Abstract:
Example embodiments provide an apparatus that is useful for recycling protein waste and producing fuel from protein waste. Waste is ground by a grinding means and digested by a enzyme digest medium composed of enzymes, preservatives, inedible egg and or a waste fluid that may include other protein sources with or without fat. The ground proteins are digested with the enzyme in recirculated digest tanks. Fat can be collected from the tank by addition of acid and separation of fat from water with a centrifuge. Alternatively the ground protein and enzyme can be fermented and gas collected from the digest tank in a pressure tank with a compressor. The protein solubles are emulsified, separated from water, and extruded before drying. Either fat or gas can be used to fuel a dryer. Example embodiments provide a highly digestable paletable food stuff from protein waste which is usable for pet, livestock, or an aquaculture diet.

Description:
PRIORITY STATEMENT 
       [0001]    This is a Continuation-In-Part of U.S. application Ser. No. 12/925,359 filed on Oct. 20, 2010, which is a Continuation of U.S. application Ser. No. 11/706,123 filed Feb. 14, 2007 (which issued as U.S. Pat. No. 7,851,210 on Dec. 14, 2010), which is a Continuation-In-Part of U.S. application Ser. No. 10/607,691 filed Jun. 30, 2003 (which issued as U.S. Pat. No. 7,226,778 on Jun. 5, 2007), the entire contents of each application and patent being incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    Example embodiments relate, in general, to apparatuses and processes for naturally recycling protein waste into feed and, more specifically, to apparatuses and processes for enzymatically digesting, emulsifying and drying protein waste including feathers for use in animal feed. 
         [0004]    2. Description of the Related Art 
         [0005]    A mass of waste is accumulated on a regular basis in such operations as poultry production facilities. Protein waste such as carcasses from animal production facilities pose problems for disposal. For example, such problems include odor and generation of bacteria in building. Carcasses are currently disposed of in many ways including land filling and burning. Natural gas production from waste materials is also known in the art and such processes typically also result in a byproduct which is used as animal feed or fertilizer. Some facilities process the protein waste to produce a component for animal feed but these plants often are not designed to provide a mostly closed system and, consequently, air, moisture, and other contaminants may enter creating an environment where microorganisms can multiply and destroy the quality or usefulness of the processed protein waste. 
         [0006]    And, although there may be processing plants at which protein waste may be disposed and recycled, there is not an efficient way to remove the waste from the site to the processing plant in such time and condition as necessary for efficient processing. The timing of such disposal is essential to managing toxicity and odors yet it is not feasible for each animal production plant to also operate a processing plant for its protein waste. 
         [0007]    Animal feed requires a protein component. In addition to the carcasses which can be processed for protein recovery, feathers are inexpensive and also high in protein, however, feathers are difficult for animals to digest. And, although there are processes known for forming feather meal, often these processes require steam which, if too hot, will denature the proteins in the feathers and reduce their nutritional values. It is also known that certain bacterial strains produce keritinase which is an enzyme capable of degrading feathers and that, properly employed, such degradation can result in material that can be used in animal feeds. See U.S. Pat. Nos. 4,908,220; 4,959,311. 
         [0008]    In addition, it is known in the art to provide a means to grind swine or poultry waste and then mix it with ingredients that will facilitate fermentation of the protein waste. See U.S. Pat. No. 5,713,788. The invention disclosed therein provides a specific grinding mechanism which includes a grinding drum with a helical groove on its outer surface in which a length of chainsaw chain, teeth side out, is positioned. This invention does not include a way to re-circulate and thoroughly mix the ground protein and catalyst but, instead, depends on a metered application of catalyst to the ground protein waste as it moves past the grinder wherein the metering of the catalyst is triggered by the load on the grinder. This is deficient in that no additional mixing of the ground protein waste and catalyst is contemplated such that there is substantial risk that it will not be appropriately mixed and the catalytic action will be hampered. 
         [0009]    What is needed is a way for the animal production facilities to efficiently and timely dispose of animal waste in such a way that is non-toxic and odor free. In addition, the system has to be affordable for the animal production facilities and the resultant recycled product must be usable. Preferably, a mostly closed system should be used to eliminate environmental contaminants and to provide avenues for recycling by-products. Finally, for any disposal of feathered animals, the system must provide a method of breaking down not only softer protein sources, but also feathers and in a manner that does not denature or destroy the food value of the proteins. 
         [0010]    Example embodiments provide a system wherein animal protein waste is processed in such a way that a portion of the system may be mobile and can be taken from one animal production facility to another or simply positioned at one facility until it reaches capacity. 
         [0011]    Example embodiments also provide a protein processing system which is capable of degrading feathers without destroying their food value. 
         [0012]    Example embodiments also provide a way for many different and maybe distant animal production facilities to have routine access to a processing facility. 
         [0013]    Example embodiments also provide a means for recycling and breaking down the animal protein wastes and to recycle by-products of the process. 
         [0014]    Example embodiments also provide an apparatus with mixing and grinding capabilities associated with one another in a manner that results in a mostly closed system which may be an efficient process for digesting, emulsifying and drying the recycled protein waste while also providing a means for recycling other byproducts such as water and for minimizing growth of damaging micro organisms. Example embodiments also provide an apparatus for recycling animal protein that produces fuel from the digesting or fermentation of animal protein waste. 
         [0015]    Example embodiments also provide an apparatus for animal protein recycling that produces fuel and uses the produced fuel to power portions of the apparatus. 
       SUMMARY 
       [0016]    Example embodiments provide an apparatus and process for naturally recycling poultry carcasses or parts thereof for use as a nutritional supplement. The apparatus may have four modules: (1) a pH adjustable enzymatic digest medium mixing assembly, (2) a mobile grinding assembly which may be mounted on a truck trailer; (3) a digesting and emulsifying assembly which may include a heated tank and separator or alternatively a fermentation assembly; and (4) a drying system. 
         [0017]    The enzymatic digest medium of example embodiments may include protease/keritinase, inedible egg or a waste fluid that includes protein with or without fat, water as needed, and a preservative. The amount of preservative to be added to the medium may be determined by a circuit using data from a load sensor on the grinding means to control a variable frequency drive which may control the speed of a preservative pump. The digest medium mixing assembly may be equipped with a pH probe and monitor which may trigger the addition of an acidic solution as needed to adjust a pH of the enzymatic digest. 
