Patent Publication Number: US-2016229629-A1

Title: Waste compactor system for vehicles

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation in part of U.S. application Ser. No. 14/614,812 filed on Feb. 5, 2015, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     FIELD OF INVENTION 
     The present invention relates to a waste compactor system directed to substantially reducing the weight and volume of compacted waste in order to minimize waste removal and disposal costs and more specifically to such a system integrated into a waste compactor vehicle. 
     BACKGROUND 
     Compactors used for compacting waste have been well known for many years. These compactors utilize a hydraulic ram positioned in a chamber to compact the waste into a denser form. The hydraulic ram compacts the waste against a solid surface within the chamber. In addition to compacting the solid material, a portion of the liquid contained in the waste material may be extracted from the solid waste when pressure is applied by the hydraulic ram. The extracted liquid is discharged from the chamber via drainage slots, grates or holes located in the chamber. Self-contained compactors are typically used for the storage and removal of solid waste containing liquid waste. By regulation, these compactors are designed so that the compactor is attached to a waste container for storage of the compacted waste and the entire system is hauled to the waste disposal site. This eliminates any cross-contamination between the liquid waste and the environment while disposing of the waste. During the compaction process, waste is reduced in volume by removing the air voids located within the waste bulk. A typical compaction ratio of the waste achieved is 3:1. 
     The compaction of waste is economically advantageous because it significantly reduces the cost of waste disposal for large producers of waste, such as supermarkets, malls, large restaurants, hotels, hospitals and institutions. However, the costs are still significant. One cost associated with waste disposal is the tipping fee, which is based on the number of instances a waste hauler needs to empty a waste container. This cost may be reduced using a compaction process as it allows for more waste to be stored in a waste container, thereby reducing the number of times a waste hauler needs to empty the waste unit. Another cost is the disposal fee, which is based on the overall weight of the waste stored in the waste container. This cost can be minimized by removing liquid from the waste, thereby reducing the disposal weight. 
     However, the liquid removed from the waste must be disposed of as well. Liquid waste is typically removed from the compaction chamber either via a pumping mechanism or gravimetrically. The liquid waste is maintained in a separate vessel to be disposed by maintenance personnel or a third party vendor off-site. Disposing of this extracted liquid waste off-site induces further costs however these costs are still substantially less than the fees associated with maintaining the liquid waste within the solid waste. Further issues that arise with extracting the liquid waste during compaction and later disposing of the liquid waste off-site include the requirement of additional footprint for liquid waste storage on-site and the logistics for the solid waste generator to store the liquid waste. 
     Certain waste compactor systems have incorporated liquid evaporation in order to dispose of the liquid waste on-site after being extracted from the solid waste during compaction. These systems address, to some extent, the issues described above. However, the evaporation techniques utilized in the aforementioned compaction systems are limiting because either they fail to substantially dispose of all the extracted waste liquid, they rely solely on electrically powered heating elements which require a significant amount of energy, or they vaporize the liquid waste by heating the liquid beyond its boiling point. Furthermore, in some instances, the evaporation is performed within the compaction chamber which is not suitable for treating industrial and municipal solid waste containing plastics or other waste with a comparable melting point. Therefore, prior art compactor systems do not provide an overall cost effective and energy efficient solution for waste disposal. 
     SUMMARY 
     In one aspect, the invention features a vehicle for collecting and compacting waste for disposal. The vehicle includes a compaction chamber, configured to receive and compact waste, including an opening for inserting waste to be compacted and a plurality of apertures in at least one internal surface of the compaction chamber. There is a compactor, configured to apply pressure to the waste in the compaction chamber to reduce a volume of the waste, wherein, when the compactor applies pressure to the waste, liquid and residual solid waste exits the compaction chamber through the plurality of apertures. There is a liquid collection system, configured to collect the liquid and the residual solid waste from the plurality of apertures, wherein the liquid collection system includes an evaporation system configured to evaporate at least a portion of the liquid removed from the waste. 
     In other aspects of the invention, one or more of the following features may be included. The liquid collection system may further include a filter unit configured to receive the liquid and the residual solid waste from the plurality of apertures, the filter unit including a filter through which the liquid passes, the residual solid waste remaining on a surface of the filter. The filter unit may further include a first end, a second end, and a scraper device, the filter being positioned between the first end and the second end, and the second end including an opening in communication with the compaction chamber; wherein the scraper device is configured to travel in an extension mode from the first end to the second end across the surface of the filter to remove the residual solid waste from the filter and force the residual solid waste out of the opening of the second end and into the compaction chamber and to travel in a retraction mode from the second end to the first end. The filter unit may further include a closure assembly for sealing the opening in the second end, wherein the closure assembly is configured to open when the scraper device forces the residual solid waste out of the filter unit into the compaction chamber through the opening in the extension mode and wherein the closure assembly is configured to close after the scraper device travels to a position within the opening in the retraction mode. The filter unit may include a first actuator interconnected to the scraper device and configured to extend the scraper device in the extension mode from a retracted position proximate the first end to an extended position to cause the scraper device to remove the residual solid waste from the filter and force it out of the opening of the filter unit and configured to retract the scraper device in the retraction mode from the extended position proximate the second end to the retracted position. The closure assembly may include a door and at least one spring affixed to the door to bias the door in a closed position, and wherein the scraper device may open the door as it is forced against the door when it moves to the extended position in the extension mode and the door may close due to the spring bias as the scraper devices moves toward the retracted position in the retraction mode. The filter unit may further include a pair of guide members each having a top and a bottom surface, the guide members being disposed on opposite sides of the surface of the filter and extending from proximate the first end to proximate the second end of the filter unit. The scraper device may travel under the bottom surfaces of the guide members as the scraper devices moves from the retracted position to the extended position in the extension mode to maintain contact between the scraper device and the filter and the scraper device may be in contact with the top surfaces of the guide members as the scraper device moves from the extended position to the retracted position in the retraction mode to maintain separation between the scraper device and the filter. The filter unit may further include a second actuator, configured to move the scraper device away from the surface of the filter and position the scraper device on the top surfaces of the guide members as the scraper devices moves from the extended to the retracted position in the retraction mode to maintain separation between the scraper device and the surface of the filter. The bottom surfaces of the guide members may be positioned a distance less than or equal to a height of the scraper device from the surface of the filter to provide a downward force from the scraper device on the surface of the filter as the scraper device travels in an extension mode from the first end to the second end across the filter. 
