Patent Application
20250137245
The present application claims priority to Canadian Patent Application No. 3,218,218, filed Oct. 31, 2023, the contents of which are incorporated by reference herein in their entirety.
The present disclosure relates to a storm water interceptor, and in particular to a storm water interceptor for removing sediment, screening debris and/or separating oil from storm water runoff.
Rain water/storm water and other runoff are typically absorbed into the ground. However, in cases where absorption is not possible, such as in locations where there are asphalt, concrete or other at least somewhat impervious surfaces, such runoff often enters sewer or drainage systems, where it is eventually drained into a body of water such as a lake or river. Examples of such impervious areas include parking lots, roads/boulevards, gas stations, loading docks and roadside rest areas, though these are just examples and it will be appreciated that many other locations have impervious surface areas where runoff enters a sewer or drainage system. During severe rainfalls, storm water runoff levels can rise dramatically in areas where the water cannot be sufficiently absorbed into the ground. Accordingly, there is a need for storm water systems to be able to handle elevated volumes of water on such occasions.
It is preferable that storm water (sewer or drainage) systems also intercept undesirables, such as oil based products, grit, sediment, debris and other waste that mix in with the storm water from entering into lakes or rivers. Regulations concerning efficiency standards for the separation of such undesirables are set by various government agencies, such as a provincial Ministry of the Environment in Canada or local by-law regulators. Accordingly, there is a need for storm water systems to be able to separate oil, grit and other debris from the storm water itself.
Oil/grit separators have been around for many years. Through the use of one or more chambers, they are designed to remove sediment, screen debris and separate oil from storm water before the water is deposited in a lake or river. A typical oil/grit separator unit operates by settling sediment and particulate matter, screening debris, and separating free surface oils from storm water runoff. However, many of these oil/grit separators do not accommodate high or elevated volumes of storm water very well, as they are either not large enough in size or not configured efficiently. During high runoff volumes, many of these separators allow for storm water to “bypass” the normal oil/grit separation and be directly deposited into a body of water, thus elevating pollution levels in the body of water.
Typical oil/grit separators are installed beneath the surface of an impervious area. This is typically done for space conservation in urban or ultra-urban environments. In addition to not being able to efficiently separate oil and grit during high flow volumes, some oil/grit separators are difficult and expensive to install in these sub-surface locations. For example, U.S. Pat. No. 6,077,448 discloses a multi-chambered oil/grit interceptor that is very large. While there is more than one chamber within the interceptor, the interceptor itself has one very large tank, which would be cumbersome to install. For example, a crane with a long boom may be required to lift and install this and/or other similar oil/grit separators.
Some oil/grit separators and storm water treatment systems have modules that are separate and do not form a single tank. For example, see U.S. Pat. Nos. 6,546,962, 6,371,690 and 5,746,911. However, these separators and systems have complex interconnections and other barriers that make them difficult to install. As well, their configurations make them less than optimal in terms of efficiently separating oils and grits from storm water. This leads to poorer performance, including during times of high water volumes. Poorer performance during high storm water volumes is also known to occur in prior art configurations that employ barriers known as weirs. Weirs are less desirable, as they permit storm water to flow untreated directly through a storm water treatment system in times of high water volumes.
A further problem faced by prior art oil/grit separators is that they sometimes include multiple chambers and mechanisms that make routine maintenance more time-consuming and/or costly. Where the separator requires disassembly to perform maintenance, this exacerbates the foregoing problem.
A further problem faced by prior art oil/grit separators is the issue of pipe clogging. Where large debris, such as sticks or plastic bags, enters the storm water treatment system, inlet orifices and other conduits that have not had the benefit of earlier filtering or screening, and/or that are small in size may become plugged, thus causing a back up of storm water. In addition, prior art oil/grit separators having screens or other moving parts that can easily become plugged, or even broken, require more frequent maintenance as a result.
In view of growing urbanization, there is also a need for a storm water interceptor that is relatively quicker and easier to install. Without proper storm water management, one or more of reduced baseflow, degradation of water quality, and increased flooding and/or erosion can result. In turn, these effects can lead to one or more of reduced diversity of aquatic life, fewer opportunities for human uses of water resources, reduced quality of life and loss of property.
