Abstract:
A grease removal system includes a solid interceptor fluidly coupled to a grease trap tank, which is fluidly coupled to a secondary tank. The secondary tank contains an enzyme solution which biodegrades the grease. The grease removal system may also include a solid interceptor fluidly coupled to a grease trap tank which is fluidly coupled to a replaceable container. Grease is diverted from the grease trap tank into the replaceable container and thereafter discarded. The grease removal system may include a grease trap tank utilizing a unique arrangement of grease baffles and solids baffles which work together to isolate grease within a single region of the grease trap tank for ease of disposal. Finally, the grease removal system includes two level sensors which detect the level of grease within the grease trap tank and, at the appropriate level direct the accumulated grease from the grease trap tank.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/464,489, filed Apr. 22, 2003, U.S. Provisional Application No. 60/457,206, filed Mar. 25, 2003, and U.S. Provisional Application No. 60/500,399, filed Sep. 5, 2003, which are incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the treatment of wastewater products and, more particularly, to a grease trap design for minimizing the disposal of grease, fats and oils from wastewater. 
     2. Description of Related Art 
     Grease traps are typically located in restaurants, meat and poultry processing plants, slaughter houses and other industries having excessive amounts of greasy wastewater and foreign materials, such as insoluable solids, that must be treated to prevent the discharge into sanitary sewer systems. The overtaxing of municipal sewage treatment facilities has become a serious problem in many communities and ordinances requiring a reduction in volume of grease and insoluble solids discharged into municipal sewers are becoming more widespread and stringent. 
     When greasy wastewater is discharged through a wastewater disposal system, the grease accumulates on the interior walls of associated piping. As the grease coating grows, it obstructs the flow of wastewater in the sewage pipe. Grease traps are typically utilized to intercept and remove this grease prior to entrance into the disposal system. In many instances, grease traps are not properly cleaned or maintained which may result in inadequate removal of grease. 
     In an effort to improve the separation and collection of grease and foreign materials, grease traps may have a series of compartments. However, these compartmentalized grease traps typically utilize removable screens, level and temperature sensors, valves and heating devices to properly maintain the flow and separation of grease from the wastewater. Grease traps of this type require frequent cleaning to remove accumulated materials. Cleaning of these grease traps is an unpleasant task that can become very messy and tedious. However, if the grease trap is not properly maintained, the grease will collect on the sensors and valves, thereby causing the grease trap to function improperly. Therefore, there is a need for a simple grease trap that minimizes the above-mentioned deficiencies due to improper cleaning and maintenance. 
     Grease traps are well known in the art for receiving and processing a mixture of water and grease. The water and grease mixture is introduced within the grease trap tank where a baffle obstructs the flow of the water and grease mixture causing the grease and water mixture to slow down in velocity. The grease trap includes a settling chamber, whereby the grease floats on top of the water and the water is removed from the bottom of the grease trap. In each grease trap design, a portion of the grease, or the solids, however small, will end up passing through the grease trap. Therefore, it is an object of the present invention to lower the amount of grease and/or solids that pass through the grease trap. 
     SUMMARY OF THE INVENTION 
     In one embodiment a grease removal system has a grease trap tank with outer walls and a bottom connected to the outer walls. An inlet extends through an outer wall of the grease trap tank, wherein the inlet has a center and a lower end. An outlet extends through an outer wall of the grease trap tank, wherein the outlet has a center and a lower end. An outlet grease baffle is positioned between the inlet and the outlet and extends downwardly across the tank to an elevation spaced from the tank bottom defining a passageway therethrough to permit effluent having a specific gravity greater than grease to pass but to retain and accumulate grease on the surface of the effluent within the grease trap tank. The outlet grease baffle defines a grease chamber within the tank between the inlet and the outlet grease baffle. A discharge portal having a center and a lower end extends through the grease trap tank outer wall in the grease chamber to the outside of the grease trap tank, wherein the lower end of the discharge portal is above the lower end of both the inlet and outlet to permit removal of liquid grease from the surface of the effluent passing through the grease trap. 
     In another embodiment, a method of removing grease from an effluent comprises the steps of providing a grease trap tank having outer walls and a bottom connected to the outer walls, an inlet through an outer wall of the grease trap tank, wherein the inlet has a center and a lower end, and an outlet through an outer wall of the grease trap tank, wherein the outlet has a center and a lower end. Effluent laden with grease is introduced into the grease trap. A substantial portion of the grease is separated from the effluent by allowing the grease to float upon the other effluent. Grease that rests upon and above the other effluent is discharged by allowing the grease to flow from the tank at a certain level. The discharged grease is then directed through a discharge portal and out of the grease trap tank. 