     In yet other aspects of the invention, one or more of the following features may be included. The plurality of apertures may have a width ranging from ¼ inch to 1/32 inches. The filter may comprise a filter material having a plurality of openings with a width ranging from 0.01 inch to 0.05 inch. The filter may further comprise a perforated plate to support the filter material. The liquid collection system may further comprise a liquid collection chamber in communication with the filter unit, the liquid collection chamber configured to receive the liquid from the filter unit. The evaporation system may include an evaporation chamber in communication with the liquid collection chamber and configured to receive and evaporate the liquid. The evaporation chamber may include at least one nozzle through which the liquid from the liquid collection chamber flows to produce a spray in the evaporation chamber. The evaporation chamber includes a first heater to heat the spray to at least above 32 degrees F., and more specifically to approximately 140 degrees F., to cause the spray to evaporate. The first heater may include an aperture for receiving the exhaust gas of the vehicle to provide heat. The first heater may have a surface area and the first heater includes one or more fins to increase the surface area of the first heater. The evaporation system may include a second heater to preheat the liquid prior to the liquid flowing through the nozzle. The second heater may include an aperture for receiving the exhaust gas of the vehicle to provide heat. The second heater may have a surface area and the second heater includes one or more fins to increase the surface area of the second heater. The evaporation system may include a line interconnecting the evaporation chamber to the compaction chamber to transport un-evaporated liquid from the evaporation chamber to the compaction chamber. There may be a line for transporting the liquid between the liquid collection system and the evaporation chamber and a first filtration unit disposed in the line to remove particles from the liquid. The liquid may be transported from the liquid collection system to the evaporation chamber by a pump. The size of the particles removed by the first filtration unit may range from 0.5 micron to 5 microns. There may further be included a second filtration unit disposed in the line to remove hydrocarbons and odor from the liquid and wherein the second filtration unit comprises activated carbon. 
     In another aspect of the invention there is a vehicle for collecting and compacting waste for disposal, including a vehicle frame and a compaction system mounted on the vehicle frame. The compaction system includes a compaction chamber, configured to receive and compact waste, including an opening for inserting waste to be compacted and a plurality of apertures in at least one internal surface of the compaction chamber. There is a compactor, configured to apply pressure to the waste in the compaction chamber to reduce a volume of the waste, wherein, when the compactor applies pressure to the waste, liquid and residual solid waste exits the compaction chamber through the plurality of apertures. There is a liquid collection system, configured to collect the liquid and residual solid waste from the plurality of apertures, wherein the liquid collection system includes a filter unit and an evaporation system configured to evaporate at least a portion of the liquid removed from the waste. The filter unit is configured to separate the liquid and the residual solid waste, the filter unit including an opening in communication with the compaction chamber to enable the residual solid waste to be moved into the compaction chamber. 
     An object of the invention is to reduce hauling and disposal costs by substantially reducing the weight and volume of the waste. 
     A further object of the invention is to provide a high pressure compaction system to substantially reduce the volume of waste produced and to extract a considerable amount of the liquid from the waste to substantially reduce the weight of the compacted waste. 
     A further object of the invention is to provide a waste compactor system with optimized compaction, liquid removal and energy efficiency. 
     A further object of the invention is to provide a waste compactor system with the above features integrated into a waste compactor vehicle. 
     Additional objects and advantages of the invention will become apparent as the following description proceeds; and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a waste compactor system according to this invention; 
         FIG. 2  is a perspective view of the waste compactor of  FIG. 1  with the external housing removed so the components of the system are visible; 
         FIGS. 3A-C  are perspective views of the ram and actuator assemblies; 
         FIG. 4  is a cross sectional view of the waste compactor of  FIG. 2  taken across the ram assembly; 
         FIG. 5  is a perspective view of the filter unit of the liquid collection system according to this invention; 
         FIG. 6  is a top down view of the liquid separation system of the liquid collection system according to this invention; 
         FIG. 7A  is a perspective view of the evaporation system of the waste compactor according to this invention; 
         FIG. 7B  is a cross sectional view of the evaporation system of  FIG. 7A ; 
         FIG. 8  is a cross sectional view of the closure assembly of the waste compactor according to this invention; 
         FIG. 9A-C  are flow charts depicting the operation of the control system of the waste compactor according to this invention. 
