UNDERGROUND BIORETENTION SYSTEMS
Embodiments of the present invention provide underground bioretention systems that capture and treat surface water runoff. Such underground bioretention systems have a chamber formed by a chamber floor, a chamber ceiling, and at least one chamber wall; an access opening in the chamber ceiling fitted with an access opening cover; an influent opening in the chamber ceiling or the at least one chamber wall; an effluent opening positioned in the chamber floor or the at least one chamber wall beneath the influent opening; a filtration media positioned in the chamber beneath the influent opening; and an underdrain system positioned in proximity with the chamber floor. Also in such bioretention systems, the chamber floor, the chamber ceiling, and the at least one chamber wall are comprised of a material and a design adapted to form the chamber in a manner that withstands pressure applied thereon by subterranean and ground surface materials.
The present invention relates, in general, to water capture and treatment systems and methods of using the same. More particularly, the present invention relates to modular, underground biofiltration systems for developments where a sub-optimal or inadequate amount of surface area is available for biological treatment of stormwater prior to discharge from the property.
BACKGROUND OF THE INVENTIONSWater treatment systems have been in existence for many years. These systems treat stormwater surface runoff or other polluted water. Stormwater runoff is of concern for two main reasons: i. volume and flow rate, and ii. pollution and contamination. The volume and flow rate of stormwater runoff is a concern because large volumes and high flow rates can cause erosion and flooding. Pollution and contamination of stormwater runoff is a concern because stormwater runoff flows into our rivers, streams, lakes, wetlands, and/or oceans. Pollution and contamination carried by stormwater runoff into such bodies of water can have significant adverse effects on the health of ecosystems.
The Clean Water Act of 1972 enacted laws to improve water infrastructure and quality. Sources of water pollution have been divided into two categories: point source and non-point source. Point sources include wastewater and industrial waste. Point sources are readily identifiable, and direct measures can be taken to mitigate them. Non-point sources are more difficult to identify. Stormwater runoff is the major contributor to non-point source pollution. Studies have revealed that contaminated stormwater runoff is the leading cause of pollution to our waterways. As we build houses, buildings, parking lots, roads, and other impervious areas, we increase the amount of water that runs into our stormwater drainage systems and eventually flows into rivers, lakes, streams, wetlands, and/or oceans. As more land becomes impervious, less rain seeps into the ground, resulting in less groundwater recharge and higher velocity flows, which cause erosion and increased pollution levels of watery environments.
Numerous sources introduce pollutants into stormwater runoff. Sediments from hillsides and other natural areas exposed during construction and other human activities are one source of such pollutants. When land is stripped of vegetation, stormwater runoff erodes the exposed land and carries it into storm drains. Trash and other debris dropped on the ground are also carried into storm drains by stormwater runoff. Another source of pollutants are leaves and grass clippings from landscaping activities that accumulate on hardscape areas and do not decompose back into the ground, but flow into storm drains and collect in huge amounts in lakes and streams. These organic substances leach out large amounts of nutrients as they decompose and cause large algae blooms, which deplete dissolved oxygen levels in marine environments and result in expansive marine dead zones. Unnatural stormwater polluting nutrients include nitrogen, phosphorus, and ammonia that come from residential and agricultural fertilizers.
Another major concern are heavy metals, which come from numerous sources and are harmful to fish, wildlife, and humans. Many of our waterways are no longer safe for swimming or fishing due to heavy metals introduced by stormwater runoff. Heavy metals include zinc, copper, lead, mercury, cadmium and selenium. These metals come from vehicle tires and brake pads, paints, galvanized roofs and fences, industrial activities, mining, recycling centers, etc. Hydrocarbons are also of concern and include include oils and grease. These pollutants come from leaky vehicles and other heavy equipment that use hydraulic fluid, brake fluid, diesel, gasoline, motor oil, and other hydrocarbon based fluids. Bacteria and pesticides are additional harmful pollutants carried into waterways by stormwater runoff.
Over the last 20 years, the Environmental Protection Agency (EPA) has been monitoring the pollutant concentrations in most streams, rivers, and lakes in the United States. Over 50% of waterways in the United States are impaired by one of more of the above-mentioned pollutants. As part of the EPA Phase 1 and Phase 2 National Pollutant Discharge Elimination Systems, permitting requirements intended to control industrial and non-industrial development activities have been implemented. Phase 1 was initiated in 1997 and Phase 2 was initiated in 2003. While there are many requirements for these permits, the main requirements focus on pollution source control, pollution control during construction, and post construction pollution control. Post construction control mandates that any new land development or redevelopment activities incorporate methods and solutions that both control increased flows of rain water off the site and decrease (filter out) the concentration of pollutants off the site. These requirements are commonly known as quantity and quality control. Another part of these requirements is for existing publicly owned developed areas to retrofit the existing drainage infrastructure with quality and quantity control methods and technologies that decrease the amount of rain water runoff and pollutant concentrations therein.
