Abstract:
A stormwater drainage system capable of collecting, pretreating and disposing of the stormwater runoff into a dry well. Further capable of stopping the flow of stormwater into the dry well in the event hydrocarbons or other contaminants are present in the stormwater. The system is also capable of isolating stagnant water in the system to prevent the infestation of mosquito larvae.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a stormwater pretreatment system, more particularly to a stormwater pretreatment system that uses an actuated valve to isolate the disposal well from the stormwater in the event the stormwater is contaminated by gasoline, diesel fuel, kerosene or other hydrocarbons. Further, this invention relates to a stormwater pretreatment system that isolates standing water in the oil/water separation to reduce the effect of infestation of mosquito larvae. 
   2. Prior Art 
   When it rains on unimproved natural land, the rain and stormwater runoff is either absorbed into the soil or moves along the surface of the land, moving downward towards creeks and larger and larger rivers. However, as areas become more densely populated, this natural dispersion of rain and stormwater is altered by the man-made improvements such as parking lots, roads and buildings and earth work disturbing the original contours of the land. This also leaves less open ground surface to absorb the rain, thus adding to the stormwater runoff. 
   In many cities, stormwater sewers are constructed to handle the large amount of stormwater runoff that comes off of the buildings, parking lots and roads. The stormwater sewers route the water to creeks and drainage ditches which form the tributaries to larger rivers. However, most cities in arid regions do not have a stormwater sewer; therefore, when it rains there is no pathway for disposing of the stormwater runoff coming from the buildings, parking lots, roadways, etc. 
   In many of the cities without stormwater sewers, landowners are required to construct a system to collect the stormwater runoff and a disposal well or dry well which puts the water into a pervious subsurface structure. 
   The disposal of the stormwater can be further complicated when it becomes contaminated with petroleum byproducts or other substances which can contaminate the groundwater or aquifer. As such, it is necessary to have a system which is capable of stopping the flow of stormwater runoff into the dry well when gasoline, diesel fuel, kerosene or other hydrocarbons are present in the stormwater runoff. 
   Catch basins capable of intercepting contaminated stormwater runoff are known in the art. U.S. Pat. No. 5,569,372 entitled “Catch Basin Structure for Interception of Contaminants Having Detachable Parts” issued on Oct. 29, 1996 discloses a catch basin structure equipped with a manual valve capable of stopping the flow of stormwater runoff. Likewise, U.S. Pat. No. 5,067,850 entitled “Apparatus for Detection and Containment of Pollution in a Drainage System” issued to Robert L. Gray on Nov. 26, 1991 discloses a storm drainage system including a gate which controls the release of the contents of the drainage system. The gate is motor activated which is responsive to manual activation or hydrocarbon sensor activation. 
   U.S. Pat. No. 5,160,036 entitled “Automatic Pollution Containment and Alert Apparatus for Liquid Drainages” issued to Charles P. Childers on Nov. 3, 1992 discloses an apparatus for containing liquids and pollution within a liquid drainage comprising a first conduit, a second conduit, a liquid barrier, a means for lifting, and a means for sensing pollution. In the device disclosed in the Childers&#39; patent, the one end of the second conduit can be lifted to stop the flow of the drainage. 
   While the Smith, Gray and Childers patents all disclose ways of stopping the flow of stormwater runoff in the event of contamination, they do not disclose a complete system necessary for collecting, pretreating and disposing of stormwater runoff into the groundwater or an aquifer. 
   The ENVIBRO System marketed by McGuckin Drilling, Inc. is a system to pretreat stormwater runoff and dispose of it into the groundwater or an aquifer. The ENVIBRO System, as disclosed in the brochure, has a collection chamber which feeds into a three-chambered separator which removes silt and other impurities from the stormwater. The three-chambered separator feeds into a dry well which disposes of the stormwater into the groundwater or an aquifer. The ENVIBRO System has a passageway between the three-chambered separator and the disposal well. The entry into this passageway is partially filled with a plurality of proprietary IMBIBER beads. 
   Under normal operation, water passes freely through the entryway. However, when contacted by an active organic liquid, the IMBIBER beads absorb the liquid and expand. The swollen beads fill the entry into the passageway, thus stopping the flow of contaminated water. Once the system has been activated by a pollutant, the flow of water stops. In order to reuse the system, the polluted water must be pumped off and the entryway with the beads must be replaced. This adds additional cost to the operation and requires additional time. 
   SUMMARY OF THE INVENTION 
   Due to the shortcomings of the prior art, it is an objective of the present invention to provide a stormwater pretreatment and disposal system which is capable of gathering and storing the stormwater runoff, while removing gasoline, diesel fuel, kerosene and other lighter than water contaminants as well as sediment from the stormwater and disposing of the stormwater down a disposal well, and have the capability of stopping the flow down the disposal well in the event contaminants are sensed in the stormwater. 