         FIG. 10  is a perspective view of a waste compaction vehicle including a waste compactor system according to another embodiment of this invention; 
         FIG. 11  is a perspective view of the compaction system of this invention integrated into the waste compaction vehicle; 
         FIG. 12  is a cross sectional view of the liquid collection system of the waste compaction system of  FIG. 10 ; 
         FIG. 13A-B  are perspective views of extension mode and retraction mode of the filter unit of the waste compaction system of  FIG. 10 ; 
         FIG. 14  is a perspective view of the opened closure assembly of the waste compaction system of  FIG. 10 ; 
         FIG. 15  is a perspective view of the liquid collection system of the waste compaction system of  FIG. 10 ; 
         FIG. 16A-C  are perspective views of the evaporation system of the waste compaction system of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION 
     Waste compactor  10 ,  FIG. 1 , according to this invention is shown interconnected to a typical commercial waste container  12 , which by regulation has the dimensions of 96 inch width×154 inch length×80 inch height. Waste container  12  can be removed from waste compactor  10  for transportation and disposal by a waste hauler. 
     Waste container  12  includes an opening (not shown) with dimensions of 64.5 inch width×46.5 inch height for receiving waste from waste compactor  10 . The output opening of waste compactor  10  has smaller dimensions than the opening of waste container  12  and therefore includes an interface plate (described below), contained in housing  14 , of similar dimensions to the opening in waste container  12  to enable the interface and interconnection of waste compactor  10  and waste container  12 . A gasket (not shown) between the waste container  12  and the interface plate is typically included. 
     There is a compaction housing  16  within which the waste compaction occurs. Compaction housing  16  includes feeding doors  18   a - c  through which waste is inserted for compaction. Housing  20  includes other components of waste compactor system  10 , such as the ram assembly, actuator, and liquid collection and evaporation system, which are all described in more detail below. 
     Waste compactor  10  and waste container  12  are typically stored on-site at facilities that are generators of significant amounts of waste materials. In some applications, the solid waste generated often has a fairly significant liquid component in the form of oils, water and other liquids, which greatly adds to the overall weight of the waste. When full, the waste container  12  is hauled away by a waste hauler to a waste facility for disposal. 
     Each time the waste hauler transports a waste container for disposal there is an associated hauling fee, which is referred to as a tipping fee. For a given period of time, the overall cost to dispose of the producer&#39;s waste is thus dependent on the number of instances a waste hauler needs to empty the waste container. This cost may be reduced by the use of on-site waste compaction, which allows for more waste to be stored in a waste unit, therefore reducing the number of times a waste hauler needs to empty the unit. 
     Another cost associated with the removal of the waste is the disposal fee, which is based on the overall weight of the waste stored in the waste unit. The liquid component in the waste significantly adds to the weight of the waste and thus the overall disposal cost. The disposal cost may be reduced by removing the liquid from the waste on-site before transporting the waste container. However, the liquid removed from the waste must then be separately disposed of which, while less costly than transporting it with the solid waste, still involves an associated liquid disposal cost. 
     Waste compactor  10  provides a more cost effective way of disposing waste by a) significantly reducing the size of the waste by using a high pressure compacting system, b) significantly reducing the weight of the waste by extracting liquid from the solid waste and disposing of the liquid on-site, and c) by reducing the cost of disposing the extracted liquid by evaporating a portion of the extracted liquid on site. More specifically, all of the waste liquid with a vapor pressure greater to or equal to water will be evaporated. The liquid with a vapor pressure less than water will be stored in a container and disposed of by a third party. In addition, these objectives are met while maximizing energy efficiency. A preferred embodiment, which achieves the above objectives, is described in more detail below. 
     In  FIG. 2 , there is shown a compaction chamber  30  enclosed within housing  16 ,  FIG. 1 . Compaction chamber  30  has a first end  32  and a second end  34 . Proximate first end  32  is a first opening  36  through which compacted waste may be transferred into waste container  12 . Proximate the second end  34  of compaction chamber  30  is ram assembly  38  which is interconnected to actuator system  40 . Actuator system  40  moves ram assembly  38  from a retracted position (as shown in  FIG. 2 ), where it is located proximate the second end  34  of compaction chamber  30  to an extended position located proximate the first end  32  of the compaction chamber  34 . Ram assembly  38  and actuator system  40  are contained within housing  20  shown in  FIG. 1 . The top plate of ram assembly  38  is removed in this figure so that components of actuator system  40  are visible. 
     Compaction chamber  30  also has a second opening  42  into which waste to be compacted may be inserted by an operator. The waste is inserted through opening  42  by opening either door  18   a ,  18   b , or  18   c  in housing  16  shown in  FIG. 1 . When the waste has been inserted into compaction chamber  30 , the operator may activate the waste compactor to begin a compaction mode to compact the waste into compacted waste units or blocks which are formed by the pressure exerted on the waste by the ram assembly  38  as it compacts the waste in the compaction chamber  30  against a closure assembly  44 , which includes a gate  46 . 
     Gate  46  is shown in the open position in  FIG. 2 ; however, it would be in the closed or sealed position during the compaction mode. Once the waste is compacted into a compacted waste unit or block gate  46  is opened and ram assembly  38  is activated to move the compacted waste unit through closure assembly  44  and through an opening in an interface plate  48  into waste container  12 . Interface plate  48  is affixed to closure assembly  44 , and enables the interface of waste compactor  10  with waste container  12 . 