         [0018]    The mobile grinding assembly may be moved from one animal production facility to another or may remain at one facility. The mobile grinding assembly of example embodiments may be mounted on a trailer and may include a holding tank for the enzymatic digest medium and a conveyor for loading carcasses into a grinder. The remainder of the grinding assembly may be a closed system. Once through the grinder, the ground carcasses or portions or parts thereof may be pumped into a storage tank with the enzymatic digest medium to produce a protein solubles mixture. This mixture may then be recirculated through a chopper pump for a few minutes to further reduce particle size of the ground protein waste and assure adequate mixing of the digest and the proteins and then pumped into a tanker truck for transport. Multiple batches of the protein solubles mixture may be generated so that the storage tanks may be filled and emptied as many times as necessary until all the waste has been disposed. Then, the mobile grinding assembly can be moved to another location or it can simply remain until it is needed again. 
         [0019]    The protein solubles mixture created by the mobile grinding assembly may then be moved to a centralized and stationary processing plant and transferred from the tanker truck to the digesting and emulsifying assembly. An enzyme digest of the present invention in the protein solubles mixture may work best between about 100 and 130 degrees Fahrenheit while other enzyme digests disclosed work best under 125 degrees Fahrenheit. Therefore, the digesting and emulsifying assembly may heat the mixture if needed and only periodically recirculate it until the enzymatic digest has altered the protein solubles to a mostly liquid state. For embodiments that include digestion of parts that include fats, or for enzyme digest mediums that include fat content, it may be preferred to emulsify the digested protein solubles to completely disperse the fats and proteins. The digested and emulsified proteins may then pumped into a separator tank and the bottom layer of water may be drained off periodically, leaving the emulsified proteins. The water layer may then recycled back to the portion of the system where the enzymatic digest is made. The remaining emulsified proteins may then be transferred to the drying system. 
         [0020]    In example embodiments, fats may be collected from the digest and emulsification assembly via a closeable connection and a first fats tank. Fats may be separated from the protein solubles mixture by addition of acid from an acid tank via a pump. A valve on the recirculation means may close to allow transfer of fats from the digest tank through an open closeable connection. Fats in the first fats tank may be separated from water in a centrifuge and stored in a second fats tank. The water collected may be recycled back into the digester tank. 
         [0021]    In alternative to the digest and emulsification assembly, the apparatus may include a fermentation assembly. In the fermentation assembly the protein solubles mixture is broken-down by bacteria which produces gas. Gas may be collected by a piping and compressed by a compressor into a pressure tank. Check valves along the piping prevent backflow of gas. The compressor may be controlled by a pressure sensor on the fermentation tank. 
         [0022]    The dryer system may use a carrier for surface absorption of moisture, extrusion, air flow, and heat to accomplish the removal of moisture. A carrier such as cereal, soybean meal, corn or wheat mids may be fed through a volumetric feeder to a mill where it may be finely ground to provide ample surface area for absorption. The carrier may then be conveyed to a mixer where it may be mixed with the emulsified proteins until a doughlike consistency is reached. At this point, the dough is fed into an extruder to remove additional moisture and to extrude dough pellet-like pieces which may then moved by oscillating belt to the drying apparatus. 
         [0023]    The drying apparatus may include a dryer bed which, in example embodiments, may be a conveyor belt enclosed in a housing. The housing may alternate air flow direction and have heat zones for removing yet more moisture content and a cooling zone to return the pellet-like pieces to near room temperature. The pellet-like pieces may then be moved progressively through the air flow, the heat zones and the cooling zone by the conveyor. In example embodiments, the pellet-like pieces may be sized and then run over a vibrating screen to separate the non-uniform sized pieces. Finally, the appropriately and uniformly sized pellet-like pieces may be packaged. 
         [0024]    Other objects, features, and advantages of example embodiments will be readily appreciated from the following description. The description makes reference to the accompanying drawings, which are provided for illustration of example embodiments. However, example embodiments do not represent the full scope of the invention. The subject matter which the inventor does regard as his invention is particularly pointed out and distinctly claimed in the claims at the conclusion of this specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a perspective view of a mobile grinding assembly portion in accordance with example embodiments; 
           [0026]      FIG. 2  is a diagram showing an enzymatic digest mixing assembly portion in accordance with example embodiments; 
           [0027]      FIG. 3  is a side view of a mobile grinding assembly portion in accordance with example embodiments; 
           [0028]      FIG. 4  is an enlarged plan view of the mobile grinding assembly of  FIG. 3 ; 
           [0029]      FIG. 5  is a side view of a digesting and emulsifying assembly portion in accordance with example embodiments; 
           [0030]      FIG. 6  is a side view of a fermentation assembly portion in accordance with example embodiments; 
           [0031]      FIG. 7  is a block diagram showing the components of a dough mixing apparatus and an extruder of a drying system portion in accordance with example embodiments; 
           [0032]      FIG. 8  is a block diagram of a drying apparatus of the drying system portion in accordance with example embodiments; 
           [0033]      FIG. 9  is a flow diagram showing the steps for the process for natural recycling of protein waste in accordance with example embodiments; 
           [0034]      FIG. 10  is a diagram showing an enzymatic digest mixing assembly portion in accordance with example embodiments; and 
           [0035]      FIG. 11  is a plan view of a mixing device and a grinding assembly in accordance with example embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    Example embodiments provide an apparatus and process usable for, amongst other things, naturally recycling protein waste. In example embodiments, the apparatus and process for naturally recycling protein waste may include an enzymatic digest mixing assembly shown generally as  15  in  FIG. 2 , a mobile grinding assembly shown generally as  40  in  FIGS. 3 and 4 , a digesting and emulsifying assembly shown generally as  100  in  FIG. 5  or a fermentation assembly shown generally as  200  in  FIG. 6 , and a drying system shown generally as  126  in  FIGS. 7 and 8 . These components may all be present on a movable platform or separated; for example, the mobile grinding assembly may be movable while the enzymatic digest mixing assembly is stationary. 
