Abstract:
A method and apparatus for separating oil and debris from urban water run-off, the apparatus being made up of a chamber which is mounted in a storm drain system and has an inner basin with a tilted wire wedge wire screen filter in the path of flow of the run-off, an organic absorber floats on the water as it is collected in the basin, and a discharge plate has a series of slots which are sized to regulate the flow rate of discharge of the water from the basin for removal through an outlet at the lower end of the chamber. The method and apparatus are conformable for use with existing storm drain systems along curbs or gutters as well as parking lots, runways and the like.

Description:
BACKGROUND AND FIELD OF INVENTION  
       [0001]     This invention relates to a method and apparatus for filtering trash and organic materials; and more particularly relates to a novel and improved method and apparatus for separating oil and debris from urban run-off.  
         [0002]     Environmental pollution has become a serious problem for all cities and towns across the country. Urban run-off containing debris and organic oils and other hydrocarbon materials are washing into rivers, bays and estuaries adjacent to the cities and towns. To date there has been little effort to contain this pollution. Recent Federal Regulations have begun to address the problem but, to date, the technology is not adequate. Further, a number of partially effective devices have been developed to catch debris and capture the floating oils to prevent them from moving out of containment and down to the discharge point, representative of such devices being set forth and described in U.S. Pat. No. 6,497,816 to W. Naddy, U.S. Pat. No. 6,361,248 to R. M. Maestro, U.S. Pat. No. 6,350,374 to R. R. Stever et al, U.S. Pat. No. 6,325,897 to K. Maxwell, U.S. Pat. No. 6,287,459 to J. K. Williamson, U.S. Pat. No. 6,200,484 to S. J. McInnis, U.S. Pat. No. 6,080,307 to J. F. Morris et al, U.S. Pat. No. 5,820,761 to J. M. Bamer et al, U.S. Pat. No. 5,653,880 to P. C. Mouton, U.S. Pat. No. 5,593,584, H. L. Nurse, Jr., U.S. Pat. No. 4,671,877 to B. C. Godbeer, U.S. Pat. No. 3,972,814 to A. Paszye et al, U.S. Pat. No. 3,945,920 to A. Paszye et al and U.S. Pat. No. 3,630,379 to T. D. Sharples.  
         [0003]     Of the containment systems presently in use, drainage surfaces adjacent to roads or parking lots are employed to capture storm run-off but are not very effective for containment of the run-off for organic removal. The technique of containment and absorption for organic material is flawed, also, due to the design of the water exit flow plate, since some oils flow through the holes in the plate and into the water course. In addition, the standing water in a pond is a serious problem and provides a breeding ground for mosquitoes including those which may be infected by the West Nile virus. Accordingly, there is a serious need for a containment system capable of completely separating the organic oils from the debris in urban run-off and in such a way that the separation can be carried out efficiently while avoiding standing water for any length of time, requires a minimum number of moving parts, and is readily conformable for use in existing drainage systems, such as, for example, storm drain systems presently in use.  
       SUMMARY OF THE INVENTION  
       [0004]     Among other objects and advantages of the present invention, it is an object to provide for a novel and improved method and apparatus for filtering debris and organic oils from water run-off.  
         [0005]     It is another object of the present invention to provide an apparatus of the type described for a novel and improved method and means for absorbing hydrocarbon materials from water run-off.  
         [0006]     It is a further object of the present invention to provide for a novel and improved drain for efficiently removing debris and organic oils which can be retrofit to existing drain systems and facilitates clean out of solid debris collected in the chamber as well as replacement of the organic oil absorber material.  
         [0007]     In accordance with the present invention, apparatus is provided for separating oil and debris from water run-off comprising a chamber or vault disposed in the path of the run-off having an upper inlet which is in the path of flow of the run-off, a downwardly inclined wedge wire screen extending from the inlet for advancement of the run-off thereacross, a basin including debris-collecting means for collection of solid materials at the lower end of the screen, an organic absorber disposed in the path of run-off passing through the screen for the absorption of organic oils in the run-off, an outlet at a lower end of the chamber, and discharge means for removal of run-off after it has passed through the organic absorber.  