     Actuator system  40  includes a hydraulic system  50  which includes a pump and a reservoir that are interconnected to hydraulic cylinders  52   a - c , depicted in more detail in  FIG. 3A . Hydraulic system  50  may also include a flow divider to ensure an equal amount of hydraulic fluid is distributed to hydraulic cylinders  52   a - c . The cylinders  52   a - c  are located within the interior  54 ,  FIG. 3C , of ram assembly  38  and a piston of each cylinder is affixed to ram assembly  38  via a single common coupler  45 . To secure the cylinders to the coupler, rod  56  passes through the apertures in common coupler  45  and through apertures at the ends of the pistons in cylinders  52   a - 52   c . Waste compactor  10  is designed to produce very high pressure compaction, on the order of more than 100 psi on the compaction surface  58 ,  FIG. 3B , of ram assembly  38  and even up to as much as 570 psi. A hydraulic pressure of approximately 3000 psi of pressure would be required for 570 psi of pressure on compaction surface  58  of ram assembly  38 . At these pressures, waste compactor  10  provides for a minimum waste compaction ratio of 10:1. Although, not shown in the figures, a pressure sensor on the hydraulic fluid line would be used to determine hydraulic pressure and then the pressure exerted by the ram assembly can be readily determined based on the compaction surface. 
     To ensure a smooth transfer of hydraulic pressure to ram assembly  38 , common coupler  45  provides a more uniform transfer of force from the individual hydraulic cylinders  52   a - c  to the ram assembly  38  to enable smooth travel through the compaction chamber  30 . The common coupler  44  decreases the likelihood of more force being applied to one side of the ram assembly  38  by cylinders  52   a - c  being individually coupled to ram assembly  38 . Brackets  60  and braces  62 , both depicted in  FIG. 2 , which are connected to housing  20 ,  FIG. 1 , provide resistance to the high forces generated by actuator system  40  as it causes ram assembly  38  to compact waste in waste compaction chamber  30 . 
     Sensors  72   a  and  72   b ,  FIG. 3A , e.g. spring pot sensors, mounted on ram assembly  38  are used to detect the position of ram assembly  38  as it travels within compression chamber  30 . The position information is used by the control system in the compaction and disposal modes as described below with respect to  FIGS. 9A-C . 
     Referring again to  FIG. 2 , there are a plurality of slots  64   a,b  and  66   a,b  in the bottom surface and opposing side surfaces, respectively, of compaction chamber  30 . Slots  66   b  are not visible in  FIG. 2 . The slots are used to allow liquid extracted from the waste when high pressure is applied to the waste by the ram assembly  38  during the compaction mode to exit compaction chamber  30 . The slots may take on other shapes and sizes. They may be formed in one or more internal surfaces of compaction chamber  30 . With the design of the preferred embodiment, waste compactor  10  is capable of processing solid waste to have a final liquid waste content of 30%, regardless of the starting liquid waste content of the unprocessed solid waste. 
     The number, location, and size of apertures in the surface(s) may be selected based on the particular application to achieve the desired amount of liquid removal, while preventing an excessive amount of solid waste material from passing through the apertures. Hydraulic pressure caused by compacting the liquid waste in the compaction chamber must be considered in conjunction with the pressure caused by compacting the solid waste. Too few apertures with a high ram assembly pressure will require additional structural support for the compaction chamber and the overall waste compactor system  10 . One skilled in the art will optimize the design based on the required specifications and parameters desired. 
     Additionally, channels  70 ,  FIG. 3B , may be included on the compaction surface  58  to facilitate flow of the liquid from the compaction surface  58  to the plurality of slots  64   a,b  in the bottom surface of the compaction chamber  30 . 
     Liquid from the slots  64   a,b  and  66   a,b  exits compaction chamber  30  and enters filter unit  80 ,  FIGS. 4 and 5 . The liquid passes through screen filter  82  and captures on its surface solid waste material which passed through slots  64   a,b  and  66   a,b  in compaction chamber  30 . A mesh that can screen particles 115 microns or larger is suitable. Cleaner system  84  includes a rod  86  and squeegee  88  affixed to an end of rod  86 . The cleaner system is periodically activated to cause the rod to retract and pull the squeegee across the surface of filter  82  to remove solid waste and dispose of into container  92 , which may comprise a single container or multiple smaller containers. However, the cleaner system is not activated during the movement of the ram assembly in order to contain the solid waste. Container  92  may be periodically emptied as part of routine servicing. Filter unit  80  further includes sidewalls  90   a,b  to ensure that the solid waste material is contained on the surface of filter  82  when squeegee  88  travels across it and moves the solid waste into container  92 . 
     After the extracted liquid has been filtered by filter unit  80  it then passes to a liquid separation system  101  and on to evaporation systems  102   a,b ,  FIG. 2 . The combination of filter unit  80 , liquid separation system  101  and evaporation systems  102   a,b  are collectively referred to as the liquid collection system. 
     Liquid separation system  101  is shown in more detail in  FIG. 6  to separate the filtered liquid into two components, a first liquid component having a vapor pressure greater than or equal to the vapor pressure of water and a second liquid component having a vapor pressure less than the vapor pressure of water. The filtered liquid is heated using heating tubes  104  which, in the preferred embodiment, carry hydraulic fluid from the hydraulic system. Conductivity sensors  105   a,b  and liquid level sensors  106   a,b  are used for detecting the conductivity and the level (high and low), respectively, of the liquid. Insulated piping  107  is connected to a drain in liquid separation system  101  to remove the first liquid component as it is pumped by pump unit  108  (which includes a filter) to evaporation systems  102   a,b  via insulated piping  109 . 
