Abstract:
A woodchip based bio-filtration system for odor and particulate matter removal from exhaust fan emissions from confined animal feeding operation buildings where visual inspection of the initial point of contact between the airflow from the building and the organic media can be made, and where the initial point of contact is directly sprayed with nozzles and/or stirred or agitated manually or mechanically to disperse matter (feathers, dust, fecal matter, etc.) which might tend to restrict airflow through the media.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The current direction of public sentiment is to improve air quality in the communities that they reside. With population growth and a higher density of people throughout the country, a growing number of air quality complaints have occurred. The agricultural sector probably receives the highest number of these complaints due to current production practices. Confined Animal Feeding Operations (CAFO&#39;s), where a large number of animals are housed in a small area, create a significant amount of animal feces and waste. Commonly, this waste is stored in a pit directly below the animals. To have proper air quality within the production facility for the animals, exhaust fans must pull fresh air from the outside into the building while exhausting internal odorous air. These exhaust emissions contain ammonia, hydrogen sulfide, particulate matter or dust and many other unwanted pollutants. The Environmental Protection Agency (EPA) has recently conducted a study to determine the amounts of these pollutants that are created by different species, such as poultry, dairy, swine, beef and turkey. Allowable emission levels will be determined in the very near future. 
         [0002]    To provide a remedy for odor issues, many air quality technologies have evolved. Probably the most researched has been biofiltration. Take a layer of organic media and pass air through it and you have a process called biofiltration. Activate this layer with a liquid such as water and you create an active microbial community. The bacteria within this community can then digest the particulate matter and reduce the concentration of unwanted gases. 
         [0003]    Commonly, biofiltration systems are implemented by placing wood pallets on the ground and covering them with a porous material such as snow fencing or netting creating a support floor. The media, usually wood chips, is placed over this support floor. The exhaust emissions from the production facility are enclosed by a duct that diverts the air flow into the area below the support floor and then up through the media. The University of Minnesota, South Dakota State University, Iowa State University, Purdue University to name a few have formulated design specifications for sizing these systems. 
         [0004]    However, these systems often have two major reoccurring problems. The first is a buildup of particulate matter in the media that causes clogging. The second is the media becoming anaerobic in certain areas from too much moisture. 
         [0005]    In addressing the first problem, feathers, dust and airborne fecal matter often first come in contact with the filtering media at the porous netting. This netting may be beneath one to two feet of media. As these airborne pollutants enter the filtering media, they tend to overwhelm the bacteria at the initial point of contact (IPC) and cause coating or clogging of the media that restricts airflow that can endanger the animals housed within the CAFO. To fix such problems the media must be mixed to clean the IPC. The cleaning is achieved by removing the media and mixing the buildup of particulate matter with the rest of the media and then placing it back upon the support floor. This process is very labor intensive and time consuming. 
         [0006]    The second problem with biofiltration is the maintenance of moisture levels within the media. It is generally accepted that the media moisture level should be between thirty and sixty percent to maximize the efficiency of the system. Current systems designed by the previously mentioned universities use soaker hoses or lawn sprinklers to apply water to the biofilter. Excessive rainfall or high winds can unevenly distribute water causing pockets of media to become too wet. If this occurs the media may become anaerobic and actually produce odors. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an advantage of the invention to contain biofiltration media in different ways to allow human access to the initial point of contact (IPC) between the airflow and the media. 
         [0008]    It is an advantage of the invention to have an access door to allow human access to the IPC, to simplify maintenance and cleaning and allow visual inspection of the media. 
         [0009]    It is an advantage of the invention to have spray nozzles installed in such a way that a liquid such as water can be evenly sprayed onto the media. 
         [0010]    It is an advantage of the invention to have spray nozzles that apply a liquid such as water to the IPC. 
         [0011]    It is an advantage of the invention to have human access to the IPC to manually or mechanically scrap, rake, brush or mix the IPC. 
         [0012]    It is a feature of this invention to have a pressure sensor to measure ventilation efficiency. 
         [0013]    It is another feature of this invention to have the pressure sensor connected to a warning light or other trigger mechanism. 
         [0014]    It is yet another advantage of this invention to have a mechanical rake which is activated by the pressure sensor to automatically stir the media. 
