Stormwater biofiltration system and method

Abstract

A stormwater treatment system and method for removing sediment, chemical pollutants, and debris from stormwater runoff by utilizing bioretention practices including physical, chemical and biological processes. Stormwater is directed into a primarily open-bottomed, multi-dimensional container whereby entrained sediment and other transportable materials are filtered and treated through a media filter layer consisting of inorganic and/or organic materials. A live plant (preferably a tree) situated within the container with roots resident in the media filter layer with the ability for expansion beyond the perimeter of the container through openings in one or more sidewalls. The treated water may be further conveyed beyond the perimeter of the container by additional openings and/or piping. A vertically positioned overflow/bypass/clean out piping apparatus may be included within the stormwater treatment system to provide additional water conveyance. Additional ancillary conveyance, filtration and storage facilities may be connected to the described stormwater treatment system as conditions warrant.

Claims

1. A stormwater treatment system with bioretention functionality comprising at least four substantially open vertical sidewalls and a partial horizontal top sidewall affixed to one or more of said sidewalls, wherein when said system is partially buried in the ground, said partial horizontal top sidewall exposes the interior of the system to the atmosphere; further wherein said system contains discrete layers of organic and inorganic or a mixture of organic and inorganic material; provided said system does not have a bottom wall or a sump.

2. The stormwater treatment system according to claim 1, wherein said organic and inorganic material is confined to the interior of the system.

3. The stormwater treatment system according to claim 1, wherein said organic and inorganic material extends under and out of said system.

4. The stormwater treatment system according to claim 1, wherein said inorganic material is an aggregate media.

5. The stormwater treatment system according to claim 4, wherein said aggregate media comprises sand, gravel, stone or any combination thereof.

6. The stormwater treatment system according to claim 5, wherein said inorganic media further comprises organic material, provided said inorganic media can filter stormwater entering the system while maintaining moisture to support vegetation growth.

7. The stormwater treatment system according to claim 6, wherein said inorganic media further comprises an additive comprised of iron or aluminum oxide, an expanded ceramic, or a water treatment residual no greater than 20% (5%) by volume or any combination thereof.

8. The stormwater treatment system according to claim 7, wherein said system contains a third discrete layer of material situated below the organic and inorganic layers comprising stone or aggregate or a combination thereof.

9. The stormwater treatment system according to claim 8, further comprising a separating layer situated below said third discrete layer.

10. The stormwater treatment system according to claim 9, wherein said separating layer comprises a manufactured geotextile fabric material and/or dimensional stone, provided said dimensional stone is different from the stone comprising the third layer immediately above the separating layer.

11. The stormwater treatment system according to claim 9, further comprising a base situated above or embedded within said separating layer.

12. The stormwater treatment system according to claim 9, wherein soil is located below said separating layer.

13. The stormwater treatment system according to claim 12, further comprising a horizontal under drain pipe embedded with said base and/or separating layer wherein when said drain pipe directs filtered stormwater out of the system into the surrounding ground or to a receiving facility.

14. The stormwater treatment system according to claim 13, wherein said horizontal under drain pipe contains a plurality of openings.

15. The stormwater treatment system according to claim 13, further comprising a vertical pipe extending via the exposed interior formed by the partial horizontal top sidewall wherein said vertical pipe is a clean out access pipe or an overflow or internal bypass conduit or both which directs excess stormwater that enters the system and accumulates at the top of said system out of the system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cutaway perspective various aspects of a stormwater treatment system of the present invention.

(2) FIG. 2 is a cutaway cross-sectional view of the first embodiment of the stormwater management system of the present invention with internal collection and discharge piping.

(3) FIGS. 3(a), 3(b), and 3(c) is a cutaway perspective view, plan view, and cutaway perspective view, respectively, of a second embodiment of a stormwater management system of the present invention.

(4) FIG. 4 is a cutaway perspective view of a third embodiment of a stormwater management system of the present invention with a separate top slab.