     The first liquid component is located on the bottom of the container due to its greater density and pumped until the conductivity sensors  105   a,b  detect a change in conductivity indicating that the first liquid component has been pumped out of the container and the level of the second liquid component has dropped. Pump  108  to evaporation systems  102   a,b  are turned off and compaction within compaction chamber  30  is halted. The second liquid component can then be removed via a gravity drain or other suitable means. Subsequently compaction within compaction chamber  30  is reinitiated allowing for liquid collection to begin again until the high level liquid sensor detects the liquid collection container is full. Pump  108  is restarted and pumping of the first liquid component to the evaporation system begins again. The low liquid level sensor may be used to determine when the second liquid component has been removed from the container. 
     In  FIG. 2  two evaporation systems  102   a,b  are shown; however, it is not a requirement of this invention and a single evaporation system may be used. In  FIGS. 7A and 7B  the configuration of a single evaporation system  102   a  is shown. Evaporation system  102   b  may have the same configuration. 
     The first liquid component having a vapor pressure greater than or equal to the vapor pressure of water, is received via tubing  109  (shown in  FIG. 6 ) into input duct  110  and attached to spray nozzles  112   a  and  112   b . Spray nozzles, such as the PJ Fog Nozzle, supplied by Bete Fog Nozzle, Inc. may be used. The spray nozzles should produce a droplet size of no greater than 300 microns and ideally 50-100 microns. While two spray nozzles are shown, any number could be used depending on the application. 
     Fan  114  is provided proximate the interface between the input duct  110  and the evaporation chamber  116  to entrain the spray of droplets emitted by nozzles  112   a,b  and carry them in the airflow throughout evaporation chamber sections  118 ,  120 , and  122 . In the preferred embodiment, the total length of evaporation chamber  116  is 15 linear feet and the nominal operating flow rate of fan  114  is 500-1,000 cfm with a min/max flow rate of 200/2,000 cfm respectively. Evaporation chamber sections  118 ,  120 , and  122  are folded over on one another to achieve a sufficiently long evaporation chamber while minimizing the footprint of the evaporation system  102   a  and hence the overall waste compactor  10 . The airflow is emitted to the atmosphere through outlet  124  at the end of evaporation chamber section  122 . 
     The velocity of the airflow produced by the fan  114  is selected to ensure sufficient retention time in the evaporation chamber  116  to optimize evaporation based on the various conditions. It would be a goal to minimize the length of the evaporation chamber but various factors such as droplet size, liquid temperature, and airflow velocity must be considered for the particular application. 
     One or more mist collection pads (not shown) are provided to collect any remaining moisture in the airflow. The mist collection pads may be constructed by, for example, sandwiching a 14″ non-woven, polyester filter pad between two plastic plates. The moisture collected is then re-circulated for an additional pass through the evaporation system  102   a . Additionally, one or more filters may be included at the output  114  to reduce or eliminate environmental impact of the exhausted airflow. 
     Referring to  FIG. 8 , closure assembly  44  is shown in more detail. Affixed to interface plate  48 , is closure assembly  44 , which includes gate  46 . Gate  46  is closed when waste is being compacted in the compaction chamber  30  and is opened when the compacted waste units are to be passed into waste container  12 . The top of gate  46  is attached to a header  130  which is connected on opposite sides to hydraulic cylinders  132  and  134 , which travel up and down within rails  136  and  138 , respectively. 
     Closure assembly  44  includes a bottom spring plate assembly  140  and two side spring plate assemblies  142  and  144 . The side spring plate assemblies  142  and  144  are positioned flush with the side edges of gate  46  and as gate  46  is lowered into the closed position, plates  150  and  152  engage with the side edges of gate  46 . As the sides of plate  46  engage with plates  150  and  152 , the plates are forced in the outward direction and the springs of the of side plate assemblies  142  and  144 , respectively, are compressed. The gate  46  may contain rollers, e.g.  146   a  and  146   b , positioned slightly outward, on the side edges which interface with the plates  150  and  152  of side spring plate assemblies  142  and  144 . This not only reduces the friction between the gate surfaces and the side spring plate assemblies with the compaction chamber reducing maintenance but it also properly seals gate  46  during compaction mode preventing the liquid from discharging out the gate. The side spring plate assemblies also ensure that there are no gaps where waste material may become caught during the compaction or disposal of waste as it travels through the compaction chamber  30 . Furthermore, the side spring plate assemblies provide mechanical support to the closure assembly more specifically the gate when the waste compactor system is in compaction mode. 
     Bottom spring plate assembly  140  is positioned in a recess in the bottom surface of the compaction chamber  30  (not shown in  FIG. 8 ). When gate  46  closes and engages with plate  154  of bottom spring plate assembly  140 , the springs are compressed and gate  46  travels into the recess below the surface of the compaction chamber  30 . This creates a seal between the gate and the bottom surface of the compaction chamber when the gate  46  is in the closed position. As with the side spring plate assemblies  142  and  144 , this prevents the liquid from discharging out of the bottom of gate  46  and provides mechanical support to the closure assembly when under pressure. It also ensures that there are no gaps where waste material may become caught during the compaction or disposal of waste as it travels through the compaction chamber  30 . 
     The operation of waste compactor  10  is controlled via a control system which operates according to flow charts depicted in  FIGS. 9A-C . In  FIG. 9A , flow chart  200  describes the start up sequence. In step  202  an operator activates the start-up of waste compactor  10  by pushing a start button. In step  204 , the system queries whether the feeding doors  18   a,b,c ,  FIG. 1 , are open. If they are, an indicator is activated at step  205  to alert the operator that the feeding doors are open. If the feeding doors are closed, the system proceeds to step  206  to determine if gate  46  of closure assembly  44  is open. If the gate is open, at step  208  a gate closing sequence is initiated and a redetermination is made at step  206  if the gate is closed. Furthermore, if it is determined that the gate is closed at step  206 , the compaction mode is initiated at step  210 . 
