Abstract:
A soil remediation unit that changes the use and purpose of certain commercially available aggregate mixing devices and or pug mills for removing unwanted contaminants from a quantity of contaminated soil aggregate or substrate which includes a canopy and a burner tube attached to the canopy. The burner tube includes an upper securing element and a lower adjustment element. The soil remediation unit also includes a burner supported in a desired position within the burner tube by the upper securing element and the lower adjustment element.

Description:
This application is a continuation application, claiming priority to non-provisional U.S. patent application Ser. No. 14/542,882 filed on Nov. 17, 2014 and issued on Feb. 23, 2016 as U.S. Pat. No. 9,267,684 which is based on and claims priority to provisional U.S. Patent Application No. 61/914,487 filed Dec. 11, 2013, the contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     Construction projects and work sites are often faced with issues when the soil in a work site has become contaminated with various materials. Contaminated soil may require remediation in order to remove the contaminants that may have accumulated in the soil over time. Contaminants are often found in the soil associated with industrial sites, sites related to the petroleum industry (e.g., refineries, processing facilities, and gas stations) and transportation sites (e.g., airports, rail yards, pipelines, etc.). 
     One method of decontaminating the soil in such sites includes the heating of the soil to sufficient temperature so as to burn off the various contaminants that have accumulated in the soil. One known method of performing this decontamination is by transporting the soil to a large industrial oven and heating the soil to the necessary temperature and then returning the soil to the site. This method is faced with many disadvantages including the cost of transporting the contaminated soil to the heating facility as well as the environmental issues associated with operating an industrial furnace. 
     A second method of decontamination includes heating the contaminated soil at the work site. U.S. Pat. No. 6,464,430, the contents of which are hereby incorporated by reference, includes an example of heating contaminated soil in a mobile decontamination apparatus at a work site. Known apparatus, however, include several disadvantages including efficiency, durability, and performance problems. 
     Therefore, there exists a need for an improved device that can efficiently, cost-effectively, and reliably remove contaminants from soil. 
     BRIEF SUMMARY 
     In one embodiment, a soil remediation unit for removing contaminants from a quantity of contaminated soil includes a canopy, a burner tube attached to the canopy with a height adjustment element. The soil remediation unit also includes a burner supported in a desired position by the height adjustable elements. 
     In another embodiment, the soil remediation unit additionally includes at least one vapor exhaust mechanism that includes a hatch and a port. The hatch is connected to the canopy of the soil remediation and is configured to operate in an open position and a closed position such that when the hatch is in an open position, excess vapor is permitted to exit the soil remediation unit. 
     In another embodiment, the canopy of the soil remediation unit includes a first panel, a second panel and a bar. The first panel and the second panel are joined together with a hinge at one edge. The bar fixes the first panel and the second panel at a desired angle relative to one another. 
     In still another embodiment, the soil remediation unit is configured to be attached to a pug mill through which contaminated soil is conveyed. A dirt dam can be connected to the pug mill with a notch having a predetermined height. The predetermined height of the dirt dam maintains a desired depth of soil in the pug mill and facilitates the removal of contaminants as the soil travels through the pug mill and beneath the soil remediation unit. 
     The soil remediation unit may include a burner assembly. In one example, the burner assembly includes a burner tube with an upper securing element, a lower adjustment element and an intake opening. The burner assembly also includes a burner that is secured to the burner tube by the upper securing element and the lower adjustment element. 
     In another example burner assembly, the burner assembly includes a spacer connected to the lower adjustment element and positioned between the outer surface of the burner and the inside surface of the burner tube to maintain an air gap inside the burner tube. 
     In another example burner assembly, the burner tube includes sets of lower adjustment holes. The first and second sets of lower adjustment holes in the burner tube can be positioned at different vertical heights to permit the positioning of the burner at different heights. 
     In still another example burner assembly, the burner includes an annular bottom surface that rests on the lower adjustment element when assembled into the burner tube. This configuration prevents the burner from falling through the burner tube and assists in maintaining the burner&#39;s position inside the burner tube. 
     As discussed above, the soil remediation unit can be used to remove contaminants from soil and other uses. In one example method of use, a soil remediation unit is connected to a pug mill wherein the soil remediation unit includes a canopy and a burner tube connected to the canopy. The method may also include the step of securing a burner inside the burner tube at a desired location relative to the canopy. The method may also include moving soil through the pug mill and under the soil remediation unit such that the soil is heated by the burners to remove unwanted contaminants from the soil. 
