STORMWATER FILTRATION SYSTEMS AND RELATED METHODS
A stormwater filtration system includes a chamber structure with a treatment cell open at the top to atmosphere and a surrounding wall. A filter structure in the treatment cell includes an outer wall spaced from the surrounding wall of the treatment cell to provide a water collection and settling space between the two. The filter structure includes a media bed therewithin and a top portion exposed to atmosphere and defining a planting area. Live vegetative matter within the planting area includes a root system that extends down into the media bed of the filter structure for interaction with water passing through the media bed. An inlet to the treatment cell receives stormwater, which first enters the collection and settling space, then laterally enters the filter structure for passing through the media bed and in contact with the root structure, before exiting the filter structure.
This application claims the benefit of U.S. Provisional Application Ser. Nos. 61/586,497, filed Jan. 13, 2012; 61/599,654, filed Feb. 16, 2012 and 61/691,650, filed Aug. 21, 2012, the contents of each of which are incorporated herein by reference.
TECHNICAL FIELDThis application relates generally to stormwater filtration systems and, more particularly, to systems incorporating live plant material into the filtration process.
BACKGROUNDStormwater can be a form of diffuse or non-point source pollution. It can entrain pollutants, such as trash, sediment, organic matter, heavy metals, and organic toxins, and flush them into receiving water bodies. As a consequence, natural bodies of water that receive stormwater may also receive pollutants. As used herein, the term stormwater refers to water produced as a result of a rain event, regardless of the source of collection (e.g., such as runoff from parking lots or other paved surfaces or water collected from rooftop gutter (or other collection and drainage) systems).
In an effort to address the environmental problems posed by polluted stormwater, traps and filters for stormwater have been developed.
Stormwater filtration cartridges, such as those described in U.S. Pat. Nos. 5,707,527, 6,027,639, 6,649,048, and 7,214,311, pull stormwater through a filtration bed that removes pollutants prior to discharge into a receiving water body. Improvements to such cartridges have produced highly effective filters that allow for significant throughput, as described in the references cited above, while also allowing for easy installation and replacement of the modular cartridge units.
Another known method of stormwater filtration involves the installation of horizontally-disposed filtration beds using a mixture of materials often including organic compost. Stormwater runoff directed into these beds is filtered in an action not unlike natural soil. Live plant material is sometimes added to take advantage of its pollutant uptake as well as for aesthetic value. However, such beds are generally permanent, and are not readily configured for replacement or cleaning of the bed. Moreover, installation of such beds requires significant on-site effort to achieve proper configuration of the bed, which often utilizes multiple layers. Scouring also tends to be an issue in such systems.
It would be desirable to develop a live plant matter filtration system that is simpler to install and is more readily adapted for cleaning or replacement. It would also be desirable to develop a live plant matter filtration system in which a more controlled flow through the filtration media is achieved.
SUMMARYIn one aspect, a stormwater filtration system includes a chamber structure with an upper treatment cell and a lower infiltration cell divided by a lateral wall structure, the upper treatment cell including a surrounding wall extending upward from the lateral wall structure, the upper treatment cell being open at the top to atmosphere. A filter structure is positioned in the treatment cell and supported by the lateral wall structure, where the filter structure includes an outer wall spaced from the surrounding wall of the treatment cell to provide a water collection and settling space between the filter structure and the surrounding wall of the treatment cell, and the filter structure includes a media bed therewithin, with a top portion of the media bed exposed to atmosphere and defining a planting area. Live vegetative matter planted within the planting area includes a root system that extends down into the media bed of the filter structure for interaction with water passing through the media bed. An inlet to the treatment cell receives stormwater, which first enters the collection and settling space, then laterally enters the filter structure for passing through the media bed and in contact with the root structure, before exiting the filter structure by passing down into the infiltration cell for subsequent infiltration into the surrounding earth.
The filter structure may include an internal collection space surrounded by the media bed, an outlet opening at the bottom of the internal collection space for delivering water down to the infiltration cell, and an outlet drain tube that extends down into the infiltration cell.