     The compaction mode sequence is described in flow chart  220 ,  FIG. 9B . At step  222  ram assembly  38  is activated to begin forward movement to compact waste in the compaction chamber  30 . At step  224  the position of ram assembly  38  is determined using data provided by position sensors  72   a  and  72   b ,  FIG. 3A . At step  226 , it is determined if ram assembly  38  has at least reached the start of the ideal compaction zone within the compaction chamber, which is defined as a zone between +2 inches from gate  46 ,  FIG. 2 , and +6 inches from gate  46 . The distances used herein are simply for describing a preferred embodiment and are in no way limiting. The location of the ideal compaction zone may be varied depending on the application. The specific query at step  226  is whether the position of the ram assembly  38  is greater than +6 inches from gate  46 . If the position is greater than +6 inches, this indicates that ram assembly  38  has not yet reached the ideal compaction zone. 
     If the distance is greater than +6 inches the hydraulic cylinder pressure is then checked to determine if it exceeds a pre-determined pressure level at step  228 . In the preferred embodiment, the level is 2000 psi of hydraulic pressure, which translates into approximately 380 psi of pressure on compaction surface  58  of ram assembly  38 . The pressure level may be varied depending on the application. 
     If this pressure level has been exceeded, this indicates that a substantially non-compressible object is located in the compaction chamber impeding forward motion of ram assembly  38 . Therefore, the compaction mode is terminated when at step  230  the disposal sequence is initiated in order to remove the non-compressible object from the waste compactor  10  and dispose of it in the waste container  12 . Alternatively, if the pressure at step  228  does not exceed the predetermined level, the compaction mode and forward movement of ram assembly  38  continues and the system cycles back to step  222 . 
     If at step  226  the position of the ram assembly  38  is determined to be less than +6 inches from gate  46 , this indicates that ram assembly  38  is either in the ideal compaction zone (+2 inches to +6 inches from gate  46 ) or it has passed the ideal compaction zone (+0 inches to +2 inches from gate  46 ). Furthermore, if it is determined in step  232  that the ram assembly  38  is greater than +2 inches from gate  46 , then the hydraulic cylinder pressure is checked at step  234  to determine if the pressure exceeds another, lower pre-determined pressure level. In the preferred embodiment, this pressure level is 700 psi of hydraulic pressure which translates to approximately 130 psi of pressure on the compaction surface  58  of ram assembly  38 . 
     If the pressure level exceeds 700 psi at step  234 , the system has thus detected that a desired pressure level, 700 psi of hydraulic pressure/130 psi of ram compaction pressure, has been achieved in the ideal compaction zone, indicating the formation of the desired size of a compacted waste unit for this preferred embodiment. As a result, at step  236  forward motion of the ram assembly  38  is stalled by the waste block within the compaction chamber and the pressure is held by the ram assembly for a short dwell time, e.g. 30 seconds, until the disposal sequence is initiated as set forth in  FIG. 9C . By initiating the disposal sequence the compacted waste unit will be disposed of in the waste container  12 . 
     If instead, at step  232  it is determined that the current ram assembly position is not greater than +2 inches from the gate, indicating it has passed the ideal compaction zone, then at step  240  the compaction mode is terminated and the ram assembly is fully retracted. The system waits for an operator to initiate a new start up sequence, pursuant to  FIG. 9A , after more waste material has been loaded into the compaction chamber. This approach is taken to avoid transferring the compacted waste material into the waste container  12  before a desired size waste unit has been formed. Alternatively, instead of terminating the compaction mode at step  240 , the system may be configured to automatically cycle through the compaction mode one or more additional times in the event there is additional waste to be compacted in the compaction chamber. 
     If, at step  234 , it is determined that the pressure level does not exceed 700 psi, the compaction mode and forward movement of ram assembly  38  continues and the system cycles back to step  222 . 
     In  FIG. 9C , the disposal sequence is depicted in flow chart  250 . At step  251  ram assembly  38  is backed away 2 inches from gate  46  in order to relieve the pressure off the gate when it is opened. The distances used herein are simply for describing a preferred embodiment and are in no way limiting. In step  252  gate  46  of closure assembly  44  is opened. At step  254 , the ram assembly is extended to its maximum position to move the waste from the compaction chamber  30  into the waste container  12 . The maximum pressure on surface  58  of ram assembly  38  is determined at step  256  and at step  258  the status of the waste container  12  is determined. A light indicator (not depicted) communicates to the operator the remaining capacity of the waste container. At step  260  the ram assembly is retracted and at step  262  it is determined if the ram assembly has reached a predetermined distance from gate  46 , at which time at step  264  the gate  46  is closed. At step  266  the disposal sequence is terminated. The system waits for an operator to initiate a new start up sequence, pursuant to  FIG. 9A . 
     The above waste compactor system is described as a stationary unit; however, the concepts of the invention may also be incorporated into a mobile system, such as a waste compactor vehicle. Thus, according to another embodiment of the invention, a vehicle  300 ,  FIG. 10 , for collecting and compacting waste for disposal is shown. The vehicle  300  can be any vehicle equipped with a crew cab  302  for a driver to operate the vehicle  300 , and a vehicle frame  305 . A compaction system  310  is mounted on the vehicle frame  305 , and is configured to compact the waste for disposal and collect and evaporate the liquid from the compaction of the waste. In this example, the vehicle  300  is loaded with waste to be compacted from the rear, but this invention may be applied to top or side loading vehicles as well. 
