Abstract:
A bio-reactor made according to this invention uses low temperature aerobic composting to decompose bio-compostable material. The reactor includes mixing paddles with wiper blades which aerate and agitate a set of plastic resin biochips which house microorganisms and cause the chips to come into contact with bio-compostable material. A water pipe located toward the upper portion of the bio-reactor delivers fresh or recycled water (or some mix of the two) and the bio-reactor cycles between a water cycle and a non-water cycle. Agitation also cycles on and off. Perforated bottom screens limit the size of the composted material exiting the bio-reactor. The wiper blades, which may be brushes, continually wipe the bottom screens and work to prevent blockage and build-up of debris within the bio-reactor.

Description:
CROSS REFERENCE TO PENDING APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/470,320, filed Mar. 31, 2011. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Disposing of food waste and other bio-compostable materials typically occurs by collecting the waste at or near its point of generation and then hauling the waste to a landfill. Food waste that sits in an anaerobic state in a landfill produces methane gas. According to the Environmental Protection Agency, methane gas is significantly more harmful to the environment than CO 2 . Also, landfill methods include oil- and gas-burning vehicles to haul and move the waste. 
         [0003]    An alternate method is traditional composting. However, traditional composting tends to involve a rather lengthy process and, if the compost pile is not properly maintained, a foul odor may result. Additionally, composting is not available year-round in geographic locations which have below freezing temperatures. Further, traditional composting cannot be used on-site at certain locations, such as commercial food kitchens, restaurants and cruise ships, all of which generate large quantities of food waste. 
         [0004]    An alternative to traditional composting is composting by means of a bio-reactor. Bio-reactors made by companies such as Bio-Ez/Waste-to-Water, Bio Hi-tech, and Green Key, are examples. The bio-reactor typically includes a tank into which food waste is introduced, agitated intermittently by means of paddles, and sprayed intermittently with fresh water. However, this type of bio-reactor uses a large amount of water. Keeping the micro-organisms alive in the tank of the bio-reactor is problematic, as is replenishing the organisms. Also, the entire composting process is extremely sensitive to having the right timing sequences among the water, agitation and rest cycles. Last, preventing unwanted discharge, while at the same time ensuring proper operation of the reactor, is difficult. 
       SUMMARY OF THE INVENTION 
       [0005]    Food waste and other bio-compostable material is introduced to a bio-reactor that has a high concentration of natural- and biologically produced organisms that assist the process in breaking organic material down. Along with these micro-organisms the bio-reactor introduces tap or fresh water at regular intervals and a motor turns several paddles inside the tank of the bio-reactor to create an aerobic environment for biodegradation to occur. Once the bio-compostable material is small enough to pass through a screen located in the base of the bio-reactor, the material is washed out as a manageable liquid effluent that can be reused or can be put into sewer line. 
         [0006]    Any large food processing facility where there is an abundant quantity of organic food waste may make use of this invention. Examples are schools, hospitals, military facilities, corporate cafeterias, food processors or commissaries, supermarkets and farmers markets. On average 20-40% of their waste can be diverted from typical waste-disposal means and into a bio-reactor made according to this invention. The composting process continues 24 hours a day, 7 days a week with very limited interaction with the user other than introducing additional food waste and bio-compostable materials. 
         [0007]    Objects of this invention are to provide a bio-reactor composting method and bio-reactor that (1) is more efficient, effective and reliable than current composting methods; (2) produces less odor than current bio-reactors, is quieter, and leaves no leftover sludge; (3) uses less water than current bio-reactors and produces no harmful liquids or gases; (4) is sleeker in design, requiring a smaller footprint and making controls and service connections more accessible; (5) provides a healthier sewer system without dangerous pathogens; (6) is an efficient, reliable, healthful waste management system; and (7) eliminates food-related cartage costs, minimizes excess waste management products, and eliminates risk of fines due to garbage overload 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a partial cross-section isometric view of the interior drum of a food composting bio-reactor especially well-suited for practicing the composting method disclosed herein. The housing, which is preferably made of aluminum, contains a drum for receiving food waste to be composted. Within the drum is a plurality of black plastic media chips (“biochips”) that come into contact with the food waste and provide surface area for growing microorganisms useful in decomposing the food waste added to the interior of the housing. A water pipe, located in an upper portion of the drum, has nozzles that intermittently provide a misting of cold water. The cold water is preferably fresh water but could be re-circulated water or a combination of fresh and re-circulated water. A plurality of paddles driven by a motor agitates and aerates the food waste, biochips. microorganisms and water during the agitation cycle. The agitation cycle preferably is a continuous one, meaning the food waste is continuously agitated from the moment it is introduced into the drum until the moment it exits the drum as decomposed food waste. The decomposed food waste exits the housing by way of an outlet water stream. Bottom screens prevent the biochips and larger food waste particles from entering the outlet water stream. 