A major category of technologies used to meet these requirements are referred to as structural best management practices (BMPs). Structural BMPs include proprietary and non-proprietary technologies designed to store and/or remove pollutants from stormwater. Technologies such as detention ponds and regional wetlands are used to control the volume of runoff while providing some pollutant reduction capabilities. Over the past 10 years, numerous technologies have been invented to effectively store water underground, which frees up buildable land. Various rain water runoff treatment technologies such as catch basin filters, hydrodynamic separators, media filters are used to remove pollutants. These technologies commonly work by using the following processes: screening, separation, physical filtration, and chemical filtration.
SUMMARY OF THE INVENTIONSBio-swales, infiltration trenches, and bioretention areas, commonly known as low impact development (LID) have been implemented to both control flow volumes and remove pollutants on a micro level. LID technologies have also proven successful at removing difficult pollutants such as bacteria, dissolved nutrients, and metals because they provide not only physical and chemical, but also biological filtration processes. They do so by incorporating a living vegetation element that supports a microbial community which assists in pollutant removal. Biological filtration processes have proven excellent at removing many of the pollutants that physical and chemical filtration systems alone cannot.
Conventional LID technologies, however, require substantial amounts of space. For instance, a typical bioretention design takes up approximately 4% of the buildable area of any construction project. This space requirement translates into significant reductions in the amounts of parking spaces, and therefore building sizes that can be incorporated into construction projects. The significant amounts of space taken up by conventional stormwater biofiltration systems make it more expensive, and therefore less feasible, to develop property.
Embodiments of the present invention provide underground bioretention systems that capture and treat contaminated surface water runoff. Such underground bioretention systems have a chamber formed by a chamber floor, a chamber ceiling, and at least one chamber wall; an access opening in the chamber ceiling fitted with an access opening cover; an influent opening in the chamber ceiling or the at least one chamber wall; an effluent opening positioned in the chamber floor or the at least one chamber wall beneath the influent opening; a filtration media positioned in the chamber beneath the influent opening; and an underdrain system positioned in proximity with the chamber floor. Also in such bioretention systems, the chamber floor, the chamber ceiling, and the at least one chamber wall are comprised of a material and a design adapted to form the chamber in a manner that withstands pressure applied thereon by subterranean and ground surface materials that surround the underground bioretention system and that are at least one material selected from the group consisting of a subterranean soil, a subterranean rock, a ground surface pervious material, and a ground surface impervious material.
In some embodiments, the underground bioretention system further comprises live vegetation in the filtration media. In some embodiments, the underground bioretention system further comprises mulch above the filtration media. In some embodiments, the underground bioretention system further comprises a rock backfill in proximity with the underdrain system. In some embodiments, the underground bioretention system further comprises a plant establishment media in proximity with a surface of the filtration media and live vegetation in the plant establishment media. In some embodiments, the underground bioretention system further comprises a splash guard positioned under the influent opening. In some embodiments, the underground bioretention system further comprises an inlet flow distributor and sedimentation chamber positioned under the influent opening. In some embodiments, the underground bioretention system further comprises a flow restrictor positioned in the underdrain system contains and operative to restrict a flow of water passing through the bioretention system. In some embodiments, the underground bioretention further comprises weep holes in the chamber floor. In some embodiments, the underground bioretention further comprises a bypass riser. In some embodiments, the underground bioretention system further comprises an irrigation system. In some embodiments, the underground bioretention system further comprises an access riser and a reflective material mounted on an inner surface of at least one of a wall of the access riser and the at least one chamber wall, wherein the access opening cover is adapted to allow natural light to enter the chamber. In some embodiments, the underground bioretention system further comprises an artificial light operative to emit an amount of light energy that promotes a growth of the live vegetation. In some embodiments, the underground bioretention system further comprises at least one of a battery and a solar panel operative to supply electrical power to the artificial light.
