Abstract:
A method for pretreating a wastewater stream containing grease and food particles before the stream enters a sewer includes the steps of directing said wastewater stream to a separation area; directing said wastewater stream along a preferred flow path within said separation area, said preferred flow path being sized and shaped to permit said grease to rise out of said wastewater stream; trapping said grease which rises out of said wastewater stream; extending a wastewater outlet substantially across said separation area; accelerating said remaining wastewater, carrying said food particles, through said outlet from said separation area, thereby sucking said food particles away from said separation area; and directing said wastewater and said food particles toward said sewer system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional of application Ser. No. 09/732,299, filed Dec. 8, 2000, which claims the benefit of Canadian Application No. CA 2,299,134, filed Feb. 23, 2000, the contents of all of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to the field of wastewater management, and, in particular, to devices known as grease traps, which are used for separating grease and oil from wastewater before permitting the wastewater to enter into a sanitary or storm sewer systems.  
       BACKGROUND OF THE INVENTION  
       [0003]     Some commercial establishments, such as restaurants, produce a considerable amount of waste or drainage water which often contains high levels of grease or oil. Such contaminants can adversely affect the sewage treatment plants and can clog up the sewers. Therefore, most jurisdictions require that such grease and oil be removed from the wastewater at the commercial establishment before it is permitted to enter the sewage system. To effect such removal, a restaurant will typically provide a grease trap on its wastewater outlet line. Essentially, wastewater passes into the grease trap at one end and within the grease trap, the grease which has a lower specific gravity than water rises and forms a layer on top of the grease trap. A fluid outlet from the grease trap is positioned below the level of the grease layer to permit substantially grease free wastewater to be removed. In this way, the grease is collected in the grease trap and it may be periodically removed by direct bailing the grease out of the top of the grease trap. The grease is then disposed of as solid waste, for example, at landfill sites.  
         [0004]     One problem with conventional grease traps is that particles of food are also present in the wastewater stream, such as bits of lettuce, meat and other waste solids. These solid waste particles have two significant effects. First, they significantly increase the volume of the waste layer collected. As a result, the grease trap becomes filled quickly and the collected waste must be removed frequently. Second, the bits of solid matter caught in the grease trap tend to decompose, anaerobically, which creates noxious gases, making the job of manually bailing the grease from the grease trap extremely unpleasant. Thus the prior art devices suffer from being both labour intensive (i.e. they fill quickly and require more frequent cleaning) and extremely unpleasant to maintain.  
         [0005]     A number of devices for separating waste from wastewater are already known. U.S. Pat. No. 1,407,936 discloses an apparatus and method for separating matter from effluents. The apparatus includes a container which is wide at its inlet end and narrow at its outlet end. The effluent enters the container through an inlet pipe at the bottom of the container, and the effluent stream is directed upward. At that point, solid particles settle on the floor of the container, and can be removed manually through a separate valve created for that purpose. Meanwhile, the effluent stream continues through the container, and the floating waste separates from the water stream, which is directed to the outlet pipe at the opposite end of the container.  
         [0006]     This device separates solid waste from the floating waste, such as grease, and takes the solid waste out of the effluent stream. However, the container must be manually emptied of solid waste separately from the removal of the grease. This is a time-consuming activity, and it must be done fairly frequently to prevent clogging of the inlet pipe.  
         [0007]     U.S. Pat. Nos. 2,138,985, 3,849,311 and 4,372,854, for example, also disclose devices for separating light waste, such as oil or grease, from water. However, the devices in these patents all suffer from the problem that solid waste is trapped in the trap.  
       SUMMARY OF THE INVENTION  
       [0008]     Therefore, what is desired is a device for effectively separating light waste, such as oil or grease from water. For the purpose of this invention it shall be understood that the term “light waste” shall refer to waste having a specific gravity slightly less than water and which therefore tends to rise when submerged in water. Also the term “heavy waste” shall be used to refer to waste which has a specific gravity which is greater than water, and which therefore tends to sink when placed in water. The desired device according to the present invention should also preferably function so as to prevent solid or heavy waste in the wastewater stream from being trapped in the layer of grease. Finally, the device preferably should not have to be frequently manually emptied of both solid waste and of grease.  