           [0009]      FIG. 2  is an isometric view of the mixing paddle included in the food composting bio-reactor of  FIG. 1 . The paddles, which are preferably a one-piece construction with a v-shaped or angled front paddle end having an attached wiper blade, are secured to a rotating shaft, which is preferably made of stainless steel. The paddles are offset about 90° from one another. The paddles continue to turn throughout the composting method in order to keep the food waste in motion and the bottom screens clean, thereby preventing an overflow condition from occurring. 
           [0010]      FIG. 3  is another view of the composting paddle, illustrating the connection of the wiper blades to the paddle. 
           [0011]      FIG. 4  is view of the lower portion of the drum of the compositing bio-reactor of  FIG. 1 , illustrating the water pipes which are located beneath the bottom screens. One pipe with nozzles for flushing the bottom screen is located toward the front side of the bio-reactor and a second pipe with nozzles for flushing the screen is located toward the back side. A third pipe with nozzles for flushing the bottom pan is oriented transverse to the first two pipes and is located on the side of the bio-reactor opposite the discharge outlet side. The first and second pipes direct hot water upward toward the screens. The third pipe directs hot water toward the discharge outlet side. This third pipe may operate under a different timed cycle than the first two pipes. 
           [0012]      FIG. 5  is a view of the inside of the drum of the bio-reactor of  FIG. 1 , illustrating the overflow sensor. An overflow sensor is located on each side of the housing. 
           [0013]      FIG. 6  is a view of the bio-reactor of  FIG. 1 , illustrating the chain-and-gear arrangement used to drive the paddles. The upper gear is connected to the keyed shaft that drives the paddles 
           [0014]      FIG. 7  is a view of an alternate embodiment of the chain drive tensioner of the bio-reactor of  FIG. 6 . 
           [0015]      FIG. 8  is a partial cross-section isometric view of an alternate embodiment of the interior drum of a food composting bio-reactor especially well-suited for the composting method disclosed herein. Unlike the bio-reactor of  FIG. 1 , the bio-reactor of  FIG. 8  does not include pipes for flushing the bottom screen, nor does it include a valve on the discharge water outlet to aid in the inoculation process 
           [0016]      FIGS. 9A , B, C &amp; D are front and side elevation views the housing of different sized bio-reactors of  FIGS. 1 and 8 . 
         ELEMENTS USED IN THE DRAWINGS AND DETAILED DESCRIPTION 
         [0000]    
         
           
             
                 10  Bioreactor 
                 20  Housing 
                 21  Upper portion of  20   
                 23  Lower portion of  20   
                 25  Side of  20   
                 27  Rear or back of  20   
                 28  Access door 
                 29  Water inlet 
                 31  Hot water inlet 
                 33  Water outlet 
                 35  Power inputs 
                 39  Trap or valve 
                 40  Drum 
                 41  Water pipe 
                 43  End of  41   
                 45  Spray nozzle 
                 47  Paddle shaft 
                 49  Key 
                 50  Bottom screen 
                 51  Perforations 
                 53  Screen cleaner pipe 
                 55  Nozzles 
                 60  Base pan 
                 61  Pan flush pipe 
                 63  Nozzles 
                 70  Mixing paddle 
                 71  Paddle portion 
                 73  Paddle end 
                 74  Face surface 
                 75  Wiper blade 
                 77  Connecting rod portion 
                 79  Keyway 
                 85  Level sensors 
                 90  AC Motor 
                 91  Chain-drive and gear reducer 
                 93  Chain tensioner 
                 100  Biochips 
             
           
         
       
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0054]    Referring to  FIGS. 1-9 , a method for composting food waste includes the steps of adding a food waste to a bio-reactor  10  and cycling the food waste between a water cycle, an agitation cycle, and a rest cycle. A bio-reactor  10  made according to this invention and practicing the method disclosed herein can be sized to process between 400 to 2,400 pounds of garbage every day and turn it into water. Further, the bio-reactor  10  can be located near or at the point where the waste is generated. Additionally, the bio-reactor  10  can dispose of bio-compostable materials, including but not limited to plates, cups, cutlery and straws in the same manner. 
