Abstract:
An apparatus for separating floating and non-floating particulates from drain water wherein said apparatus includes a first chamber for collecting non-floating particulates, a second chamber for collecting floating particulates, and a third chamber through which treated drain water can be discharged from the apparatus. An inlet pipe for introducing drain water into the first chamber is provided tangential to the first chamber to provide a vortex flow of drain water into said first chamber. An outlet pipe providing flow of drain water from the first chamber to the second chamber has an inlet at the vortex of drain water flow in the first chamber and an outlet that is spaced a predetermined distance from the floor of the chamber.

Description:
[0001]    The present invention relates generally to the treatment of stormwater and similar surface runoff. More particularly, the present invention relates to the removal of floatable and non-floatable matter there from so that cleaner water is returned to the environment.  
           [0002]    Eighty percent of the pollution to the North American fresh water resource has been attributed to stormwater runoff. Sediments, contaminated by hydrocarbons and their floating residuals, flow freely from paved impervious sites into storm water collection systems. Mitigated wetlands and storm water ponds are historically accepted as the method of controlling storm water quality. While ponds and wetlands are, on one hand, an effective treatment for non-point source discharges, they nevertheless undesirably occupy valuable commercial property and create an open water liability.  
           [0003]    Oil and grit separators have been used to control hydrocarbon loadings. Such a separator comprises a concrete structure linked to the storm drain system with two pools used to trap oil and grit. Such a separator is illustrated in “Hydrocarbon Hotspots in the Urban Landscape: Can they be Controlled?”  Watershed Protection Techniques , Vol. 1, No. 1, February, 1994. This article states that recent research indicates that such oil and grit separators are not effective in trapping pollutants.  
           [0004]    U.S. Pat. No. 5,759,415 describes a storm water treatment system which has a tangential inlet to a circular grit chamber wherein a swirling motion is produced to direct settleable solids toward the center and to reduce resuspension in the grit chamber. The water is released from the grit chamber into an oil chamber defined between the grit chamber and a barrier wall, which has an outlet that is located at the bottom thereof to thereby provide a baffle that traps floatables in the oil chamber. The barrier wall also has an upper overflow outlet. These outlets direct the water into a flow control chamber that has a lower outlet higher than the lower outlet from the oil chamber and has upper overflow outlet. These flow control chamber outlets, which are provided with weirs for flow control, direct the water into an outlet chamber from which the treated water is removed through a lower outlet pipe.  
           [0005]    According to the &#39;415 patent, the grit chamber outlet is in the wall thereof. Thus, water swirling along the side of the circular grit chamber wall is passed through this outlet. Suspended particulate matter may not have been adequately removed from this water by the time it passes into the outlet that is also inefficiently large in size. It is therefore considered desirable to more efficiently remove particulate matter from the water before it is passed into the oil chamber.  
           [0006]    It is accordingly an object of the present invention to provide a more efficient storm water treatment system.  
           [0007]    It is also an object of the present invention to provide such a system which is inexpensive, easy to operate, and reliable.  
           [0008]    In order to provide such a system, in accordance with the present invention, runoff water is passed tangentially into a primary chamber wherein non-floatable matter is removed by swirling action of the water, then through an outlet for passage into a secondary chamber for removal of oil and other floatable matter therefrom, the outlet being located centrally of the primary chamber to remove water from which greater amounts of non-floatable matter has been removed.  
           [0009]    The outlet from the primary chamber is preferably provided by a conduit that extends into the primary chamber with its end portion, which provides the outlet, disposed vertically.  
           [0010]    The above and other objects, feature, and advantages of the present invention will be apparent in the following detailed description of the preferred embodiment thereof when read in conjunction with the appended drawings wherein the same reference numerals denote the same or similar parts throughout the several views. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a plan view, with top covers removed to show internal structure, of a storm water treatment apparatus consistent with the present invention.  
         [0012]    [0012]FIG. 2 is a sectional side view of the apparatus of FIG. 1 taken along lines A-A of FIG. 1.  