         [0009]     Accordingly, in one aspect, the present invention is directed to a wastewater separator to separate waste from a mixed wastewater stream before the mixed wastewater stream is directed into a sewer system, the mixed wastewater stream including one or more of heavy waste, light waste and water. The wastewater separator comprises a separation container, a wastewater inlet to the separation container and a wastewater outlet from said separation container. The separation container comprises (1) a wastewater stream director within the separation container, the wastewater stream director being sized, shaped and positioned relative to the wastewater inlet to direct the wastewater stream along a preferred flow path to permit the light waste to separate from the wastewater stream in a first direction to a collection area and to permit the heavy waste to separate from the wastewater stream in a second direction towards a heavy waste removal area; and (2) a flow-directing outlet baffle within the separation container for directing the wastewater stream to the wastewater outlet from the heavy waste removal area to remove the heavy waste from the separation container.  
         [0010]     Also, the wastewater separator preferably further comprises a cover detachably attachable to the container, the cover being sized and shaped to removably cover an opening on the top of the container.  
         [0011]     The wastewater separator still further preferably comprises air entraining means associated with the wastewater inlet for entraining air into the wastewater stream.  
         [0012]     In another aspect, the invention is directed to a wastewater separator to separate light waste from a mixed wastewater stream. The wastewater separator comprises a separation container having an inlet end and an outlet end, a wastewater inlet to the separation container, a wastewater outlet from the separation container, and air entraining means associated with the wastewater inlet to entrain air into the wastewater stream. The separation container comprises a wastewater stream director in the container sized, shaped and positioned to direct the wastewater stream along a preferred flow path which is generally diagonal across the container to facilitate separation of the light waste. The separation container further comprises a flow-directing outlet baffle in the container for directing said wastewater stream from a downstream end of the preferred flow path to the wastewater outlet.  
         [0013]     In a further aspect the present invention provides a wastewater separator to separate light waste from a mixed wastewater stream, said wastewater separator comprising:  
         [0014]     a separation container having an inlet end and an outlet end;  
         [0015]     a wastewater inlet to said separation container;  
         [0016]     a wastewater outlet from said separation container; and  
         [0017]     air entraining means associated with said wastewater inlet to entrain air into said wastewater stream;  
         [0000]     said separation container comprising:  
         [0018]     a wastewater stream director in the container, said wastewater stream director being sized, shaped and positioned to direct the wastewater stream along a preferred flow path which is generally diagonal across said container to facilitate separation of said light waste; and  
         [0019]     a flow-directing outlet baffle in said container for directing said wastewater stream from a downstream end of said preferred flow path to said wastewater outlet.  
         [0020]     In a further aspect the present invention provides a method of pretreatment of a wastewater stream before said stream enters a sewer, where said wastewater stream contains grease and food particles, said method comprising the steps of:  
         [0021]     1) directing said wastewater stream to a separation area;  
         [0022]     2) directing said wastewater stream along a preferred flow path within said separation area, said preferred flow path being sized and shaped to permit said grease to rise out of said wastewater stream;  
         [0023]     3) trapping said grease which rises out of said wastewater stream; and  
         [0024]     4) directing said remaining wastewater, carrying said food particles, out of said separation area and toward said sewer system.  
         [0025]     In a further aspect the present invention provides a method of preventing grease or oil from being carried out in wastewater from a food preparation establishment to a sewer system, said method comprising the steps of:  
         [0026]     1) entraining air into said wastewater stream;  
         [0027]     2) directing said wastewater stream to a separation area; then  
         [0028]     3) directing said wastewater stream along a preferred flow path within said separation area, said preferred flow path being sized and shaped to permit said grease to rise out of said wastewater stream; then  
         [0029]     4) permitting said grease to rise out of said wastewater stream;  
         [0030]     5) containing said grease within said separation area;  
         [0031]     6) directing said wastewater stream, carrying said food particles, out of said separation area and toward said sewer system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]     Reference will now be made, by way of example only, to the drawings of the present invention which illustrate the preferred embodiment, and in which:  
         [0033]      FIG. 1  is a cross-sectional elevation view of the wastewater separator;  
         [0034]      FIG. 2  is a top view of the wastewater separator; and  
         [0035]      FIG. 3  shows the quarter-turn fastener described herein. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]     Referring now to  FIG. 1 , the wastewater separator is generally designated by reference numeral  10 . The wastewater separator  10  is for separating waste from a mixed wastewater stream before the disposal into a sewer system, where the mixed wastewater stream includes heavy waste, light waste and water. “Heavy waste” includes bits of solid food and any other waste with a density greater than that of water. Similarly, “light waste” is any waste in the mixed wastewater stream which has a density less than that of water, such as, for example, grease and oil. It will further be appreciated that the present invention is directed to a self-contained device which is used on an inlet to a sewer system from a commercial or industrial premises involved, typically, in food service preparation.  