     Another embodiment of the subject invention is directed to a grease removal system for removing grease having a grease trap tank wherein grease is accumulated upon the surface of other effluent within the tank. A discharge portal extends from the grease trap tank at a certain level on the tank to extract the accumulated grease. A replaceable container is used for collecting the grease extracted from the grease trap tank, wherein the replaceable container has an inlet. A quick connect coupling exists between the discharge portal and the replaceable container inlet for ease in removal or installation of the discharge portal with the replaceable container. 
     In yet another embodiment, a grease removal system has a grease trap tank having outer walls and a bottom connected to the outer walls. An inlet extends through an outer wall of the grease trap tank, wherein the inlet has a center and a lower end. An outlet extends through an outer wall of the grease trap tank, wherein the outlet has a center and a lower end. An outlet grease baffle is positioned between the inlet and the outlet and extends downwardly across the tank to an elevation spaced from the tank bottom to permit effluent having a specific gravity greater than grease to pass but to retain and accumulate grease on the surface of the other effluent within the grease trap tank. The outlet grease baffle defines a grease chamber within the tank between the inlet and the outlet grease baffle. A discharge portal has a center and a lower end and extends through the grease trap tank outer wall in the grease chamber to the outside of the grease trap. The lower end of the discharge portal is below the lower end of both the inlet and outlet to permit removal of liquid grease from the surface of the effluent passing through the grease trap, wherein the discharge portal has a valve therein. A first level sensor is positioned below the discharge portal, wherein the first level sensor is capable of sensing a layer of grease upon the effluent, such that when such a layer is detected, the valve in the discharge portal is opened and grease is removed from the grease trap tank until the first level sensor no longer detects a layer of grease. 
     Yet another embodiment is directed to a method of removing grease from an effluent comprising the steps of providing a grease trap tank having outer walls and a bottom connected to the outer walls, an inlet through an outer wall of the grease trap tank, wherein the inlet has a center and a lower end, and an outlet through an outer wall of the grease trap tank, wherein the outlet has a center and a lower end. Effluent laden with grease is then introduced into the grease trap. A substantial portion of the grease is separated from the other effluent by allowing the grease to float upon the other effluent. Grease is allowed to accumulate to a predetermined thickness thereby weighing upon the other effluent in the grease trap tank and depressing the level of the other effluent within the tank. When the grease layer reaches a predetermined level, a valve is opened and an extraction pump is activated to discharge the grease until the grease is removed to below a predetermined level. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of one embodiment of the grease removal system made in accordance with the subject invention; 
         FIG. 2  is a schematic of the grease trap design shown in  FIG. 1  depicting the flow of the grease trap wastewater; 
         FIG. 3  is an elevational side view of a section of the housing shown in  FIG. 2 ; 
         FIG. 4  is a block diagram showing a control scheme of the grease trap design shown in  FIG. 1 ; 
         FIG. 5  is a block diagram of a second embodiment of the grease removal system made in accordance with the subject invention; 
         FIG. 6  is a schematic of the grease trap design shown in  FIG. 5  depicting the flow of the grease trap wastewater; 
         FIG. 7  shows a grease collection bag fluidly connected to the grease trap tank shown in  FIG. 6  for collecting grease; 
         FIG. 8  is a side view of a quick connect coupling used to connect the grease collection bag to the grease trap tank system; 
         FIG. 9  is an elevational view of a grease removal system in accordance with a third embodiment of the subject invention; 
         FIG. 10  is a block diagram showing a control scheme of the grease removal system illustrated in  FIG. 9 ; 
         FIG. 11  is an elevational view of a grease removal system having a unique arrangement of baffles; and 
         FIG. 12  is an elevational view of a commercial embodiment of the grease removal system in accordance with the subject invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a block diagram of a grease removal system  10  in accordance with the present invention. The grease removal system  10  is typically placed in line with a wastewater drain line such as in a drain line of a sink. Referring to  FIG. 1 , the grease removal system  10  includes a solid interceptor  20 , a grease trap tank  30 , a secondary tank  40 , and a secondary tank pump  50 . A drain inlet  60  may be fluidly coupled to the solid interceptor  20  for allowing wastewater to enter into the solid interceptor  20 , wherein extraneous solid waste materials, such as food particles, plastic cups, straws, bits of paper, and other solid waste may be removed from the wastewater. The solid interceptor  20  may include a screen filter or bag that traps particles above a certain size. The wastewater from the solid interceptor  20  enters the grease trap tank  30  and the grease is separated from the wastewater. The grease trap tank  30  functions as a hold-up tank, wherein gravity is used to separate the grease from the water. Because grease has a lower specific gravity than water, grease floats to the surface of the wastewater in the grease trap tank  30 , thus forming a grease layer. The water under the grease layer flows out of a drain outlet  70 . Grease separated from the water is directed to the secondary tank  40 . Bacterial enzymes that are designed to bio-digest the grease are introduced into the secondary tank  40  through a metering pump  80 . These enzymes break down the waste grease, thereby also reducing the total solids in the wastewater and substantially reducing the biochemical oxygen demand (BOD) level. Broken down grease becomes carbon dioxide and water. Fluid from the secondary tank  40  is transferred to the solid interceptor  20 . The pump  50  is used to transport the broken down residual fluid and any other remaining residual matter from the secondary tank  40  into the solid interceptor  20 , wherein any untreated grease is recirculated back through the grease trap tank  30 . When the grease is properly treated, the residual fluid will not float to the top of the grease trap tank  30 , but the untreated grease and/or grease-like material will float to the top of the grease trap tank  30 . Therefore, the residual fluid, which is now no longer grease, will flow out of the drain outlet  70 . 