   Another objective of the present invention is to provide a stormwater pretreatment and disposal system as previously mentioned which is capable of being reset to allow the flow of stormwater down the disposal well once the system has been tripped without replacement of parts. This is achieved through the use of an actuated valve and a discriminating sensor capable of differentiating between contaminants and stormwater. The system can also be equipped with a remote control panel and alarm so that an operator can be alerted of the presence of contaminants in order to take the appropriate action. 
   It is a further objective of the present invention to provide a stormwater pretreatment and disposal system as previously described which is capable of isolating standing water from the ambient air in order to eliminate mosquito breeding grounds. 
   Other objects, features, and advantages will be apparent to persons of ordinary skill in the art in view of the following detailed description of preferred embodiments and the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, the needs satisfied thereby, and the features and advantages thereof, reference now is made to the following descriptions taken in connection with the accompanying drawings in which: 
       FIG. 1  is a cross sectional schematic of the preferred embodiment of the present invention. 
       FIG. 2  is a schematic diagram of the electronics to operate the system. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows the preferred embodiment of the stormwater pretreatment and disposal system  20 . The stormwater pretreatment system  20  is used to gather stormwater runoff and process it prior to disposing of the stormwater into the groundwater or an aquifer. The stormwater pretreatment system  20  is comprised of a retention area  22  with a collection vault  24 , oil/water separator  26 , dry well  28 , and a valve  30  with an actuator  32 , controls  34 , and sensing probe  36 . The retention area  22  has a bottom  38  and one or more walls  39  which form a pit to hold water. 
   The collection vault  24  is typically located in the bottom  38  of the retention area  22  such that the inlet  40  of the collection vault  24  is located in the bottom  38  of the retention area  22 . If necessary to prevent the sediment from entering the collection vault  24 , the inlet  40  can be raised slightly above the bottom  38  of the retention area  22 . The collection vault  24  has a pipe  44  which leads from the collection vault  24  to the oil/water separate  26 . The pipe  44  has a swing check valve  46 . The swing check valve  46  allows the stormwater to flow from the collection vault  24  into the oil/water separator  26 . However, when there is no flow through the pipe  44 , the swing check valve  46  closes off the passageway of the pipe  44 . This prevents mosquitoes from incubating in stagnant water found in the oil/water separator  26  and then becoming a nuisance on the property adjacent the stormwater pretreatment system  20 . 
   The oil/water separator  26  can be equipped with baffles  48  which help direct the flow of the stormwater through the oil/water separator  26  to increase dwell time in the oil/water separator  26  reduce velocity and turbulence and thus increase its efficiency. The oil/water separator  26  is also equipped with a plate coalescer  50  which is used to separate any gasoline, diesel fuel, kerosene and other hydrocarbon contaminants as well as sediment from the stormwater. 
   The oil/water separator  26  shown in figure one can also be equipped with one or more manways  52  which are used so that individuals can access the interior of the oil/water separator  26  to service and/or clean it. It can also be equipped with a pump out riser  54  used to pump out residual oil, sludge and other waste captured by the oil/water separator  26 . It can be equipped with a level sensor riser  56  used to monitor the liquid level of the oil/water separator  26 . One of more absorbent pillows  58  typically used in the industry can be placed in the oil/water separate  26  in order to absorb small amounts of oil and hydrocarbon residue floating on the surface of the stormwater. The absorbent pillows  58  can be held in place by a line attached to the top of one of the manways  52 . This allows for easy replacement of the absorbent pillows  58  without having to enter the oil/water separator  26 . 
   The oil/water separator  26  can also be equipped with a vent  60 . The vent  60  allows explosive and poison gases from the hydrocarbons to escape the oil/water separator  26 . This reduces the possibility of explosion or other worker safety issues when workers have to enter the oil/water separator  26  for maintenance. In order to minimize the incubation of mosquitoes in stagnant water in the oil/water separator  26  the vent  60  can be fitted with screen such that it allows vapor to escape through the vent  60  but restricts the movement of mosquitoes through the vent  60 . 
   There is a second pipe  62  leading from the oil/water separator  26  to the dry well  28 . The second pipe has a valve  30  which can stop the flow of stormwater through the second pipe  62 . In the preferred embodiment, the valve  30  has an actuator  32 . The actuator  32  is operated by the controls  34 . When the sensing probe  36  detects contaminants such as hydrocarbons in the stormwater, the controls  34  operate the actuator  32  to close the valve  30 . This stops the flow of the stormwater into the dry well  28  and prevents contamination of the groundwater or aquifer with hydrocarbons or other pollutants. The second pipe  62  leads to the dry well  28 . Stormwater from the second pipe  62  enters the dry well  28  where it is disposed into a pervious subsurface ground structure, the groundwater or an aquifer. 
   In the preferred embodiment, the valve  30  is a butterfly valve. However, any other type of valve capable of stopping the flow of stormwater through the second pipe  58  could be used. In the preferred embodiment, the actuator  32  is an electric operated actuator. However, the valve  30  could be operated by a pneumatic or hydraulic power. The second pipe  62  can also be fitted with an anti-siphon valve  64  to prevent siphoning during discharge into the dry well  28 . 