         [0037]    In example embodiments, the process, as is shown in the flow chart depicted in  FIG. 9 , may include an enzymatic digest medium  12  of a particular pH level that may be prepared and stored until such time as it is needed. The enzymatic digest medium  12  of example embodiments may include enzymes  14 , inedible egg  16 , a preservative  18 , and water. The enzymes  14  may include protease to break down and digest most proteins, and keritinase to aid in digestion of feathers. The preservative  18  may restrict multiplication of bacteria or microorganisms which could adversely affect the end product. Although inedible egg is a logical choice when the process is used in conjunction with poultry production, other fluid wastes such as outdated ice cream, molasses, milk by products, and others that include proteins, fat, and water or proteins without fat such as blood could be appropriately substituted. 
         [0038]    In example embodiments, a pH of the enzymatic digest medium  12  may be adjusted by a measured addition of an acid. One such acid may be phosphoric acid, to maintain a level of pH 5 or within the range of about 4-6 or 4-8. Using phosphoric acid to effect a change in pH include the added benefit of adding phosphorous to the medium and, in turn, provides a high phosphorous product which may enhance the desirability of the additive for animal feed. Other acidic solutions may also be used. For example, lactic acid is one such reasonable alternative. In the case where lactic acid is used, the fermentation process which occurs as a natural consequence of the use of lactic acid, (in addition to digestion by enzymes) also acts to break down the protein waste and lowers the pH at the same time. 
         [0039]    In example embodiments, protein waste  216 , which may be in the form of spent hens or some portions thereof, may be ground and the enzymatic digest medium  12  and ground protein waste  216  may be thoroughly mixed and re-circulated through a chopper pump  88  to produce a protein solubles mixture  84 . The protein solubles mixture  84  may be maintained at or heated to a temperature optimal for enzyme digestive action which may range between about 90 degrees Fahrenheit and about 125 degrees Fahrenheit and may be recirculated periodically until the mixture is mostly liquid. The heat created by the exothermic digestive process and the friction of recirculation in certain conditions may be enough to maintain the optimal temperature and, if not, additional heat may be provided. For example, the mixture may be recirculated for 1 hour every 12 hours for 3-4 days, however, the speed of the process may be increased if additional enzyme is used. Further, the speed is effected by the nature and content of the protein solubles mixture and may be dramatically shortened. For example, in one embodiment, digestion may be complete in as little as about 30 minutes to about 1½ hours. In example embodiments, the protein solubles mixture  84  may be strained and when the number of quills remaining in the strainer is acceptable, the digestion is complete. In example embodiments, the protein solubles mixture  84  may be emulsified to disperse fats and proteins and the protein solubles mixture  84  may be allowed to separate. A resulting water layer  125  may be drained off and recycled to be re-used for mixing enzymatic digest medium  12  and the emulsified proteins  121  may be mixed with a carrier  132 . In example embodiments, the resulting water layer  125  may be drained several times before the emulsified proteins  121  are mixed with a carrier  132 . 
         [0040]    In example embodiments the carrier  132  may be delivered to a high speed mixer  140  by volumetric feeder  130 . The carrier  132  may comprise a relatively high surface area to volume ratio which acts to absorb some of the moisture. Upon mixing with the emulsified proteins  121 , a doughlike mixture is produced. The doughlike mixture may then be extruded into a plurality of pellet-like pieces  146  and the pellet-like pieces may be passed through a drying apparatus  126  which may use air flow, multiple heat zones, and at least one cooling zone for further removal of moisture. The pellet-like pieces may be finally sized through a mill  166  to a uniform, granular size. In example embodiments the mill  166  may be a hammer mill. The off-size pellet-like pieces may be removed and the remaining uniform, granular pellet-like pieces may be packaged. An apparatus usable to accomplish the foregoing process is described below. 
         [0041]    An example of an enzymatic digest mixing assembly  15  is shown in  FIG. 2 . In example embodiments, the enzymatic digest mixing assembly  15  may be used to mix enzymes  14 , inedible egg  16 , and a preservative  18  with water to form an enzymatic digest medium  12  of a given, predetermined, preset, or optimal pH level. The enzymatic digest mixing assembly  15  may include at least one enzymatic digest mixing tank  22 , pumping means  24 , a re-circulating assembly  26 , and means for adjusting the pH level of the enzymatic digest medium  12  which, in example embodiments, may be a pH adjustment assembly  28 . The pumping means  24  of example embodiments may comprise a first centrifugal pump and the re-circulating assembly  26  may comprises a first inductor nozzle  27  associated with the pumping means  24  and a return pipe  29  for circulating the enzymatic digest medium  12 . In example embodiments, the enzymatic digest mixing assembly  15  may further include load cells  25  associated with a digital scale  25   a  and positioned such that addition of the enzymes  14 , preservatives  18 , and inedible egg  16  can be measured. It is also contemplated that, in addition to external measuring of the ingredients, other internal measurement options such ultrasound and light beams may be used to monitor the amounts of each ingredient as it is added. 
         [0042]    The pH adjustment assembly  28  of example embodiments may include a pH probe  30 , a pH monitor  32 , and a first positive displacement pump  34  all electrically associated, and a supply of acidic solution  36  fluidly connected to the positive displacement pump  34  and to the enzymatic digest mixing tank  22  through a check valve  38 . The first positive displacement pump  34  of example embodiments may include a variable speed motor. In example embodiments, the variable speed motor may be configured to pump 1-10 gallons per minute. In example embodiments, the enzymatic digest medium  12  may be formed and or placed in the mixing tank  22  and recirculated while a pH of the enzymatic digest medium  12  is monitored by the pH monitor  32 . For example, the enzymatic digest medium  12  may be recirculated for at least 3-5 minutes while the pH probe  30  provides a pH level to the pH monitor  32 . In example embodiments, the pH monitor  32  may compare the pH level with an optimal, preset, predetermined, or given level and send a signal to the positive displacement pump  34  to move the acidic solution  36  into the mixing tank  22  where recirculation continues. The re-circulating assembly  26  may continue to mix the enzymatic digest medium  12 , the pH probe  30  may again measure the pH level, and the monitor  32  may compare the level to the optimal, preset, predetermined, or given level, and again determine whether acidic solution  36  should be added to the mixing tank  22 . When the pH level reaches the optimal, preset, predetermined, or given level, the enzymatic digest medium  12  is ready to be used or stored. 