     The discussion directed to the schematic illustrated in  FIG. 1  applies equally to the top view of the grease removal system illustrated in FIG.  2  and will be further expanded with details illustrated in both FIG.  2  and  FIG. 3 , which is a side elevational view of one embodiment of the grease removal system. 
       FIG. 2  shows the solid interceptor  20 , grease trap tank  30 , secondary tank  40  and pump  50  all enclosed within a housing  90 . While the housing  90  may have a single lid covering its entire open top, the housing  90  may also have a plurality of lids for enclosing the open top of different portions of the housing  90 . The housing  90  and any lids may be made of metal, such as steel or cast iron, or a polymeric material such as polyvinylchloride (PVC). However, it should be appreciated that the drain inlet  60 , solid interceptor  20 , grease trap  30 , secondary tank  40 , pump  50  and drain outlet  70  are all in fluid communication and are all sealed such that the wastewater is contained therein without breaching such containment. 
     Directing attention to  FIGS. 2 and 3 , the grease trap tank  30  has walls  32  and a bottom  34  connected to the walls  32 . The drain inlet  60  is in fluid communication with the grease trap tank  30  through the wall  32 , wherein the drain inlet  60  has a center  62  and a lower end  64 . The drain outlet  70  is in fluid communication with an opposing outer wall  32  and, furthermore, has a center  72  and a lower end  74 . An entrance baffle  100  extends across the width of the grease trap tank  30  such that fluid entering through the drain inlet  60  is directed against the entrance baffle  100  and, upon impact with the entrance baffle  100 , loses its horizontal velocity component wherein it is thereafter directed downwardly toward the bottom  34  of the grease trap tank  30  where it resides within the grease trap tank  30 . Once the wastewater travels under the entrance baffle  100 , the grease in the relatively still wastewater has an opportunity to float to the top surface, thereby forming a grease layer. It should be appreciated that during operation of the grease removal system, the level of wastewater within the grease trap will not be lower than the lower end  64  of the drain inlet  60  or the lower end  74  of the drain outlet  70 . The entrance baffle  100  is removable to purge any grease that may accumulate on the surface of the wastewater between the wall  32  at the solid interceptor outlet  24  and the entrance baffle  100 . 
     An outlet grease baffle  105  is positioned between the drain inlet  60  and the drain outlet  70  and extends downwardly in the tank  30  to an elevation A spaced from the tank bottom  34  defining a passageway  110  therethrough to permit effluent having a specific gravity greater than grease to pass while retaining and accumulating grease on the surface of the effluent within the grease trap tank  30 . The outlet grease baffle  105  defines a grease chamber  106  within the grease trap tank  30  between the drain inlet  60  and the outlet grease baffle  105 . A first solids baffle  107  prevents any solid waste that may have passed through the solid interceptor  20  from being washed through the passageway  110  to the drain outlet  70 . It should be appreciated that, as illustrated in  FIG. 2 , the grease outlet baffle  105  is aligned with the wall  32  of the grease trap tank  30 . However, it is entirely possible for the grease outlet baffle  105  to be located on either side of the locations illustrated in FIG.  2 . As an example, the grease outlet baffle  105  may be spaced from the wall  32  in the direction of the outlet grease baffle  107 . 