         [0013]    [0013]FIG. 3 is a section view taken along line  3 - 3  of FIG. 1.  
         [0014]    [0014]FIG. 4 is an enlarged plan view of a conduit of the apparatus of FIG. 1.  
         [0015]    [0015]FIG. 5 is a sectional view taken along lines  5 - 5  of FIG. 2. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    Referring to the drawings, there is illustrated generally at  10  an apparatus for treating water  12 , such as stormwater or other surface runoff such as, for example, from industrial, commercial, and urban applications. The water  12  is treated by removing non-floatable matter such as sand, hydrocarbon-laden sediment, debris, silt, and heavy metals, illustrated at  14 , and floatable matter such as oil and other petroleum-based liquids, illustrated at  16 , therefrom. The contaminated water is received through inlet pipe  18 , as illustrated at  19 , and the treated water is discharged through outlet pipe  20  for return to the environment, as illustrated at  21 , or as otherwise desired.  
         [0017]    The apparatus  10  comprises a primary chamber, illustrated at  22 , for removing sediment and other non-floatables  14  from the water, a secondary chamber, illustrated at  24 , for removing oil and other floatables  16  from the water, and a tertiary effluent chamber, illustrated at  26 . The water  12  initially enters the primary chamber  22  by flowing through inlet pipe or conduit  18  and is discharged from the tertiary chamber  26  although outlet conduit  20 . The inlet conduit  18  typically would be an existing conduit sized for the flow rate to be handled, and the apparatus  10  typically would be constructed at the site for connection of the conduit  18  thereto.  
         [0018]    The primary chamber  22  may be contained within a housing  28  which has a circular wall  30 , a floor  32 , and a ceiling  34  suitably joined together and composed of suitable material such as, for example, high strength steel-reinforced corrosion-resistant precast concrete suitable for heavy truck traffic loading. The floor  32  is desirably a monolithic base section for desirably providing anti-floatation of the housing  28 . The housing  28  may, for example, be on the order of about 6 to 10 feet high and about 6 to 10 feet in inside diameter depending on the flow rate, on the order of about 3 to 26 or higher cubic feet per minute, the apparatus is to be capable of handling. The pipe  18  is suitably sealingly secured in an opening in the wall  30  of housing  28 . Conduit  18  as well as other conduits described in this specification, which may be composed of steel, plastic, or other suitable material, may be suitably sealingly secured in openings in their respective walls by means of grout, illustrated at  19 , or other suitable means. The secondary and tertiary chambers  24  and  26  respectively may be contained within a similarly shaped and sized housing  36 , and which is shown to have a circular wall  31 , a floor  33 , and a ceiling  35 . Alternatively, chamber  24  nad  26  may be contained in separate housings. Housing  36  may be otherwise suitably shaped, such as, for example, rectangular in a horizontal plane. Outlet pipe  20  is suitably sealingly secured within an opening in the wall  31  of housing  36 . Inlet  18  and outlet  20  are located at about the same height intermediate the heights of the housings  28  and  36  respectively, for example, at or slightly below mid-height. Outlet pipe  20  exits radially of housing  36 , i.e., in a direction along a direction in which a diameter of the housing extends. The outlet pipe  20  is sized to handle the flow rate and thus would typically have a diameter equal approximately to the diameter of inlet pipe  18 .  
         [0019]    When, during a storm event, the water flow through pipe  18  is near the capacity of pipe  18  (flow rate for which pipe  18  is sized), the water is flowed into the chamber  22  at high velocity to achieve a long path length for the solids during travel through the first chamber which allows the non-floatable solids  14  to desirably be deposited out or dropped to the bottom of the chamber  22  and thereby become separated from the water. The storm event creates the energy to achieve the desired velocity.  
         [0020]    If desired, a suitable check valve may be installed on pipe  18  to prevent back-flow as well as to provide a nozzle effect by opening only under a head pressure thereby providing the desired velocity when there is flow into the chamber  22 . A suitable check valve for this purpose is a Tideflex™ valve marketed by Red Valve Company, Inc. of Pittsburgh, Pa. Such a valve may be especially desirable in tidal areas to prevent back-flow.  
