Abstract:
A waste processing method comprises shredding a batch of waste to produce shredded waste; grinding the shredded waste in a volume of water in a grinder to produce a mixture of ground waste particles and water; straining the mixture of ground waste particles and water; returning to the grinder the water and the ground waste particles having sizes larger than a extracting residual water from the ground waste particles having sizes smaller than the selected size; returning the residual water to the grinder; and drying the ground waste particles having sizes smaller than the selected size.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application Ser. No. 60/553,914, filed Mar. 16, 2004. 
     
    
     BACKGROUND  
       [0002]     The present disclosure relates to a system for processing waste. In particular, the present disclosure relates to a system for processing waste by reducing volume and producing a usable byproduct.  
         [0003]     Communities produce large volumes of waste each and every day. The waste produced is disposed of in many ways. In most communities, the waste (i.e., household waste) is deposited into plastic garbage bags and then temporarily stored in a garbage can. The garbage can is periodically placed at a curbside for removal by the local waste removal service. The waste removal service collects the community waste into larger trucks and compacts the waste to a certain degree. The waste is then transported to a waste collection facility for further processing or transported directly to a local landfill. The processed waste can be separated and sorted into various types of waste prior to transportation to a landfill.  
         [0004]     In other prior art waste removal techniques, the waste is transported to a waste incinerator. In other prior art waste removal techniques, the waste is packaged onto barges, shipped offshore and dumped into the ocean.  
         [0005]     In the prior art waste processing techniques, the waste is not efficiently reused. The landfills are rapidly becoming full and will no longer be a viable solution to waste removal. The incineration techniques are environmentally harmful, are not cost effective, and require government subsidies to operate. The ocean dumping is detrimental to the ocean environment and the extent of damage to the earth&#39;s oceans has yet to be completely understood.  
         [0006]     What is needed in the art is a waste disposal processing system that efficiently processes waste and provides a useful byproduct.  
       SUMMARY  
       [0007]     A waste processing system comprises a waste loader configured to receive waste. A shredder is coupled to the waste loader. The shredder includes at least one blade disposed in a shredder housing. The shredder is configured to shred and reduce waste into a refined composition. A grinding tank is disposed downstream of the shredder. The grinding tank is configured to further reduce the particle size of the waste by use of mechanical agitation and impact between grinding elements and the waste within an aqueous solution disposed in the grinding tank. A screen is disposed downstream of the grinding tank. The screen separates the waste composition based on particle size. The screen is configured to drain away the water for reuse in the grinding tank. A water extractor is coupled to the screen and is configured to further extract moisture from the waste composition. A drying tunnel and shaker table is coupled to the water extractor. The drying tunnel and shaker table is configured to remove additional moisture and air trapped in the waste composition.  
         [0008]     According to another aspect of the present invention, the powdered waste may be mixed with a binder material and may then be cast into blocks. The cast blocks have useful properties and may be used for construction and decorative applications. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a perspective view of exemplary waste disposal processing system.  
         [0010]      FIG. 2  is front view of an exemplary waste disposal processing system.  
     
    
     DETAILED DESCRIPTION  
       [0011]     A waste disposal processing system is disclosed. The waste disposal processing system includes a waste loader configured to receive waste and load the waste into a shredder. The shredder shreds and reduces the waste into a refined composition. The waste disposal system includes a grinding tank downstream of the shredder. The grinding tank is configured to further reduce the particle size of the waste by use of mechanical agitation and impact between grinding elements and the waste within an aqueous solution in the grinding tank. The waste composition is further processed through a screen located downstream of the grinding tank. The screen separates the waste composition based on the particle size. The water is also drained away for reuse in the upstream grinding tank. A water extractor is coupled to the screen and is configured to further extract moisture from the waste composition. A drying tunnel and shaker table is located downstream of the water extractor. The drying tunnel and shaker table remove additional moisture and air trapped in the waste composition. A powdered solid material remains as a useful byproduct having a significant reduction in volume from the original waste disposed in the waste disposal processing system.  
         [0012]     Referring to  FIGS. 1 , and  2 , exemplary embodiments of the waste disposal processing system are illustrated in a schematic and perspective view, respectively. The waste disposal processing system  10  includes a waste loader  12  configured to receive waste and load the waste into a shredder  14 . The waste loader  12  can include a container  16  configured to receive and contain waste. In an exemplary embodiment, the container can be sized with and opening about  28  inches by  22  inches and about  38  inches high. It is contemplated to provide variations in the dimensions.  