     Discharge portal  115  has a lower end  119  which extends through the grease trap tank wall  32  to the outside of the grease trap tank  30 . The lower end  119  of the discharge portal  115  is above the lower ends  64 ,  74  of the drain inlet  60  and the drain outlet  70  to permit removal of grease from the surface of the effluent passing through the grease trap tank  30 . As illustrated in  FIG. 3 , the level of the wastewater within the grease trap tank  30  is at a particular elevation W as a composite mixture of both effluent and grease. However, once past the entrance baffle  100 , when the specific gravity of the grease begins to cause separation, the grease floats upon the effluent and a layer of grease G begins to float on top of the effluent E in the tank  30 . As more wastewater passes through the grease trap tank  30 , the layer of grease G becomes thicker and thicker until the level exceeds that of the lower end  119  of the discharge portal  115 .  FIG. 3  has been exaggerated to highlight this difference. At that point, the discharge portal  115  permits removal of the grease G from the surface of the effluent E passing through the grease trap tank  30 . In the embodiment illustrated in  FIGS. 2 and 3 , the discharge portal  115  directs the grease G into the secondary tank  40 , wherein the secondary tank  40  retains an enzyme solution which acts upon and decomposes the grease therein. As illustrated in  FIG. 3 , the discharge portal  115  is comprised of a skim plate  120  which selectively blocks a portion of slot  122  to define the lower end  119  of the discharge portal  115 . In essence, in this embodiment, the discharge portal  115  has a spillway such that when grease G accumulates on the effluent E to a sufficient thickness, the grease G will proceed to pass over the spillway into the secondary tank  40 . Simultaneously, effluent E exits the grease trap tank  30  through the passageway  110  at the bottom of the outlet grease baffle  105  and thereafter passes through the drain outlet  70 . The lower end  74  of the drain outlet  70  may be at substantially the same level as the lower end  119  of the discharge portal  115 . Through this arrangement, the amount of effluent passing through the discharge portal  115  is minimized while the grease G passing through is maximized. The time it takes to fill the secondary tank  40  is dependent upon the amount of grease in the incoming wastewater and the height of the lower end  119  of the discharge portal  115 . 
     Effluent traveling through passageway  110  may still contain residual grease which may be retained in the clean out portion  108  of the grease trap tank  30 . A threaded access port  109 , sealed with a plug (not shown) provides access to the clean out portion  108  for removing any grease that may accumulate therein. 
     As illustrated in  FIGS. 1-3 , the grease trap tank  30 , through the discharge portal  115 , directs grease removed from the surface of the effluent passing through the grease trap tank  30  into a secondary tank  40 , whereupon an enzyme solution acts upon and biodegrades the grease. It should be noted, and will be discussed in an alternate embodiment of the subject invention, that the discharge portal  115  of the grease trap tank  30  may also direct the flow of grease into a removable container such as a grease bag. 
     Bacterial enzymes can be introduced into the secondary tank  40  continuously through the operation of a metering pump  80  or, alternatively, may be introduced intermittently through a timer associated with the metering pump  80 . In either case, the amount of enzymes to be added to the secondary tank  40  is determined by the requirements of the wastewater. Also, in certain installations, the enzymes can be introduced manually, either on a daily basis or at other intervals. Although not illustrated in the Figures, an aerator or agitator can be provided within the secondary tank  40  to promote the dispersion of the enzyme solution with the grease. 
     Directing attention to  FIG. 2 , the secondary tank  40  may include a level indicator, such as a mechanical float switch  130  that is in communication with the pump  50 . When the float switch  130  reaches a certain level, the pump  50  may turn on for a specified amount of time, thus transporting the broken-down fluid and other residual materials from the secondary tank  40  into the solid interceptor  20  via a conduit such as hose  52 . The secondary tank  40  has an outlet  42  (shown in phantom in  FIG. 3 ) defined in the bottom half of a secondary tank wall  45  so that the prior reacted contents in the secondary tank  40  can be emptied from the bottom of the tank  40 .  FIG. 3  illustrates the location of the outlet  42  relative to the wall  45  of the secondary tank  40 . 
     Additionally, a hose  52  extending from the pump  50  used to transfer effluent from the secondary tank  40  to the solid interceptor  20  connects to the solid interceptor  20  at the re-circulating effluent inlet  22 . As illustrated in  FIG. 2 , a first hose section  53  of the hose  52  is connected to an inlet of the pump  50 , while a second hose section  54  of the hose  52  is connected to an outlet of the pump  50  and the re-circulating effluent inlet  22  of the solid interceptor  20 . A valve  56  may optionally be placed in the first hose section  53  of the hose  52 . Whenever the pump  50  is removed for servicing, the valve  56  may be closed, thus preventing effluent from breaching the confines of the system. The re-circulating effluent inlet  22  is typically above the wastewater level in the solid interceptor  20 , thus eliminating the need for a second valve. The secondary tank pump  50  is positioned to extract fluid from the bottom of the secondary tank  40 . This may be achieved with hose  52  extending from the bottom of the secondary tank  40 . 
