Abstract:
A method for treating wastewater, comprising distributing the wastewater into a disposal trench, percolating the wastewater through primary filtration treatment material positioned within the trench, transferring the wastewater into a storage area filled with storage material, percolating the wastewater through secondary treatment material, transferring the wastewater away from the secondary treatment material and into the environment, wherein the secondary treatment material is positioned at a distance horizontally from the trench and a device for treating wastewater, comprising at least one disposal trench adapted to receive, transport and percolate wastewater therefrom, primary filtration treatment material positioned within the trench and adapted to receive and percolate wastewater therethrough, a storage area filled with storage material, secondary treatment material positioned at a distance horizontally from the trench adapted to receive and percolate wastewater therethrough, means for transferring the wastewater away from the secondary treatment material and into the environment.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to wastewater treatment, and more particularly relates to wastewater treatment methods and an apparatus in which wastewater is stored, treated and disposed of after treatment into the surrounding environment. 
       BACKGROUND OF THE INVENTION 
       [0002]    Conventionally, wastewater treatment and disposal may include the utilization of a field (hereinafter sometimes referred to as a “wastewater field”) into which the wastewater is disposed, by means of an absorption/percolation/leaching processes, using, for example, trenches into which perforated pipes or tiles (hereinafter “perforated pipes”) are positioned, the wastewater flowing through the perforated pipes and into the ground, and thereafter the wastewater is subjected to a process known as evapotranspiration (a combination of evaporation, whereby the wastewater moves through the soil and is evaporated into the air above the soil, and transpiration, whereby the wastewater moves through the soil, the wastewater thereafter transpiring into the air through the leaves of the plants growing thereon on that soil). Although evapotranspiration provides certain benefits in the context of wastewater treatment, conventional evapotranspiration fields limit the depth of the field and may have a negative impact on the field&#39;s overall storage capacity, and surface area requirements. 
         [0003]    Advantageously, the apparatus and method of the present invention either entirely removes the evapotranspiration portion of the wastewater treatment field, or alternatively, positions the evapotranspiration portion of the wastewater treatment field remotely from the trenches in which the perforated pipes are positioned. This removal or repositioning of the evapotranspiration portion of the wastewater treatment field can significantly increase the storage capacity of the wastewater treatment field, and/or can significantly reduce the wastewater treatment field&#39;s required surface area, making it possible to install a larger scale wastewater treatment field at a given location. It also permits the trenches in which the perforated pipes are positioned to be located in areas where evapotranspiration would otherwise not be affective. 
       SUMMARY OF THE INVENTION 
       [0004]    Accordingly, one object of the present invention is to provide a wastewater treatment field with increased wastewater storage and handling capacity. 
         [0005]    Accordingly, another object of the present invention is to provide a wastewater treatment field with a reduced surface area and/or reduced trench length. 
         [0006]    Accordingly, another object of the present invention is to provide a wastewater treatment field in which the trenches in which the perforated pipes are positioned are located in areas where evapotranspiration would otherwise not be affective. 
         [0007]    According to one aspect of the present invention, there is provided a method for treating wastewater, the method comprising the steps of distributing the wastewater into a disposal trench; percolating the wastewater through primary filtration treatment material positioned within the trench; transferring the wastewater into a storage area filled with storage material; percolating the wastewater through secondary treatment material; transferring the wastewater away from the secondary treatment material and into the environment; wherein the secondary treatment material is positioned at a distance horizontally from the trench. 
         [0008]    According to another aspect of the present invention, there is provided a device for treating wastewater, comprising, at least one disposal trench adapted to receive, transport and percolate wastewater therefrom; primary filtration treatment material positioned within the trench and adapted to receive and percolate wastewater therethrough; a storage area filled with storage material adapted to receive and store wastewater; secondary treatment material positioned at a distance horizontally from the trench adapted to receive and percolate wastewater therethrough; means for transferring the wastewater away from the secondary treatment material and into the environment. 
         [0009]    The advantage of the present invention is that it provides a wastewater treatment field with increased wastewater storage and handling capacity. 
         [0010]    Another advantage of the present invention is that it provides a wastewater treatment field with a reduced surface area and/or reduced trench length. 