In view of growing urbanization, including densification, there is also a need for an improved storm water interceptor that accomplishes the typical objectives of an interceptor, including providing treatment of storm water effluent without bypass at least somewhat independent of the storm intensity, without occupying an inordinate amount of space.
Accordingly, there is a need for a storm water interceptor that addresses one or more of the needs described above, and/or that is able to accommodate one or more of elevated volumes of water, efficiently or sufficiently separating out oils and grits, reducing the amount of storm water bypassing the treatment stage, easier maintenance, and easier and/or more efficient assembly and/or installation.
According to a first aspect of the present invention there is provided a storm water interceptor comprising: an inlet conduit connected to a treatment tank, the inlet conduit for delivering storm water to the treatment tank, an aluminum grate located within the treatment tank and below the inlet conduit, and an outlet conduit connected to the treatment tank, the outlet conduit extending away from the treatment tank, and having an invert located above the aluminum grate and an orifice located below the aluminum grate.
According to a further aspect of the present invention, the orifice of the outlet conduit is substantially horizontal.
According to a further aspect of the present invention, the substantially horizontal orifice of the outlet conduit comprises a fixed step.
According to a further aspect of the present invention, the outlet conduit comprises a removable plug.
According to a further aspect of the present invention, the outlet conduit comprises a tee conduit connecting the orifice of the outlet conduit with a portion of the outlet conduit extending away from the treatment tank.
According to a further aspect of the present invention, the aluminum grate includes an access hatch.
According to a further aspect of the present invention, an aluminium lifting chain is affixed to the access hatch.
According to a further aspect of the present invention, an aluminum ladder is affixed to an interior wall of the treatment tank.
According to a further aspect of the present invention, the treatment tank is substantially cylindrical and comprises two or more modular sections made of pre-cast concrete.
According to a second aspect of the present invention there is provided a storm water interceptor comprising: at least two treatment tanks, wherein the at least two treatment tanks comprise a primary treatment tank and a secondary treatment tank, an inlet conduit connected to the primary treatment tank, the inlet conduit for delivering storm water to the primary treatment tank, an aluminum grate located within the primary treatment tank and below the inlet conduit, a connecting conduit connected to the primary treatment tank, the connecting conduit connecting to the secondary treatment tank, and an outlet conduit connected to the secondary treatment tank, the outlet conduit comprising an invert and extending away from the secondary treatment tank.
According to a further aspect of the present invention, the outlet conduit comprises a substantially horizontal orifice, wherein the invert of the outlet conduit is located above the substantially horizontal orifice of the outlet conduit.
According to a further aspect of the present invention, the invert of the outlet conduit is located below an invert of the input conduit.
According to a further aspect of the present invention, the invert of the outlet conduit is located above an invert of the input conduit.
According to a further aspect of the present invention, the connecting conduit comprises a substantially horizontal orifice at the primary treatment tank and a substantially vertical orifice at the secondary treatment tank, and an invert of the connecting conduit is located above the substantially horizontal orifice of the connecting conduit at the primary treatment tank.
According to a further aspect of the present invention, an overflow conduit connects the primary treatment tank and the secondary treatment tank.
According to a further aspect of the present invention, the overflow conduit comprises a substantially horizontal orifice, wherein an invert of the overflow conduit is located above the substantially horizontal orifice of the overflow conduit.
According to a further aspect of the present invention, the aluminum grate includes an access hatch and an aluminium lifting chain is affixed to the access hatch.
According to a further aspect of the present invention, an aluminum ladder is affixed to an interior wall of at least one of the primary and secondary treatment tanks.
According to a further aspect of the present invention, at least one or the primary and secondary treatment tanks are substantially cylindrical and comprises two or more modular sections made of pre-cast concrete.
According to a further aspect of the present invention, the aluminum grate is located above the connecting conduit.
According to a further aspect of the present invention, the aluminum grate is located below an invert of the outlet conduit.
Further features and advantages of the present disclosure will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
A storm water interceptor for the separation of trash, grit, oil, sediments and/or other debris from storm water is disclosed herein.