     Directing attention to  FIG. 4 , the control scheme  140  includes the mechanical float switch  130 , the pump  50 , a power source  145 , such as an AC outlet, an on/off switch  150 , and an optional start/stop button  155  (shown in phantom). When the on/off switch  150  is turned on, power from the power source  145  energizes the control scheme  140  hardware. When the float switch  130  is activated due to a high level in the secondary tank  40 , the pump  50  turns on, thus transferring the contents in the secondary tank  40  to the solid interceptor  20 . The pump  50  can remain on for a specified amount of time or until the secondary tank  40  is emptied. As an option, the pump  50  could be manually operated by activating the start/stop button  155 , thus providing a self-cleaning arrangement. The pump  50  can also remain on for a specified amount of time or can shut down when the start/stop button  155  is activated again. Activation of the start/stop button  155  bypasses activation of the pump  50  by the float switch  130  and provides a self-cleaning cycle by transferring the contents in the secondary tank  40  to the solid interceptor  20 . “Self-cleaning” is meant to define a condition, wherein a person does not need to physically clean the grease trap tank  30  and associated components by hand. 
     To assist in the self-cleaning of the grease trap tank  30 , hot water, such as that from the hot water tap of a sink faucet, may be added to the grease trap tank  30 . Whenever the pump  50  is activated, the operator/user may allow the hot water to enter the solid interceptor  20  through the drain inlet  60  to aid in cleaning. The hot water raises the temperature and fluid level of the wastewater in the grease trap  30 , thus assisting in melting any solidified grease, and increasing the amount of the grease being removed through the discharge portal  115  into the secondary tank  40 . 
     In operation, wastewater from the grease source enters the solid interceptor  20  through the drain inlet  60  and large solid waste particles are filtered therein. The wastewater then flows through the outlet  24  of the solid interceptor  20  into the grease trap tank  30 . The wastewater then is deflected by entrance baffle  100  and forced to travel under the entrance baffle  100 , wherein the horizontal velocity of the wastewater is decreased and wherein the grease is separated from the wastewater. As the wastewater flows under the entrance baffle  100 , a grease layer G forms on the top surface of the wastewater. The wastewater that does not contain the grease remains underneath this grease layer and flows through passageway  110  to the drain outlet  70 . As the grease layer reaches a certain height, it overflows through the discharge portal  115  into the secondary tank  40 . Grease-eating bacterial enzymes are pumped into the second tank  40  via the metering pump  80  and decompose the grease. When a certain level is reached in the secondary tank  40 , the float switch  130  is activated, which causes the pump  50  to turn on, thus pumping the contents of the secondary tank  40  into the solid interceptor  20 , wherein the separation process is repeated. The broken-down fluid passes through the drain outlet  70  and any remaining residual materials from the grease trap tank  30  will be re-circulated back into the secondary tank  40 . If the contents of the secondary tank  40  do not reach a certain level to activate the float switch  130 , the user may bypass the float switch  130  and turn on the pump  50  by pressing the start/stop button  155 . When the pump  50  is activated, the user may also manually introduce hot water into the grease trap tank  30 . This self-cleaning arrangement aided by the introduction of any hot water reduces the frequency for manually cleaning of the grease removal system  10 . Furthermore, this system is capable of effectively removing grease from the effluent to a level of 100 ppm or less of grease. 
     The embodiment of the subject invention just disclosed is directed to a grease removal system  10  which does not require parts, such as automatic valves, heating probes, and electronic level sensors that can accumulate a build-up of grease and function improperly. The self-cleaning arrangement of the present invention reduces this excessive build-up of grease. Therefore, the present invention reduces the likelihood of the grease removal system  10  malfunctioning due to improper cleaning and maintenance. 
     While what has been discussed so far is a grease removal system that utilizes re-circulation and a secondary tank containing bacterial enzymes to break down the grease, it is also possible to direct grease from the discharge portal of the grease trap tank into a replaceable container such that the grease may be transported and disposed of in an environmentally proper fashion. 