The filter structure may include an internal collection space surrounded by the media bed, an outlet opening at the bottom of the internal collection space for delivering water down to the infiltration cell, and an upper end of the internal collection space is exposed to ambient environment and having an associated one way air release valve for delivering air out of the internal collection space.
The treatment cell may include an overflow pipe for delivering excess flows that enter the collection and settling space into the infiltration cell without such excess flows traveling through the filter structure and before such excess flows cause water level in the collection and settling space to exceed a top of the media bed.
In another aspect, a stormwater filtration system includes a chamber structure with a treatment cell open at the top to atmosphere, the treatment cell having a surrounding wall. A filter structure is positioned in the treatment cell and includes an outer wall spaced from the surrounding wall of the treatment cell to provide a water collection and settling space between the filter structure and the surrounding wall of the treatment cell. The filter structure includes a media bed therewithin and a top portion of the media bed exposed to atmosphere. An inlet to the treatment cell receives stormwater, which first enters the collection and settling space, then laterally enters the filter structure for passing through the media bed before exiting the filter structure. The media bed may define a planting area, with live vegetative matter planted within the planting area and including a root system that extends down into the media bed of the filter structure for interaction with water passing through the media bed.
The filtration system may include a pipe arrangement for delivering water from the treatment cell to at least one infiltration chamber.
The chamber structure may be formed by a vertically oriented pipe structure. The pipe structure may be one of a plastic pipe, a corrugated metal pipe or a steel reinforced polyethylene pipe. The chamber structure may also be a concrete manhole structure.
The treatment cell may deliver treated water directly into the surrounding earthen material.
The chamber structure may include a bottom wall with an outlet pipe incorporated therein, and the filter structure may include an internal collection space surrounded by the media bed, and an outlet opening at the bottom of the internal collection space and connected for delivering water out of the filter structure and into the outlet pipe. The outlet pipe may extend horizontally within the bottom wall for delivering water away from the chamber structure.
The collection and settling space may include an overflow outlet for delivering excess flows that enter the collection and settling space out of the treatment cell without such excess flows traveling through the filter structure and before such excess flows cause water level in the collection and settling space to exceed a top of the media bed.
The filter structure may include an internal collection space surrounded by the media bed, an outlet opening at the bottom of the internal collection space for delivering water out of the treatment cell, and an upper end of the internal collection space exposed to ambient environment and having an associated one way air release valve for delivering air out of the internal collection space.
The filter structure may include multiple spaced apart internal collection spaces within the media bed, each internal collection spaced having an outlet opening toward the bottom of the internal collection space and connected for delivering water out of the filter structure.
The filter structure may include an internal collection space for receiving stormwater that flows through the media bed, the internal collection space defined by a permeable wall within the media bed. The chamber structure is positioned in proximity to a curb, and the inlet to the treatment cell is connected to a curb inlet pathway. The curb inlet pathway may include both a lateral opening through the curb and an upper opening covered by a grate-type structure.
The filter structure may include an internal collection space for receiving stormwater that flows through the media bed, the internal collection space defined by a permeable wall within the media bed, with a top of the internal collection space and permeable wall are covered by media of the planting area.
Fig. illustrates an embodiment shown live plant matter in the media bed;
A runoff reduction planter system is provided and operates as a treatment and on-site infiltration product designed to match the runoff reduction goals of new stormwater regulations while working within the typical constraints of modern site design. The system offers a high treatment capacity, attractive vegetated footprint, extended maintenance life and modular design.
As seen in the embodiment shown in
Again referring to
Notably, the top of the filter basket is open to expose the media and provide a planting area 36 for vegetative matter (e.g., small trees, shrubs and grasses). The planting area 36 is accessible at ground surface level through a central opening in tree ring type structure 38. Vegetative matter planted in area 36 will offer root growth downward into the annular media space 24 such that the roots can take up pollutants etc. captured in or passing through the media.