         [0021]    The pipe  18  is disposed, as illustrated in FIG. 1, to be tangential to the primary chamber  22 , i.e., it extends in a direction, in a horizontal plane, generally of a direction in which a tangent to the chamber  22  in the horizontal plane extends The high velocity water is thus introduced into the primary chamber  22  tangentially in order to effect a circular or swirling motion, illustrated at  40 , to the water about the vertical axis  42  of the chamber  22  to form a void or vacuum or vortex and thereby drawing toward and into the vortex bodies subject to its action, i.e., drawing suspended particles  14  in the water into the vortex and dropping them onto the bottom of the chamber  22 , as illustrated in FIG. 2. This vortex action is provided to also keep the non-floatable particles  14  on the chamber bottom so that they don&#39;t become re-entrained or resuspended in the water.  
         [0022]    The water with the non-floatable matter  14  removed is then removed from the primary chamber  22  for passage into the secondary chamber  24  through an outlet  50 . If the outlet was located in the circular chamber wall  30 , as in the aforesaid Vortechnics apparatus, the water may not be as devoid of non-floatable matter as water nearer the vortex. Water is preferably removed near the vortex where it is more devoid of non-floatable matter. This allows a higher quality of partially treated water to be delivered to the secondary chamber  24  for more efficient water treatment. In accordance with the present invention, one section of a pipe or other suitable conduit  144 A is received and suitably sealingly secured in adjacent openings  46  and  48  in the walls of primary and secondary chambers  22  and  24  respectively disposed a spaced distance, for example 12″ as shown in FIG. 2, from the bottom surfaces of the chambers thereof for delivery of the water to the secondary chamber  24 . The other end portion of the pipe  144  is positioned to extend vertically at the center  42  of the primary chamber  22  and terminates slightly above the height of pipe  18  at the inlet  38  to provide the opening  50  to serve as an inlet for the water at the center  42 . The opening  50  is positioned at the center of the chamber  22  so that they are at the center of the vortex, the rotating motion of the water and the resulting low pressure at the vortex causes entrained particles to fall downwardly into a stable pile so that the water, but not the diverted particles, enters the intake at that location. Thus, the pipe extends horizontally from the secondary chamber  24  into the center of the primary chamber  22  then bends 90 degrees to extend vertically to its terminal end. The pipe  144  may be supported above the floor  32  of the housing  28  by a section of pipe  144 C. The floor  32  provides a surface on which the non-floatable material  14  is received. The pipe  144  extends vertically upward above the height of the inlet  18 . The entrance to the pipe may be shaped like an inverted truncated cone. Located in the center of the opening  50  may be an anti-vortex device  157 . The anti-vortex device may be made of a suitable material such as a plastic or metal.  
         [0023]    An anti-retrainment plate  17  is shown installed below the inlet of conduit  18  (for example, about 6 to 12 inches below the inlet). Such a shelf is considered to be optional. Without wishing to be bound by theory here or elsewhere in this specification, it is believed that such a plate  17  may be desirable to accelerate the settling of the solids  14  and provide some separation between the settled solids and the swirling water flow  40  whereby the space below the plate  17  may be relatively less turbulent so that the solids may more efficiently be kept separated. The anti re-entrainment plate  17  creates a flow gradient and pressure differential within swirling water flow  40 . This pressure differential allows sediment to fall below the plate and to be trapped thus preventing re-entrainment.  