         [0043]    A particular example of the enzymatic digest medium  12  includes, per ton, about 2½ pounds of protease and keritinase  14 , about 2 pounds of preservative  18 , and the remaining pounds inedible egg  16  and water. In this example, the pH was lowered to about 5 by addition of phosphoric acid  36 . This pH level is optimal for this particular enzymatic digest medium, however a range from about 4-6 may be effective and the amount of enzyme may be altered according to the speed of digestion desired and the enzymes used. 
         [0044]    In example embodiments, once the enzymatic digest medium  12  has been prepared, it can either be stored or it can be moved via a transporting device  37 , such as a tanker truck, to the mobile grinding assembly  40  where it may be mixed with ground protein waste  216 . Referring now to  FIGS. 3 and 4 , the mobile grinding assembly  40  comprises a movable platform  42  which may include a front portion  43 , a mid portion  44  and a rear portion  45 , a conveyor belt  56  for moving protein waste, a holding tank  58  in which the enzymatic digest medium  12  is stored, at least one prep tank  60 ,  62 , and a pump  64  to move the enzymatic digest medium  12  from the holding tank  58  to the at least one prep tank  60 ,  62 , in example embodiments, the movable platform  42  may be a semi trailer. The mobile grinding assembly  40  may further comprise a grinding means  66  which may include a grinder inlet  67  positioned near the conveyor belt  56 , a grinder plate  68 , a grinder outlet  69 , and at least one grinder knife  70 , wherein the grinder outlet  69  is positioned such that output from the grinder outlet  69  may flow by closed connection  71  into a hydro pump  82  the hydro pump  82  having a lower outlet  74 . A specific non-limiting example of the grinding means  66  is a Weiler Meat Grinder utilizing a 7/16″ plate. However, different plate combinations may be used such as double-cut, double-knife combinations with a ¾″ or ⅜″ plate in this situation, one knife may be positioned on the inside of the grinder plate  68  and another on the outside of the grinder plate  68 . 
         [0045]    The grinding assembly  40  may further comprise a mixing means  80  which, in example embodiments, may comprise at least one second positive displacement pump  72 , which may be fluidly connected to the at least one prep tank  60 ,  62  and to the hydro pump  82  of the grinding means  66  such that the enzymatic digest medium  12  can be moved to the hydro pump  82  where output from the grinder outlet  69  is mixed with the enzymatic digest medium  12  to form a protein solubles mixture  84 . The enzymatic digest medium  12  may be pumped against the grinder outlet  69  and may wash ground protein waste down into the hydro pump  82 . The lower outlet  74  of the hydro pump  82  is fluidly connected to a centrifugal chopper pump  88  which is further associated with the at least one prep tank  60  or  62  and a recirculation piping system  92  including an inductor nozzle  90 . This arrangement provides a way to move the protein solubles mixture  84  through the chopper pump  88  and into the prep tank  60  via the inductor nozzle  90  which may be positioned to generate a circular flow in the prep tank  60 . The mixture  84  may be continually recirculated through the chopper pump  88  until it is of desired consistency and thoroughly mixed. This may require several minutes. 
         [0046]    The protein solubles mixture  84  may then transported to the digesting and emulsifying assembly  100 , an example of which is shown in  FIG. 5 , either via pumping it directly or by pumping it first to a tanker truck  94  and then to the assembly  100 . The mobile grinding assembly  40  may be a closed system wherein the grinder inlet  67  is the only input open to the environment. 
         [0047]    Where more than one prep tank  60 ,  62  is present, one prep tank  60  may be recirculated or unloaded while another is being filled and recirculated. In this example embodiment, a separate chopper pump may be associated with each prep tank. 
         [0048]    In example embodiments, the front portion  43  of the movable platform  42  may be occupied by a power source  75 , for example, a generator, the mid portion  44  of the movable platform  42  may be occupied by the holding tank  58  and prep tanks  60 ,  62 , and the rear portion  45  may be occupied by the grinding means  66 . The conveyor belt  56  may be associated with or occupy the rear portion  45 . In example embodiments, the at least one prep tank  60 ,  62  may be a cone-bottomed tank. 
         [0049]    The apparatus of example embodiments may further include an electronic load sensor  96 , a programmable logical computer circuit  97 , a variable frequency drive  98 , and a preservatives pump  99  to deliver preservative  18  to the enzymatic digest medium  12 . The load sensor  96  may be located on the grinding means  66  to sense a load of the grinding means  66 . The variable frequency drive  98  controls the preservatives pump  99 . The load sensor  96  and variable frequency drive  98  may be connected to the programmable logical computer circuit  97 . The programmable logical computer circuit  97  may be programmed with a program to determine the amount of preservative to pump based on a load. 
         [0050]    In example embodiments, a relationship may be established between the amperage load on the grinding means  66  and the desired revolutions per minute to run the preservatives pump  99 . The following program is usable in example embodiments: 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
               
               
                 Grinder Amp 
                 Load 
                 Preservative Pump RPM 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 40 amps 
                 no load 
                 0 
                 RPM 
               
               
                 50 amps 
                 25% load 
                 437 
                 RPM 
               
               
                 60 amps 
                 50% load 
                 875 
                 RPM 
               
               
                 70 amps 
                 75% load 
                 1300 
                 RPM 
               
               
                 80 amps 
                 Full load 
                 1800 
                 RPM 
               
               
                   
               
             
          
         
       
     
         [0051]    The digesting and emulsifying assembly  100  of example embodiments may be stationary or mobile or some portions may be mobile, while others are stationary. A non-limiting example of the digesting and emulsifying assembly  100  is shown in  FIGS. 5 and 6 . As shown in  FIGS. 5 and 6 , the digesting and emulsifying assembly  100  may include a digester tank  101  for digesting the protein solubles mixture  84 , a means  102  for heating the mixture  84 , a means  103  for recirculating the mixture  84  for periodic mixing, a means  107  for collecting fats from the digester tank  101 , and an emulsifier  105 . In example embodiments, the means  103  for recirculating the mixture  84  may include a centrifugal pump  104 . The emulsifier  105  may be fluidly connected to a pump  106 , the digester tank  101 , and a separator tank  108 . 