In operation, water enters the curb inlet (or other inlet) and begins to fill an annular collection and settling space 40 between the basket and the inside wall of the treatment cell. The water travels laterally into the filter basket through wire screen wall 20 and then passes radially through the media space 24 and is filtered by the media and/or root system before passing into the internal collection space 26. The treated water then flows downward into the infiltration space or cell 14 for infiltration into the surrounding earth. In this regard, the chamber structure may include numerous openings 42 of any suitable size and shape to allow radial outward infiltration and/or may sit atop of a bed of gravel or stone 43 to allow infiltration out of the bottom of the cell 14.
While the illustrated embodiment shows the entire vertical height of the chamber/vault sidewalls buried, it is recognized that in some installations some or all of the vertical height (particularly of the treatment cell) could be above ground level, such as when the unit is positioned to receive water from a downspout, downhill from a parking lot or from a pumped source. Although the system may be implemented without plants per
Notably, the filter basket may be configured to facilitate removal and replacement with another basket if necessary. In a preferred implementation, (i) the dimensions of the basket may range from between about 3 and 5 feet in diameter and about 3 to 5 feet tall, resulting in a significant treatment surface area of about 28 to 79 square feet and treatment capacity of between about 28 and 158 gallons-per-minute (gpm), (ii) the volume of the treatment cell (including space occupied by the basket) may be in the range of between about 392 cubic feet and 679 cubic feet, and (iii) the volume of the infiltration cell may be in the range of between about 0 to 250 cubic feet, with a desired infiltration surface area of 9200 square feet. However, it is recognized that in some cases the infiltration could be directly from the treatment cell into the ground, without making use of the infiltration cell. Likewise, piped outlets from the treatment cell are possible as explained in further detail below.
The embodiment of
Although the embodiment of
Also shown in
Typically, the filter basket may be assembled within the treatment cell, off-site of final installation, and then transported to the installation site within the treatment cell. This methodology protects the basket during transport and facilitates the use of the treatment cell structure for the purpose of transport. Where the treatment cell and infiltration cell are both used, they may be transported in sections and stacked and sealed on-site at the time of installation.
Although the embodiments described above contemplate a single filter basket of generally right circular cylinder shape being located in the treatment cell, variations are possible. For example,
Regardless of the exact shape or number of filter basket structures used, the internal valve system within each filter basket may be configured to provide controlled and desired flow rate through the filter media. Specifically, the hydraulics of the media/center tube arrangement are configured such that a minimum trickle flow rate be maintained over most of the head range to allow for full head levels within the center collection space. This head level is used to achieve the maximum flow rate goal and further to establish standing water column suction thru the media. A variable control feature may be used to minimize differential head. Important to the variable function of the valve at the higher flow rates is that the valve/float arrangement should vary outlet flow area gradually with center tube head to avoid on/off short cycling behavior.
The projected area of the valve obstruction is most influential on these drag forces, with the range of forces from several to 25 or more pounds depending on the size and shape of the valve body. Additional complications to the behavior of the inline obstruction concept relates again to these dynamic forces and how they vary with valve position when filling vs. draining further contributing to short cycle valve actuation.
As an alternative to the obstruction or plunger type valve, a vertically aligned concentric tube valve might be used. This design has been shown to reduce significantly the projected area and shape effect forces, parallel plate vs. sphere obstruction, but can be vulnerable to particulate jamming when designed for sufficiently low (trickle) flow rates.
In the preferred embodiment, variable valve performance with control of gravitational hydraulic forces within the wide range of flow rate is desired. The valve, with limited available stroke length due to geometries of the system, should operate to effect significant changes in flow area, with the obstruction remaining in the high velocity zone to provide as long of a variable range as possible. Although when remaining in this high flow zone the drag force differential between actuating levels is less, the rapid rate of change of flow area results in similarly dramatic force dynamics and on/off cycling response.