         [0037]     The wastewater separator  10  comprises a wastewater inlet  12 , a wastewater outlet  14  and a separation container  22 . The separation container  22  is filled with water which is the medium typically used to transport and dispose of various liquid and solid wastes and which form the bulk of the mixed wastewater stream. The mixed wastewater stream is admitted to the separation container  22  through the wastewater inlet  12 , and exits from the separation container  22  through the wastewater outlet  14 . As will be more particularly described below, the light waste is separated from the wastewater stream in the separation container  22 , and trapped there in what is referred to as a collection area. The wastewater stream exits the separation container  22  through the wastewater outlet  14 , carrying the heavy waste. As will be appreciated from the explanation which follows, the separation of the mixed wastewater stream into a collected light waste and removed heavy waste is accomplished in part by directing the wastewater stream along a preferred flow path through the separation container  22 .  
         [0038]     The wastewater inlet  12  is sized and shaped to be in water-tight communication with a wastewater pipe carrying the wastewater stream to the wastewater separator. Similarly, the wastewater outlet  14  is sized and shaped to be in water-tight communication with a further wastewater pipe which carries the wastewater stream away from the wastewater separator  10  and into a sewer.  
         [0039]     Preferably, to achieve this water-tight communication, the wastewater inlet  12  and the wastewater outlet  14  include an inlet adaptor  18  and outlet adaptor  20 , respectively, which adaptors facilitate the plumbing connection between each of the wastewater inlet  12  and outlet  14 , and the wastewater pipes (not shown) which carry the wastewater stream. In the preferred embodiment, the inlet adaptor  18  and the outlet adaptor  20  are straight connections (as opposed to, say, 90° elbow connectors). However, the inlet and outlet adaptors  18  and  20  may be any shape and/or size that is necessary to achieve the water-tight connection with the wastewater pipes carrying the wastewater stream to and from the wastewater separator  10 .  
         [0040]     It will be appreciated by those skilled in the art that the wastewater inlet and outlet  12  and  14  need not include adaptors  18  and  20 . Rather, any configuration is sufficient if it allows the wastewater stream to travel from the wastewater pipe through the wastewater inlet  12 , and through the wastewater outlet  14  to the other wastewater pipe. So, for example, the inlet  12  and outlet  14  may simply be pipe sections, without adaptors, that are sized and shaped to be inserted directly into the wastewater pipes by pressure fit. Of course it will be appreciated by those skilled in the art that any such plumbing connection must be made in accordance with local building and safety codes. What is important is that the inlet and outlet configurations allow the wastewater stream to travel from the wastewater pipe through the wastewater inlet  12 , and through the wastewater outlet  14  to the next downstream wastewater pipe for delivery to a sewer system.  
         [0041]     In the preferred embodiment, the separation container  22  is rectangular in both vertical and horizontal cross section. Thus, the container  22  includes a substantially rectangular container floor  24 , and four substantially rectangular walls  26 ,  28 ,  30  and  32  extending generally orthogonally upwardly from the edges of container floor  24  such that a closed container  22  is formed. The walls  26 ,  28 ,  30  and  32  are all of the same height. The wastewater inlet  12  extends through the upper portion of inlet wall  26  and the wastewater outlet  14  extends through the upper portion of outlet wall  28 . This form is preferred because it can be molded from plastic, for example, by injection molding. Further, conventional grease traps tend to be rectangular and thus by making the instant invention rectangular as well, it can be fit into the existing space for a conventional trap as a retrofit.  
         [0042]     The preferred size range for the container is between 10 and 20 gallons, with 12 gallons being the optimum size. This size is the volume of the container, and this volume has proved adequate for a waste stream rated at 20 gpm. It will be appreciated that the device should be large enough that it does not have to be emptied too frequently, but small enough to fit comfortably into interior building space in the back of a kitchen, storage area or the like.  