         [0052]    In example embodiments, the digester tank  101  may be a non-pressure tank with a cone bottom  109  enclosed within a housing  110 . The heating means  102  of example embodiments may include a heating element  111  and water (not shown) enclosed in the housing  110 . The housing  110  of example embodiments may be a vented water jacket. The heating element  111  of example embodiments may heat the water in the housing to about 120° F. and in turn may warm the protein solubles mixture  84  from about 90° F. to about 110° F. The protein solubles mixtures  84  may be recirculated while it digests. In certain conditions friction from circulation and the exothermic digestion may provide heat sufficient to maintain the digest medium at an optimal temperature and reduce or negate the need for additional heat. 
         [0053]    The fat collection means  107  of example embodiments may include an acid storage tank  112 , a positive displacement pump  113 , the centrifugal pump  104 , a first fats storage tank  117 , a centrifuge  118 , and a second fats storage tank  119 . After digestion of the protein solubles mixture  84  in the digest tank  101 , the fat (not shown) may be separated from the protein solubles  84  by recirculating the protein solubles  84  with acid (not shown). In example embodiments, acid may be stored in the acid storage tank  112  and pumped into recirculation means  103  by the positive displacement pump  113  while the protein solubles  84  are recirculated. Alternatively, the acid could be pumped solely by the centrifugal pump  104 . A pH probe  114  in the digest tank  101  may control the pump  113  and/or the centrifugal pump  104  to stop the pumps at a desired pH level. 
         [0054]    Because acid may be introduced into the protein solubles  84 , the pH of the protein solubles  84  may drop causing fat (not shown) to settle out of the digest tank  101 . The settled fat may be pumped out of the digester tank  101  using the centrifugal pump  104 . The recirculation means  103  includes a recirculation valve  115  and a closable connection  116  connecting the digest tank  101  to the first fat storage tank  117 . During recirculation, the recirculation valve  115  is open and the closeable connection  116  is closed. During collection of fat the recirculation valve  115  is closed and the closeable connection  116  is open. In example embodiments the centrifugal pump  104  may stop pumping fat when all of the fat in the digester tank  101  has been removed as confirmed by visual operation. 
         [0055]    The centrifuge  118  may be fluidly connected to the first storage tank  117  and the second fat storage tank  119 . The centrifuge  118  may act to pump the fat from the first storage tank  117  and separate water from fat. The separated water (not shown) may be recirculated back into the protein solubles mixture  84  and water may be recycled in example embodiments. Separated fats may be stored in the second storage tank  119 . The stored fats may be used as a fuel source for the drying system  120  or for other purposes. 
         [0056]    After digestion and removal of fat, the protein soluble mixture  84  may be pumped into the emulsifier  105  for further removal of fats. Emulsification produces emulsified proteins  121  which may be transferred to a separator tank  108 . The separator tank  108  may have a closeable opening  123  in fluid connection with the enzymatic digest mixing tank  22 . A water layer  125  may form in the separator tank  108  and the water layer  125  may be drained for use in mixing additional digest medium  12 . 
         [0057]    Referring to  FIGS. 7 and 8 , the emulsified proteins  121  may be moved to the drying system  120  which may include a dough mixing apparatus  122 , an extruder  124  and a drying apparatus  126 . An example of the dough mixing apparatus  122  is shown in  FIG. 7 . As shown in  FIG. 7 , the dough mixing apparatus  122  may comprise a volumetric feeder  130  for measuring an absorbing carrier  132  which may be mixed with the emulsified proteins  121 . In example embodiments, the dough mixing apparatus  122  may be positioned over a mill  134  for finely grinding the absorbing carrier  132 . The mill  134  may, for example, be a high speed hammer mill or disc mill. The dough mixing apparatus may further include a second conveyor belt  136  which may move the absorbing carrier  132  from the mill  134  to a high speed continuous mixer  140 . A third positive displacement pump  142  may be associated with the separator tank  108  and may move the emulsified proteins  121  to the high speed mixer  140  where it may be mixed with the absorbing carrier  132  to produce a doughlike mixture. In example embodiments, the absorbing carrier  132  may be a substance with characteristics like wheat mids, soybean meal, corn, or a previously dried material made for such purpose and the third positive displacement pump  142  may be of the variable speed variety. 
         [0058]    In example embodiments, the doughlike mixture may be moved to the extruder  124  which may pressure-force moisture out and produce a plurality of pellet-like pieces  146 . In example embodiments the pellet-like pieces may have a thickness of about 3/16″ and of random length. The pellet-like pieces  146  may be extruded onto an oscillating belt  148  which may distribute the pellet-like pieces  146  evenly and connect the extruder  124  to the drying apparatus  126 . Additional moisture may be removed by the drying apparatus  126  using heat and air movement. An example of the drying apparatus  126 , as shown best in  FIG. 8 , may comprise a dryer bed  150  positioned to receive the pellet-like pieces  146  from the oscillating belt  148 , a housing  152  through which a dryer bed conveyor belt  154  may move and convey the pellet-like pieces  146  and which may include at least one heating zone  156 ,  158 ,  160 , at least one cooling zone  162 , and means to direct airflow  164 . The mill  166  may receive the pellet-like pieces  146  after they emerge from the housing  152  and size the plurality of pellet-like pieces  146  to a uniform size. A vibrating screen  170  may be used to remove any of the plurality of the pellet-like pieces  146  which are of a non-uniform size. In example embodiments, the means to direct airflow  164  may comprise fans positioned to alternate the flow of air to provide uniformity in drying. In example embodiments, the heat zones  156 ,  158 ,  160  may provide temperatures of 300, 275, and 250 Fahrenheit, in this order, such that the maximum temperature of the plurality of pellet-like pieces does not exceed 250 Fahrenheit. If the heat of the pellet-like pieces  146  exceeds this level their taste may be too bitter and the amino acids may be degraded. The cool zone  162  may return the pellet-like pieces  146  to within about 10 degrees of ambient temperature. Vents may return the heated air from the cool zone  162  to the heat zones. 
         [0059]    The protein solubles mixture  84  may alternatively be digested through fermentation. In this example embodiment, the pH of the enzymatic digest medium  12  may be adjusted using lactic acid. The fermentation itself replaces the enzymatic digest and a fermentation assembly  200  replaces the digest and emulsification assembly  100 . The fermentation assembly  200  may include a non-vented low pressure tank  202 , a means  264  for recirculating protein solubles  84 , and a means  206  for collecting gas. 