         [0011]    Another advantage of the present invention is that it provides a wastewater treatment field in which the trenches in which the perforated pipes are positioned are located in areas where evapotranspiration would otherwise not be affective. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    A preferred embodiment of the present invention is described below with reference to the accompanying drawings, in which: 
           [0013]      FIG. 1  is a cross-sectional view of a previously known (prior art) trench in a wastewater field; 
           [0014]      FIG. 2  is a vertical cross-section through the settling chamber and distribution box and portions of the wastewater field; 
           [0015]      FIG. 3  is an enlarged view of a portion of the vertical cross-section of  FIG. 2 ; 
           [0016]      FIG. 4  is a cross-sectional view of two trenches in a wastewater field of one embodiment of the present invention; 
           [0017]      FIG. 5  is an enlarged view of a portion of the vertical cross-section of  FIG. 4 ; 
           [0018]      FIG. 6  is a cross-sectional view from above of a wastewater field of one embodiment of the present invention; 
           [0019]      FIG. 7  is an enlarged view of a portion of the cross-section of  FIG. 6 ; 
           [0020]      FIG. 8A  is a cross-sectional view of an alternative embodiment of the wastewater field of the present invention; 
           [0021]      FIG. 8B  is an enlarged view of a portion of the vertical cross-section of  FIG. 8A ; 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. 
         [0023]    As illustrated in  FIG. 1 , the conventional (prior art) trench system used for wastewater may utilize a trench typically of a depth of between 24 and 36 inches and typically being at the least 18 inches wide at the bottom  6 , the wastewater passing through a perforated pipe  4 , typically surrounded by a bed  5  of 0.75 inch to 2.5 inch sized washed stone, the perforated pipe  4  typically being at least 6 inches above the bottom  6  of the trench, and the bed  5  of washed stone typically covering the perforated disposal pipe  4  by a minimum of 2 inches. A layer of untreated building material  8  or like material is positioned on top of the bed  5  of washed stone, and thereafter a bed of backfill  10 , typically between  12  and 23 inches in thickness is applied on top of the layer of untreated building material  8 , grass  12  or other plant life typically being planted on top of the backfill  10 . Typically, the bottom of the trench is a least 3.25 feet above any bedrock, impervious strata, or groundwater  14 . 
         [0024]    In the trench  45  or pit system (hereinafter collectively referred to as a “trench”) used in the preferred embodiment of the present invention, as illustrated in  FIG. 4 , a perforated pipe  30  is supported on and secured by height adjustable perforated pipe supports  34 , which are preferably made of stainless steel or other material known to a person skilled in the art, which height adjustable perforated pipe supports  34 , as illustrated in  FIG. 5  are preferably attached by way of nuts  18 B and bolts  18 A, which bolts  18 A are preferably anchored or otherwise securely fastened to transverse concrete base supports  36  which are positioned intermittently along a channel  38  as illustrated in  FIGS. 6 and 7 , the height adjustable perforated pipe supports  34  support the perforated pipes  30  and are height adjustable, to allow, during the construction of the trench system, for the perforated pipes  30  to be gently downwardly sloping (away from the distribution box  28  as more fully described herein) so that the gravity draws the wastewater through the perforated pipes  30  within the trench and away from the distribution box  28 . 
         [0025]    As illustrated in  FIG. 4 , in the preferred embodiment of the present invention, the channel  38  has concrete vertical walls  41  and a concrete removable cover  40 , transverse concrete base supports  36  intermittently positioned within the channel  38  forming a series of chambers  44  along the length of the channel  38  as illustrated in  FIGS. 6 and 7  into which chambers  44  wastewater flows from the perforated pipes  30  positioned therewithin, which wastewater thereafter flows from the chambers  44  and percolates into and through a heavy biological mat active within the primary filtration treatment material  43  (preferably rock or other material known to a person skilled in the art, having a flow rate of preferably 4-12), and thereafter preferably through a strong, durable and water permeable geo-textile fabric  47  surrounding and containing the primary filtration treatment material  43 , the now partially treated wastewater thereafter entering the storage material  49  (which is preferably large rocks with lots voids or fillable space therebetween) positioned therebeneath as illustrated in  FIG. 2 , it being understood that while wastewater is within the storage material  49 , the treatment of the wastewater is ongoing. In one embodiment of the present invention, as illustrated in  FIG. 4 , primary injection pipes  46 , connected to, for example, a surface connection pipe (not shown) may be used to inject dosing chemicals or water under pressure into the primary filtration material  43  to thereby breakup, loosen or dissolve any biological material unduly blocking the flow of wastewater through the primary filtration material  43 . 