         [0013]     The waste loader  12  can include a lift  18 . The lift  18  is configured to elevate the container and reorient the container  16  in order to empty the waste from the container  16  into the shredder  14 . The container  16  can clip to the lift via a spring-loaded clip (not shown), and variants thereof. In an exemplary embodiment, the lift  18  can comprise a chain driven by a  12 Volt DC motor (not shown). The motor can also be a variable speed motor of multiple sizes depending on the size of the container  16 . In the exemplary embodiment illustrated, the waste loader  12  is configured to receive waste in the container  16 . The lift  18  raises the container  16  up to the shredder  14  and turns the container  16  over to empty the contents of the container  16  into the shredder  14 . The lift  18  returns the container  16  to a position ready for receiving additional waste. The container  16  can also be manually operated in other embodiments. The container  16  can be constructed of plastic, metal, wood, combinations thereof, and the like. It is contemplated that the waste loader  12  can include manual or automatic instrumentation and controls for ease of operation.  
         [0014]     The shredder  14  shreds and reduces the waste into a refined composition. The shredder  14  includes a shredder housing  20  having an inlet  22  and outlet  24 . In an exemplary embodiment, the shredder housing  20  can be about 28 inches wide by about 22 inches wide and about 36 inches deep. The shredder housing  20  can comprise hard materials, such as, ⅛ inch steel plate, plastic, wood, aluminum, copper, brass, screen, mesh, and galvanized sheet metal, and the like.  
         [0015]     The shredder  14  includes a plurality of blades  26  configured to shred waste in the shredder  14 . The blades  26  can be configured into a pattern of outlet rows  28  arranged as four rows of blades oriented with each blade axis perpendicular to the depth of the shredder housing  20  and aligned along the long width of the shredder housing  20 . In a non-limiting exemplary embodiment, each blade  26  is a disc of about 7.25 inches in a circular saw blade configuration. The size and number of teeth on each blade  26  can be varied. Each row of blades  26  can comprise, for example, 52 blades.  
         [0016]     In an exemplary embodiment, the four rows of blades  28  can be located about 12 inches from the outlet  24 . The blades  26  can overlap. In an exemplary embodiment, the blades  26  can overlap by about 3.5 inches. An inlet row  30  set of blades can be located proximate the inlet  22 . In an exemplary embodiment, the inlet row  30  can comprise 2 rows of blades  26  located about 6 to about 12 inches from the inlet  26  in the shredder housing  20 . In an exemplary embodiment, all blades  26  can be mounted on a shaft or rod about ⅜ inches. The blades  26  can be space apart by about ½ inch for the outlet rows  28  and about 2 inches for the inlet rows  30 . In an exemplary embodiment, the inlet blades  30  can be spaced apart equally to fill the available space. In another exemplary embodiment, there are two rows of thirteen inlet blades  30 .  
         [0017]     In other embodiments, the shedder  14  can include mill stones, grinding rocks of various hardness, solid metal wheels, grinding discs, cutting discs, sand paper, hardwood of oak, and pecan, and the like. In an exemplary embodiment, the shredder blades  26  can operate at about 1800 rpm and be driven by, for example, a 2-horsepower electric motor or a 5-hp gasoline engine. In a preferred embodiment, the shredder  14  is configured to shred the waste into about a ¼ inch diameter size for minimum grinding time. The waste can be reduced to about 55% to 65% of original volume when being discharged from the outlet  24 . It is contemplated that the shredder  14  can reduce the waste to a larger size and with lower volume reductions, while creating a longer grinding process to occur.  
         [0018]     The waste disposal system includes a grinding tank  32  downstream of the shredder  14 . The grinding tank  32  is configured to further reduce the particle size of the waste by use of mechanical agitation and impact between grinding elements  34  and the waste within an aqueous solution  36  in the grinding tank  32 . The grinding tank  32  includes a tank wall  38  defining an interior  40  and an exterior  42 . The grinding tank  32  includes an inlet  44  and an outlet  46 . The inlet  44  is proximate the outlet  24  of the shredder  14  and is configured to receive the waste from the shredder  14 . The processed waste is discharged from the outlet  24  of the shredder  14 .  