         [0060]    In example embodiments, the fermentation tank  202  may have a means  208  for heating the mixture  84  comprising a cone bottom  210  surrounded by a housing  212  filled with water (not shown) and heated by a heating element  214 . The heated water in turn heats the protein solubles mixture  84  and microorganisms (not shown) within the tank  202 . The microorganisms in the tank  202  may be bacteria that produce methane gas. In example embodiments, the recirculation means  264  may include a centrifugal pump  216  that may recirculate the contents of the tank  202 . In example embodiments, the gas collection means  206  may comprise piping  218  in fluid connection with the tank  202 , a compressor  220 , and a pressure tank  222 . During recirculation, the bacteria may produce gas (not shown) and may increase pressure in the tank  202 . In example embodiments, the tank  202  may include a pressure sensor  224  to monitor pressure in the tank  202 . At the appropriate pressure, the pressure sensor  224  may activate the compressor  220  which may compress the gas for storage in the pressure tank  222 . As a safety measure, the pressure tank  222  may include a pressure guage  226 . To prevent backflow of gas, the piping  218  may include check valves  228  located before and after the compressor  220 . The stored methane gas may be used as a fuel source for the dryer system  120  or for other purposes. After digestion and collection of gas, the protein soluble mixture  84  may be pumped into the emulsifier  105  for further removal of fats consistent with the earlier described example digest and emulsification assembly  100 . 
         [0061]    Example embodiments provide a process to treat animal byproducts or only portions of animal carcasses. For example, some embodiments provide a method to treat blood and feathers which are waste products of a poultry processing plant, and to treat this mixture on site at least to the degree necessary to avoid bacterial contamination and reduce other negative effects of a rendering plant. The method reduces or minimizes problems associated with odor and bacteria, such as  salmonella  and  E. coli . Embodiments also provide a method of treating byproducts in a manner that is sanitary. The various embodiments will provide a product that is a high protein material. One use of the high protein material is as an additive to existing animal foods and/or as a new ingredient for animal foods. For example, the high protein material may be added to a feed additive. 
         [0062]    In example embodiments, blood and feathers, and optionally offal, necks, backs and/or wings, may be collected on site of a rendering plant or a slaughter plant. These products may be collected into stationary or mobile tanks. In example embodiments, the blood may be combined with enzymes and preservatives to form an enzymatic digest medium; the enzymatic digest medium, in turn, may be combined with the feathers, and optionally offal and/or other parts remaining. Preferably the feathers are ground prior to addition to the enzymatic digest medium which will decrease the time necessary to achieve the degree of digestion required. The enzymes in the enzymatic digest medium will liquefy substantially all of the feathers (and offal, if present) and the progress of the digestion can be monitored by checking the level of quills remaining. Once the number of quills or quill parts is at the desired level, the digestion process may be allowed to end by removing the heat supply, or adjusting the pH or by other known means. The digested mixture may be stored for a relatively long period of time. It may be used in its liquid state or dried using heat, and thereafter milled in the presence of cereal that operates as a carrier or combined with another material prior to or during drying. 
         [0063]    Where offal is included in the digest medium, or added to the digest medium at a later time, fat will be present. The fat may be separated as described herein, and the remaining portion be emulsified, with drying of the material to follow. 
         [0064]    In example embodiments, the processes may occur in a mobile or a stationary system. The digest equipment may include a tank for producing the digest medium and another tank for the actual digestion process. The second tank may be equipped with a means to stir the enzymatic digest and the animal byproducts and a means to pump the material out when finished. The first and second tanks may be configured with a heating system to heat the mixture of the animal byproducts and the enzymatic digest medium while the mixture is mixing. 
         [0065]      FIG. 10  is a view of an enzymatic digest mixing assembly  15 ′ in accordance with example embodiments. In example embodiments, the enzymatic digest mixing assembly  15 ′ of  FIG. 10  is similar to the example enzymatic digest mixing assembly  15  of  FIG. 2 . For example, as shown in  FIG. 10 , the enzymatic digest mixing assembly  15 ′ may include an enzymatic digest tank  22 ′ which may be configured to receive a preservative  18 ′, at least one enzyme  14 ′, an organic material  16 ′, and water. In example embodiments, the preservative  18 ′, the at least one enzyme  14 ′, the organic material  16 ′, and the water may be mixed in the enzymatic digest tank  22 ′ to form an enzyme digest medium  12 ′. In example embodiments, a moisture content of the enzyme digest medium  12 ′ may be about 65% or greater to render the enzyme digest medium  12 ′ usable for digesting animal byproducts (for example, feathers, to be explained later). 
         [0066]    In example embodiments the organic material  16 ′ may be blood, for example, avian blood such as chicken or turkey blood. The at least one enzyme  14 ′ may be a protease, a lipase, a keratinase, an amylase, or a combination thereof. Thus, the at least one enzyme  14 ′ may be capable of breaking down proteins or fats that may be present in the enzyme digest medium  12 ′ or proteins or fats that may be combined with the enzyme digest medium  12 ′. For example, the enzymatic digest medium  12 ′ may be combined with feathers either during the production of the enzymatic digest medium  12 ′ or added to the enzymatic digest medium  12 ′ at a later time. 
         [0067]    In example embodiments, the preservative  18 ′ may be a preservative or an agent that prevents or reduces microbial growth. For example, non-limiting examples of the preservative  18 ′ are sodium bisulfate, meta-bisulfate, a reducing agent, potassium sorbate, sodium sulfate, phosphoric acid, and hydrochloric acid. The proper selection of a preservative or a combination of preservatives depends on the materials to be digested and the enzyme digest itself. In example embodiments, the enzyme digest medium  12 ′ may be stably stored for a long period of time due to the presence of a preservative  18 ′. For example, the enzymatic digest medium  12 ′ may be stored for several months prior to its use. 