         [0026]    In one embodiment of the present invention, as illustrated in  FIG. 2 , as the wastewater enters into the storage material  49 , it is pulled downwardly by gravity and is dispersed within the storage material  49  before reaching the previously existing or impervious material  88 . Thereafter, the wastewater flows through the secondary treatment material  50  (preferably with a percolation rate of between 5 to 15 minutes per inch), and thereafter through a layer of gravel  54 , through a purpose-constructed or engineered wetland  56 , the vegetation (not shown) in which is fed by the treated wastewater, the treated wastewater preferably flowing through armour rock  58  (to protect the shore against ice from the purpose-constructed or engineered wetland  56  during the winter) and thereafter discharged into an estuary (not shown). In one embodiment of the present invention, an impervious-to-water flow block  60  may also be used to force the treated wastewater through the purpose-constructed or engineered wetland  56 . In one embodiment of the present invention, the top of the field  72  (preferably made of Class-A stone) sheds the majority of the surface water from the field (the Class-A stone will preferably not extensively impair the passage of oxygen into the interior of the field) the surface water thereafter preferably flowing through the gravel  54  and into the purpose-constructed or engineered wetland  56  area. In an alternative embodiment of the present invention, as illustrated in  FIG. 2 , a preferably flat surface  76  is provided in the gravel  54  which may provide a work platform for workers or equipment for the purposes of maintaining the gravel bed  54 , the shore of the purpose-constructed or engineered wetland  56  area, and if necessary, to provide access to the secondary treatment material  50 . 
         [0027]    In one embodiment of the present invention, as illustrated in  FIG. 2 , a secondary top  80  is provided (preferably made of fine particulate material of a type known to a person skilled in the art), which is separated from the storage material  49  by way of a geo-textile fabric  82 , which geotextile fabric  82  protects the storage material  49  from receiving fine particles from the top  72  (grass or other surface covering) or secondary top  80 . In this embodiment of the invention, the secondary top  80  aids in the dispersion of surface water and provides for an efficient placement of the top  72 . 
         [0028]    In one embodiment of the present invention, as illustrated in  FIG. 2 , the distribution box  28 , (with a lid  29  thereon), and a settling chamber  23  (each preferably made of poured concrete or other material known to a person skilled in the art) are positioned upon a preferably gravel foundation bedding  70 . As illustrated in  FIG. 2 , in one embodiment of the present invention, a semi-impervious flow restricter  52  may be positioned within the secondary treatment material  50 , as a result of which more wastewater will be retained for storage within the storage material  49  before entering the secondary treatment material  50 , and as a result of which wastewater may be forced closer to the surface of the secondary treatment material  50  to benefit from evapotranspiration and increased oxygen levels. 
         [0029]    In one embodiment of the present invention, as illustrated in  FIGS. 2 and 3 , a air or water line  62  with an above-ground connection point  66  fitted with a non-return valve  64  (the non-return valve to stop water from flowing back into the system) and a shutoff valve/riser assembly  66  (#27) may be used the purposes of conducting operations and maintenance, by supplying air or water or other liquids through the primary injection pipes  46 , which, in one embodiment of the present invention, as illustrated in  FIGS. 4 and 8B , are positioned within the primary filtration treatment material in the trench, which when supplied with water or other liquids, will supply water or other liquids into the primary filtration treatment material to thereby clean up the primary treatment material (rock) in the trench  45 . In an alternative embodiment of the present invention, pressurized air may be supplied by way of the primary injection pipes  46  into the primary filtration treatment material to thereby clean up the primary treatment material (rock) in the trench  45 . 