In theory, the velocity at a given head level should remain relatively constant as indicated by the equations below:
V=Q/Af=Co(2gh)1/2 (1)
FD=cdeAp(V2/2gc) (2)
FB=egVF−W (3)
However, in this case the changing geometry of the orifice and dramatic changes in volumetric flow contribute to the dynamic behavior. Equation 1 is a simplified Bernoulli's equation for discharge from a tank and relates the flow velocity to hydraulic head and orifice geometry. Equation 2 is a derived relationship for the form or pressure downward drag force on an object in a fluid stream and shows the influence of projected area, flow velocity, and the shape drag coefficient. Equation 3 defines the relationship for net buoyancy lift of the valve, float buoyancy less weight of the actuating assembly.
The above coefficients Co and Cd vary widely for size, shape, and fluid pressure distributions for both before and after the orifice and surrounding the surface of the object in the flow stream. Valve behavior has been observed to tend along these relationships with force balance changing with actuation cycle of the valve.
Exemplary valve configurations are shown in
In the desired implementation, water enters the basket collection space and a small trickle leaves the collection space downward and enters the infiltration cell. As the collection space begins to fill with water air is purged through the one-way valve at the top of the space (or in embodiments such as
Referring now to FIGS. 9 and 10A-10C, a valve embodiment that reduces dynamic drag and is therefore more practical to implement on a commercial basis is shown. The valve includes an outer tube 80 and an inner tube 82 sized to be inserted within tube 80. Although the tubes are shown as being right circular cylinder in configuration, other tubular shapes may be used, such as oval cylinders or triangular, rectangular or other multi-sided cylinders. The inner tube is connected to a shaft 84 via coupler 85 and the shaft extends upward to a float 86. The inner tube includes one or more slotted openings 88 through its sidewall, which opening(s) may be shaped and/or positioned such that flow area through the sidewall of tube 82 increases when moving from the apex of the opening 88 downward along the height of the tube 82. In the illustrated embodiment the slot 88 has a weir-type shape such that the flow area through the sidewall of tube 82 increases progressively (i.e., the first inch of reveal of the slot may result in a flow area of X m2, the second inch of reveal of the slot may result in an additional flow area of 1.5X m2 or 2X m2 and the third inch of reveal of the slot may result in additional flow are of 2X m2 or 3X m2 (i.e., total flow area in the first two inches of 2.5X m2 or 3X m2 and total flow area in the first three inches of reveal of 4.5X m2 or 6X m2). However, other embodiments are contemplated. For example, the sidewall opening may be rectangular in which case the flow area will increase linearly as the water level in the collection space rises.
When the tube 82 is in a lowered position within tube 80 (per
A trickle opening 90 may also be provided as shown to allow a small flow even when the valve is in the closed position of
In an alternative arrangement, the stationary outer tube 80 may include the sidewall opening slot and movement of the inner tube 82 upward and downward may respectively reveal and close the flow area of the opening. Moreover, in such an arrangement where the opening is in the outer tube, the inner tubular member could be merely an arcuate panel that aligns with the sidewall opening of the outer tube, with the top of the outer tube closed and the connection structure 84 slidingly extending upward through the top of closed upper end of the outer tube.
It is recognized that the variable flow control valving described above can also be incorporated into more traditional stormwater filter cartridges, such as those shown in U.S. Pat. No. 5,707,527 or 7,214,311 (copies attached—where the variable flow valve structure would replace the valve structure described in such patents), or other commercially available stormwater filtration cartridges, as well as other stormwater filtration systems where there is a similar desire to variably control flow through a bed of filtration media, regardless of bed orientation.
The float valve utilized in the filter basket structure described herein could also incorporate an air passage 92 (see
Variations and modifications of the runoff reduction planter system are possible. For example, embodiments in which no infiltration cell is provided are contemplated, such as an embodiment in which the outlet(s) from the treatment cell feed directly into a permeable gravel space below the treatment cell. In the embodiment of
Referring again to
Referring to
Referring to
Referring now to
Referring again to
The water level that initially causes upward movement of the float and tube may be considered a threshold water level of valve operation. Once the float and tube begin to move upward, the sidewall openings 322 of the tube will begin to be exposed, with more and more flow area of the sidewall openings being revealed as the float and tube move further and further upward. Thus, more and more flow out of the collection space 306 is permitted as the tube and float move further and further upward. Likewise, as flow into the filter structure decreases below the full flow limit, the water level in the collection space moves further and further downward from the fully raised position, and the flow area of the sidewall outlets is increasingly covered to permit less and less flow through the outlet openings and thus decreasing flow through the media bed. In this manner, the valve assembly is able to provide a variable outflow that seeks to closely match the incoming flow.
