Abstract:
An input chamber receives runoff water to be cleaned. Part of the way up the chamber wall is a restricted outlet which feeds a system for cleaning the water. At a still higher elevation another opening allows runoff water to flow to an extended detention chamber. Near the top of the chamber is an outlet pipe. A vertical baffle in front of the outlet cleans water that flows under the baffle on its way to the outlet. When the incoming flow rate is very high, water passes over the baffle to the outlet.

Description:
RELATED CASES 
     I claim the benefit of (a) my prior provisional application Ser. No. 60/905,612 filed Mar. 7, 2007 and (b) my prior provisional application Ser. No. 60/905,520 filed Mar. 7, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     When it rains on a parking lot, a road, or other impervious surface, the water will not permeate into the ground as it once did, and instead this water will runoff and discharge directly into a stream or receiving body. Since these impervious surfaces typically have vehicles or traffic on them, an accumulation of pollutants will occur between rain events. This runoff is then concentrated because it is unable to be absorbed into the ground, and the pollutants are concentrated as well. This has caused a severe degradation of our waterhsheds. Although many technologies now exist to treat this problem, a single structure multistage treatment system has advantages of ease of maintenance, better efficiency, lower cost, and longer life. 
     SUMMARY OF THE INVENTION 
     When runoff water is cleaned, according to the present invention, there are three levels of flow. The first of the three levels is herein referred to as low flow. This level of flow involves a substantial cleaning by any suitable cleaning method, old or new, such as gravity separation (see for example Pank U.S. Pat. Nos. 5,746,911 and 6,264,835), or by filtering (Pank U.S. application Ser. No. 11/030,939, filed Jan. 7, 2005, and Pank U.S. publication no. U.S. -2007-0023352-A1 dated Feb. 1, 2007). 
     When the incoming flow rate exceeds the maximum low rate of flow the excess flow, up to a predetermined level, is diverted to an extended detention chamber where it is stored. The maximum flow rate of runoff water comprising said low rate of flow plus said excess is hereby defined as an intermediate rate of flow. 
     The high flow rate exceeds the intermediate rate. 
     The portion of the intermediate flow that does not exceed the low flow rate is cleaned by the same cleaning method and apparatus as though it was water at a low rate of flow. 
     Similarly, that portion of the high rate of flow, which does not exceed the intermediate flow rate, is cleaned as fully as though it was at said intermediate flow rate. 
     If cleaning of the water in said extended detention chamber is deemed necessary, such water may be passed from such chamber through a filter, or other cleaning device, before it is fed to an outlet. 
     To save space, part of the extended detention chamber may be below the elevation of the outlet that is fed by the extended detention chamber, in which case the invention contemplates that the lower portion of the extended detention chamber be emptied by siphoning. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of the preferred form of the invention. 
         FIG. 2  is a sectional view along line A-A of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of parts  42 ,  45  and  46  of  FIGS. 1 and 2 . 
         FIG. 4  is a plan view of a modified form of the invention. 
         FIG. 5  is a cross-section along line A-A of  FIG. 4 . 
         FIGS. 6 and 7  are schematic drawings of two modifications that may be made. 
     
    
    