In some embodiments, the underground bioretention filtration media is placed over a layer of matrix underdrain structure. In some embodiments, the filtration media is at least one member selected from the group consisting of an inert material and a cation exchange material. Some embodiments of the present invention provide underground bioretention systems that capture and treat contaminated surface water runoff. Such underground bioretention systems have a first chamber formed by a first chamber floor, a first chamber ceiling, and at least one first chamber wall and a second chamber formed by a second chamber floor, a second chamber ceiling, and at least one second chamber wall. In such bioretention systems, at least one of the first chamber ceiling and the second chamber ceiling further comprises an access opening fitted with an access opening cover; at least one of the first chamber ceiling or the at least one first chamber wall and the second chamber ceiling or the second chamber wall further comprises an influent opening; at least one of the first chamber floor or the at least one first chamber wall and the second chamber floor or the second chamber wall further comprises an effluent opening, the second chamber comprises a filtration media in proximity with the second chamber floor and an underdrain system in proximity with the second chamber floor; and the at least one first chamber wall further comprises a first coupling opening and the at least one second chamber wall further comprises a second coupling opening, the first coupling opening and the second coupling opening are fitted together in a manner that places the first chamber and the second chamber in substantially leak-free fluid communication, the influent opening and the effluent opening are not both positioned in the first chamber or the second chamber, the first chamber floor, the first chamber ceiling, and the at least one first chamber wall are comprised of a material and a design adapted to form the first chamber in a manner that withstands pressure applied thereon by subterranean and ground surface materials that surround the underground bioretention system and that are at least one material selected from the group consisting of a subterranean soil, a subterranean rock, a ground surface pervious material, and a ground surface impervious material, and the second chamber floor, the second chamber ceiling, and the at least one second chamber wall are comprised of a material and a design adapted to form of the chamber in a manner that withstands pressure applied thereon by subterranean and ground surface materials that surround the underground bioretention system and that are at least one material selected from the group consisting of a subterranean soil, a subterranean rock, a ground surface pervious material, and a ground surface impervious material.
Referring to
At the center of the underground bioretention system 10 is chamber 100. The chamber 100 has a floor 130, ceiling 110, and walls 120. The modular design of bioretention systems according to the present invention allows the system to scale to various sizes and shapes. The chambers of bioretention systems according to the present invention are generally square or rectangular in shape, but they may be circular or triangular in shape as needed for particular installation sites. Referring again to
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In some embodiments, access opening covers comprise a solid hatch that prevents water from entering into the chamber. In some embodiments, access opening covers comprise a grate that prevents pedestrians and vehicles from entering the chamber, but allows stormwater or other surface water runoff to enter the chamber.
Referring again to
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The rock backfill 610 is placed directly under filtration media 600 and placed evenly around the perforated pipe of the underdrain system 340. So placed, rock backfill 610 enhances the transfer of passing water from the filtration media 600 to the perforated pipe of the underdrain system 340.
In some embodiments, living vegetation in underground bioretention systems according to the invention are one or more of plants, bacteria, and fungi. In some embodiments, artificial lights are installed into chamber walls of bioretention systems according to the present invention. In some embodiments, artificial lights used in bioretention systems according to the present invention are one or more of a florescent light, a high pressure sodium light, a metal halide light, and a light emitting diode. Florescent lights provide moderate amounts of light spectrum range and output to support plant growth. High pressure sodium and metal halide provide high amounts of light spectrum range and output appropriate for plant growth. In recent years, an array of blue and red light emitting diodes have been used to provide the same benefits of high pressure sodium and metal halide lights; but with less power usage, making them an environmentally and financially sound option. In some embodiments, lights are available with ballasts that allow for air venting with fans to remove excessive heat. In some embodiments, such artificial light ballasts are waterproof to provide an additional level of safety. Artificial lights used in some embodiments of the present invention are powered by electricity supplied by one or more of the grid, solar panels, or batteries.
Referring again to
In some embodiments, underground bioretention structures are built to handle site specific loading conditions. Surface loads applied to underground bioretention systems vary based upon pedestrian and vehicular traffic, and can be broken down into the following categories. Parkway loading includes sidewalks and similar areas that are adjacent to streets and other areas with vehicular traffic. Indirect traffic loading includes areas that encounter daily low speed traffic from vehicles ranging from small cars up to semi-trucks. Direct traffic loading includes areas, such as streets and other parkways, that encounter a high volume of high speed traffic from vehicles ranging from small cars to large semi-trucks. There is also heavy duty equipment loading that includes traffic from, e.g., airplanes and heavy port equipment. Accordingly, underground bioretention systems of the present invention may be constructed having walls, floors, and/or ceilings of various thicknesses and strengths (e.g., differing thicknesses of concrete or steel or differing amounts of rebar) such that they achieve a parkway load rating (e.g., a H5 load rating), an indirect traffic load rating (e.g., a H20 load rating), a direct traffic load rating (e.g., a H20 load rating), or a heavy duty equipment load rating (e.g., a H25 load rating), as required for a given installation site.
Although the disclosure has been provided in the context of certain embodiments and examples, it will be understood by those skilled in the art that the disclosure extends beyond the specifically described embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. Accordingly, the disclosure is not intended to be limited by the specific disclosures of embodiments herein.