         [0015]    It is an advantage of this invention to be modular in design to allow for multiple installations. 
         [0016]    It is an advantage that the IPC is covered with a transparent material to allow sunlight in. 
         [0017]    It is an advantage that the IPC is covered to control rainfall and wind and better maintain the system. 
         [0018]    It is an advantage of this invention to be significantly smaller than conventional biofiltration systems. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]      FIG. 1  is a side view of an egg production facility that houses laying hens with the invention/applicator attached. 
           [0020]      FIG. 2  is an end view of an elevated roof concept that attaches to an industrial production facility. 
           [0021]      FIG. 3  is an end view of the bottom exhausting system of the present invention in an elevated horizontal setting. 
           [0022]      FIG. 4  is a side view of the system of  FIG. 3  applicator with the elevated horizontal setting. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In  FIG. 1  an egg production facility  112 , is featured to house chickens that produce feces and said feces is contained within the production facility. Exhaust fans  101 , take air from inside the production facility  112 , and release the air outside the production facility  112 . These fans may range from 3000 cubic feet per minute (CFM) to 25,000 CFM, however other suitable fans could be used where appropriate to the particular application. 
         [0024]    For this applicator setting, one end of the porous media containment tray  100  is placed on the ground. The dimensions of this tray are approximately 6 foot by 9 foot by 5 inches thick and accommodate CFM ranges from 3000 CFM to 10,000 CFM. A larger dimension porous media containment tray  100 , would be required for a CFM capacity above 10,000 CFM&#39;s. The other end of the porous media containment tray  100 , is set in such a way as to enclose the exhaust fan  101 . In some installations, the production facility&#39;s external wall may be utilized as a part of the enclosing structure. In other installations where the fan is set away from the production facility&#39;s external wall, a back panel or wall must be fabricated. The porous media containment tray  100 , uses gravity to contain the media eliminating the need for two-sided walls (other than the thickness of the containment tray  100 ). The angle of the porous media containment tray  100 , is placed in such a way as to not exceed 35 degrees and is supported by the adjustable legs  104  or suitable stationary supports. The porous media containment tray  100 , is made of stainless steel or other durable material. The bottom of the porous media containment tray  100 , has polyvinylchloride coated chicken wire or other suitable durable mesh material attached to it to allow air through the media but not allow the media to fall through it. The holes in the chicken wire are approximately ¾ inch squares. The enclosure walls  105 , around the porous media containment tray  100 , are made of ½ inch 2 sided MDO board or other suitable durable material. For exhaust fans that are set out from the production facility&#39;s external walls, an enclosing back panel will be required. An access door  106 , is cut into the enclosure walls  105 , to allow a human to at least partially enter and visually inspect the IPC. The exhaust fan&#39;s emissions  101 , are channeled underneath the porous media containment tray  100 , and then allowed to pass through the layer of organic media from the bottom/up. Spray nozzles  113 , are placed above and below the porous media containment tray  100 . The spray nozzles  113 , are attached to the porous media containment tray  100 , by use of a bracket and bolt. The spray nozzles  113 , are interconnected and placed in a way to cover the entire media bed equally. The spray nozzles  113 , can be 1 gallon per minute full cone nozzles or other suitable volume and pattern nozzles. The entire spraying system is then attached to a water source and hydration system controller  107 . A humidity sensor may be incorporated as part of or co-located with the water source and hydration system controller  107  and used in automating the hydration system. 
         [0025]    The pressure sensor  109 , is placed inside the enclosure walls  105 , and connected to a triggering device and system operation and maintenance control module  102 . The air pressure tolerance level is determined and programmed into the pressure sensor  109 . As dust builds up at the IPC the ventilation compromise can be monitored. 