         [0030]    With reference to  FIGS. 2 ,  3  and  6 , wastewater enters a chamber  14  with a manhole access, through collector mains  16 , the volume of the wastewater preferably being measured as it enters the chamber  14 . The wastewater flow from the collector mains  16  is combined, and thereafter travels (as illustrated by the arrow  19  in  FIG. 3 ) within a large collector main  18 , for example, beneath the ground, or as illustrated in the embodiment of  FIG. 2 , beneath a road surface  20 , and thereafter empties into a first compartment  22  of a settling chamber  23 . The wastewater  5  thereafter flows through passage pipes  24  or passageways into a second compartment  26  within the settling chamber  23 . The settling chamber  23  provides wastewater treatment, by providing retention time, and by protecting the distribution box  28  (further described herein) from receiving turbulent flows of wastewater. In one embodiment of the present invention, it may also be adapted to provide aeration in a manner known to a person skilled in the art, and/or to provide an insertion point for chemicals in a manner known to a person skilled in the art, and/or for providing a pump or other device for pumping wastewater into the disposal field. In one embodiment of the present invention, baffles (not shown) may be positioned within the settling chamber  23  to collect and store floating matter which may be present in the wastewater flow. 
         [0031]    As wastewater enters the first compartment  22  of the settling chamber  23 , it displaces an equal volume of existing wastewater from the first compartment  22  of the settling chamber  23  into the second compartment  26  of the settling chamber  23 , which in turn displaces an equal volume of existing wastewater from the second compartment  26  of the settling chamber  23 , into the distribution box  28  by way of a connection pipe  31 . In normal operation, the distribution box  28  provides further retention time for the wastewater, and additionally, as illustrated in  FIG. 6 , delivers an equal flow of wastewater to each disposal trench through the perforated pipes  30  which are connected to the distribution box  28  (which perforated pipes  30  may in one embodiment of the present invention, extend a short distance  29  into the distribution box  28 ) and adapted to receive wastewater therefrom for delivery to the disposal trench  32  as more fully described herein. Wastewater flows into, and along the perforated pipes  30  from which it is released (by way of the perforations therein), preferably, rather evenly, into the disposal trenches  32  in which the perforated pipes  30  have been installed. 
         [0032]    As illustrated in  FIGS. 8A and 8B , an alternative embodiment of the present invention is provided, a field top  84  (preferably made of Class A stone) being provided and adapted to shed surface water. In this embodiment of the present invention, topsoil and vegetation  86  positioned remotely from the trench  45  (or in an alternative embodiment of the present invention, trenches) is used to promote evapotranspiration and thereby assisting in the wastewater treatment process. In this embodiment of the invention, wastewater flows to and through the distribution box  28  as previously described herein, and into the perforated pipe  30 , from which it passes into the chamber  44 , and thereafter the primary filtration treatment material  43  (preferably rock or other material known to a person skilled in the art, having a flow rate of preferably 4-12), a strong, durable and water permeable geo-textile fabric  47  surrounding and containing the primary filtration treatment material  43  and the storage material  49  (which is preferably large rocks with lots voids or fillable space therebetween) positioned therebeneath as illustrated in  FIG. 8 . The water thereafter may enter the gravel  54  which acts as a secondary treatment material, provides partially treated wastewater storage capacity, and by permitting the partially treated wastewater to flow therethrough, delivers partially treated wastewater to the topsoil and vegetation  86 , and allows for high levels of aerobic bacteria action on the partially treated wastewater (it being understood that the selection, quantity, and placement of the gravel  54  and the vegetation  86  should reflect a balance between maximizing evapotranspiration potential and minimizing the breakout risk of insufficiently treated wastewater). In this embodiment of the invention, a secondary top  80  is also provided (preferably made of fine particulate material of a type known to a person skilled in the art). In this embodiment of the invention, the secondary top  80  aids in the dispersion of surface water and provides for an efficient placement of the top  84  (preferably made of Class-A stone). 
         [0033]    In a further alternative embodiment of the present invention, a water barrier may also be positioned inside a field to direct wastewater flow for a variety of purposes, such as, for example, forced evapotranspiration and for other purposes as would be known to person skilled in the art. 
         [0034]    While the present invention has been described with reference to perforated pipes, as would be known to a person skilled in the art, various alternative products are available as substitutes for perforated piping, which alternative products are also understood to be within the scope of the present invention. 
         [0035]    The present invention has been described herein with regard to preferred embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.