     Directing attention to  FIGS. 5-7  and utilizing reference numbers that are common to the elements in the first embodiment discussed with respect to  FIGS. 1-4 , a grease removal system  210  includes a solid interceptor  20 , a grease trap tank  30 , an optional extraction pump  215 , an extraction valve  217  and a replaceable container  220 , such as a grease bag. Just as before, the drain inlet  60  is fluidly coupled to the solid interceptor  20  for allowing wastewater to enter into the solid interceptor  20 , wherein the solid interceptor may include a screen or bag filter for trapping particles above a certain size. The wastewater from the solid interceptor  20  enters the grease trap tank  30 , whereupon the grease is separated from the wastewater. The grease trap tank  30  functions once again as a hold-up tank wherein gravity is used to separate the grease from the water. Because the grease has a lower specific gravity than water, grease floats to the surface of the grease trap tank  30  thus forming a grease layer. The water under the grease layer flows out the drain outlet  70  and the grease layer accumulates in the grease trap tank  30  until a layer of grease accumulates to a predetermined level. The discharge portal  115  is connected to the extraction valve  217  such that the predetermined level of grease within the grease trap tank  30 , the extraction valve  217  is opened to transfer the grease through the discharge portal  115  and into the replaceable container  220 . The extraction pump  215  may be included to assist with the transfer of grease to the replaceable container  220 . However, in a preferred embodiment, the extraction pump  215  is not present and the grease travels directly through the extraction valve  217  to the replaceable container  220 . 
     The details of the solid interceptor  20  and the grease trap tank  30  may be identical to those previously disclosed with respect to  FIGS. 1-3  with the exception that now the secondary tank  40  and the associated pump  50  are absent because the present embodiment does not provide any re-circulation of wastewater or exposure of grease to bacterial enzymes but deposits the grease directly in the replaceable container  220  for removal. 
     The extraction valve  217  may be a solenoid operated valve which may act as a control valve to start and stop the flow of grease through the discharge portal  115 . Directing attention to  FIGS. 6 and 7 , grease flowing from the discharge portal  115  through the extraction valve  217  may travel through a conduit  225  into the replaceable container  220 . The replaceable container is in an enclosure  230 . The enclosure  230  may be placed on a scale  235  which includes a scale sensor (not shown) used to determine whether or not the replaceable container  220  is full. The conduit  225  may also include a stopper or check valve (not shown), wherein the residual grease in the conduit  225  ceases to flow when the container  220  is being changed out. Additionally, in the event the replaceable container  220  becomes full, the valve  217  will be closed such that no additional grease may be directed to the replaceable container  220 . 
     Effluent traveling under the outlet grease baffle  105  may still contain residual grease which may be retained in the clean out portion  108  of the grease trap tank  30  and may be removed through an access port (not shown). 
     Directing attention to  FIGS. 8 and 12 , the conduit  225  extending between the pump  215  and the replaceable container  220  may be connected to the replaceable container  220  by a quick connect coupling  240 . 
     A typical quick connect coupling  240  ( FIG. 8 ) may be comprised of a male member  245  connected to the conduit  225 , wherein the male member  245  has a snap connection portion  247 . The quick connect coupling  240  also has a female member  250  connected to the replaceable container  220 , wherein the female member  250  includes a release button  252  which releases an engaging element within the female member  250 . This quick connect coupling  240  enhances the efficiency of the grease removal system  210  by making disposal of a filled replaceable container  220  and installation of a fresh replaceable container a much simpler process. 
     While the embodiments of the grease trap tank  30  so far disclosed discuss only a single grease baffle  105 , the path the wastewater takes through the grease trap tank  30  may be manipulated to enhance the ability of the grease trap tank  30  to remove grease from the wastewater. 
     Identical elements from previously disclosed embodiments will be referred to using identical reference numbers. For purposes of discussion, the grease trap tank  430  illustrated in  FIG. 9  will be described as including a primary settling region  265  and a secondary settling region  270  separated by an intermediate grease baffle  275  extending from the top of the grease trap tank  430  downwardly to a distance W from the bottom  434  of the grease trap tank  430 . It should be noted, however, that  FIG. 9  does not show the solids interceptor  20  but shows the drain inlet  60  attached directly to the grease trap tank  430 . Although not shown, the design illustrated in  FIG. 9  may include such a solids interceptor  20 . The intermediate grease baffle  275  and the first solids baffle  107  in conjunction with the outlet grease baffle  105  cause the wastewater to move in a torturous path, thereby preferably retaining the majority of the grease-laden water in the primary settling region  265  and retaining still additional grease-laden water in the secondary settling region  270 . A second solids baffle  280  contributes to the tortuous path and to maximizing the efficiency of grease separation within the primary settling region  265  and the secondary settling region  270 . Each of the solids baffles  107  and  280  extends upwardly from the bottom  434  of the tank  430  and is located adjacent to the intermediate grease baffle  275  to provide a channel  285  with a torturous path between the inlet  60  and the outlet  70 . 