         [0055]    The bio-reactor  10  uses low temperature aerobic composting to control odor and contains a plurality of black plastic media chips (“biochips”)  100  that provide high surface area for harboring and growing micro-organisms useful in decomposing the food waste added to the drum  40  located in the interior of the housing  20  of the bio-reactor  10 . The biochip  100  is a plastic resin-based material about the size of a small pellet. Each biochip  100  is slightly porous on its opposing ends. Preferably, the drum  40  of the bio-reactor  10  is filled with the quantity of biochips  100  necessary to bring the total level of biochips  100  to about 2 inches below the shaft  47  which drives the mixing paddles  70 . 
         [0056]    The microorganisms can be introduced automatically via a simple pump (not shown). To achieve the initial inoculation, a pneumatic trap or valve  39  located toward the lower portion  23  of the bio-reactor  10  remains closed to fill with the drum  40  with an appropriate amount of water. Milk and sugar are added to the micro-organism, biochips  100 , and water mixture, and the mixture is continuously agitated for about 8 to 10 hours prior to introducing any food waste into the drum  40 . In another embodiment of bio-reactor  10 , the valve  39  is not used and inoculation occurs through a liquid bacteria sprayed from above. The micro-organisms decompose the food waste into a liquid effluent and trace amounts of CO 2 . The effluent is then discharged through a water outlet  33 . Depending on facility location and desired level of filtration, the possibilities for the effluent can range from irrigation, compost tea, non-potable plumbing, and potable water. The amount of effluent produced is approximately the weight in water of the food waste introduced to the bio-reactor  10 . 
         [0057]    The water cycle preferably includes a fresh water source. The amount of fresh water deployed during the water cycle may vary and the amount of time during which fresh water is deployed is based upon such factors as food-type, processing time, input frequency and total waste. Some preferred water cycles, arranged in order from a heavy duty cycle to a light duty cycle, are (1) on 30 seconds, off 10 minutes; (2) on 25 seconds, off 10 minutes; (3) on 20 seconds, off 10 minutes; and (4) on 15 seconds, off 10 minutes. The water is delivered by a water pipe  41  located toward the upper portion  23  of the housing  20 . In a preferred embodiment, the pipe  41  has a spray nozzle  45  located at each end  43 . Depending on the size of the bio-reactor  10 , there can be more than two spray nozzles  45  or only one spray nozzle  45 . The water cycle may be controlled by a selector switch on a control panel (not shown) of the bio-reactor  10 . 
         [0058]    The agitation cycle is provided by a plurality of spaced-apart and offset mixing composting paddles  70 . The mixing paddles  70  are preferably of one-piece construction with the paddle portion  71  being integral to the connecting rod portion  77 . The connecting rod portion  77  preferably includes a keyway  79  that receives a complementary shaped key  49  located on the paddle shaft  47 . An AC motor  90  is used to rotate the paddle shaft  47 , through a chain-driven and gear-reduced arrangement  91 , thereby causing the mixing paddles  70  to turn. Standard 110V power is used (compared to prior art composters which required 220V power). A chain tensioner  93 A or B ensures that the paddle shaft  47  continues to rotate at the proper speed. The speed and amount of agitation is determined based upon such factors as food-type, processing time, input frequency and total waste. Preferably, the paddles  70  run continuously and at the same speed throughout the agitation cycle and may push or pull their way through the compostable material. The access door  28  to the drum  40  may be equipped with duel inductive-type proximity sensors (not shown) to ensure the door  28  is closed prior to the bio-reactor  10  cycling. 