Claims
1. An underground bioretention system, to capture and treat contaminated surface water runoff, comprising: wherein the chamber floor, the chamber ceiling, and the at least one chamber wall are comprised of a material and a design adapted to form the chamber in a manner that withstands pressure applied thereon by subterranean and ground surface materials that surround the underground bioretention system.
- a chamber formed by a chamber floor, a chamber ceiling, and at least one chamber wall;
- an access opening in the chamber ceiling fitted with an access opening cover;
- an influent opening in the chamber ceiling or the at least one chamber wall;
- an effluent opening positioned in the chamber floor or the at least one chamber wall beneath the influent opening;
- a filtration media positioned in the chamber beneath the influent opening; and
- an underdrain system positioned in in proximity with the chamber floor, and
2. The underground bioretention system of claim 1, further comprising live vegetation in the filtration media.
3. The underground bioretention system of claim 1, further comprising a mulch above the filtration media.
4. The underground bioretention system of claim 1, further comprising a rock backfill in proximity with the underdrain system.
5. The underground bioretention system of claim 1, wherein the filtration media is placed over a layer of matrix underdrain structure.
6. The underground bioretention system of claim 1, further comprising a plant establishment media in proximity with a surface of the filtration media and live vegetation in the plant establishment media.
7. The underground bioretention system of claim 1, further comprising a splash guard positioned under the influent opening.
8. The underground bioretention system of claim 1, further comprising an inlet flow distributor and sedimentation chamber positioned under the influent opening.
9. The underground bioretention system of claim 1, further comprising a flow restrictor, and wherein the flow restrictor is positioned in the underdrain system and operative to restrict a flow of water passing through the bioretention system.
10. The underground bioretention system of claim 1, further comprising weep holes in the chamber floor.
11. The underground bioretention system of claim 1, further comprising a bypass riser.
12. The underground bioretention system of claim 1, wherein the filtration media is at least one member selected from the group consisting of an inert material and a cation exchange material.
13. The underground bioretention system of claim 2, further comprising an irrigation system.
14. The underground bioretention system of claim 2, further comprising an access riser and a reflective material mounted on an inner surface of at least one of a wall of the access riser and the at least one chamber wall, wherein the access opening cover is adapted to allow natural light to enter the chamber.
15. The underground bioretention system of claim 2, further comprising an artificial light operative to emit an amount of light energy that promotes a growth of the live vegetation.
16. The underground bioretention system of claim 15, further comprising at least one of a battery and a solar panel operative to supply electrical power to the artificial light.
17. An underground bioretention system, to capture and treat contaminated surface water runoff, comprising:
- a first chamber formed by a first chamber floor, a first chamber ceiling, and at least one first chamber wall;
- a second chamber formed by a second chamber floor, a second chamber ceiling, and at least one second chamber wall, wherein: at least one of the first chamber ceiling and the second chamber ceiling further comprises an access opening fitted with an access opening cover, at least one of the first chamber ceiling or the at least one first chamber wall and the second chamber ceiling or the second chamber wall further comprises an influent opening, at least one of the first chamber floor or the at least one first chamber wall and the second chamber floor or the second chamber wall further comprises an effluent opening, the second chamber comprises a filtration media in proximity with the second chamber floor and an underdrain system in proximity with the second chamber floor, the at least one first chamber wall further comprises a first coupling opening and the at least one second chamber wall further comprises a second coupling opening, the first coupling opening and the second coupling opening are fitted together in a manner that places the first chamber and the second chamber in substantially leak-free fluid communication, the influent opening and the effluent opening are not both positioned in the first chamber or the second chamber, the first chamber floor, the first chamber ceiling, and the at least one first chamber wall are comprised of a material and a design adapted to form the first chamber in a manner that withstands pressure applied thereon by subterranean and ground surface materials that surround the underground bioretention system, and the second chamber floor, the second chamber ceiling, and the at least one second chamber wall are comprised of a material and a design adapted to form of the chamber in a manner that withstands pressure applied thereon by subterranean and ground surface materials that surround the underground bioretention system.
18. The underground bioretention system of claim 17, further comprising live vegetation in the filtration media.
19. The underground bioretention system of claim 18, further comprising an access riser and a reflective material mounted on an inner surface of at least one of a wall of the access riser, the at least one first chamber wall, and the at least one second chamber wall, and wherein the access opening cover is adapted to allow natural light to enter the chamber.
20. The underground bioretention system of claim 18, further comprising an artificial light operative to emit an amount of light energy that promotes a growth of the live vegetation.
21. The underground bioretention system of claim 18, further comprising at least one of a battery and a solar panel operative to supply electrical power to the artificial light.
Type: Application
Filed: Aug 9, 2013
Publication Date: Feb 12, 2015
Inventor: Zacharia Kent (Oceanside, CA)
Application Number: 13/962,995
International Classification: E03F 1/00 (20060101);