     In another example, the step of securing a burner inside the burner tube requires only one of three upper securing elements to be moved relative to the burner tube. 
     In still another example, the step of securing a burner includes resting the bottom edge of the burner on the adjustment element and moving the securing element radially inward to contact the outer surface of the burner. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       Certain embodiments are shown in the drawings. However, it is understood that the present disclosure is not limited to the arrangements and instrumentality shown in the attached drawings, wherein: 
         FIG. 1  is an illustration of one embodiment of a soil remediation unit at a work site in accordance with the present disclosure. 
         FIG. 2  is an illustration of the embodiment of the soil remediation unit of  FIG. 1 . 
         FIG. 3  is a plan view of one panel of another embodiment of a soil remediation unit in accordance with the present disclosure. 
         FIG. 4  is an illustration of an embodiment of a burner tube in accordance with the present disclosure. 
         FIG. 5 . is a side view of the embodiment of the burner tube of  FIG. 4 . 
         FIG. 6  is a top view of the embodiment of the burner tube of  FIG. 4 . 
         FIG. 7  is a sectional view of a panel of another embodiment of the soil remediation unit in accordance with the present disclosure. 
         FIG. 8  is an illustration of another embodiment of the soil remediation device on a pug mill in accordance with the present disclosure. 
         FIG. 9  is an illustration of one embodiment of a security strap in accordance with the present disclosure. 
         FIG. 10  is an illustration of another embodiment of a soil remediation device in accordance with the present disclosure. 
         FIG. 11  is a plan view of an embodiment of a dirt dam in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting and understanding the principles disclosed herein, references are now made to the preferred embodiments illustrated in the drawings and specific language is used to describe the same. It is nevertheless understood that no limitation of the scope of the invention is thereby intended. Such alterations and further modifications in the illustrated device and such further applications of the principles disclosed as illustrated herein are contemplated as would normally occur to one skilled in the art to which this disclosure relates. 
       FIG. 1  shows one embodiment of soil remediation unit  100 . As shown in use on a job site, soil remediation unit  100  is connected to or is positioned over pug mill  102 . Pug mill  102  can be any suitable device that moves soil  106  from an intake to an outlet  108 . As will be discussed in more detail below, burners  200  positioned along soil remediation unit  100  heat contaminated soil  106  to sufficient temperatures such that contaminants in contaminated soil  106  are burned off to result in decontaminated soil exiting the pug mill  102  at outlet  108 . In one embodiment, burners  200  are connected to a fuel source  104  to produce the raised temperatures in soil remediation unit  100 . In this embodiment, each burner is connected to an individual quantity of fuel. However, in other embodiments, burners  200  can be connected to a single manifold that, in turn, is connected to a single source of fuel. In this embodiment, a single drum, tank, or other volume of fuel can be used instead of individual tanks serving each burner. In the embodiment shown, fuel source  104  is propane. Other types of fuel can also be used so long as the necessary temperatures can be reached to remove the contaminants from the soil. For example, natural gas and other types of liquefied petroleum gas may also be used. 
       FIG. 2  shows, in further detail, soil remediation unit  100 . Soil remediation unit  100  may include burner  200 , burner tube  202 , canopy  204  and vapor exhaust mechanism  222 . Canopy  204 , in this embodiment, is the central support element of soil remediation unit  100 . Canopy  204  is the member of soil remediation unit  100  that secures the various other elements in position relative to pug mill  102 . In addition, canopy  204  can serve to enclose an area around the contaminated soil such that sufficient temperatures can be reached to decontaminate the soil. In this embodiment canopy  204  includes first panel  206  and second panel  208  attached together via hinge  212  that joins the upper edges of first panel  206  and second panel  208 . This type of construction of canopy  204  allows first panel  206  and second panel  208  to move relative to each other along hinge  212  such that soil remediation unit  100  can be adjusted to fit pug mills of varying shapes and sizes. Canopy  204  can be made of various types of materials. In one embodiment, canopy  204  is made of  12  gauge sheet steel but other sizes and types of material can also be used. 
     Canopy  204  may also include reinforcement elements  210 . Reinforcement elements  210  are members connected to first panel  206  and second panel  208  to provide rigidity to the panels. Reinforcement elements  210  may be positioned in various configurations so long as they provide the rigidity necessary to manipulate canopy  204  as needed and to support the various other elements of soil remediation unit  100 . In one embodiment, as shown in  FIGS. 2 and 3 , reinforcement elements  210  are positioned in a ladder configuration with two elements aligned along the top and bottom of first panel  206  with one or more elements connecting the top and bottom elements. Reinforcement elements  210  can be symmetrically positioned on second panel  208  to provide similar rigidity to second panel  208 . Other configurations of reinforcement elements can also be used. 