     DETAILED DESCRIPTION 
     During low flow conditions, influent water enters the device through the inlet pipe  14  from which it flows directly into the primary chamber  12 , causing the water level in chamber  12  to rise. When the water level in the primary chamber  12  rises, water is skimmed from the surface of that chamber by a pipe  15  that penetrates the wall  30  between the two chambers  12  and  13 . This pipe delivers the inflow water to the storage chamber  13 , where it enters horizontally below the water surface through a 90 degree fitting in the pipe  15 . When the water enters the storage chamber  13 , the entrained sediments and floatables separate from the water stream—sediments settle to the structure floor and oils rise to the water surface. The additional water entering the storage chamber  13  through pipe  15  displaces clean water from the center of the column of chamber  13  and this storage outflow enters the storage chamber outlet pipe  40  and flows into the filtration chamber  41 . The treated water enters the filtration chamber horizontally through a 90 degree fitting on the storage chamber outlet pipe  40 . 
     The extended detention chamber  46  has a large portion thereof below the level of pipes  40  and  42 , hence any water flow in pipes  40  and  42  will tend to fill the extended detention chamber  46 . The extended detention chamber  46  is high enough to feed water by gravity through filters  47  to output  44 , so that once flow begins from the extended detention chamber to output  44 , via filters  47 , a siphon effect can empty nearly all, if not all, of the water in the extended detention chamber  46 . 
     When the flow rate into the device increases to a rate above said low flow conditions, a second flow path is added in addition to the ones employed for said low flow conditions. When the water level in the primary chamber  12  rises to a point higher than the horizontal invert of the secondary flow pipe  42 , water begins to flow into the secondary flow pipe  42  from below the water surface of the primary chamber  12 . This secondary treatment flow is free of oils and other floatable pollutants, and it is conveyed through the storage chamber  13  via pipe  42 . The geometry (small diameter, for example) of the secondary flow pipe  42  limits the flow rate through this path in such a way as to continue sedimentation in the primary chamber  12  throughout design conditions as well as to accommodate the low flow paths as outlined above. 
     The low flow, via pipes  40  and/or  42 , into the filtration chamber  41  ensures that the first flow to arrive at chamber  41  is used to “prime” the filter devices and thereby enable full filtration flow to occur immediately. There is a one-way valve  43  located in the extended detention weir plate  45 . As water enters the filtration chamber, the one way valve  43  will be held shut by the pressure difference between this chamber and the water in the extended detention pipes. The seal on valve  43  does not need to be perfect; a restricted condition is all that is necessary. Once the water elevation in filtration chamber  41  is high enough, the filters are primed and flow through the filters will begin. At this point excess water flow goes over the extended detention weir  45  and into the extended detention chamber  46 . After the storm subsides and the filtration chamber  41  drains down, the cartridges go into siphon, and the flap valve  43  opens and releases the water from the extended detention chamber  46  into the filtration chamber  41 . 
     For runoff flow rates up to the device&#39;s design treatment flow rate, 100% of the water that enters the device system is treated by both the physical separation in first stage of the device (through chambers  12  and  13 ) and the media filtration of the second stage in the filtration chamber  41 . When the influent flow rate is greater than the filtration capacity of the devices, but less than the maximum treatment flow rate of the first stage of the device, the excess water is diverted to the extended detention chamber  46 , where it is stored until it can be released through the one way valve  43  to the filtration chamber  41  at a low flow rate. In the filtration chamber  41 , the water is passed through the filter cartridge(s)  47 , and then collected in an underdrain manifold  48  and discharged through the treated water outlet pipe  44 . If the extended detention chamber  46  is full, the treatment continues because as the water enters the primary chamber  12 , it must flow below the baffle  17  and then over the outlet control weir  31  to the outlet pipe  18 . 
     The baffle  17 , the outlet basin  19 , the outlet baffle  31  and the output conduit  18  of this case have the same position relative to each other and to the walls of vault  10  as do parts  17 ,  18 ,  19 ,  31  of  FIGS. 1 and 2  of my copending application filed Mar. 5, 2008. 
     When the runoff flow rate into input  14 , exceeds the treatment capacity of all of the parts hereinabove described (in chambers  12 ,  13 , and  41 ), this very high flow passes over the top of baffle  17  and from there unrestricted into outlet pipe  18 . Outlet pipe  18  and treated water from outlet pipe  44  may be directed to different outfalls, or may be recombined downstream into a single outlet pipe. When the very high flow passes over baffle  17  to output  18 , the incoming water also continues to follow the paths outlined for intermediate flow. 
     MODIFIED FORM OF THE INVENTION 
       FIGS. 4 to 7  are modifications of the system of  FIG. 3 . Similar parts in the preferred form ( FIGS. 1 to 3 ) and the modifications of  FIGS. 4 to 7  have similar reference numbers. 
     In the modified form of the invention, the two effluent flow streams (treated effluent and overflow effluent) are combined into a single outflow stream within the device itself. This modified form is shown in  FIGS. 4 and 5 . 
     During runoff flow up to the design treatment capacity of the first stage of the invention, the modified form functions identically to the preferred form of the invention. The treated water effluent in pipe  44 , however, does not exit the device. Instead the treated water outlet  44  flows into a vertical standpipe  50  in the primary chamber  12  of the device. At the floor of the structure, standpipe  50  makes a 90 degree bend and exits the device through a penetration in the outer wall and becomes outlet pipe  18 . 
     When flow into the device exceeds the treatment capacity of the first stage of the device, excess water flows over the top of the standpipe  50  and directly downward to outlet pipe  18 . This excess flow is combined with the treated effluent from pipe  50  and the combined flow is discharged to a single outlet pipe. 
       FIG. 8  shows that a filter may be substituted for the gravity cleaning system of chamber  13 . 
       FIG. 9  shows that a filter, or other type of water cleaning device may be inserted in pipe  22 . 
     When a filter is referred to it may be of the type set forth in my copending formal application Ser. No. 11/030,939.