Notably, the tube 316 is open at the top to provide a fluid passage downward through the full length of the tube. Thus, as the water level in the collection space 306 rises, displaced air can enter the top opening and move downward through the tube and out of the filter structure to prevent creation of an air lock condition. Water is also pulled upward into the cap, displacing air, and allowing the float to rise within the cap. This feature is particularly useful in embodiment in which the top of the collection space is covered by the upper portion of the media bed (e.g., as per the
A further feature that enhances performance of the valve assembly is the provision of vertically and laterally extending recessed grooves 330 in the outer surface of the tubular member 316 in the region below the openings 322. These grooves create a small external pathways through which water can travel once the openings 322 have been exposed, and the flow through such pathways tends to cause the tubular member and float to rotate during outflow conditions, reducing the likelihood that the tubular member will seize up due to frictional forces or the presence of and dirt or media. Thus, a system in which the valve assembly is caused to rotate during outflow has been found to enhance reliability of the valve assembly.
The subject valve assembly can be used in other media bed control applications (e.g., without locating the valve internally of the bed), including horizontal radial flow media beds and vertical flow media beds. The valve could also be used to control other stormwater flows based upon water level, regardless of whether the flow travels through a media bed at all.
While the foregoing embodiments are primarily described as systems in which the chamber structure is buried, it is recognized that variations in which the chamber structure is not buried are possible. For example, the filter basket could sit in a manhole with a perforated base so that and water just flows down through the media through the base. The perforated portion of the base may always be set to a minimum distance from the peripheral edge of the basket.
Thus, included within the above description are the following concepts.
A wetland biofilter chamber comprising: one or more outer side walls and a floor section (e.g., wall of cell 12 and floor 70) defining a substantially enclosed chamber (e.g. the treatment cell) with the top open to the air (e.g., through tree ring 38); a media filtration bed (e.g., annular bed between 20 and 22) disposed within the chamber and defined by one or more permeable inner side walls (e.g., screen 20), wherein the permeable inner side walls of the media filtration bed are separated from the outer side walls of the chamber (e.g., screen 20 spaced from wall 12) and define a catch basin for receiving an influent (e.g., annular space between screen 20 and wall 12 is where incoming water initially collects); a collection tube (e.g., 26 defined by screen 22) disposed within the media filtration bed and extending vertically from a top portion of the media filtration bed to a lower portion of the media filtration bed (e.g., space 26 in
The wetland biofilter chamber of ¶0079, wherein the outer side walls and floor section are impermeable (e.g., concrete walls or plastic walls so that water can collect and move through the filtration bed before passing to the infiltration cell).
The wetland biofilter chamber of ¶0079, wherein the one or more outer side walls include an intake opening (e.g., via curb inlet 32) to receive an influent into the catch basin.
The wetland biofilter chamber of ¶0079, wherein the collection tube is permeable (e.g., screen 22 is permeable).
The wetland biofilter chamber of ¶0079, wherein the permeable collection tube is perforated (e.g., screen 22 is perforated).
The wetland biofilter chamber of ¶0079, wherein the height of the collection tube is approximately the full height of the media filtration bed (e.g., per
The wetland biofilter chamber of ¶0079, wherein the collection tube further comprises a restriction plate which restricts the flow of filtered influent to the outlet tube (e.g. the orifice restrictor disc engaged by the float valve and mentioned in ¶0048).
The wetland biofilter chamber of ¶0085, wherein the restriction plate is connected with a flotation valve disposed within the collection tube which controls the restriction plate based on a level of influent in the collection tube (e.g. the orifice restrictor disc engaged by the float valve and mentioned in ¶0048).