     In another embodiment of canopy  204 , as shown in  FIG. 10 , reinforcement elements may include one or more elements positioned at predetermined intervals along first panel  206  that extend from a bottom edge of first panel  206  to an upper edge of first panel  206 . Reinforcement elements  210 , in this embodiment, may be lengths of right-angle brackets wherein the legs of the right-angle bracket are secured to an outer surface of first panel  206  by welding or other methods of attachment known to one of ordinary skill in the art. In this configuration, reinforcement elements  210  create triangular-shaped channels with the outer surface of first panel  206 . In other embodiments, other shapes of reinforcement elements can be used. Rectangular, arched, hollow and solid shapes can also be used as reinforcement elements on canopy  204 . 
     As shown on  FIG. 10 , canopy  204  may also include bar  1000 , one or more loops  1002 , one or more tabs  2004  and flange  220 . Flange  220  is a feature of canopy  204  that provides further rigidity to first panel  206  and second panel  208 . Flange  220 , in this embodiment, is a portion of first panel  206  or second panel  208  formed at a right angle to the outer surface of first panel  206  or second panel  208  or into a C or U-shape. Flange  220 , however, can be a separate piece of material welded or otherwise joined to canopy  204  by means known to one of ordinary skill in art. In the embodiment shown in  FIG. 10 , flange  220  also includes a fastening element to which bar  1000  is connected. In this embodiment, bar  1000  is connected to flange  220  on first panel  206  as well as to flange  220  on second panel  208 . As can be appreciated, the angle of canopy  204  can be varied by moving first panel  206  relative to second panel  208  and securing each panel relative to one another by bar  1000 . In this manner, canopy  204  can be varied to operate in conjunction with pug mills of varying widths and sizes. To assist in this regard, bar  1000  includes a series of adjustment holes  1006 . Canopy  204  is secured into a desired alignment by connecting bar  1000  to canopy  204  by inserting a bolt or other fastener through an adjustment hole on bar  1000  and through an attachment hole on each flange  220  located on first panel  206  and second panel  208 . Canopy  204  can further include a rigidity element  1008 . As shown on  FIG. 10 , rigidity element  1008  can be a steel L-shaped bracket that further reinforces the connection of bar  1000  to flange  220 . Other configurations and materials of rigidity element  1008  can also be used. Canopy  204  can also be similarly equipped with a second bar  1000  located at the opposite end of canopy  204 . In this embodiment, bar  1000  is a u-shaped steel channel, however, other shapes and materials can be used as well. 
     Referring back to  FIG. 10 , canopy  204  may also include one or more loops  1002 . In this embodiment loop  1002  is a u-shaped member with either end attached to first panel  206 . Loop  1002  can be welded or otherwise attached to first panel  206 . Loop  1002  can also be configured in other shapes so long as the shape facilitates the attachment of hooks, cables, ropes, chains or other means that may be used to lift or move canopy  204  during transport, set-up, or take-down. Loops  1002  can be located at various locations on first panel  206  and can also be positioned on second panel  208 . 
     Canopy  204  may also include one or more tabs  1004 . Tabs  1004  may be a rectangular piece of steel with a hole in one end as shown in  FIG. 10 . Other configurations and materials may also be used. Tab  1004  extends outward from first panel  206  of canopy  204  for fixing canopy  204  relative to a pug mill. To this end, two tabs  1004  may be positioned on the lower edges of first panel  206  or second panel  208 . In other embodiments, first panel  204  or second panel  208  are of sufficient length such that tab  1004  is not needed for attachment to a pug mill. In these embodiments, first panel  206  or second panel  208  is provided with a hole through the panel. These holes can be similarly used for fixing canopy  204  to a pug mill. 
     As shown in  FIGS. 2 and 3 , soil remediation unit  100  may also include vapor exhaust mechanism  222 . Vapor exhaust mechanism is the element of soil remediation unit  100  that can allow gases, such as steam, to escape from the area located under canopy  204 . As can be appreciated, when extremely moist soil, aggregates, or mud is heated in soil remediation unit  100 , the water or other liquids mixed with the soil may be changed into a vapor or gas form. This vapor can build up under canopy  204  and can saturate the mixture of gas located in the region near burners  200  such that the burners may not perform efficiently. This reduced efficiency can be remedied by releasing surplus trapped steam or vapor from under canopy  204  through vapor exhaust mechanism  222 . 