         [0024]    The anti-retrainment plate  17  is a plate that extends horizontally and may be supported by the wall  30 . The plate has a centrally located opening  121 , preferably circular, for allowing non-floatables  14  to settle to the bottom of the primary chamber  28 . The opening  121  has a diameter that is substantially greater than that of the conduit  144  (for example, about twice the diameter of conduit  144 ) to provide an area underneath the vortex for the particles of sediment  14  to drop through. The plate may optionally have a plurality of openings or cutouts, illustrated at  17 A in FIG. 5, spaced circumferentially about the plate  17  to allow a continuity of the swirling motion  40  below and above the plate  17 . For example, the plate  17 , which may have a thickness of about ¾ inch and may be composed of a similar material as an anti-vortex device  157  is composed, may have a plurality (four shown) of openings  17 A equally spaced circumferentially about the plate and each of which may be square in shape, have a length and width each of approximately one tenth of the diameter of chamber  22 , and be positioned approximately midway of a radius of chamber  22 . Other opening shapes are also contemplated including circles, triangles, rectangles, and quadrilaterals as well as different quantities of opening, and arrangement.  
         [0025]    A plurality of vortex breakers  11  with a sediment distribution notch may be circumferentially located about the floor  32  of the first chamber  22 . The vortex breakers can be used to break the vortex flow and slow the flow and encourage suspended sediment to be deposited in chamber.  
         [0026]    An opening  51  located in the pipe  144  provides for a coriolus intake of stormwater at low flow rates such as during lighter storms. The stormwater enters the first chamber  22  through the inlet  18  and exits the first chamber through the vertical pipe  144  and travels to the second chamber  24 . In the embodiment shown, the opening is approximately 2″ in diameter and is located at or below the level of the inlet pipe  18 . The size of the opening may depend on the capacity of stormwater to be treated. A second opening  52  may be provided above the openings  51  by a small distance of, for example, about 6 inches in order to handle, in conjunction with openings  50 , an increased flow rate. This also allows the openings  51  and  52  to be sized desirably small for increased efficiency of sediment removal, i.e., the sediment does not as easily enter the openings  51  and  52  when they are smaller. The single openings  51  and  52  may be replaced by a plurality of openings circumferentially disposed about the periphery of the pipe  144 . For example, each opening  51  and  52  may comprise about 6 openings equally spaced circumferentially and each having a diameter of about 1 inch. A suitable baffle may be provided over each of the openings  51  and  52  to deflect particles, which have not already fallen, away from the openings  51  and  52  so that good efficiency of the apparatus  10  can be maintained. Thus, the coriolis intake is provided to allow the stormwater above the separated solids to pass virtually sediment-free to the next treatment phase in secondary chamber  24 .  
         [0027]    An overflow pipe or other suitable conduit  54  extends between the primary and tertiary chambers  22  and  26  respectively near the ceilings thereof, and is suitably sealingly attached in openings  25  and  29  in the walls thereof, for dumping some of the treated (due to the swirling action  40 ) water into the tertiary chamber  26  if the flow rate into the primary chamber  22  exceeds its capacity to handle it. The overflow pipe  54  extends radially, i.e., in a direction along which a diameter of the housing extends, into the first chamber  22  approximately half way to the axis  42 . A first end  54 A of the pipe  54  is cut at an angle to the vertical axis. The pipe provides an anti-vortex effect at high flows. Details of the angle are shown in FIG. 4. The angle may face towards or away from the inlet pipe  18 . The angle is shown at 30°, although other angles are contemplated, preferably ranging from about 10° to about 80°. The second end  54 B of the pipe  54  extend through an opening  68  in a barrier wall  58  that separate the second and the third chambers.  
         [0028]    Oil and other floatable material  16  is separated from the water in the secondary chamber  24 , i.e., means are provided for preventing the floatable material from entering the tertiary effluent chamber  26 . The secondary chamber  24  is provided to be relatively quiescent, suitable for allowing oil and other floatable matter to float to the top without disruptedly mixing back into the water whereby such separation may efficiently occur. In order to prevent oil from entering the tertiary chamber  26 , the barrier wall  58  extends upwardly from the floor  33  of the housing  36  and stops just below the ceiling  33 , leaving a gap  59 . Two openings  58 A and  58 B are formed along the lower edge of the wall  58  and the sidewall  31 . The openings  58 A and  58 B are offset from the longitudinal axis of the pipe  144 A. The top edges of the openings  58 A and  58 B are lower than the exit of the horizontal pipe  144 A. Stormwater exiting pipe  144 A enters the second chamber  24 . The stormwater exits the second chamber  24  through the openings  58 A and  58 B and enters the third chamber  26 . The stormwater follows a flow path, illustrated at  60 . Since water entering chamber  26  comes from the bottom of the body of water in chamber  24  and since oil and other floatables rise to and float on top of the water, the flow path  60  is accordingly provided so that they do not enter the third chamber  26 .  