         [0043]     It will be appreciated by those skilled in the art that a rectangular shape for the container  22  is preferred. The wastewater separator  10  will typically be located under flat floors and/or against flat walls, and the wastewater pipes will typically run parallel to those walls and/or pipes. As such, is preferred to have a container  22  whose dimensions are similarly flat so as to allow the wastewater separator  10  to fit more easily into its required location. However, as stated above, the container  22  may be any shape that allows it to hold water, and allows for the separation of light waste from the wastewater stream, without departing from the scope of the invention.  
         [0044]     The separation container  22  further comprises a wastewater stream director within the container  22 , and most preferably releasably coupled thereto in a manner hereafter described. The wastewater stream director is sized, shaped and positioned relative to the wastewater inlet to direct the wastewater stream along a preferred flow path within the container  22 . In the preferred embodiment, the wastewater stream director comprises a flow-directing inlet baffle  34  attached to the wall  26  over the inlet  12  for directing the wastewater stream passing through the inlet  12  downward to the bottom of the container  22 . Also provided is a separation flow director in the form of a ramp  36  immediately downstream of the baffle  34 . In the most preferred form the ramp  36  is attached to, by being formed in, the container floor  24 .  
         [0045]     It will be appreciated that the wastewater stream director need not be solely in the form of the flow-directing inlet baffle  34  and the ramp  36 . For example, other configurations of elements could be used to accomplish the same function, such as using the flow-directing inlet baffle  34  as the wastewater stream director. What is desired is to direct the wastewater stream along the preferred flow path, and any structure that does so can serve as the wastewater stream director.  
         [0046]     The wastewater separator  10  further comprises a heavy waste removal area  42  which, in the preferred embodiment, comprises the portion of the bottom of the container  22  which is immediately downstream from the upper edge  38  of ramp  36 .  
         [0047]     The separation container  22  further comprises a flow-directing outlet baffle  44 , in the container  22 , and most preferably removably coupled thereto, for directing the wastewater stream from the heavy waste removal area  42  in the container  22  to the wastewater outlet  14 . The outlet baffle inlet  48  (i.e. the inlet of the flow-directing outlet baffle  44 ), is preferably adjacent to and downstream from the heavy waste removal area  42 , on the floor  24 . It is preferable to position the outlet baffle inlet  48  as low as possible in the container  22  so as to ensure that light waste is not drawn into the outlet baffle  44  and out through the wastewater outlet  14 .  
         [0048]     The separation of the mixed wastewater stream by the present invention can now be understood. As the wastewater stream enters through the wastewater inlet  12 , it contacts the flow-directing inlet baffle  34 , which is sized, shaped and positioned to direct the wastewater stream downward to the bottom of the container  22 . The upper portion of the flow-directing inlet baffle  34  acts as a mixing section which converts the wastewater stream to a substantially isotropic fluid. As such, air bubbles introduced at this point are permitted to adhere to the small grease droplets which have an affinity for each other. Also, the flow-directing inlet baffle  34  is sized and shaped so that, as the water strikes the inlet baffle  34  and tumbles downward, the flow of the wastewater stream becomes turbulent and air bubbles introduced at a flow control orifice are mixed into the wastewater stream. Thus, in the preferred embodiment, the flow-directing inlet baffle  34  also acts as an air entraining means, associated with the wastewater inlet  12 , for entraining air into the mixed wastewater stream.  
         [0049]     The mixed wastewater stream exits from the flow-directing inlet baffle  34  and flows along the ramp  36 . Good results have been obtained with a ramp having a radiused top as shown. The combination of the flow-directing inlet baffle  34  and the ramp  36  functions to direct the wastewater stream along a preferred flow path within the container  22 . As more particularly described below, the preferred flow path permits the light waste to separate from the wastewater stream in a first direction to a collection area and permits the heavy waste to separate from the wastewater stream in a second direction towards the heavy waste removal area  42 .  