         [0019]     The tank wall  38  is coupled to a rotary mechanism (not shown) and is configured to rotate in order to agitate the waste and the grinding elements  34  in the interior  40 . The grinding elements  34  can comprise about 2 inch to about 3 inch diameter grinding balls. It is contemplated that the grinding elements  34  can comprise various types of grinding materials, such as, sand, gravel, rocks, scrap metal, bricks, hard wood, chipped concrete, aluminum, brass, copper, and the like. The process can also include high pressure steam and water jets, high pressure sand, and the like. A volume of water is added to the grinding tank  32  to promote the grinding process. The amount of water and grinding elements  34  added to the grinding tank  32  depends on the processing time and quality of grinding desired. In a preferred embodiment the grinding time should be about 30 minutes and the quality of shredding, water and grinding elements can be adjusted appropriately.  
         [0020]     The tank wall  38  can comprise, for example, a cement-mixing tank. The rotary mechanism can be the power takeoff of the cement-mixing tank. The tank may be portable and may be mounted, for example, on a multi-axle truck chassis. The grinding tank  32  can rotate at about 18 rpm to about 60 rpm. The rate of rotation can vary depending on the process speeds desired. The tank wall  38  can be configured in a 18 inch by 18 inch grinding tank by a predetermined length. The tank wall  38  can be ½ inch sheet metal. In alternate embodiments the tank wall  38  can comprise plastic, copper, brass, aluminum, galvanized sheet metal, and the like. The inlet  44  can be about 30 inches in diameter.  
         [0021]     In an alternate embodiment, the grinding tank  32  can comprise a flow-through style arrangement. Instead of a closed container, the tank wall can comprise an open-ended tube or pipe with the waste material flowing through from the inlet to the outlet. The grinding elements  34  can comprise rods or long tubes that impinge on the material but remain inside the tank wall interior  40 . The tank wall  38  outlet  46  includes a lid  48  that is removable and configured to contain the waste and water mixture during grinding and allow for discharge of the waste with the retention of the grinding elements  34 . The lid  48  can comprise a solid plate and a screen mesh that can be interchangeable during processing. The solid plate and screen can also be integral.  
         [0022]     The waste composition is further processed through a screen system  50  located downstream of the grinding tank  32 . The screen system  50  separates the waste composition based on the particle size. The water is also drained away for reuse in the upstream grinding tank  32 .  
         [0023]     In an exemplary embodiment illustrated in  FIG. 2 , the screen system  50  can comprise a series of screens as is known in the art. For example, three screens  52 ,  54 ,  56  having varying mesh dimensions for segregating the materials based on size with the larger size above the smaller size in series may be used. In an exemplary embodiment, screen  52  can be a 10-mesh screen, screen  54  can be a 20-mesh screen, and screen  56  can be a 28-mesh screen. It is contemplated that any number of screens can be employed. The screen  50  can be agitated by an agitator, such as a motor (not shown). Screens  52 ,  54 , and  56  may be disposed at an angle as known in the art and discharge chutes may be provided to return particles that do not pass through screens  52 ,  54 , and  56 , as well as most of the water, to the grinding tank  32 .  
         [0024]     The agitation motor can operate at about 1800 rpm. The speed of the motor and thus the agitation can be varied. In an exemplary embodiment, the displacement of the screen agitation can be from about 2 inches to about 3 inches. In an exemplary embodiment, the screen  50  can be rectilinear measuring about 4 feet by about 6 feet. The screen  50  can comprise a stainless steel placed into a wrap around deck of about ¼ inch by 2 inches angle iron. The deck and screen material can comprise plastic, iron, copper, brass, aluminum, wood, galvanized sheet metal, and the like. The deck and screen can be any size and configuration. The waste material can drain by gravity through the screen  50  to a water extractor  58 .  
         [0025]     The water extractor  58  is coupled to the screen  50  and is configured to further extract moisture from the waste composition. An exemplary water extractor  58  suitable for use in the present invention is a dewatering drum filter, such as those available from Dorr-Oliver Eimco of Salt Lake City, Utah. The water extractor  58  is used to extract as much water as possible from the waste materials. The water extractor  58  draws the water off the waste material through fine mesh with vacuum or pump suction, that varies based on the density of the material. The water is pumped back to the grinding tank  32  for reuse. The dewatered material is dropped to a drying pad  60  below for further processing. The water extractor  58  can comprise a stainless steel, copper, brass, aluminum, plastic, and the like. The water extractor  58  can operate at variable speeds as well constant speed depending on the density of the material processed.  