(5) FIGS. 5(a) and 5(b) is a cutaway cross-sectional view, and plan view, respectively, of a fourth embodiment of inflow and outflow pipes and openings of a stormwater management system of the present invention.

(6) FIG. 6 is a cutaway cross-sectional view of a fifth embodiment of a stormwater management system of the present invention.

(7) FIGS. 7(a) and 7(b) is a cutaway perspective view, and plan view, respectively, of a sixth embodiment of a stormwater management system of the present invention.

(8) These renderings are included for illustrative and interpretive purposes relative to specific embodiments and applications and should not be construed as the sole positioning, configurations, or singular use of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

(9) The present invention is designed to be a stormwater management system hereby stormwater combined with mixed debris, sands, sediment, entrained and dissolved chemical and biological pollutants are separated, treated and/or remediated via physical, chemical, and biological processes prior to being infiltrated to the subsurface environment, and/or discharged to a separate drainage system. Referring now to the drawings, and specifically to FIG. 1, the present invention is comprised of a substantially water impermeable open bottomed container 1 of various dimensions and configurations with an open bottom and vertical sidewalls 10, 11, 12, 13, of various height and enclosure, and horizontal (top) sidewall 2 at least partially open to the environment. The container contains a mixture and/or discreet layer(s) of both organic and inorganic materials (media) which may or may not extend beyond the outside perimeter of the container. The container maintains vegetative plant(s) 5 whose roots 8 are resident in the media and are able to communicate unrestricted with the surrounding native soils or introduced soils 9.

(10) While continuing to reference FIG. 1, and also FIG. 2, the following description includes the preferred embodiment, manner of operation, and pollutant removal function(s). Stormwater enters the substantially water impermeable open-bottomed container 1 through one or more openings located on the container or through an opening 3 on a sidewall that abuts a street or impervious surface 4 with associated curbing 7. The preferred embodiment of the container is of a water tight concrete, metal, or plastic (or other impermeable substance) fabrication. The configuration, horizontal dimensions and shape of this container is primarily determined based on site logistics, and the size of the appropriate media dimensions to accommodate the flow emanating from the contribution area that makes up the incoming stormwater flow.

(11) Incoming stormwater flows immediately into the container 1, quantities of sand, sediment, and other floatable or non-floatable matter entrained within the stormwater flow also enters the container and accumulate on the surface of the media 6.

(12) As the water infiltrates through the media, additional quantities of sands and sediment may either become resident in the media or continue entrained with the water flow. Additionally, organic nutrients such as nitrogen and phosphorus, amongst others, and metals such as zinc and copper, amongst others, within the stormwater flow may adhere to the aggregate media and/or continue to pass through the media. The media is comprised of a mixture of aggregates (e.g., sand, gravel, stone), and organics, to achieve a substantial rate of infiltration, while maintaining moisture holding capacity to maintain biological activity and support plant growth. An embodiment would be the incorporation of an additive in the aggregate media that would contain an iron or aluminum oxide product, an expanded ceramic, and/or a water treatment residual of no greater than 20% (5%) by volume to enhance the nutrient removal potential of the non-amended media.

(13) The water infiltrates through, and then exits the media layer of the container. The infiltrating water than typically communicates with an underlying layer of stone or other aggregate 14. A preferred embodiment would be a separating layer 19 consisting of either or both a manufactured geotextile fabric material, and a dimensional stone differing from that of the aforementioned underlying layer of stone/aggregate. The base of the container is envisioned to either rest on top of this stone/aggregate layer, or be partially embedded within this layer. It is envisioned that native soils or introduced soils 9 would be resident below this layer of stone. Depending upon the infiltration capacity of these soils, water would be allowed to freely migrate and/or infiltrate both vertically and horizontally. A preferred embodiment would be that an underdrain pipe 15 is provided adjacent to the bottom of the container within the stone layer 14 having a plurality of openings 16 that receive the infiltrating stormwater as it flows through the overlying media. This stormwater may then be transferred outside the footprint of the container and directed to another receiving facility. Associated with the underdrain pipe is a vertical pipe 17 which serves as either a cleanout access pipe, or as an overflow or internal bypass conduit to collect and transfer incoming stormwater that enters the container and then rises above the surface of the media. This vertical pipe is accessible through an opening(s) in the top sidewall 2. A plastic, fiberglass or metal-based fabricated grate or plate 50 may enclose portions of the top sidewall of the container. An opening 20 within the grate would allow the plant's trunk to extend through the grate and the top sidewall. The grate may be fixed or secured to the top sidewall of the container by way of fastening devices or other appurtenances.