With reference to the embodiment depicted in
The treatment tank 21 is preferably cylindrical or substantially cylindrical in shape. The treatment tank 21 has a cover 27. Depending on site installation requirements, the cover 27 for the treatment tank 25 may be, for example, a solid manhole lid or a catch basin grate. A finish grade for the cover 27 may be set using well known pre-cast moduloc rings varying in thickness from 50 mm to 100 mm.
The treatment tank 21 may comprise four sections, namely, a flat cap 28 (or transition section), an upper barrel section 29, a middle barrel section 30, and a lower barrel section 31. Alternative embodiments may have a greater or fewer number of sections within a tank. Being part of the treatment tank 21, these sections 28, 29, 30, 31 may be modular in nature. The sections are preferably at least substantially cylindrical and preferably have interior and exterior wall portions. At the lower end of the treatment tank 21 may be a base 32. Each of the four sections 28, 29, 30 and 31, and the base 32, are each preferably made from reinforced pre-cast concrete. Inside treatment tank 21 is a ladder 33 for access by maintenance personnel. Ladder 33 is affixed to the interior walls of sections 29, 30, and/or 31.
Between sections 28, 29, 30, and/or 31 is preferably a rubber mastic at each joint 40, 39, and 38. The rubber mastic should preferably be heated until it is pliable before joining together any of the various sections 28, 29, 30, 31 of the treatment tank 21. Following such joining, each of the joints 38, 39, 40 are preferably mortared both inside and outside the respective section walls 28, 29, 30, and 31. Such mortaring preferably utilizes sand and Portland cement with an acrylic and polymer admixture to ensure proper bonding. Where possible and available, a flexible waterproof caulking is preferably used instead of mortar.
Further securing of the various sections 28, 29, 30, and 31 of the treatment tank 21, is preferably accomplished by anchoring frost straps (not shown) vertically to the outside of the treatment tank 21. Preferably, such frost straps would be in the form of a 600-1200 mm×75 mm×6 mm galvanized plate and would be connected by a ¾ inch stainless steel nut and bolt combination that is anchored to some or all of the treatment tank walls of sections 28, 29, 30, and/or 31.
With respect to base section 32, it preferably has 200 mm-thick reinforced pre-cast concrete that is also preferably made monolithic with section 31. Much like the other modular components of the present invention, base section 32 can be easily lifted and set into place by an excavator or equivalent equipment (not shown). Furthermore, raising or lowering the elevation of the base section 32 and lower barrel section 31 dictates the sump capacity of the treatment tank 21. For example, the taller lower barrel section 31 is, the greater its capacity.
Connected to treatment tank 21 is an input conduit 50, which permits storm water to enter the treatment tank 21. The input conduit 50 is preferably made of PVC or HDPE piping. From an input orifice 51 of the input conduit 50, storm water is deposited into the treatment tank 21. In the example embodiment of
The treatment tank 21 preferably has a maintenance platform comprised of a trash grate 68, preferably made of aluminum. Grate 68 may be referred to as a “trash rack”. Grate 68 acts to separate relatively large debris, such as sticks, rocks, plastic, tin cans and other large debris, from entering the lower barrel section 31, and to minimize blockages of output conduit 60 or adjacent conduits. Storm water passes over and through the aluminum grate 68 as it flows from the inlet orifice 51 of the middle barrel section 30 to the lower barrel section 31. The aluminum grate 68 of the treatment tank 21 may have a hinged access hatch 67, which is connected to a stainless-steel lifting chain 41 that may attach to a ladder rung of the ladder 33. The hatch 67 is preferably 600×600 mm in size, which assists with making maintenance more efficient for a vacuum truck to clean the entire bottom of the sump in section 31, as such an opening is unlike a number of conventional treatment tanks that only have enough space for a suction hose and cannot be moved around.
The location of the aluminum grate 68 results in storm water passing through it, in turn reducing flow velocities, and thereby causing less disturbance of trapped emulsified oil in treatment tank 21.
Grate 68 is preferably made of aluminum. Aluminum is preferred over conventional alternatives because of its light weight making it easier to lift open for maintenance. Aluminum is also preferred over conventional alternatives because of its efficiency and/or effectiveness in treating storm water present in the treatment tank 21.