The wetland biofilter chamber of ¶0079, wherein the catch basin has a width suited for a basket size of between 3 and 5 feet (e.g., 3.5 to 6 feet or more).
The wetland biofilter chamber of ¶0079, wherein the height of the inner side walls is approximately 100% of the height of the chamber walls (e.g., screen 20 shown the same height as the treatment cell, but could be shorter).
The wetland biofilter chamber of ¶0079, wherein the thickness of the media filtration bed is suited for a basket size of between 3 and 5 feet in diameter (e.g, between 2.75 feet and 4.75 feet in radial thickness).
A method of filtering influent in a biofilter chamber, comprising: receiving an influent into a catch basin of the biofilter chamber with one or more outer side walls and a floor section defining a substantially enclosed chamber with the top open to the air, wherein the catch basin is disposed around an inner periphery of the chamber between one or more outer side walls of the chamber and one or more inner permeable inner side walls of a media filtration bed (e.g. initial water inflow to space between screen 20 and walls of treatment cell 12 and above floor 70); filtering the influent through the media filtration bed (e.g., water passes through media space 24); collecting the filtered influent from the media filtration bed at a collection tube extending vertically within the media filtration bed from a top portion of the media filtration bed to a lower portion of the media filtration bed (e.g., water enters collection space 26 defined by screen 22 that extends the full height of the bed); passing the filtered influent from the collection tube to at least one outlet opening connected with an outside of the biofilter chamber (e.g., water leaves the opening at the bottom of the collection space 26 to enter the infiltration cell).
The method of ¶0090, further comprising receiving the influent into the catch basin from an opening in the top of the biofilter chamber (e.g., water can flow in through tree ring 38).
The method of ¶0090, further comprising restricting the flow of influent using a restriction plate disposed within the collection tube (e.g., by operation of the orifice restrictor disc engaged by the float valve and mentioned in ¶0048).
The method of ¶0092, further comprising restricting the flow of filtered influent when a flotation valve disposed within the collection tube and connected with the restriction plate falls below a defined level (e.g., by lowering of the float into contact with the orifice restrictor disc per the float valve mentioned in ¶0048).
Claims
1. A stormwater filtration system, comprising:
- a chamber structure including an upper treatment cell and a lower infiltration cell divided by a lateral wall structure, the upper treatment cell including a surrounding wall extending upward from the lateral wall structure, the upper treatment cell being open at the top to atmosphere;
- a filter structure positioned in the treatment cell and supported by the lateral wall structure, the filter structure comprising an outer wall spaced from the surrounding wall of the treatment cell to provide a water collection and settling space between the filter structure and the surrounding wall of the treatment cell, the filter structure including a media bed therewithin and a top portion of the media bed exposed to atmosphere and defining a planting area;
- live vegetative matter planted within the planting area and including a root system that extends down into the media bed of the filter structure for interaction with water passing through the media bed; and
- an inlet to the treatment cell that receives stormwater, which first enters the collection and settling space, then laterally enters the filter structure for passing through the media bed and in contact with the root structure, before exiting the filter structure by passing down into the infiltration cell for subsequent infiltration into the surrounding earth.
2. The stormwater filtration system of claim 1, wherein
- the filter structure includes: an internal collection space surrounded by the media bed, an outlet opening at the bottom of the internal collection space for delivering water down to the infiltration cell,
- and an outlet drain tube extends down into the infiltration cell.
3. The stormwater filtration system of claim 1, wherein
- the filter structure includes: an internal collection space surrounded by the media bed, an outlet opening at the bottom of the internal collection space for delivering water down to the infiltration cell; an upper end of the internal collection space exposed to ambient environment and having an associated one way air release valve for delivering air out of the internal collection space.
4. The stormwater filtration system of claim 1 wherein the treatment cell includes an overflow pipe for delivering excess flows that enter the collection and settling space into the infiltration cell without such excess flows traveling through the filter structure and before such excess flows cause water level in the collection and settling space to exceed a top of the media bed.