         [0050]     The preferred flow path is indicated in  FIG. 1  by the dotted line, and has a first section in the container  22 , as well as a second section. The first section extends upward from the downstream end of the flow-directing inlet baffle  34  and away from the wastewater inlet  12 . The separation of the light waste from the wastewater stream takes place in the first section. Because the light waste is of higher buoyancy than water, the light waste will rise to the collection area at the surface  60  of the water contained in the container  22 . Preferably the first section of the preferred flow path will extend diagonally from the bottom of the inlet end of the container  22 . Such a flow path maximizes and optimizes the flow path length and hence the time for buoyancy separation of light waste, thus enhancing the amount of separation of light waste. Also, the air bubbles that are entrained into the wastewater stream by the flow-directing inlet baffle  34  will enhance the separation of the light waste from the wastewater stream. This enhancement results from the greater buoyancy of the air bubbles, which will also tend to rise to the surface of the water, and which will thus exert a force upon the light waste in the form of grease droplets (for which the air bubbles have an affinity as noted above) and propel it to the surface.  
         [0051]     It will be appreciated by those skilled in the art that the air entraining means can take other forms than the inlet baffle  34 . For example, the air entraining means could be a separate device or machine which actively and mechanically inserts bubbles into the wastewater stream. What is important is that the air entraining means mixes air into the wastewater stream before the separation stage, so that air bubbles will be present to assist in the separation of light waste.  
         [0052]     As the wastewater stream exits the flow-directing inlet baffle  34 , the heavy waste is carried up the ramp  36  and past the upper edge  38  by the force of the current in the wastewater. At this point, the heavy waste will fall from upper edge of the ramp into the heavy waste removal area  42 . The radius of the top edge is useful because it discourages turbulent flow of the liquid passing over the ramp. Turbulent flow is undesirable because it can both carry heavy waste past the heavy waste removal area and erode trapped grease from the surface, if it reaches that area. The present invention contemplates increasing the cross-sectional area and thus slowing the inlet flow stream to reduce the likelihood of turbulent flow in the separation area. This slower flow carries the heavy waste up, over and then down the far side of the ramp into the waste removal area. A more acute top edge  38  could lead to undesirable turbulence. Thus the ramp is preferably configured to encourage, as much as possible, over the design flow rates for the specific application, laminar flow up and over the ramp and then through the outlet.  
         [0053]     The path of the heavy waste is shown by solid arrows in  FIG. 1 . Preferably, the flow-directing inlet baffle  34  has an outlet area which is sized and shaped to slow the wastewater stream sufficiently to permit the heavy waste to settle downward as it is gently carried along by the slow current. As can now be appreciated, as the mixed wastewater stream is slowed, the heavy waste has more time to fall, under the influence of gravity and the relative buoyancy effects, towards the bottom of the container  22 . Thus, most preferably, as the heavy waste reaches the upper edge  38  of the ramp  36  it will generally be at the bottom of the container  22  and most likely in contact with the ramp  36 . Similarly, the separation of light waste is facilitated, as the light waste has more time to separate from the wastewater stream due to a slower flow.  
         [0054]     When the wastewater stream reaches the surface  60  of the water near the outlet side of the container  22 , it turns and enters the second section of the preferred flow path. The second section of the preferred flow path extends downward from the downstream end of the first section, and curves back toward the outlet baffle inlet  48 , because the only exit from the container  22  is through the flow-directing outlet baffle  44  to the wastewater outlet  14 . As the outlet baffle inlet  48  is adjacent to the heavy waste removal area  42 , the wastewater stream travels through the heavy waste removal area  42  to enter the outlet baffle inlet  48 , which acts as a heavy waste collector. The outlet baffle inlet  48  is sized, shaped and positioned to remove heavy waste falling from the wastewater stream from the heavy waste removal area  42  as the wastewater stream is directed out of the container  22 . As it does so, it picks up the heavy waste in the heavy waste removal area  42  and carries it through the flow-directing outlet baffle  44  to the wastewater outlet  14 .  
         [0055]     It will be appreciated by those skilled in the art that the outlet baffle inlet  48  need not be directly adjacent to the heavy waste removal area  42 , nor is it necessary for the preferred flow path to extend directly through the heavy waste removal area  42 . However the simplest and most preferred form of the invention allows for the suction created by the wastewater stream entering the outlet baffle inlet  48  to suck the heavy waste into the outlet baffle inlet  48 . Less preferred but still feasible is to use mechanical means to push the heavy waste to the outlet baffle inlet  48 . This is less preferred because it would be more expensive, more difficult to use and more likely to fail. What is important is that the preferred flow path should have a combined trajectory and flow rate that permits the heavy waste in the mixed wastewater stream to be directed to the heavy waste removal area  42 .  