         [0026]     A drying tunnel and shaker table  62  is located downstream of the water extractor  58 . The drying tunnel and shaker table  62  remove additional moisture and air trapped in the waste composition. In exemplary embodiments, at least one drying pad  60  receives the waste composition downstream of the drying tunnel and shaker table  62  for the final curing and hardening of the waste composition.  
         [0027]     The drying tunnel  64  can be, for example, about 15 feet in length and about 4 feet wide and located over the shaker table  66 . A cover  67  can be included over the table and be set at a minimum of about 24 inches from the shaker table. The cover can comprise, for example, a 10 gauge galvanized sheet metal although other materials can be used. The shaker table  66  can comprise two hollow legs  68  centrally located at the shaker table  66 . Pistons  70  are disposed within the hollow legs  68  and are configured to agitate the table and contents thereon. In an exemplary embodiment, the legs  68  can be about 3 inches in diameter and the pistons  70  can be about 2 inches in diameter and comprise a solid rod material. A motor, such as a 3-hp motor (not shown) can be coupled to each piston  70  via a 6 inch piston plate. The motors can be mounted on the floor directly in line with the legs  68 . The piston plate can include adjustment holes for speed adjustment. The connector rod from the piston plate can be a solid rod including a pivot pin about 6 inches up on the rod connected to the piston plate. The motor can operate at about 1800 rpm. The table is configured to be vertically displaced from about 1 inch to about 3 inches.  
         [0028]     Rubber grommets  72  can be employed with the table between a stationary frame  74  and moveable table deck  76 . In an exemplary embodiment, eight grommets  72  can be employed in an equally spaced pattern and attached to the frame and configured for shock absorption. The table frame  74  can comprise a ¼ inch by 3 inch angle iron and the movable table deck  76  can comprise a ¼ inch sheet metal decking. The frame  74  and decking  76  can be welded. In other exemplary embodiments, the table can comprise wood, sheet metal, copper, brass, stainless steel, aluminum, galvanized sheet metal, and the like. The drying tunnel and shaker table  62  can include blowers  78  fluidly coupled to the drying tunnel  64  at an end proximate the material input end of the table. The blower can be about 11,000 CFM or greater.  
         [0029]     The drying pad  60  can be included and located to receive the materials after the drying tunnel and shaker table  62  or after the water extractor  58 . The drying pad  60  can be large enough for one week of waste material processing. The drying pad  60  can be about 100 feet by 100 feet in size. The drying pad  60  can comprise concrete material and include sealed surfaces and containment barriers for the prevention of material leakage. Finger type agitators and ambient air can also be employed in the drying process.  
         [0030]     A powdered fibrous material remains as a useful byproduct having a significant reduction in volume from the original waste disposed in the waste disposal processing system. As has been disclosed herein, all of the waste material that is not processed into a byproduct is returned to the grinding tank  32 . A single-component waste material, such as glass, or soft metals such as aluminum, may be processed according to the techniques of the present invention.  
         [0031]     According to another aspect of the present invention, the powdered material that remains can be used for counter tops, wall tile, floor tile, patio pavers, table tops, artistic painting, paint pigmentation, decorative wall paint, cement filler mixture, and wall insulation and the like. The powdered material is mixed with a binder material such as latex, patch cement, tile grout, etc. According to one embodiment of this aspect of the invention, approximately equal amounts of the powdered byproduct and binder may be mixed with water and set in a mold. Too much water will adversely affect drying time and will also affect the quality of the final product (e.g., produce soft spots or discoloration on the top of the drying casting). It has been found that about 5.7 ounces of water per pound of material is satisfactory. Drying time depends on ambient temperature and humidity. Ideal temperature has been observed to be between about 70° to about 80° F.  
         [0032]     While embodiments and applications of this disclosure have been shown and described, it would be apparent to those skilled in the art that many more modifications than mentioned above are possible without departing from the inventive concepts herein. The disclosure, therefore, is not to be restricted except in the spirit of the appended claims.