     As illustrated in  FIG. 9 , there is one solids baffle spaced on each side of the intermediate grease baffle  275 . In particular, first solids baffle  107  is placed upstream and second solids baffle  280  is placed downstream of the intermediate grease baffle  275 . In one embodiment, each of the two solid baffles  107 ,  280  is equally spaced on opposite sides of the intermediate grease baffle  275 . Additionally, the height L of each of the solids baffles  107 ,  280  may be equal. The intermediate grease baffle  275  may be spaced from the side of the grease trap tank  430  closest to the drain inlet  60  by a distance X equal to between one-half and three-quarters the length of the grease trap tank  430 . Additionally, the channel  285  formed by the at least one solids baffle  107  and the intermediate grease baffle  275  has a cross-sectional area that is approximately equal throughout the channel  285  as it extends past the first solids baffle  107 , second grease baffle  275  and second solid baffle  280 . Furthermore, the height of the channel  285  at the bottom of the intermediate grease baffle  275  may be approximately between one-twentieth to one-quarter of the height H of the grease trap tank  430 . The solids baffles  107 ,  280  have a height L less than one-quarter of the height H of the grease tank trap  430 . In one embodiment, the channel  285  at the bottom  434  of the intermediate grease baffle  275  has a height T which is the same height as the height L of each of the solids baffles  107 ,  280 . 
     In operation, grease-laden water passes through the drain inlet  60  and is directed downward by entrance baffle  100 . First solids baffle  107 , second grease baffle  275  and second solids baffle  280  cause the water to move in a tortuous path thereby preferably retaining a majority of the grease-laden water within the primary settling region  265 . Wastewater continues past the intermediate grease baffle  275  into the secondary settling region  270  wherein additional grease is retained. Water continues through passageway  110  where it travels upward and is discharged through the drain outlet  70 . 
     Effluent traveling through passageway  110  may still contain residual grease which may be retained in the clean out portion  108  of the grease trap tank  30 . A threaded access port  109 , sealed with a plug (not shown) provides access to the clean out portion  108  for removing any grease that may accumulate therein. 
     In the event of pressure build up within the tank  30 , an air relief passage  290  acts to relieve such pressure. 
       FIG. 10  shows a control scheme  500  for automatically removing grease from the grease trap tank  430  illustrated in FIG.  11  and these two Figures will be discussed together. The control scheme  500  includes a first level sensor  505 , a second level sensor  510 , a scale sensor  515 , an extraction valve  217 , heaters  525 , a display panel alarm  530 , a power supply  535  and a controller  540 . Power from the power supply  535  energizes the components of the control scheme  500 . In particular, when grease begins to accumulate on the surface of the grease-laden water, the first level sensor  505  is activated when no water (only grease) is present at the level of the first level sensor  505 . At this point, as illustrated in  FIG. 11  by level  545 , the first level sensor  505  and the second level sensor  510  are completely covered by water. 
     The first level sensor  505  and the second level sensor  510  may be capacitive sensors. This type of sensor has been found to be more sensitive than other sensors, such as optical sensors, at detecting the presence of water and grease. Whatever sensors are used, they will be coated with grease during usage and the capacitive sensors operate more effectively to detect water and grease even in this coated condition. 
     Generally speaking, a capacitive sensor operates by forming an electrostatic field between an active electrode on the sensor and a ground. Any object entering the field will increase the capacitance. Different objects create more or less capacitance. When the increase in capacitance is large enough, an oscillation is set up which is detected by an evaluation circuit, which then changes the state of an output circuit. 
     As the grease removal system  430  continues to operate and grease-laden water continues to enter through drain inlet  60 , grease builds down from the top and displaces the water such that, as illustrated by water level  550 , the first level sensor  505  is no longer covered by water but is covered by a layer of grease. Each of the first level sensor  505  and the second level sensor  510  is capable of distinguishing between water and grease and, therefore, as a result, at the point the first level sensor  505  no longer senses water, the controller  540  causes the extraction valve  217  to open, thus allowing grease to flow through the extraction valve  217  and, as illustrated in  FIG. 12 , through the conduit  225  into the replaceable container  220 . The replaceable container  220  is a bag-like container which may be made of polyethylene and nylon. When the first level sensor  505  no longer senses grease, the controller  540  causes the extraction valve  217  to close, thus stopping the flow of grease through the extraction valve  217  and the conduit  225 . The first level sensor  505  may be positioned at a height of about 90-100% of the height between the bottom  434  of the tank  430  and the lower end  64  of the inlet  60 . The second level sensor  510  may be positioned at a height of about 60-80% of the height between the bottom  434  of the tank  430  and the lower end  64  of the inlet  60 . 