     A shown in  FIG. 11 , the compaction system  310  includes a compaction chamber  330  where waste collected is compacted in a conventional manner. A liquid collection system  320  is included according to this invention which may be integrated into the compaction vehicle  300 . The compaction chamber  330  includes a loading region  336 , which is part of a loading unit  337 , into which waste to be compacted is inserted by one or more operators. When full, an operator activates the loading unit  337  to transfer (via a hydraulic system) the waste in loading region  336  to another region of compaction chamber  330  proximate a plurality of apertures  338  disposed on the bottom internal surface  339  where the waste is compacted. Compactor system  310  applies pressure to the waste in the compaction chamber  330  to reduce a volume of the waste during compaction. The apertures  338  can be configured in various sizes and shapes to allow the passage of the maximum amount of liquid from the waste as it is compacted while minimizing the passage of residual solid waste through the apertures. In this example, the apertures  338  are slots having a length of 24 inch and a width of 1/16 inch. In other embodiments, the apertures  338  can have slots with a width ranging from ¼ inch to 1/32 inch. There could alternatively be a plurality of circular apertures having diameters raging from 1/16 inch to ⅜ inch. 
     Filter unit  340  located immediately below compaction chamber  330  is configured to receive the liquid and residual solid waste exiting compaction chamber  330  through apertures  338 . Filter unit  340  may be located in other places in compaction system  310  in which case the liquid and residual waste would be pumped thereto. Filter unit  340  separates the liquid and residual solid with a filter  342 . The residual solid waste captured by filter  342  may be cycled back to the compaction chamber  330  through opening  350  by a scraper device  351 . Opening  350  is in communication with loading region  336  of compaction chamber  330 . This operation will be described in more detail below. 
     In  FIG. 12  liquid collection system  320  is shown in more detail. Disposed on the bottom internal surface of filter unit  340  is filter  342  which is configured to allow only the liquid to pass through, leaving the residual solid waste on the top surface of filter  342 . Thus, upon entering of the filter unit  340 , the liquid and the residual solid waste are further separated by the filter  342 . The design of the filter  342  can vary in order to allow the separation. In this example, the filter  342  can include a filter material  343  (visible in  FIGS. 13A-B ). The filter material has a plurality of openings with a mesh size of 24×24. The filter material uses wire that is 0.0075 inch in diameter and with an opening size ranging from 0.01 inch to 0.05 inch (preferably from 0.012 inch to 0.047 inch). In this example, opening size is 0.034 inch. The filter  342  can further include a perforated plate  345  (visible in  FIG. 14 ) to support the bottom of the filter material  343 , the perforated plate having a plurality of holes with a width of ¼ inch. In other embodiments, the width of the holes can also vary (e.g., ranging from ½ inch to ⅛ inch). 
     Filter unit  340  also includes the scraper device  351  interconnected to a first actuator  352 . The scraper device  351  travels from a first end  353  to a second end  354  of the filter unit  340  across the top surface of the filter  342  in an extension mode. The scraper device  351  travels from the second end  354  to the first end  353  in a retraction mode. The scraper device  351  can be driven by any suitable power resource. For example, the scraper device  351  is driven by a motor  355 . 
     The filter unit  340  can further include a closure assembly  356  to seal the opening  350  in the second end  354  to allow residual solids captured by filter  342  to be cycled back to the compaction chamber  330  through opening  350  by scraper device  351 . The closure assembly  356  is configured to open upon the extension of the scraper device  351 , and close upon the retraction of the scraper device  351 . Any mechanism of the opening and closing of the closure assembly is within the scope of the invention. For example, shown in  FIG. 12 , the closure assembly  356  includes a door  358  and one or more springs  360  affixed to the door  358  to bias the door  358  in a closed position. The scraper device  351  opens the door  358  as it is forced against the door when it moves to the extended position in the extension mode and the door  358  closes due to the spring bias as the scraper devices  351  moves toward the retracted position in the retraction mode. In other embodiments, the closure assembly  356  may include a motion sensing unit that opens the door  358  based on a detection of the extension of the scraper device  351 , and closes the door  358  based on a detection of the retraction of the scraper device  351 . 
       FIGS. 13A-B  further illustrate the operation of scraper device  351  in the extension and retraction modes. Guide members  362  (only one is shown in this view) are disposed on two opposite internal surfaces  363  of the filter unit  340  and extending from proximate the first end  353  to proximate the second end  354  of the filter unit  340 . In the extension mode,  FIG. 13A , the scraper device  351  travels under the bottom surfaces  364  of the guide members  362  to maintain contact between the scraper device  351  and the filter  342 . The distance, d, between the bottom surface  364  of guide members  362  and filter  342  may be equal to or less than the height, h, of scraper device  351  to ensure there is contact with and positive pressure exerted on the surface of filter  342  by scraper device. As a result, the scraper device  351  removes the residual solid waste remaining on the on the top surface of the filter  342 , and forces the residual solid waste out of the filter unit  340  through the opening  350 . 