         [0068]    In example embodiments, the enzymatic digest mixing tank  22 ′ may be further configured to receive a pH controlling medium  36 ′. In example embodiments, the pH controlling medium  36 ′ may be a basic medium or an acidic medium. For example, non-limiting examples of the pH controlling medium  36 ′ may be sodium hydroxide or phosphoric acid. The addition of the pH controlling medium  36 ′ may be helpful in regulating a pH of the enzyme digest medium  12 ′. In example embodiments, the pH controlling medium  36 ′ may be added to the enzymatic digest mixing tank  22 ′ by a pH adjustment assembly  28 ′ which may be comprised of a pump  34 ′, a pH monitor  32 ′, and a pH probe  30 ′. In example embodiments, the pH probe  30 ′ may be exposed on an inside of the enzymatic digest tank  22 ′ and thus may be exposed to the enzymatic digest medium  22 ′. 
         [0069]    In example embodiments, the pH probe  30 ′, the pH monitor  32 ′, and the first positive displacement pump  34 ′ may be electrically associated, and a supply of pH controlling medium  36 ′ may be fluidly connected to the positive displacement pump  34 ′ and to the enzymatic digest mixing tank  22 ′ through a check valve  38 ′. 
         [0070]    The first positive displacement pump  34 ′ of example embodiments may include a variable speed motor. In example embodiments, the variable speed motor may be configured to pump 1-10 gallons per minute. In example embodiments, the enzymatic digest medium  12 ′ may be formed or placed in the mixing tank  22 ′ and recirculated while a pH of the enzymatic digest medium  12 ′ is monitored by the pH monitor  32 ′. For example, the enzymatic digest medium  12 ′ may be recirculated for at least 3-5 minutes while the pH probe  30 ′ provides a pH level to the pH monitor  32 ′. In example embodiments, the pH monitor  32 ′ may compare the pH level of the enzymatic digest medium with a predetermined, preset, or optimal pH level and send a signal to the positive displacement pump  34 ′ to move the pH controlling medium  36 ′ into the mixing tank  22 ′ where recirculation continues. The re-circulating assembly  26 ′ may continue to mix the enzymatic digest medium  12 ′, the pH probe  30 ′ may again measure the pH level, and the monitor  32 ′ may compare the pH level to the predetermined, preset, or optimal pH level and again determine whether the pH controlling medium  36 ′ should be added to the mixing tank  22 . When the pH level reaches the predetermined, preset, or optimal pH level, the enzymatic digest medium  12 ′ is ready to be used or stored. 
         [0071]    In example embodiments, the enzymatic digest mixing assembly  15 ′ may be used to mix the at least one enzyme  14 ′, the preservative or preservatives  18 ′, the organic material  16 ′, and water. The enzymatic digest mixing assembly  15 ′ may also be usable for mixing the pH controlling medium  36 ′ with the enzymes  14 ′, the preservative  18 ′, the organic material  16 ′, and the water to form the enzymatic digest medium  12 ′ of a predetermined, preset, or optimal pH level. For example, the enzymatic digest mixing assembly  15 ′ may produce an enzymatic digest medium  12 ′ having a pH of about 7. In example embodiments, the enzymatic digest mixing assembly  15 ′ may include a pump  24 ′ and a re-circulating assembly  26 ′. The pump  24 ′ of example embodiments may comprise a first centrifugal pump and the re-circulating assembly  26 ′ may comprise a first inductor nozzle  27 ′ associated with the pump  24 ′ and a return pipe  29 ′ for circulating the enzymatic digest medium  12 ′. In example embodiments, the pump  24 ′ may alternatively be another type of pump, for example, a chopper pump. 
         [0072]    In example embodiments, the enzymatic digest mixing assembly  15 ′ may further include load cells  25 ′ associated with a digital scale  25   a ′ and positioned such that addition of the at least one enzyme  14 ′, preservatives  18 ′, and organic material  16 ′ can be measured. It is also contemplated that, in addition to external measuring of the ingredients, other internal measurement options such ultrasound and light beams may be used to monitor the amounts of each ingredient as it is added. 
         [0073]    In example embodiments, the enzymatic digest mixing assembly  15 ′ may be a stationary structure. For example, the enzymatic digest mixing assembly  15 ′ may be a stationary structure used at a slaughter house. In this case, the organic material  16 ′ may be blood, for example, avian blood, and the blood may be transferred to the mixing tank  22 ′. In this particular nonlimiting example embodiment, the avian blood produced as part of a slaughter operation may be mixed with the at least one enzyme  14 ′ and the preservative or preservatives  18  in the enzymatic digest mixing tank  22 ′. Due to the presence of the preservative  18 , the mixture of the blood, the enzymes  14 ′, and the preservative  18 ′ may be stored for a relatively long period of time. Thus, the enzymatic digest medium  12 ′ may be stored in the mixing tank  22 ′ for an indefinite period of time or may be pumped to a holding tank for an indefinite period of time. In example embodiments, a pH of the enzymatic digest medium  12 ′ may be controlled via the pH adjustment assembly  28 ′. For example, the pH of the enzymatic digest medium  12 ′ may be controlled to be around 7. 
         [0074]    In example embodiments, the mixing tank  22 ′ may be transportable and thus may be moved from one facility to another facility. In the alternative, the enzymatic digest medium  12 ′ may be pumped from the mixing tank  22 ′ to a holding tank which may be loaded on a truck. Example embodiments, however, are not limited thereto. For example, the entire enzymatic digest mixing assembly  15 ′ may be truck mounted. Thus, the entire enzymatic digest mixing assembly  15 ′ may be mobile. 
         [0075]    In example embodiments, the enzymatic digest medium  12 ′ may be usable for digesting proteins, for example, proteins from feathers. For example, an avian slaughtering operation may produce by products such as blood, offal, and feathers. The blood may be used as the organic material  16 ′ in producing the enzymatic digest medium  12 ′. At least one of the feathers and offal may be collected, ground, and added to the enzymatic digest medium  12 ′ either during a production of the enzymatic digest medium  12 ′ or afterwards. 
