL Baffle	Residential, Commercial		Yes	Sizing with SHSAM [71]	Top of SAFL baffle roughly 2-6 in above top of inlet, Sump depth below outlet >= 3 ft, bottom of SAFL baffle at 1 ft below invert of outlet . Max inlet diameter: 15-54 inches	Baffle wall [72]; [73]
Prinsco Preserver Dissipator	Urban	Any	Yes. All parts retrofittable through 24" opening.	Sized with spreadsheet calculator or flow tables	Inlet(s) and outlet should be similar in elevation. Components should be centered on associated pipe, horizontally & vertically. Max. pipe size of 48".	na
Deep sump catch basin	Residential, Office, Retail [74]		No	Rate-based sizing, flow not to exceed capacity of inlet grate [75]	Outlet below water surface level to allow floatables to remain on top. Inlet 4 ft above water surface level.	Hooded outlet to prevent floatable materials and trash from entering storm drain system, weep hole above outlet pipe [76]; [77]
Forebay/pre-settling basin		Wet Pond, Storm Water Treatment Wetland	No	V with 1-2 ac imp area = 0.01* WQV; Max depth = 12 in; V with 2-5 ac imp area = 0.02 * WQV; Max depth = 18 in; V with 5-10 ac imp area = 0.03 * WQV; Max depth = 18 in; V with >10 ac imp area = 0.03 * WQV; Max depth = 24-30 in [78]	Size outlet based on avg release rate and average head (elev. diff. between permanent pool water surface elev. and water quality volume elev.), non-erosive conditions. [79] Rip rap channel, pipe outlet or concrete channel with a notch outlet can be constructed between forebay and downstream practice [80]	Anticipate overflow of forebay basin. Adequate protection of downstream structure or berm is necessary along with appropriate erosion control measures. If piped flows are used in the design, minimum recommended pipe diameter is 8 in, and recommended only for larger catchments.

Above ground and below grade storage and settling - installation and maintenance recommendations

Above ground and below grade storage and settling - 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 erosion	Cost considerations (equipment needed and man hours)
Pretreatment row on underground storage/filtration	no data	At least every 6 months for first year of operation, then varies by location			Periodically remove sediment by back-flushing water and vacuuming manhole sump [81]		Vacuum truck
StormTech Isolator Row	Installation instructions available here.	At least every 6 months for first year of operation, then varies by location [82]	Step by step maintenance procedures		Clean-out when average depth of sediment exceeds 3 inches [83]		Vacuum/JetVac combination vehicle [84]
Prinsco HydroStor Sediment Row		More frequent during first year of operation, then varies by location			Clean-out when average depth of sediment ranges from 1-3 inches		Vacuum/JetVac combination vehicle
Settling chamber/vault					Remove sediment once depth reaches 6 inches or more [85]
Oil/water/grit separators		After every major storm but at least once per month [86]			Clean out at least twice per year [87]
Hydro Dry Screen		Every 3-6 months during first year, then site specific [88]	Maintenance and inspection checklist [89]		Remove sediment once depth exceeds maximum clean-out depth [90]		Vacuum truck
Suntree Nutrient Separating Baffle Box (NSBB)		After each runoff event initially, then at least quarterly. Local and State regulation may require every 90 days [91]	Inspection and maintenance checklist; [92]		Vacuum out sediment chambers when sediment accumulation exceeds 50% storage volume [93]		Vacuum truck
Manhole Baffle Box		Frequently for first two years following installation, then site specific [94]			Fully cleaned at least once per year [95]		Vacuum truck; One half day; Average cost $450 [96]
Environment 21 StormPro		At least quarterly until a more accurate schedule can be determined [97]	Maintenance data sheet		Sediment should be removed when sediment depth in first chamber is 50% of design sediment storage depth or at least once per year [98]		Truck-mounted sewer and catch basin cleaner with vacuum pump [99]
BaySeparator by BaySaver		At least every 6 months initially, then site specific [100]	Maintenance instructions		Cleaning recommended every 12-36 months or when 2 feet of sediment have accumulated [101]		Vacuum truck [102]
Sump Manhole with SAFL Baffle	45 minute installation [103]	Three times per year for first two years			Sediment removed before it reaches the bottom of the SAFL baffle		Vacuum truck [104]
Prinsco Preserver Dissipator	15 minute installation.	Spring and fall inspections recommended. More frequent inspections are recommended following installation until a routine maintenance frequency is be determined.	[105]	Yes	Sediment removed when average depth reaches 1x pipe dia. below the outlet.	na	Vacuum truck
Deep sump catch basin		Four times per year and at the end of foliage and snow- removal seasons [106]			Four times per year or when deposit depth is greater than ½ depth from bottom of invert to lowest pipe [107]	Hood required	Vacuum truck or clamshell bucket [108]
Forebay/pre-settling basin	Hard floor (concrete or grouted stone) allows definition of bottom and ease of maintenance. Provide appropriate stabilized maintenance access for heavier equipment at no more than 2% cross slope and no more than 10% longitudinal slope	Monthly [109]			Four times per year or when sediment depth is >3 ft. A hard bottom such as concrete facilitates removal, during design ensure forebay is vehicle accessible [110]; [111]	Forebay should be designed to withstand 2-yr and 10-yr velocities without scouring [112]	Vacuum truck skid-loader, or backhoe