     In one embodiment, vapor exhaust mechanism  222  may include hatch  214  and port  218 . Port  218  is an opening in canopy  204  that allows gas or vapor to escape from the area beneath canopy  204 . Port  218  can be any feature of canopy  204  so long as it allows gas or vapor to flow from the area under canopy  204  to the area above canopy  204 . Port  218  can be a hole, a slot, a membrane, or a series of holes or slots or other suitable features. Hatch  214 , in this embodiment, is a rectangular piece of metal that can slide in grooves or retention members. Hatch  214  can be in an open position, as shown in  FIG. 2 , that allows vapor to escape through port  218 . Hatch  214  can also be moved to the normal closed position by sliding hatch  214  in the grooves or retention members such that port  218  is covered by hatch  214  and gas or vapor is prevented from escaping through port  218 . In other embodiments, hatch  214  can be configured in other shapes and materials known to one of ordinary skill in the art. In addition, hatch  214  may be connected to canopy  204  with a hinge, pivot pin, or other member that allows hatch  214  to move from an open position in which vapor can escape through port  218  to a closed position in which vapor is limited from escaping through port  218 . 
     As shown in  FIGS. 2-8 , soil remediation unit  100  may also include burners  200  and burner tubes  202 . Burners  200 , in one embodiment, are cylindrical in shape. At an upper end of burner  200 , riser  216  is attached. Riser  216 , in one embodiment, is a length of pipe that is attached to burner  200  at one end and attached to fuel source  104  at the other. In this configuration, riser  216  conveys fuel to burner  200 . Burner  200  may also include a nozzle, orifice or other features known to one of ordinary skill in the art through which fuel is expelled and combusts resulting in a heat source for the heating of contaminated soil. As shown in  FIG. 7 , an outer surface of burner  200  is configured such that it fits within burner tube  202 . In other embodiments, burner  200  can be configured in different shapes and different materials so long as the burner introduces sufficient quantities of heat to soil remediation unit  100  to effectively decontaminate soil. 
     Soil remediation unit may also include burner tube  202 . Burner tube  202 , in one embodiment, is the element of soil remediation unit  100  that allows for the adjustment and positioning of burner  200  as well as facilitating an efficient operation of burner  200  and prolonging the life of burner  200 . Burner tube  202 , in this embodiment, is cylindrical in shape with an inner and outer surface through which various openings extend therethrough. As stated above, the inner surface of burner tube  202  defines a volume in which burner  200  can be positioned and adjusted. In one embodiment, burner tube  202  is a steel cylindrical tube with an inner diameter of 4 inches, an outer diameter of 4.5 inches and a height of 6.75 inches. Other sizes, however, can be used. 
     As stated above, Burner tube  202  allows burner  200  to be positioned and adjusted. To this end, burner tube  202  may include one or more upper securing holes  504  and one or more lower adjustment holes  506 ,  508 . Upper securing and lower adjustment holes can be threaded or smooth bore holes. Upper securing and lower adjustment elements  616 ,  618  can be inserted through the upper securing and lower adjustment holes to position and adjust burner  200  within burner tube  202 . The upper securing and lower adjustment elements  616 ,  618  can be threaded fasteners, pins, rods or other suitable retention members. In one embodiment, burner tube  202  includes a series of upper securing holes evenly distributed around the circumference of burner tube  202  approximately 0.75 inches under an upper edge of burner tube  202 . In this embodiment, three upper securing holes are positioned at 120 degrees from each other around burner tube  202 . Burner tube  202 , as shown in  FIG. 4 , can also include a series of first lower adjustment holes  506  and a series of second lower adjustment holes  508 . In one embodiment, the series of first lower adjustment holes  506  and series of second lower adjustment holes  508  are located approximately 1.75 and 2.625 inches above a lower edge of burner tube  202 . The series of first and second lower adjustment holes can be distributed evenly around the circumference of burner tube  202 . In one embodiment, the series of first and second lower adjustment holes  506 ,  508  can include three holes in each series positioned at 120 degree intervals around burner tube  202 . The series of lower adjustment holes can be staggered with respect to upper securing holes  504  such that burner  200  is more firmly supported when securing element  616 , and adjusting element  618  located in the series of adjustment holes contact burner  200 . In one embodiment, upper securing holes are positioned at 120 degree intervals equally spaced around burner tube  202 . The lower adjustment holes, in this embodiment, are positioned out of phase with the upper securing holes to distribute the retention of burner around its circumference. In one embodiment, the upper securing and lower adjustment holes are out of phase with each other by 60 degrees. In other embodiments, other configurations of upper securing and lower adjustment holes  504 ,  506 ,  508  can be used including more or less holes and different distributions of the holes around burner tube  202 . 