   The operation of the stormwater pretreatment system  20  is operated by electronic controls  34 . These controls can be a programmable logic controller or hardwire electrical controls. The sensing probe  36  typically used would be a hydrocarbon discriminating probe which is capable of sensing the presence of hydrocarbons, such as gasoline, diesel fuel, kerosene and other hydrocarbons in the stormwater. The sensing probe  36  can be placed in a protective cage  66 . This protects the probe  36  from the flow of stormwater and any debris that may be present in the stormwater. 
   The control panel  34  would be mounted near the pretreatment and disposal system  20 . In the preferred embodiment the control panel  34  can be equipped with audio alarm and/or a visual readout or light to notify the operator of the presence of contaminants in the stormwater. This would allow the operator to take appropriate measures to remove contaminants from the system  20 . 
     FIG. 2  is a valve control schematic of the preferred embodiment. The schematic shows the valve actuator  32  which can maintain the valve in an open or closed position. In the preferred embodiment shown, there is a first indicator  18 , such as a green light, which would indicate when the valve  30  is open. A second indicator  70 , such as a red light, can show when the valve  30  is closed. A third indicator  72 , such as a flashing red light, can be used as an alarm beacon when the presence of hydrocarbons are found. The third indicator  72  can also be accompanied by an audible alarm  74 .  FIG. 2  also shows a probe float switch  76 , which is necessary when the system  20  is operated where the valve  30  is in a normally closed position. The probe float switch would typically be located in the same protective cage  66  as the sensing probe  36 . 
   The system  20  can be operated in two modes. The first mode is where the valve  30  is in a normally open position. The second mode would be when the valve  30  is in a normally closed state. In the first mode, where the valve  30  is maintained in a normally open position, the stormwater runs off of the property and is captured in the retention area  22  where it flows into the collection vault  24 , through the pipe  44  and into the oil/water separator  26 . Baffles  48  and the plate coalescer  50  help reduce the velocity of the flow of stormwater through the oil/water separator  26 . This in turn allows sediment to fall out of the stormwater flow. This also helps lighter contaminants such as gasoline, diesel fuel, kerosene and other hydrocarbons to float to the top, where small quantities can be removed by the absorbent pillows  58 . The stormwater then flows through the second pipe  62 , through the open valve  30  and into the dry well  28 . The stormwater is then absorbed into a permeable subsurface ground structure. 
   If hydrocarbon contaminants are sensed by the sensing probe  36 , the controls  34  operate the actuator  32  which closes the valve  30 . This stops the flow of contaminated stormwater into the dry well  28 . The controls also activate a third indicator  72 , such as a flashing light and an audible alarm  74 , to notify the operator that the system  20  has detected contaminants and the second indicator  70  will show the valve  30  is closed. 
   The operator can then assess the situation. If the sensing probe  36  has sent out a false signal, the operator can override the signal and open the valve  30  allowing the system  20  to continue pretreating the stormwater and putting it into the dry well  28 . However, if contaminants are determined to be present, the operator can make arrangements to remove the contaminants from the stormwater, contained by the system  20 . Once the contaminants have been removed, the actuator  32  can be used to open the valve  30  and dispose of the remaining uncontaminated stormwater. 
   In the event the system  20  is operated in the second mode, the actuator  32  would maintain the valve  30  in a closed position and the second indicator  70  would be on. Stormwater would be allowed to accumulate in the retention area  22 . Once the probe float switch  76  senses the presence of stormwater, the controls  34  would operate the actuator  32  to open the valve  30 . A first indicator light  18 , typically a green light mounted on the controls  34 , would indicate to an operator that the valve  30  was open. The opening of the valve  30  would allow the stormwater to flow through the system as previously described. In the event gasoline, diesel fuel, kerosene, other hydrocarbons or other contaminants were detected by the sensing probe  36 , the controls  34  would then operate the actuator  32  to close the valve  30 , thus stopping the flow of contaminated stormwater into the dry well  28 . The presence of the contaminants would cause the third indicator  72  and the audible alarm  74  to be activated to notify an operator of the presence of the contaminants. The second indicator  70  would be activated to show the valve  30  was closed. The operator could then determine the problem and act accordingly as previously described. 
   In the preferred embodiments just described, the first, second and third indicators,  18 ,  70  and  72 , were indicated to be various types of light, however, other types of indicators commonly known in the art could be used. Likewise, various types of audible alarms could also be used. The system  20  can be adapted to detect and contain contaminants other than hydrocarbons by using a different type of sensing probe capable of detecting the presence of the applicable contaminant. 
   The foregoing specifications and drawings are only illustrative of the preferred embodiments of the present invention. They should not be interpreted as limiting the scope of the attached claims. Those skilled in the arts will be able to come up with equivalent embodiments of the present invention without departing from the spirit and scope thereof. 
   