     Each time the extraction valve  217  is open, additional grease is deposited within the replaceable container  220 . When the scale sensor  515  senses that the replaceable container  220  is full-based upon the weight of the grease-laden container  220 , the scale sensor  515  activates the controller  540  causing the extraction valve  217  to close. As an example, when the weight of the grease-laden replaceable container reaches 20 pounds, the sensor  515  activates the controller  540  to close the extraction valve  217 . However, grease-laden water may continue to flow within the drain inlet  60  and water may continue to flow from the drain outlet  70 . However, for so long as the replaceable container  220  is full, the extraction valve  217  will remain closed. Nevertheless, because the grease trap tank system continues to operate, grease will continue to accumulate within the grease trap tank  430 . Activation of the scale sensor  515  also causes the controller  540  to activate the display panel alarm  530  indicating that the replaceable container  220  is full. When the replaceable container  220  is emptied or replaced with an empty container, the display panel alarm  530  is reset (i.e., by pressing a button), and the scale sensor  515  deactivates allowing the extraction valve  217  to open at the appropriate time. However, in the event the extraction valve  217  does not open at the appropriate time to drain grease from the grease trap tank  430 , whether because the system is malfunctioning or because the replaceable container  220  is full and the extraction valve  217  is instructed not to open, if the grease continues to build down to the level of the second level sensor  510 , then the second level sensor  510  activates causing the controller  540  to activate the alarm  530  indicating that an overload has occurred. The second level sensor  510  can also activate the extraction valve  217  causing the extraction valve  217  to open if the replaceable container  220  is not full as indicated by the scale sensor  515 . Additionally, since grease is much easier to handle in the liquid state, a temperature sensor  555  may monitor the temperature of the effluent within the grease trap tank  430  and may regulate the water/grease temperature through the heater  525  in the grease trap tank  430 . Preferably, the heaters  525  may maintain the temperature of the water/grease between 115-135° F., preferably about 125° F. 
     Also illustrated in  FIG. 12  are the extraction valve  217 , the heaters  525  and the temperature sensor  555 . 
     Directing attention to  FIG. 11 , it should be appreciated that the level of the water in the primary settling region  565  will be different than the level of the water in the secondary settling region  570  when there is an accumulation of grease in the primary settling region  565 . 
     Briefly stated, if there is a substantial accumulation of grease within the primary settling region  565 , then the level of the water in the primary settling region  565  will be depressed. On the other hand, the secondary settling region  570  may have some grease but a substantially smaller amount of grease than that found in the primary settling region  565 . The layer of grease floating upon the water within the primary settling region  565  will push that level of water down while the water within the secondary settling region  570 , since it has no or a substantially less amount of grease floating upon its surface, will be raised. This featurv is beneficial because at the time the extraction valve  217  is open, grease will flow out of the valve until the first level sensor  505  is submerged in water. As the grease exits the extraction valve  217 , the water in the secondary settling region  570  will seek equilibrium with the water in the primary settling region  565  and, as a result, the column of water within the primary settling region  565  will actually be pushed upwardly, thereby ensuring that the grease is forced at least as high as the extraction valve  217  at the end of the draw-off cycle, to permit the grease to more effectively discharge from the grease trap tank  430 , and reset the extraction valve  217  and the sensors to the initial state. 
       FIG. 12  is an elevational view of a commercial embodiment of the grease removal system illustrated in FIG.  11  and shown schematically in FIG.  6 . The solid interceptor  20  has a screen or bag filter therein (not shown) to trap solids above a certain size. The wastewater leaves the solid interceptor  20  and travels to the grease removal system  30  where it is further processed. The operation of the first level sensor  505  and the second level sensor  510  has been discussed in conjunction with FIG.  11 . As previously discussed, grease is removed from the surface of the wastewater by the extraction pump  215 . The grease is then directed through the conduit  225 , past the quick connect coupling  240  and into the replaceable container  220 . When the weight of the replaceable container  220  filled with grease reaches a certain threshold, the replaceable container  220  is replaced. The replaceable container  220  rests within enclosure  230 , which itself rests upon a scale  235 . 
     Although the embodiment described in  FIGS. 10-12  discharges grease through the extraction valve  217  and into a conduit  225 , wherein it is deposited into a replaceable container  220 , it is entirely possible for the extraction valve  217  to deposit the grease into a secondary tank  40  such as that illustrated in  FIGS. 1 and 2 , whereby the grease is then decomposed by an enzyme solution resident within the secondary tank  40 . 
     In an illustrative example, the grease trap tank may have a capacity to hold 30 gallons of grease/water. The flow rate through the grease trap tank could be 15 gallons per minute and the sensor scale could detect a full replaceable container of approximately 20 pounds, while the grease tank retains its maximum capacity of 30 pounds of grease. 
     While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. The presently preferred embodiments described herein are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.