         [0056]     It will also be appreciated by those skilled in the art that the preferred flow path need not be the precise flow path shown in  FIG. 1 . Rather any number of flow paths through the container  22  may act as the preferred flow path. What is important is that the preferred flow path be sized and shaped to permit the light waste to separate from the wastewater stream in a first direction to a collection area and to permit the heavy waste to separate from the wastewater stream in a second direction towards the heavy waste removal area  42 .  
         [0057]     The light waste that has been separated and has floated to the surface  60  of the water in the container  22  will need to be periodically emptied. Accordingly, the wastewater separator  10  will preferably comprise a cover  52 , detachably attachable to the container  22 . A gasket  53  is also provided to make a good seal between the cover  52  and the container  22 . Most preferably, the cover  52  will include four quarter-turn fasteners  54  at each corner of the cover  52 . “Quarter-turn fastener” refers to a fastener which is sized and shaped to grip the cover  52  to the container  22  when in its closed position. However, the fastener can be moved to an open position by swivelling it approximately 90°, or a quarter turn. In the open position, the cover  52  and container  22  are not held together. As shown in  FIG. 3 , the quarter-turn fasteners  54  preferably have a convenient finger grip portion  56 , allowing easy manipulation for quickly fastening or unfastening the cover  52 . Quarter-turn fasteners are preferable because they effectively and strongly secure the cover  52  to the container  22 , while still allowing the cover  52  to be quickly detached. However, it will be appreciated by those skilled in the art that quarter-turn fasteners are not specifically required for the invention. For example, the cover  52  may be detachably attachable by any suitable means, such as, for example, magnets attached to the cover  52  and container  22 . It will also be appreciated that, though it is preferable for the cover  52  to be detachably attachable to the container  22 , the cover  52  may be more permanently attached, such as, for example, by screws. This, however, is not preferred, since the process of emptying the wastewater separator  10  would be much more time consuming. Similarly, the cover  52  need not be attached at all (i.e. it may just rest on the container  22 ), though this is not preferable either, for the cover  52  may get jolted aside, and wastewater may then leak or spill from the top of the container  22 .  
         [0058]     Every so often, the entire wastewater separator  10  will need to be cleaned (as opposed to merely emptying the light waste). This cleaning would include wiping down and scouring all of the surfaces inside the container  22 . To facilitate such cleaning, it is preferable that the flow-directing inlet baffle  34  and the flow-directing outlet baffle  44  be detachably attached to the container  22 . In this way the baffles  34  and  44  themselves, as well as the surfaces of the container  22  behind the baffles  34  and  44 , can be easily cleaned.  
         [0059]     Most preferably, the baffles  34  and  44  will be sized and shaped so as to be slidably insertable into tracks mounted on the walls  26  and  28 . The tracks secure the baffles  34  and  44  to the container  22 , while allowing them to be easily withdrawn for cleaning. This withdrawal would be most preferably facilitated by a pair of inlet handles  55  on the flow-directing inlet baffle  34 , and a pair of outlet handles  57  on the flow-directing outlet baffle  44 . While a pair of handles on each baffle is most preferable for balancing ease of manipulation with ease of manufacture, it will be appreciated that one handle on each baffle can serve the same function. Similarly, three or more handles can also be included in order to provide a variety of possible grip points for a person withdrawing the baffles.  
         [0060]     It will be appreciated that other means may be used to make the baffles detachably attachable to the container  22 . For example, the baffles and the container  22  may both contain complementary snap fittings which allow the baffles to be snap-fitted onto the container  22 . What is important is that the baffles be easily detachable from the container  22 , yet be attached strongly enough attached so as not to detach during the operation of the wastewater separator  10 . In the preferred embodiment, the baffles are held in position by securing the cover in place.  