     
       
             
             
           
         
             
                 
             
             
               Element number 
               Description of element 
             
             
                 
             
           
           
             
               20 
               Stormwater pretreatment and disposal system 
             
             
               22 
               Retention area 
             
             
               24 
               Collection vault 
             
             
               26 
               Oil/water separator 
             
             
               28 
               Dry well 
             
             
               30 
               Valve 
             
             
               32 
               Actuator 
             
             
               34 
               Controls 
             
             
               36 
               Sensing probe 
             
             
               38 
               Bottom (of the retention area) 
             
             
               39 
               Wall(s) (of the retention area) 
             
             
               40 
               inlet (collection vault) 
             
             
               42 
               Curb (retention area) 
             
             
               44 
               Pipe 
             
             
               46 
               Swing check valve 
             
             
               48 
               Baffles 
             
             
               50 
               Plate coalescer 
             
             
               52 
               Manways 
             
             
               54 
               Pump out riser 
             
             
               56 
               Level sensor riser 
             
             
               58 
               Absorbent pillows 
             
             
               60 
               vent (oil/water separator) 
             
             
               62 
               Second pipe 
             
             
               64 
               anti-siphon valve 
             
             
               66 
               Protective cage 
             
             
               68 
               First Indicator (valve open) 
             
             
               70 
               Second Indicator (valve closed) 
             
             
               72 
               Third Indicator (alarm) 
             
             
               74 
               Audible alarm 
             
             
               76 
               Probe float switch 
             
             
               78 
             
             
               80 
             
             
               82 
             
             
               84 
             
             
               86 
             
             
               88