In particular, it is preferable for the grate 68 of the maintenance platform to be constructed of aluminum because of its atomic structure. The free aluminum oxide atoms present in the aluminum causes electrolysis of the free electron in the outer valence layer of an aluminum atom molecule, which may have the effect of changing the polarity of effluent and/or suspended particle molecules. Depending on the polarity between particle molecules, an attraction or repulsion takes place causing suspended solids to coagulate and settle to the bottom of the treatment tank 21.
With reference to
Vertical conduit 53 forces storm water to move in an upward (vertical) direction, preferably causing suspended solids to settle out into the sump in lower barrel section section 31.
A tee conduit 58 connects vertical conduit 53 to the outlet conduit 60. Fastened to the upper opening of the tee is a removable plug 55 connected to a handle 56 that lifts to open for maintenance personnel to access the vertical conduit 53 and/or outlet conduit 60 should either become plugged with debris.
The retention time of treatment tank 21 can be controlled, including increased in duration, in at least two ways (or a combination of both). In a first exemplary embodiment, conduits 53, 58, and 60 have a diameter that is less than the diameter of input conduit 50. In a second exemplary embodiment, the elevation of the invert of outlet conduit 60 is above the elevation of the invert of inlet conduit 50. A greater retention time, preferably in combination with the presence of an aluminum trash gate 68 to increase the contact time between the storm water and the aluminum, is advantageous for improving retention of solids and effluent, which results in increased efficiency of the storm water interceptor.
With reference to
A second exemplary embodiment of the present invention involves the use of more than one treatment tank. For example, a primary treatment tank 10 and a secondary treatment tank 12 are shown in
The treatment tanks 10, 12 are preferably cylindrical or substantially cylindrical in shape. Each tank 10, 12 has a cover 27, 16, respectively. Depending on site installation requirements, the cover 27 for the primary treatment tank 10 is preferably a solid manhole lid as shown or a catch basin grate. The cover 16 for the secondary treatment tank 12 is preferably a solid manhole lid (as shown) to keep large debris from entering the secondary treatment tank. A finish grade for covers 27, 16 may be set using pre-cast moduloc rings varying in thickness from 50 to 100 mm.
Inside primary treatment tank 10 is preferably four sections, namely, a flat cap 28 (or a transition section), an upper barrel section 29, a middle barrel section 30, and a bottom barrel section 31. However, alternative embodiments may have a greater or fewer number of sections within the primary treatment tank. Being part of the primary treatment tank 10, these modular sections 28, 29, 30, 31 are preferably each made from reinforced pre-cast concrete.
Inside secondary treatment tank 12 is preferably four sections, namely, a flat cap 24 as shown (or a transition section), a lower barrel section 27, a middle barrel section 26, and a bottom barrel base section 25. Both the primary treatment tank 10 and the secondary treatment tank 12 include a ladder 33, which allows access and egress. The ladder 33 is affixed to the inside of the walls of the primary treatment tank 10 and the secondary treatment tank 12. In one embodiment, the ladder 33 is constructed of aluminum.
Connecting the middle barrel section 30 of the primary treatment tank 10 with the middle barrel section 26 of the secondary treatment tank 12 is done via a connecting or lower conduit 56, which is preferably made of either PVC or HDPE piping. Such lower conduit 56 may be a straight connection from the primary treatment tank 10 to the secondary treatment tank 12 with no bending. In another embodiment, the lower conduit 56 may have bends ranging from 0 to 90degrees, or alternatively as site specifications may require. For example, there may be cases where there is a need to communicate storm water through the storm water interceptor around a street comer, or between the primary and secondary treatment tanks in a relatively crowded underground urban area.
The lower conduit 56 has a horizontal lower orifice 57 in the primary treatment tank 10 that permits storm water to enter in an upward (vertical) fashion based on an inverted elbow configuration 58. Storm water must take a 90-degree tum at an inverted elbow 58 then travel horizontally through the lower conduit 56 to the vertical lower orifice 59, in the middle barrel section 26 of the secondary treatment tank 12. The inverted elbow configuration ensures that the horizontal lower orifice 57 is below the invert elevation of the lower conduit 56. As such, the inverted elbow configuration 58 facilitates vertical flow into the lower conduit 56 to ensure suspended hydrocarbons and other lighter than water plastics are trapped in primary treatment tank 10, such as in barrel section 29 or 30 of primary treatment tank 10.