         [0029]    In order to prevent oil-laden water exiting pipe  144 A from passing directly into pathway  60  so that good separation efficiency of the apparatus  10  is maintained, an upper portion of the pipe  144 A is removed leaving only a lower portion  64  at the end  144 B of pipe  144 A. The lower portion  64  of the pipe  144 A is secured in the barrier wall  58 . The stormwater travels along the pipe  144 A and is redirected by the barrier wall  58  so that the floatables  16  have time to rise after the water passes out of the pipe  144 A. The gap  59  may allow storm water to pass in the event of a high flow rate.  
         [0030]    The passage of the stormwater, with non-floatables  14  removed in the primary chamber  22  and with floatables  16  removed in the secondary chamber  24  enters the tertiary effluent chamber  26  for its removal through pipe  20  to the environment in an environmentally desirable cleansed state.  
         [0031]    Thus, the trapped floating contaminants  16  in secondary chamber  24  are raised with the water level therein, which is kept at that level or higher by the height of exit pipe  20  so that the floatable contaminants, created by the storm event and subsequent storm events, are not washed out through the pipe  20 . The stormwater level in secondary chamber  24  is normally maintained during quiescent periods at the height of the exit pipe  20 .  
         [0032]    An opening, illustrated at  80 , is contained in the ceiling  34  for venting as well as to allow access to primary chamber  22  for removing the sediment  14  therefrom and otherwise maintaining it. Similarly, a vent opening, illustrated at  82 , is contained in the ceiling  35  and which allows access to chamber  24  and  26  for skimming the oil  16  from the surface of the water and removal thereof and otherwise for maintenance. Opening  80 , which may have a diameter of, for example, about 24 inches, is suitably positioned so that it is not directly over the outlet provided by pipe  144  Opening  82  may be similarly sized. To each of these openings is suitably installed, in known manner, a hatch  86  with a suitable vented cover  88 , each of cast iron, steel, plastic, or other material. In order to allow for elevation change, i.e., so that the vent outlets are desirably above grade, riser rings  90  are provided between the respective ceiling and the cover  88 , and the riser rings are suitably sealed to each other and to the ceiling and the cover by, e.g., butyl joint material, illustrated at  92 , or other suitable means. The number of riser rings  90  (three shown for each hatch) will vary depending on elevation. The hatch for the primary chamber is illustrated with the riser rings apart for ease of illustration.  
         [0033]    If desired, additional equipment may optionally be added to the apparatus  10  for improving the separation efficiency thereof. For example, the secondary chamber  24  may be provided with an ECOSEP™ oil-water separator, marketed by env21™ of East Pembroke, N.Y., or other suitable high efficiency separator (with internal storage containment) for additional treatment (during non-storm events) to purify down to perhaps about 5 parts per million of non-emulsified free oil. For another example, a suitable coalescing filter structure, conventionally known in the art, may be attached to the outlet of the pipe  144 A in the secondary chamber  24  to coalesce floatable particles into clumps thereof so that they more efficiently rise to the surface.  
         [0034]    Thus, in accordance with the present invention, the outlet from the primary chamber is provided at the location of the vortex in order to receive water with a maximum of non-floatable particles removed therefrom so that the contaminant removal efficiency may be maximized, to achieve a removal rate efficiency of perhaps about 80 percent for a typical bimonthly rainfall activity.  
         [0035]    It should be understood that, while the present invention has been described in detail herein, the invention can be embodied otherwise without departing from the principles thereof, and such other embodiments are meant to come within the scope of the present invention as defined in the following claim(s)