Storm Water Filtration System Using Box Culverts

Abstract

An apparatus and method for use in conjunction with box culverts to collect and filter or otherwise treat dirty or polluted storm water runoff or other fluid is disclosed. One or more filter devices with filter media is used in connection with a box culvert. One or more internal bypass assemblies is disposed along a vertical surface in the box culvert. One or more concrete slabs is installed within the box culvert and forms a false floor below the filter devices. The false floor provides an annular space through which fluid can bypass the filter devices and be released to a drainage system.

What is claimed is: 
     
         1 . A filtration apparatus comprising:
 (a) a culvert comprising an inlet opening, a pair of opposing side walls, a pair of opposing haunches, and a bottom slab;   (b) a filter bay disposed within the culvert, downstream from the inlet opening, the filter bay comprising (i) a base member disposed above the bottom slab and supported by the opposing haunches of the culvert, (ii) filter medium resting on the base member, and (iii) a bypass channel extending laterally between the base member and the bottom slab of the culvert; and   (c) a bypass structure disposed between the inlet opening and the filter bay, the bypass structure comprising (i) a first interior wall disposed on the bottom slab, (ii) a second interior wall disposed on the base member and separated from the first interior wall by a substantially hollow space, and (iii) a fluid conveying apparatus extending laterally through a portion of the bypass structure;   wherein the inlet opening and the filter medium are in fluid communication through the fluid conveying apparatus of the bypass structure; and further wherein the inlet opening and the bypass channel are in fluid communication through the substantially hollow space of the bypass structure.   
     
     
         2 . The filtration apparatus of  claim 1 , further comprising a gross pollutant hood positioned in front of a portion of the first interior wall. 
     
     
         3 . The filtration apparatus of  claim 1 , further comprising a drain down tube downstream from the inlet opening. 
     
     
         4 . The filtration apparatus of  claim 1 , further comprising one or more secondary culverts coupled to the culvert, each secondary culvert comprising one or more filter bays. 
     
     
         5 . The filtration apparatus of  claim 4 , further comprising one or more substantially vertical separation plates disposed between adjacent filter bays of adjacent culverts. 
     
     
         6 . The filtration apparatus of  claim 4 , further comprising a secondary culvert comprising an outlet section. 
     
     
         7 . The filtration apparatus of  claim 4 , further comprising a shared inlet pipe coupled to the inlet opening, wherein a secondary culvert is adapted to receive fluid from the shared inlet pipe. 
     
     
         8 . The filtration apparatus of  claim 1 , further comprising secondary filter bays coupled to the filter bay. 
     
     
         9 . The filtration apparatus of  claim 1 , further comprising an access riser comprising a moveable access cover along a top surface of the culvert. 
     
     
         10 . The filtration apparatus of  claim 1 , further comprising a plurality of bypass structures disposed within the culvert. 
     
     
         11 . The filtration apparatus of  claim 1 , further comprising one or more intermediate surfaces disposed between the first interior wall and the bottom slab. 
     
     
         12 . The filtration apparatus of  claim 1 , further comprising one or more intermediate surfaces disposed between the second interior wall and the base member. 
     
     
         13 . An apparatus adapted to cooperatively engage with a culvert comprising:
 (a) a culvert comprising one or more side walls, an inlet opening along at least one side wall, and a bottom slab;   (b) a first chamber disposed within the culvert and downstream from the inlet opening;   (c) a second chamber disposed within the culvert and downstream from the first chamber, the second chamber comprising a base member, filter medium resting on the base member, and a bypass channel extending laterally between the base member and the bottom slab;   (d) a bypass unit disposed between the first and second chambers, the bypass unit comprising a first interior wall, a second interior wall separated from the first interior wall by a substantially hollow space, and a fluid conveying apparatus extending laterally through a portion of the bypass unit;   wherein the bypass channel forms a route for storm water exceeding the capacity of the first chamber.   
     
     
         14 . The apparatus of  claim 13 , further comprising a gross pollutant hood positioned in front of a portion of the first interior wall. 
     
     
         15 . The apparatus of  claim 13 , further comprising a drain down tube in the first chamber. 
     
     
         16 . The apparatus of  claim 13 , further comprising one or more secondary culverts coupled to the culvert, wherein each secondary culvert comprises filter medium. 
     
     
         17 . The apparatus of  claim 16 , further comprising one or more substantially vertical separation plates disposed between adjacent culverts. 
     
     
         18 . The apparatus of  claim 16 , wherein one of the secondary culverts comprises an outlet section. 
     
     
         19 . The apparatus of  claim 16 , further comprising a shared inlet pipe coupled to the inlet opening, wherein a secondary culvert is adapted to receive fluid from the shared inlet pipe. 
     
     
         20 . The apparatus of  claim 13 , further comprising an access riser comprising a moveable access cover along a top surface of the culvert. 
     
     
         21 . The apparatus of  claim 13 , further comprising a plurality of bypass units disposed between the first and second chambers. 
     
     
         22 . A method of processing fluid using a culvert comprising the steps of:
 (a) selecting an inlet of a culvert, the culvert comprising one or more side walls and a bottom slab;   (b) passing fluid from the inlet of the culvert to a first chamber disposed within the culvert;   (c) passing fluid from the first chamber through a bypass unit comprising a first interior wall, a second interior wall separated from the first interior wall by a substantially hollow space, and a fluid conveying apparatus extending laterally through a portion of the bypass unit;   (d) releasing fluid accumulating below the height of the first interior wall through the fluid conveying apparatus of the bypass unit to a second chamber disposed within the culvert, the second chamber comprising a base member disposed above the bottom slab and filter medium resting on the base member; and   (e) releasing fluid accumulating above the height of the first interior wall through the substantially hollow space in the bypass unit to a channel extending laterally between the base member and the bottom slab.   
     
     
         23 . The method of  claim 22 , further comprising the step of separating gross pollutants through a floatables weir positioned in front of a portion of the first interior wall. 
     
     
         24 . The method of  claim 22 , further comprising the step of removing fluid accumulating below the height of the fluid conveying apparatus through a drain down tube positioned in the first chamber. 
     
     
         25 . The method of  claim 22 , further comprising the steps of releasing filtered flows from the second chamber and releasing unfiltered flows from the channel. 
     
     
         26 . The method of  claim 22 , further comprising the step of passing fluid exiting the culvert through one or more secondary culverts, each comprising filter medium. 
     
     
         27 . The method of  claim 26 , further comprising one or more substantially vertical separation plates disposed between adjacent culverts. 
     
     
         28 . The method of  claim 22 , wherein the culvert comprises secondary culverts coupled to the second chamber. 
     
     
         29 . The method of  claim 22 , wherein the culvert further comprises an access riser comprising a moveable access cover along a top surface of the culvert. 
     
     
         30 . The method of  claim 22 , further comprising the step of passing fluid from the first chamber through a plurality of bypass units. 
     
     
         31 . The method of  claim 22 , wherein the channel between the base member and bottom slab forms an alternate route for fluid flow. 
     
     
         32 . The method of  claim 22 , wherein said the first chamber directs fluid flow via an equalizing port. 
     
     
         33 . The method of  claim 22 , wherein said the filter medium rests on one or more recesses on a surface of the base member. 
     
     
         34 . The method of  claim 22 , wherein a hole is used to position the bypass unit at a substantially center portion of the base member.