During installation, it is preferred that conduit 59 is pushed into watertight gaskets 37. This is accomplished by having holes in the walls of barrel section 30 of the primary treatment tank 10 and barrel section 26 of the secondary treatment tank 12 drilled or created according to applicable specifications (e.g., elevation and diameter) to ensure the watertight gaskets fit securely into the barrel section walls.
Further connecting the primary treatment tank 10 and secondary treatment tank 12 may be an overflow conduit 52, which is preferably made of either PVC or HDPE piping. The overflow conduit 52 allows bypass in case the storm water interceptor is not maintained and the trash grate 68 or the lower conduit 56 become plugged. Additionally or alternatively, the overflow conduit 52 allows bypass in case of a high volume of runoff. Preferably, the overflow conduit 52 has an inverted elbow configuration 55 at its first end at the primary treatment tank 10 such that the overflow conduit 52 has a horizontal overflow orifice 53, and at the secondary treatment tank 12 has a vertical overflow orifice 54. Due to possible backwater effects during full flow conditions of the input conduit 50, the invert elevation of the overflow conduit 52 is above the elevation of the horizontal orifice 53 and should be above (or at least the same as) the obvert elevation of the input conduit 50 (i.e., the obvert is the elevation of the top of input conduit 50). The elevation of the overflow conduit 52 acts as a control of the elevation of retained runoff. In this regard, a relatively higher elevation overflow conduit 52 will allow for a relatively higher elevation of retained runoff. In turn, this effect on elevation of retained runoff has an impact on retention time of retained runoff within the primary treatment tank 10. For example, if the overflow conduit 52 is positioned at a relatively higher elevation, this will generally promote a greater retention time for the retained runoff than the same primary treatment tank 10 that has a relatively lower elevation overflow conduit 52.
Connected to the secondary treatment tank 12 is an output conduit 60, which permits treated storm water to exit the storm water interceptor. Output conduit 60 is preferably made of PVC or HDPE piping. The output conduit 60 has a horizontal orifice 61 that permits storm water to enter the output conduit 60 in an upward (vertical) fashion based on an inverted elbow configuration 62. The inverted elbow configuration ensures that the horizontal output orifice 61 is located below the invert elevation of the output conduit 60 (i.e., the invert is the elevation of the bottom of the horizontal portion of the output conduit 60), as such a configuration acts to trap suspended oil and facilitates proper functioning of the system. The effectiveness of the secondary treatment tank 12 to separate suspended solids increases as the difference between the invert elevation of conduit 60 and the obvert elevation of conduit 56 becomes greater.
The elevations of the horizontal lower and output orifices 57 and 61 may vary depending on oil and sump capacity requirements. The degree in which the secondary treatment tank 12 retains emulsified oils further depends upon the elevation of the horizontal output orifice 61, compared to the invert elevation of conduit 60. Performance is increased as the elevation of the horizontal output orifice 61 decreases relative to the invert elevation of outlet conduit 60. Once moving horizontally in the output conduit 60, treated storm water may travel to a body of water such as a lake, river, ocean, or otherwise.
The vertical distance between the invert elevation of the output conduit 60 and the horizontal orifice 61 determines the capacity in which the secondary treatment tank 12 may hold oils and other petroleum like products. Much like the lower conduit 56, the output conduit 60 is equipped with a 90-degree inverted elbow 62 that limits the amount of oil from escaping the secondary treatment tank 12 during extreme high flow storm events. Preferably, 1.5 meters or greater is maintained between the invert of the horizontal orifice 61 and the bottom sump of base section 25 to prevent blockage from grit and sediment.
The efficiency of the storm water interceptor increases as the distance between the equilibrium water level (Hw) and the horizontal orifice 61 increases.
With reference to
With reference to
With reference to
It will be apparent to persons skilled in the art that a number of variations and modifications can be made to the storm water interceptor described herein. For example, although specific embodiments are described herein, it will be appreciated that modifications may be made to the embodiments without departing from the scope of the current teachings of the storm water interceptor described herein. For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, are only schematic and are non-limiting of the elements' structures. It will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention, which scope is defined by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 3218218 | Oct 2023 | CA | national |