         [0008]     The organic oil absorber is in the form of a buoyant pillow or pad which will float on top of the water that accumulates in the basin, and the optimum rate of flow of water through the basin is regulated by a series of vertically spaced, horizontally extending discharge orifices. Although the organic oil absorber is located beneath the screen, the screen is preferably hinged at the bottom so that it will open up to permit access to the pillow and permit ease of replacement of the pillow once it has become saturated with the organic oils. I have previously devised a Coanda effect screen characterized by having tilted wires to achieve highly efficient debris and particulate filtration. The current invention has been found to be particularly effective in the separation of organic oils from the water and debris without impeding the flow of run-off, reference being made to my copending application for patent Ser. No. 10/430,858, filed 5 May, 2003 entitled APPARATUS AND METHOD OF PARTICULATE REMOVAL FROM LIQUIDS, and incorporated by reference herein.  
         [0009]     The above and other objects, advantages and features of the present invention will become more readily appreciated and understood from a consideration of the following detailed description of preferred and modified forms of the present invention when taken together with the accompanying drawings in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a somewhat schematic view shown partially in section of a first form of separation system in accordance with the present invention;  
         [0011]      FIG. 2  is an elevational view of the discharge plate in one sidewall of the screen box;  
         [0012]      FIG. 3  is a front elevational view partially in section of the arrangement of the filtration screen and acceleration plate in relation to a storm drain; and  
         [0013]      FIG. 4  is a somewhat schematic view partially in section of another embodiment of the separation system adapted for use in a parking lot. 
     
    
     DETAILED DESCRIPTION  
       [0014]     Referring in more detail to the drawings, there is shown by way of illustrative example in FIGS.  1  to  3  a separator apparatus  10  for separating debris and organic oils from water, such as, for example, urban run-off flowing along a gutter G between a curb C and either side of a street and having storm drains located at spaced intervals in the curb C which flanks one side of the gutter and is slightly raised with respect to the gutter. The apparatus  10  of the present invention is readily conformable for use with existing curbs and gutters by installing a chamber or vault  12  beneath the curb C such that an upper inlet  14  is aligned with the opening or drain D which is typically provided with spaced metal bars, not shown, to prevent larger debris from passing into the drain system.  
         [0015]     The chamber  12  is made up of vertical side and end walls  20  and  21 , one of the side walls  20  including the inlet  14  and a lower outlet  22 . An upper flat, removable manhole cover  26  is positioned in a top wall  28  to permit access to the interior of the chamber  12  for cleaning purposes in a manner to be described.  
         [0016]     A basin  30  is suspended within the chamber  12  by a suitable bracket  31  which is anchored to the sidewall  20 . The basin  30  is made up of a basin end wall  32 , a discharge plate  34  opposite to the end wall  32  and opposite side walls  36  along with a bottom wall  38  which slopes downwardly from the end wall  32  to the lower end of the discharge plate  34  and is spaced above a bottom wall or floor  24  of the chamber. An acceleration plate  40  of bowed or arcuate configuration and having a lift handle  41  slopes downwardly from the lower edge of the inlet  14  over the bracket  31  into abutting relation to the upper end of a tilted wire wedge wire screen  42 . The screen  42  inclines downwardly inside of the basin  30  to terminate in a lower edge which is hinged as at  44  to the bottom wall or floor  38  of the basin  30 . The tilted wire wedge wire screen  42  has horizontally extending, vertically spaced, tilted wires  46  as illustrated in  FIG. 1  traversing the entire width of the basin  30  between the opposite side walls  36 . The drain water run-off flows downwardly over the acceleration plate  40  and along the screen  42  to filter out any debris which collects as represented at T at the foot or base of the screen and along the floor surface  38 .  
         [0017]     As best seen from  FIGS. 1, 2  and  3 , the discharge plate  34  is of generally rectangular configuration having a series of vertically spaced horizontally extending slots  56  substantially traversing the width of the plate. A hood or baffle  58  is disposed in overhanging relation to each of the slots  56  so that the water is forced to flow upwardly around the lower open end of each baffle  58  and out through the slot  56  to flow downwardly through the channel or space  60  between the discharge plate  56  and sidewall  20 . The baffle  58  also acts to prevent organic oil on the surface of the run-off from passing through the slot  56 . The slots  56  are uniform in length and width with the exception of lower slot  57  which is narrower in length and width. This is to permit the filtered water to be discharged downwardly toward the outlet  22  with a minimum of residual water left in the bottom of the chamber or vault  12 .  