5. A stormwater filtration system, comprising:
- a chamber structure including a treatment cell open at the top to atmosphere, the treatment cell having a surrounding wall;
- a filter structure positioned in the treatment cell and comprising an outer wall spaced from the surrounding wall of the treatment cell to provide a water collection and settling space between the filter structure and the surrounding wall of the treatment cell, the filter structure including a media bed therewithin, a top portion of the media bed exposed to atmosphere; and
- an inlet to the treatment cell that receives stormwater, which first enters the collection and settling space, then laterally enters the filter structure for passing through the media bed before exiting the filter structure.
6. The stormwater filtration system of claim 5 wherein
- the media bed defines an exposed planting area;
- live vegetative matter is planted within the planting area and includes a root system that extends down into the media bed of the filter structure for interaction with water passing through the media bed.
7. The stormwater filtration system of claim 5, further comprising:
- the chamber structure including an infiltration cell below the treatment cell.
8. The stormwater filtration system of claim 5, further comprising:
- a pipe arrangement for delivering water from the treatment cell to at least one infiltration chamber.
9. The stormwater filtration system of claim 5 wherein the chamber structure comprises a vertically oriented pipe structure.
10. The stormwater filtration system of claim 9 wherein the pipe structure is one of a plastic pipe, a corrugated metal pipe or a steel reinforced polyethylene pipe.
11. The stormwater filtration system of claim 5 wherein the chamber structure is a concrete manhole structure.
12. The stormwater filtration system of claim 5 wherein the treatment cell delivers treated water directly into the surrounding earthen material.
13. The stormwater filtration system of claim 5 wherein:
- the chamber structure includes a bottom wall with an outlet pipe incorporated therein;
- the filter structure includes: an internal collection space surrounded by the media bed, an outlet opening at the bottom of the internal collection space and connected for delivering water out of the filter structure and into the outlet pipe.
14. The stormwater filtration system of claim 13 wherein the outlet pipe extends horizontally within the bottom wall for delivering water away from the chamber structure.
15. The stormwater filtration system of claim 5 wherein the collection and settling space includes an overflow outlet for delivering excess flows that enter the collection and settling space out of the treatment cell without such excess flows traveling through the filter structure.
16. The stormwater filtration system of claim 15 wherein the overflow outlet is positioned such that excess flows that enter the collection and settling space are delivered out of the treatment cell before such excess flows cause water level in the collection and settling space to exceed a top of the media bed.
17. The stormwater filtration system of claim 5, wherein the filter structure includes:
- an internal collection space surrounded by the media bed,
- an outlet opening at the bottom of the internal collection space for delivering water out of the treatment cell;
- an upper end of the internal collection space exposed to ambient environment and having an associated one way air release valve for delivering air out of the internal collection space.
18. The stormwater filtration system of claim 5 wherein
- the filter structure includes: multiple spaced apart internal collection spaces within the media bed, each internal collection spaced having an outlet opening toward the bottom of the internal collection space and connected for delivering water out of the filter structure.
19. The stormwater filtration system of claim 5 wherein
- the filter structure includes an internal collection space for receiving stormwater that flows through the media bed, the internal collection space defined by a permeable wall within the media bed;
- the chamber structure is positioned in proximity to a curb, the inlet to the treatment cell is connected to a curb inlet pathway.
20. The stormwater filtration system of claim 19 wherein
- the curb inlet pathway includes both a lateral opening through the curb and an upper opening covered by a grate-type structure.
21. The stormwater filtration system of claim 5 wherein
- the filter structure includes an internal collection space for receiving stormwater that flows through the media bed, the internal collection space defined by a permeable wall within the media bed, wherein a top of the internal collection space and permeable wall are covered by media of the planting area.
Type: Application
Filed: Jan 14, 2013
Publication Date: Jul 18, 2013
Inventor: Gregory T. Kowalsky (Portland, OR)
Application Number: 13/740,872
International Classification: E03F 5/14 (20060101);