     In retraction mode,  FIG. 13B , the scraper device  351  is in contact with the top surfaces  366  of the guide members  362  as the scraper device  351  moves from the extended position to the retracted position to maintain separation, s, between the scraper device  351  and the filter  342 . Upon retraction of scraper device  351 , a second actuator  368  ( FIG. 12 ), moves the scraper device  351  up and away from the top surface of the filter  342 . As scraper device  351  is being retracted and moved up it is positioned on the top surfaces  366  of the guide members  362  as the scraper device  351  moves from the second end  354  to the first end  353  of the filter unit  340  in the retraction mode. This is done to ensure that any remaining residual solid waste on the filter  342  is not forced back toward the first end of the filter unit  340 . The second actuator  368  can be driven by any suitable power resource. For example, the second actuator  368  can be driven by a motor. The top surfaces  366  of guide members  362  may be angled downward from the second end of filter unit  340  toward the first end so that the separation, s, between scraper device  351  and the surface of filter  342  decreases as the scraper device moves toward the first end. Once in the fully retracted position the scraper device comes off of the guide members  366  and is positioned on the surface of filter  342  by the second actuator  368 . 
       FIG. 14  further illustrates the opening mechanisms of the closure assembly  356 . The closure assembly  356  may be configured so that the scraper device  351  is in contact with the door  358  upon extension, and forces the door  358  to open from the biased closed position of the door  358  by the spring  360  (shown in  FIG. 12 ). Door  358  includes side panels  359   a,b  which travel in tracks  361   a  and  361   b  (not visible in this view). Scraper device  351  includes vertical blocks  363   a  and  363   b  (not visible in this view) which impact dowel  365  to force door  358  open. The residual solid waste removed from the filter  342  by the scraper device  351  can then be forced out of the filter unit through the opening  350 . As the scraper device  351  is retracted, springs  360  cause the door  358  to move in the direction of travel of the scraper device  351  until vertical blocks  363   a,b  lose contact with dowel  365  and door  358  seals opening  350 . 
     As shown in  FIGS. 12 and 15 , the liquid collection system  320  further includes a liquid collection chamber  370  configured to receive the liquid exiting from the filter unit  340  through the filter  342 . The liquid collection chamber  370  can be disposed in various positions of the vehicle  300 . For example, shown in  FIGS. 12 and 15 , the liquid collection chamber  370  can be mounted on the bottom of the filter unit  340 . Various shapes of the liquid collection chamber  370  are also within the scope of the invention. For example, the liquid collection chamber  370  can be cubic, cylindrical or conical. 
     A line  373  ( FIG. 15 ) may be included in the liquid collection system  320  to transport the liquid from the liquid collection chamber  370  to an evaporation system  374 . The liquid may be transported, for example, by a pump  375 , from the collection chamber  370  to evaporation system  374 . The liquid collection system  320  may also include one or more filtration units. For example, a filtration unit  376  may be configured to remove particles from the liquid. In some embodiments, the size of the particles removed by the filtration unit  376  can range from 0.5 to 5 microns. A second filtration unit  377  may also be included in the liquid collection system  320  to remove hydrocarbon and odor from the liquid. The material used in the second filtration unit  377  may, for example, be activated carbon. 
       FIG. 16A  further shows another perspective of a portion of vehicle  300 . The evaporation system  374  is mounted on the vehicle  300  and uses the exhaust gas from the exhaust pipe  378  of the vehicle  300  as a heating resource. The evaporation system  374 ,  FIG. 16B , includes an evaporation chamber  379 , in which the liquid is evaporated. A nozzle  380  can be disposed on one internal surface of the evaporation chamber  379 , and configured to spray the liquid transported by the line  373  into the evaporation chamber  379 . The nozzle can be any type of nozzle described above in earlier embodiments according to this invention. The evaporation system  374  also includes a first heater  382 , configured to heat and evaporate the spray. The first heater  382  can be configured to heat the spray to a temperature above 32 degrees F. to cause the spray to evaporate in the evaporation chamber  379 . In this example, the first heater  382  heats the spray to approximately 140 degrees F. Evaporation system  374 ,  FIGS. 15 and 16A , may further include a second heater  383  to heat the liquid prior to the liquid flowing through the nozzle  380 . Any heating resource used by the first and the second heaters is within the scope of the invention. In this example, the exhaust gas of the vehicle  300  is to be used as the heating resource. Additionally, multiple fins  384  may be disposed in the evaporation chamber  379  to increase the surface area of the heater  382  in order to better facilitate the evaporation of the liquid. The evaporation system  374  also includes an opening  386  on an internal surface of the evaporation chamber  379 , through which the gas formed by the evaporation of the liquid exits the evaporation chamber  379 . 
     Illustrated in  FIG. 16C , the second heater  383  may include a heating chamber  387  configured to heat the liquid to a temperature above 32 degrees F. The second heater  383  may also include a coiled line  388  in which the liquid to be heated passes through the heating chamber  387 . Additionally, multiple fins  389  may be disposed in the heating chamber  387  to increase the internal surface area of the heating chamber  387 . In this example, the heat received from the exhaust gas passing through second heater  383  of the vehicle  300  is transferred by the fins  389  to create heated air in the heating chamber  387 , and heat the coiled line  388  and the liquid therein. The temperature to which the liquid was heated may be determined by the retention time of the liquid through the coiled line  388 . 
     Referring again to  FIG. 15 , in some embodiments, a second line  381  may be included in the liquid collection system  320  to transport un-evaporated liquid (e.g., oil) from the evaporation system  374  to the compaction chamber  330 . In this example, the second line  381  delivers the un-evaporated liquid to the loading region  336  of the compaction chamber  330 . The transportation of un-evaporated liquid is driven by a second pump  385 . 
     While preferred embodiments of the present invention have been shown and described herein, various modifications may be made thereto without departing from the inventive idea of the present invention. Accordingly, it is to be understood the present invention has been described by way of illustration and not limitation. Other embodiments are within the scope of the following claims.