         [0018]     The water together with any organic oils are free to pass through the screen  42  and accumulate as represented at W in the basin. Any organic oils will float on the top surface of the water and an organic absorber pillow  50  is comprised of an outer mesh-like or porous container or bag  52  filled with a hydrophobic material  54  which is typically used in oil spills to absorb oil. The absorber  50  is also provided with one or more lift handles  55  to permit replacement by pivoting the screen  42  laterally about the hinge  44  by grasping the handle  41  on the acceleration plate  40 . The manhole cover  26  permits easy access to the lift handle  55  on the absorber  50 . Also, the manhole cover  26  can be lifted to permit insertion of a suction device to remove the trash or debris T on the floor  38  of the basin  30 . The density of the pillow  50  is controlled to be buoyant and float on the top surface of the water W where the organic oils will tend to collect; also, the pillow  50  is of a width to substantially traverse the width of the discharge plate  34  so as to be in the path of flow of the water through the discharge plate in a manner now to be described.  
         [0019]     In the event that the water level should increase more rapidly than it can be discharged through the slots  56 , the basin end wall  32  serves as an overflow pier so as to prevent water from backing up through the inlet and to escape over the pier in the direction of the arrows and downwardly for removal through the outlet  22  and back to the system. It will be apparent that the specific spacing and inclination of the screen  42  away from the discharge plate  34  may be varied according to the space required for the absorber  50  to be freely movable up and down with the water level. Similarly, dimensioning of the slots  56  can be regulated according to the flow rate or the capacity of water run-off encountered.  
       Alternate Forms of Invention  
       [0020]     An alternate form of invention is illustrated in  FIG. 4  in which like parts are correspondingly enumerated to those of FIGS.  1  to  3 . The alternate form of invention is designed primarily for use in connection with a drainage surface or parking lot and, in place of a solid top wall  28  with manhole cover  26  of the form of FIGS.  1  to  3 , utilizes a grate  60  at a low point in the surface of the parking lot. The basin  30 ′ is modified to eliminate the acceleration plate of the first form and to extend the tilted wire wedge wire screen  42 ′ directly from the upper end of the discharge plate  34 ′ to the lower hinged end  44 ′ on the floor  38 ′ of the basin  30 ′. A baffle  62  is positioned above the discharge plate  34 ′ and inclined downwardly toward the screen  42 ′ to deflect the water run-off and cause it to flow by gravity downwardly along the screen  42 ′. In addition, a main baffle plate  64  is hinged as at  66  to an end wall  32 ′ and is capable of pivoting upwardly and downwardly through a controlled angle to direct the flow rate of water passing through the grate  60  and the water level W′ in the basin  30 ′. The baffle  64  is supported by a bracket support  68  which prevents the baffle  64  from coming into contact with the screen  42 ′. As in the first form, the absorber pillow  50 ′ is buoyant and free to follow the water level so as to intercept any organic oils on the surface of the water before the oils come into contact with baffles  58 ′ which further prevent the oils from escaping through the discharge slots  56 ′.  
         [0021]     It will be evident that the slots  56 ′ may extend continuously across the discharge plate  34  so that the passage of water is restricted by the size of each slot  56 ′. This sometimes results in the overtopping of the screen  42 ′ and discharge plate  34 ′. However, this problem is overcome by the sizing of the slots  56 ′. The entire process can be accelerated by increasing the size of the slots  56 ′ in the plate  34 ′ from the lower end to the upper end of the plate  34 ′. This configuration will pass more water depending upon the flow and level of water in the device thereby reducing the size and cost of the device and outlet structure, since the more rapidly the device can be emptied the more effective the process will become.  
         [0022]     When used in association with parking lot run-off, the device is designed to be of sufficient volume to capture the expected run-off from the impervious surfaces. The device may also be placed in a swale which may then be planted with broad-leaved grass and plants to catch the floating organic oils and solvents. It must also be capable of capturing debris and passing water without becoming plugged and, to this end, the system of  FIG. 4  is most desirably located at a low center of a slightly sloped parking lot. Gravity will draw the run-off to pass through the grate  60  and into the basin  30 ′.  
         [0023]     It is therefore to be understood that while preferred forms of invention are herein set forth and described, the above and other modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and reasonable equivalents thereof.