         [0076]      FIG. 11  is a view of a mixing system  80 ′ that may be usable for mixing animal products, for example, feathers and/or offal, with the enzymatic digest medium  12 ′. The mixing system  80 ′ may be substantially the same as the mixing system  80  illustrated in  FIG. 4 . For example, the mixing system  80 ′ may comprise at least one second positive displacement pump  72 ′, which may be fluidly connected to the at least one prep tank  60 ′,  62 ′ and to the hydro pump  82 ′ such that the enzymatic digest medium  12 ′ can be moved to a hydro pump  82 ′ where output from the grinder outlet  69 ′ is mixed with the enzymatic digest medium  12 ′ to form a protein solubles mixture  84 ′. The enzymatic digest medium  12 ′ may be pumped against the grinder outlet  69 ′ and may wash ground protein waste down into the hydro pump  82 ′. The lower outlet  74 ′ of the hydro pump  82 ′ may be fluidly connected to a centrifugal chopper pump  88 ′ which may be further associated with the at least one prep tank  60 ′,  62 ′ and a recirculation piping system  92 ′ including an inductor nozzle  90 ′. This arrangement provides a way to move the protein solubles mixture  84 ′ through a chopper pump  88 ′ and into the at least one prep tank  60 ′,  62 ′ via the inductor nozzle  90 ′. The system may be arranged to generate a circular flow in the at least one prep tank  60 ′,  62 ′. The mixture  84 ′ may be continually recirculated through the chopper pump  88 ′ until it is of desired consistency and thoroughly mixed. This may require several minutes, for example, sixty (60) minutes. 
         [0077]    In example embodiments, animal byproducts, such as feathers and offal, may be ground by grinding means  66 ′ which may be substantially the same as the grinding means  66 . As in the previous non-limiting example embodiments, the animal by products, for example, the feathers and/or offal, may mix with the enzyme digest medium  12 ′ in a closed connection  71 ′ which may be substantially the same as the closed connection  71 . 
         [0078]    In example embodiments, the at least one prep tank  60 ′,  62 ′ may be a jacketed prep tank that may be heated by injecting steam into the jacket. For example, the at least one prep tank  60 ′,  62 ′ may be a conventional cone bottomed tank. Thus, the at least one prep tank  60 ′,  62 ′ may be heated during the mixing process. For example, the at least one prep tank  60 ′,  62 ′ may be heated such that a temperature of the mixture  84 ′ is heated to about 110° F. or to a range up to about 125° F. or below. 
         [0079]    In example embodiments, the at least one prep tank  60 ′,  62 ′ may be a truck mounted or may be part of a fixed structure. Thus, the at least one prep tank  60 ′,  62 ′ may be stationary or mobile. 
         [0080]    In example embodiments, after the mixture  84 ′ of the animal product and the enzymatic digest medium  12 ′ has been thoroughly mixed in the at least one prep tank  60 ′,  62 ′ and the animal byproducts have been properly liquefied by the enzymatic digest medium  12 ′, the mixture  84 ′ may be sent to a dryer, for example, a drum dryer, a conveyor dryer, a spray dryer, or a fluid bed dryer, which may be used to dry the mixture  84 ′. 
         [0081]    In example embodiments, when only feathers are used as the animal byproducts, the enzymatic digest medium  12 ′ may only contain keritinase and the enzymatic digest medium  12 ′ may be controlled to have a pH of between about 6 and about 8, for example, about 7. In addition, when only feathers are used as the animal byproducts, the mixture  84 ′ may be thoroughly digested provided it is mixed for a time, for example, greater than about twenty minutes up to about 1½ hours, at a temperature of about 100 F to a temperature at or below about 125 F. Applicants have found that a mixture of one part blood and preservative to about two parts feathers is acceptable for producing a mixture  84 ′ which is thoroughly digested within about an hour. In this particular embodiment, because feathers contain relatively little fat, the mixture  84 ′ may be dried in the dryer without a need to remove fat therefrom. 
         [0082]    In example embodiments, the mixture  84 ′ may be stored for a relatively long time. For example, the mixture  84 ′ may be stored for several months. In addition, because the mixture  84 ′ is substantially liquid, the mixture  84 ′ may be pumped from the at least one prep tank  60 ′ and  62 ′ to a holding tank. The holding tank may be a stationary structure. In the alternative, the holding tank may be movable by a truck. Thus, the mixture  84 ′ may be moved from one location to another location. Because the mixture  84 ′ may be moved, a location of a dryer may vary. For example, the dryer may be at a slaughterhouse. In the alternative, the dryer may be located at a site which is remote from the slaughterhouse. In example embodiments, the dryer may be located between slaughterhouses. For example, if a certain region includes two slaughterhouses separated by fifty miles, the dryer may be located between to the two slaughterhouses, for example, twenty five miles from each slaughterhouse. 
         [0083]    In example embodiments, when only feathers and offal are used as the animal byproducts, the enzymatic digest medium  12 ′ may contain keritinase, protease, lipase or some combination thereof and may be mixed to have a pH of about 7. In addition, when only feathers and offal are used as the digested protein, the mixture  84 ′ may be thoroughly digested in about fifteen minutes to about one hour provided it is mixed at a temperature of about 110 F to about 120 F and not above about 125 F. Applicants have found that a mixture of one part blood and preservative to about two parts feathers and offal is acceptable for producing the mixture  84 ′ which may be digested within about an hour. In this particular embodiment, because feathers and offal contain relatively little fat, the substantially liquefied mixture  84 ′ may be dried in the dryer without a need to remove fat therefrom, however, the fat may optionally be separated prior to drying the remaining substantially liquefied mixture. 
         [0084]    Example embodiments are not limited to treating only feather and offal. For example, the apparatus of example embodiments may also be usable for digesting other animal byproducts such as heads, feet, necks, and backs of birds along with blood and offal or without offal. As in the earlier explained embodiments, at least one of the feet, necks, and backs may be fed into the grinding means  66 ′ and then mixed with the enzymatic digest medium  12 ′ in the at least one prep tank  60 ′ and  62 ′. For example, the ground heads, feet, neck, and backs may be mixed with the enzymatic digest medium  12 ′ for greater than about twenty minutes (for example, about one hour) at a temperature between 100 F and 120 F and a pH of between about 6 and about 8, for example, about 7. In example embodiments, the enzymatic digest medium  12 ′ may include at least one of lipase, protease, and amylase to digest at least one of the ground heads, feet, neck and backs. 
         [0085]    Thus, example embodiments has been described in an illustrative manner. It is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. 
         [0086]    Many modifications and variations of example embodiments are possible in light of the above teachings. For example, it may be possible for all parts of the system to be made in mobile form or for none of the system to be mobile. Many different pumps are available and may be used according to need. The enzymatic digest medium can be altered to accommodate different protein/bone/feather combinations. Therefore, within the scope of the appended claims, the inventor so defines his invention.