(14) FIGS. 3(a), 3(b) and 3(c) depicts the first embodiment of the present invention which incorporates one or more openings 21, 22, 23, 24 on one or more sidewalls 10, 11, 12, 13 of the container to service one or more incoming and/or outgoing pipes 42, 43, 44 of predetermined dimension and length either straight line or manifold 41 with fittings 45 to receive and/or discharge stormwater communication with the container 1 of the present invention. These pipes could be accessed through the top sidewall 2 of the container, or through a surface grate or plate 50. The ability to connect piping in a multi-directional configuration allows for more flexibility in positioning the stormwater treatment system for both receiving incoming stormwater and discharging outgoing stormwater. Now referring specifically to FIG. 3(c), this embodiment incorporates one or more openings 91, 92 on one or more sidewalls of the container 1 to allow for the free movement of water that has accumulated above the media within the container to flow horizontally beyond the exterior walls of the container, and thereby further communicate with the media 6, and adjoining soil 9, providing a more expansive infiltration area.

(15) Now referring to FIG. 4 of a stormwater management system of the present invention, another embodiment of the invention would be that the container would be fabricated in two or more sections with a separate top slab 60 that would rest on or be affixed to the four sides, 61, 62 63, 64 of the container. Having a separate top slab would allow for making slight surficial elevational and side-to-side adjustments if site conditions require such adjustment. A separate top slab would also lessen the overall filling weight of the structure at time of installation particularly for large dimension containers.

(16) FIGS. 5a, and 5b depict another embodiment of the present invention which allows for incoming pipes from deeper elevations to enter the container. Often times, due to the location and elevation of upgradient catch basins or other facilities that collect stormwater for discharge to a stormwater management system such as the present invention, the point of entry to the container must be several feet below surface grade. Such factors as existing site conditions, drainage layout plans, and natural or artificial slopes, stormwater conveyance pipes must traverse a subject site at elevations several feet below ground surface 70. In this embodiment one or more incoming pipes 71 would enter the container at a depth below ground surface. Incoming water would discharge into a closed bottomed four-sided chamber 72 which is monolithic or attached to the container and would be composed of concrete, metal, or a plastic material. As the water rises within this chamber, it would flow over the interior top sidewall 73 of the chamber, and/or flow through one or more pipes 74 that have been cast in, or are otherwise traversing through the interior sidewall of the chamber. The water would then flow onto the media 6 within the container, and infiltrate through the media, as detailed in the present invention of FIGS. 1 & 2.

(17) FIG. 6 depicts another embodiment which illustrates a particular piping schematic of the present invention as a stormwater management system that accepts incoming water from an underground pipe emanating from either a building's roof, or an upgradient source or location such as an underground pipe, catch basin and/or other storm water receiving receptor. Water enters the container from an inlet pipe 80 situated on a primarily horizontal plane. Water passing over one or more openings 81 located on the inlet pipe, would have the ability to flow through the openings and make contact with the surface of the media 6 within the container. Water which is not able to flow through the aforementioned openings, would continue to flow through the pipe before connecting with a separate underdrain pipe 82 with a plurality of openings that is collecting infiltrating water flow. Both flows would then combine and continue on a primarily horizontal plane and then exit through one or more sides of the container. An embodiment would be that a vertical riser pipe 83 with an open or closed top 84 may be connected to the horizontal underdrain pipe. The purpose of this pipe would be to collect water that rises above the surface of the media within the container for evacuation through the underdrain pipe, or another outlet point; and/or to serve as a cleanout port to be accessed through an opening in the top 85 of the container or through an associated grate, plate or other removable fixture 86.