     As shown in  FIG. 7  and described above, the series of upper securing and lower adjustment holes  504 ,  506 ,  508  may be threaded or non-threaded. In one embodiment, the upper securing holes  504  are threaded and upper securing elements  616  are threaded fasteners that are inserted into the adjustment holes and secured in position. In other embodiments, the adjustment holes are non-threaded. In one such example, adjustment element  616 ,  618  may be a bolt and nut or a pin that is inserted into an adjustment hole and secured in position. One such example is shown in  FIG. 7  where lower adjustment hole  506 ,  508  is non-threaded and lower adjustment element  618  is a bolt whereby, after being inserted through lower adjustment hole  506 ,  508 , the lower adjustment element  618  is secured in position via spacer  702 . The adjustment and securing elements can be arranged such that the fasteners or pins radially converge and hold burner  200  in position. 
     In another embodiment, two of the three securing elements that are positioned in upper securing holes  504  are stationary and the third securing element can be secured against burner  200  to secure burner in position. In this manner, the stationary upper securing elements maintain an equal air gap and burner  200  can be centered within burner tube  202 . Additionally, only one securing element (i.e., the third non-stationary upper securing element) needs to be manipulated to secure or release burner  200 . Tether  802 , further explained below, can be connected to this third non-stationary upper securing element. 
     In other embodiments and as shown in  FIG. 7 , the adjustment elements located in the lower adjustment holes are configured such that the adjustment element extends into burner tube  202  so that the lower edge of burner  200 , when inserted into burner tube  202 , sits on the adjustment element. In this embodiment, spacer  702  can be included on an adjustment element to assist in maintaining an equal air gap between the inner surface of burner tube  202  and burner  200 . Spacer  702  can be any suitable sleeve of material that can be placed over the adjustment element to maintain the air gap. In one embodiment, spacer  702  is a nut secured onto a bolt and burner  200  sits on the exposed length of the bolt after the nut secures the bolt in position in the lower adjustment hole. As can be appreciated, in such a configuration, the vibration or movement of soil remediation unit  100  is less likely to loosen the adjustment element and the likelihood of burner  200  moving or falling out of position is reduced. 
     Further shown in  FIGS. 4-6 , burner tube  202  includes intake opening  502 . Intake opening  502  permits ambient air to enter burner tube  202  and interact with burner  200 . The flow of air into burner tube  202  permits efficient combustion of fuel that exits burner  200 . In one embodiment, intake opening  502  is a 2.25 inch diameter opening but other sizes and shapes can be used as well. Further shown in this embodiment, particularly in  FIG. 7 , intake opening  202  can be positioned to reside just above the first or second panel  206 ,  208  of canopy  204 . This arrangement permits the flow of air from above soil remediation unit  100  into burner tube  202 . Intake opening  502  can be a series of openings of equal or varying sizes positioned around the circumference of burner tube  202 . In one example, three 2.25 inch diameter holes are positioned around the circumference of burner tube  202  at 120 degrees from each other such that they are evenly distributed. In other examples, different configurations of intake openings can be used such as, two intake openings positioned opposite one another or an increased number of smaller holes. 
     The arrangement and structure of burner tube  202  and burner  200  impacts the efficiency, reliability and durability of soil remediation unit  100 . In one embodiment, as discussed above, burner  200  is supported by adjustment elements positioned around the circumference of burner tube  202 . This configuration maintains an air pocket between the outer surface of burner  200  and the inner surface of burner tube  202 . In addition, as stated above, the lower edge of burner  200  can sit on a series of fasteners positioned in the series of lower adjustment holes  506 ,  508 . This can, in part, lower the risk of burner  200  from moving or falling into the area below canopy  204 . To further reduce this risk, soil remediation unit  100  can also include tethers  802  as shown in  FIG. 8 . Tether  802  is a length of material that is connected to burner tube  202  and burner  200 . Tether  802  can be any suitable length of material such as chain, metal cable or the like. In a situation wherein the adjustment elements that support burner  200  fail, tether  802  prevents burner  200  from falling into the area under the canopy  204  where the burner could be damaged from the increased heat or the rotating components of pug mill  102 . 