         [0061]     Referring now to  FIG. 2 , it can be seen that in the preferred embodiment, inlet baffle inlet  62  corresponds in size to the wastewater inlet  12 , which in turn corresponds in size to the wastewater pipe that carries the wastewater stream to the wastewater separator  10 . As the inlet baffle  34  extends downward, it widens, so that at the inlet baffle outlet  40  the inlet baffle  34  extends substantially across the container, from wall  30  to wall  32 . This configuration is preferable because it allows the entire width of the container  22  to be used for the process of waste separation. As the entire width of the container is in use for separation, the ramp  36  and the outlet baffle inlet  48  also extend substantially across the width of the container  22 . The outlet baffle  44  is wide at the outlet baffle inlet  48 , but small in height, compared to the outlet of the inlet baffle. This has the effect of accelerating the flow through the inlet of the outlet baffle. This encourages the heavy waste to be sucked away. The outlet baffle then changes shape as it extends upward to the wastewater outlet  14 , in order to correspond in size and shape with the other wastewater pipe carrying the wastewater away from the wastewater separator  10 . Also shown is an air relief valve  44  on the outlet baffle  48 , which prevents suction from being able to establish a flushing action in the event of a sudden flow. Such a flushing action could cause the trap to completely empty, which is undesirable.  
         [0062]     As discussed above, the flow-directing inlet baffle  34  is preferably sized and shaped to slow the wastewater stream as it leaves the inlet baffle  34 . This is achieved by selecting the cross-sectional area of the inlet baffle  34  to be such that the flow speed of the liquid is reduced as it leaves the inlet baffle  34 . Thus, the inlet baffle  34  is wide at its outlet end and of sufficient height such that the cross-sectional area produces slow, smooth preferably laminar flow out of the outlet  40 . The actual size of the outlet will vary depending upon the flow rate, which will also vary with the application. Reasonable results have been achieved with an outlet cross-sectional area of between 10 and 13 square inches with about 11.6 square inches being the most preferred for a typical use of 20 gpm.  
         [0063]     It can now be appreciated that the present invention separates the light waste from the heavy waste in a mixed wastewater stream and directs the light waste to a collection area while directing the heavy waste to a heavy waste removal area where the heavy waste is essentially automatically removed with the wastewater stream. Thus, with the present invention, the heavy waste need not be manually emptied from the wastewater separator separately from the light waste, nor does the heavy waste get trapped along with the light waste. As a result, the container does not need to be emptied as often. Also, the process of emptying the container is less unpleasant, as there is no heavy waste decomposing an aerobically in the container and releasing noxious gases.  
         [0064]     There may be other ways of achieving the separation of the heavy waste from the mixed wastewater stream through, for example, mechanical means, without departing from the scope of the invention, but such other solutions are likely to be more complicated, more expensive and more likely to require extra maintenance. Therefore it is believed that the use of gravity, through relative buoyancy effects, and flow manipulation to slow the flow to maximize the potential for buoyancy separation of the present invention is the most preferred solution.  
         [0065]     Referring now to  FIG. 3 , the quarter turn fastener  54  is shown. The fastener  54  preferably includes a finger grip portion  56  to allow for easy turning while opening and closing the fastener.  
         [0066]     From its closed position, when the fastener is turned by about 90°, it is moved to its open position, and no longer grips the cover  52  to the container  22 .  
         [0067]     It will be appreciated by those skilled in the art that the wastewater separator  10  is used in a moist environment conducive to corrosion. Thus, the wastewater separator  10  is preferably composed of molded plastic to resist corrosion. The use of molded plastic is also preferable because it makes the wastewater separator  10  simpler and less expensive to manufacture than if metal were used. A reduction in corrosion can also be achieved through use of stainless steel, or another metal if coated to inhibit corrosion.  
         [0068]     While the foregoing embodiments of the present invention have been set forth in considerable detail, it will be apparent to those skilled in the art that various modifications can be made to the invention without departing from the scope of the attached claims. Some of these variations are discussed above and others will be apparent to those skilled in the art. For example, the container  22  may be made of any solid material sufficiently strong to contain water in the wastewater separator  10 . Also, the preferred flow path may be any flow path which permits the light waste to separate from the wastewater stream in a first direction to a collection area and permits the heavy waste to separate from the wastewater stream in a second direction towards the heavy waste removal area  42 . What is considered important in this aspect of the present invention is to provide a wastewater separator which effectively separates and traps light waste from a wastewater stream, while ensuring: (1) that heavy waste is not trapped in the layer of light waste; and (2) that the heavy waste need not be emptied from the wastewater separator manually on a regular basis.