         [0059]    The bio-reactor  10  includes means for preventing the plurality of biochips from entering the outlet water stream. In a preferred embodiment, perforated bottom screens  50  located in the lower portion  21  of the housing  20  and above the base pan  60  of the bio-reactor  10  are used for this purpose. (The base pan  60  is sloped toward the water outlet  33 .) The size of the perforations  51  in the screens  50  is very important. If the perforations  51  are too large, then the effluent contains partially decomposed food waste. If the perforations  51  are too small, then decomposed food waste cannot exit the bio-reactor  10 , new waste cannot be introduced, and the decomposition process stops. Therefore, the bio-reactor  10  also includes means for limiting the particle size distribution of the decomposed food waste entering the outlet water stream. The perforated bottom screens  50  may be used for this purpose. The bottom screens  50  limit the maximum particle size exiting the bio-reactor  10  to about 0.040″ in diameter. 
         [0060]    To prevent the perforations  51  in the bottom screens  50  from becoming blocked by debris, the paddle portion  71  of each mixing paddle  70  includes a wiper blade (or sweeper)  75  at its paddle end  73 . The wiper blade  75  may be constructed of polyurethane or its equivalent. Wiper blade  75  may also be constructed of a brush material. The paddle portion  71  is preferably constructed so that its paddle end  73  includes a pair of blades  75  oriented at about a 90° angle to one another, or each blade  75  may be a single piece blade that extends across the normally arranged face surfaces  74  of the paddle end  73  (or across a single, straight face surface  74 ). The face surface  74  is preferably arranged so that blade  75  is oriented oblique to the direction of travel of the mixing paddle  70 . The paddle portion  71  may also be arranged or rotated so that the wiper blade  75  pulls through the compostable material rather than pushes through it. 
         [0061]    As each mixing paddle  70  rotates, the paddle  70  aerates the compostable material within the drum and the wiper blade  75  passes over the bottom screen  50  and prevents debris from settling for too long a period of time on the screen  50 . Preferably, one wiper blade  75  does not overlap the adjacent wiper blade  75 . A spacing of about 1 inch between adjacent wiper blades  75  has proved adequate. Additionally, pipes  53  having a plurality of nozzles  55  may be located below the bottom screens to direct hot water under pressure toward the bottom screens  50 . These “screen cleaner” pipes  53  preferably deliver water for 30 seconds and then remain off for 30 minutes. Another pipe  61  located below the bottom screens  50  and opposite the water outlet  33  directs water under pressure toward the discharge water outlet  33 . This “pan flush” pipe  61  has a plurality of nozzles  63  and preferably delivers water for 20 seconds and then remains off for 1 hour. (Other screen cleaning and base flush cycles may be used, and the screen cleaner pipes  53  may be eliminated altogether.) The wiper blades  75  in conjunction with the nozzles  55 ,  63  (or nozzles  63  alone) prevent debris build-up from occurring on the screens and within drum  40 . 
         [0062]    The control panel (not shown) ma y be fitted with a sensor warning light and dual capacitive liquid level sensors  85  to prevent an overflow condition within the housing  20 . The level sensors  85  are located just inside the bio-reactor near the upper portion  23  on the left and right hand sides  25  of the bio-reactor. In the event one or both of these sensors  85  sense an overflow condition for a predetermined amount of time (e.g., 6 seconds), the warning light flashes. If only one sensor  85  indicates the overflow condition, the bio-reactor  10  operates in a normal cycle. However, if both sensors  85  indicate the overflow condition, the bio-reactor  10  will go into safe mode. No fresh water will be added and the motor  90  will go into constant run mode. After a predetermined amount of time passes in safe mode (e.g. 1 hour), the bio-reactor  10  will recheck the sensors  85 . 
         [0063]    The bio-reactor  10  preferably locates the water inlets  29 ,  31  and power inputs  35  on a side  25  of the housing  20  so that the back  27  of bio-reactor  10  can go flush up against a wall, thereby saving space. The hot water inlet  31  may be located flush with the base pan  60  of the bio-reactor  10 . 
         [0064]    The preferred embodiments described above are illustrations which provide enabling examples of a bio-reactor made and practiced according to this invention. The invention itself is defined by the following claims, which cover designs which are equivalent to those illustrated here.