     As can be seen in  FIGS. 1, 2 and 8 , soil remediation device  100  includes one or more pairs of burners  200  and burner tube  202 . In the embodiment shown, four sets of burners  200  and burner tubes  202  may be included on each of the first panel  206  and the second panel  209  of canopy  204 . The four sets of burners  200  and burner tubes  202  can be placed in a linear relationship and at a desired position along the first panel  206  and the second panel  208 . Other configurations, however, can also be used. For example, in another embodiment, the arrangement of burner tubes  202  and burners  200  is staggered. In this configuration each neighboring burner tube is located at a different position along first panel  206  and second panel  208 . The staggering of burner tubes  202  and burners  200  can assist in distributing the heat produced from burners  200  to the contaminated soil. Still further, in another embodiment, the configuration of burner tubes  202  along first panel  206  and second panel  208  can follow other paths such as arcs, wave-patterns, or the like. In addition, the number of burner tubes along first panel  206  and second panel  208  can be increased or decreased. 
     In another embodiment, as shown in  FIG. 3 , the distribution of burners  200  and burner tubes  202  on first panel  206  versus second  208  can be offset. As shown in  FIG. 3 , openings  300  in which burner tubes  202  can be positioned are not centered on first panel  206 . In such an embodiment, when two panels are manufactured using the same burner distribution as shown on  FIG. 3  and then are subsequently attached together at an upper edge, because openings  300  are not centered on the panel, openings  300  on a first panel  206  and a second panel  208  will be offset from each other along the length of canopy  204 . This arrangement can assist with the distribution of heat within soil remediation unit  100 . The size of soil remediation unit  100  can also be varied to balance and address varying needs associated with different quantities of contaminated soil, the size of pug mill  102 , work site size limitations, and other issues known to one of ordinary skill in the art. As the size of soil remediation unit is varied, so too can the size and quantity of burners  200  and burner tubes  202 . 
     As described above, soil remediation unit  100  can be used in conjunction with a pug mill  102  as shown in  FIG. 1 . To connect soil remediation unit  100  to pug mill  102 , security strap  902  can be used. As shown in  FIG. 9 , security strap  902  can include a top interface surface  908  with slot  904  and vertical interface surface  910  with connection point  906 . Security strap  902  can be attached to canopy  204  to secure canopy  204  to a pug mill  102 . Connection point  906  can be used to attach security strap  902  to a member of pug mill  102  and slot  904  can be connected to the first panel  206  or the second panel  208  of canopy  204 . A bolt, pin, rivet or other suitable fastener can be used for these connections. In the embodiment shown in  FIG. 9 , security strap  902  is formed from a single steel blank and is bent into the desired configuration. Other embodiments can also be used such as an adjustable security strap with a hinge connecting the top interface surface to the vertical interface surface. 
     As shown in  FIG. 11 , soil remediation unit  100  can also include dirt dam  1100 . Dirt dam is a substantially planar piece of material with the configuration as shown in  FIG. 11 . Dirt dam  1100  can include notch  1102  and fastener points  1104 . In operation without dirt dam  1100  fixed to pug mill  102 , soil can exit pug mill  102  upon reaching exit outlet  108 . Alternatively, dirt dam  1100  can be fixed to the end of pug mill  102 . On a pug mill with dirt dam  1100  in place, soil is limited from exiting pug mill  102  until soil  102  accumulates to a predetermined height such that it can empty from pug mill  102  by falling over the top of dirt dam  1100 . As can be appreciated, the height of dirt dam  1100  can play a role in the amount of time any given portion of soil remains in pug mill  102 . Thus, with a dirt dam in place, increased mixing can take place and each portion of soil will be subjected to decontamination heating. Dirt dam  1100  can be made of various materials and in various configurations according to the size of the pug mill  102  and the desired mixing effects that it may induce. In one embodiment dirt dam  1100  is made of a 0.25 inch steel size to the configuration shown in  FIG. 11 . Notch  1102  can be approximately 18 inches in length and be centrally located on dirt dam  1100 . Connection points  1104  can be used to fix dirt dam  1100  to pug mill  102  and can be 0.4375 inch holes in either end of dirt dam  1100 . Alternatively, dirt dam can be fixed to pug mill  102  using brackets, grooves or other suitable retention features. 
     While the particular preferred embodiments have been shown and described, it is obvious to those skilled in the art that changes and modifications may be made without departing from the teaching of the disclosure. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as limitation. The actual scope of the disclosure is intended to be defined in the following claims when viewed in their proper perspective based on the related art.