(18) FIGS. 7a and 7b depicts still another embodiment with similar configuration to previous figures represented of the present invention. In this embodiment, a flexible impervious or semi-impervious subsurface membrane liner 55 surrounds a substantial portion of the container 1. The purpose of this liner would be to provide a barrier between the container and media 6 associated with the container, and that of native or adjoining soils 56. Inlet and outlet piping of various diameter would be able to penetrate and otherwise traverse the wall of the liner. Such circumstances which may include this embodiment would be if the stormwater management system of the present invention was located proximal to identified sensitive environmental receptors which require protection or segregation. Such examples of these receptors could be water bodies 57, wetlands, drinking water protection areas and other examples. Another circumstance where the embodiment of a liner and/or barrier would be beneficial would be if contaminated soil or groundwater was present proximal to the stormwater management system, whereby infiltrating water associated with the stormwater management system could potentially comingle with or otherwise make contact with contaminated soil or groundwater thereby spreading the contamination further. The use of a flexible liner would also allow for the expansion of the collection and treatment area beyond the foot print of the container, and therefore not be constrained by the dimensions of the container, allowing for the maximization of the filtrating media area. The flexible impervious or semi-impervious subsurface membrane liner is envisioned to be composed of rubber, polyethylene, or other material(s) either unique or in composite and typically designed to be a barrier to separate one physical area from another physical area.

(19) Several of the embodiments of the invention may be connected to a sump pump. A sump pump is a pump used to remove water that has accumulated in a water collecting sump basin, commonly found in the basement of homes. The water may enter the perimeter drains of a basement waterproofing system, funneling into the basin or because of rain or natural ground water, if the basement is below the water table level. Sump pumps are used where basement flooding happens regularly and to solve dampness where the water table is above the foundation of a home. Sump pumps send water away from a house to any place where it is no longer problematic, such as the stormwater treatment system of the present invention.

(20) There are generally two types of sump pumpspedestal and submersible. In the case of the pedestal pump, the motor is mounted above the sumpwhere it is more easily serviced, but is also more conspicuous. The pump impeller is driven by a long, vertical extension shaft and the impeller is in a scroll housing in the base of the pump. The submersible pump, on the other hand, is entirely mounted inside the sump, and is specially sealed to prevent electrical short circuits. There is debate about which variety of sump pump is better. Pedestal sump pumps usually last longer (25 to 30 years) if they are installed properly and kept free of debris. They are less expensive and easier to remove. Submersible pumps will only last 5 to 15 years. They are more expensive to purchase but can take up debris without clogging.

(21) Sump pump systems are also utilized in industrial and commercial applications to control water table-related problems in surface soil. An artesian aquifer or periodic high water table situation can cause the ground to become unstable due to water saturation. As long as the pump functions, the surface soil will remain stable. These sumps are typically ten feet in depth or more; lined with corrugated metal pipe that contains perforations or drain holes throughout. They may include electronic control systems with visual and audible alarms and are usually covered to prevent debris and animals from falling in.

(22) The foregoing descriptions and drawings should be assumed as illustrative only of the principles of the invention. The invention may be configured in a variety of shapes and sizes and is not limited by the aforementioned dimensions, construction and operation of the identified parts, materials or embodiments. It is understood that numerous modifications, changes, and substitutions of the invention will readily occur to those skilled in the art and may be resorted to falling within the scope and spirit the invention.

(23) While the previous description contains many specifics, these should not be construed as limitations on the scope of the invention, but as exemplifications of the presently preferred embodiments thereof. Thus the scope of the invention should be determined by the appended claims and their legal equivalents. It is not desired to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art, without departing from the spirit and scope of the appended claims.