         [0026]    In another applicator setting,  FIG. 2 , two porous media containment trays  100 , are placed back-to-back. The exhaust fan&#39;s emissions  101 , are contained by the enclosure walls  105 , and channeled through the media. The angle of the porous media containment trays  100 , are placed in such a way as to not exceed 35 degrees and are supported by the adjustable legs  104  or suitable stationary support structures. An access door  106 , is cut into the enclosure walls  105 , to allow a human to enter and inspect the IPC. Spray nozzles  113 , are placed above and below the porous media containment tray  100 . The spray nozzles  113 , are attached to the porous media containment tray  100 , by use of a bracket and bolt. The spray nozzles  113 , are interconnected and placed in a way to cover the entire media bed equally. The spray nozzles  113 , can be 1 gallon per minute full cone nozzles or other suitable volume and pattern nozzles. The entire spraying system is then attached to a water source and hydration system controller  107 , and may include therein and be automated with the use of humidity sensors, microprocessors, electronic valves, etc., and other means for controlling hydration. 
         [0027]    The pressure sensor  109 , is placed inside the enclosure walls  105 , and connected to a triggering device and system operation and maintenance control module  102 . The air pressure tolerance level is determined and programmed into the pressure sensor  109 . As dust builds up at the IPC, the ventilation compromise can be monitored. If ventilation threshold tolerance is exceeded, a cleaning of the IPC is achieved by manually scraping or brushing the IPC or by manually or mechanically spraying the IPC of the porous media containment tray  100 , thus relieving the ventilation compromise. 
         [0028]    In  FIG. 3 , the production facility  110 , may house swine. The exhaust fan  101 , takes air from inside the production facility  110 , and releases the air outside the production facility  110  into the filtering system. The air flow is directed by the transparent enclosing structure  108 , which is made of polycarbonate or other suitable transparent material. The transparent enclosing structure  108 , is supported by support beams  111 , and attached to the porous media containment tray  100 , by using a siding bracket  116 . The exhaust air is directed downward through the porous media containment tray  100 . The exhaust fans  101 , may range from 3000 cubic feet per minute (CFM) to 10,000 CFM. The porous media containment tray  100 , is elevated above the ground and placed horizontally with the ground and supported by the adjustable legs  104 . Adjustable legs  104 , allow for more flexibility in enclosing the exhaust fan. However, suitable stationary support structures may be used. The size of the applicator varies upon the volume of emissions that are passed through it and the air quality levels desired. In this application the fan CFM is 6000 and the porous media containment tray  100 , is 6 foot by 12 foot by 5 inches thick. The porous media containment tray  100  is made of stainless steel or other durable material. The bottom of the porous media containment tray  100 , has polyvinylchloride coated chicken wire or other suitable durable mesh material attached to it to allow air through the media but not allow the media to fall through it. The holes in the chicken wire are approximately ¾ inch squares. 
         [0029]    Spray nozzles  113 , are placed only above the porous media containment tray  100 . This applicator setting creates the IPC to be on the top of the media eliminating the need for spray nozzles  113 , to be placed below the porous media containment tray  100 . The spray nozzles  113 , are attached to the support beams  111 , by use of a bracket and bolt. The spray nozzles  113 , are interconnected and placed in a way to cover the entire media bed equally. The spray nozzles  113 , can be 1 gallon per minute full cone nozzles or other suitable volume and pattern nozzles. The entire spraying system is then attached to a water source and hydration system controller  107 . 
         [0030]    An access door  106 , is placed at the end of the applicator to allow access to the IPC. The pressure sensor  109 , is placed inside the translucent and/or transparent enclosing structure  108 , and connected to a triggering device and system operation and maintenance control module  102 . This sensor can be preset to identify predetermined ventilation thresholds. If, for instance, a reduction in ventilation capacity of thirty percent is the triggering point, a stirring rake  114 , can move across the top of the media to mechanically mix and blend the media reducing the ventilation compromise. This stirring rake  114 , may spin, turn, roll, vibrate or move slowly across the media. Tracks  115 , for guiding the stirring rake  114 , are added to the sides of the containment tray. The media may also be manually stirred or mixed with the use of a garden rake or similar device. 
         [0031]      FIG. 4  is a side view of the horizontal applicator setting. The production facility  117 , may house turkeys. The exhaust fan  101 , takes air from inside the production facility  117 , and releases the air outside the production facility  117 , into the filtering system. The air flow is directed by the transparent enclosing structure  108 , which is made of polycarbonate or other suitable transparent material. The transparent enclosing structure  108 , is attached to the porous media containment tray  100 , by using a siding bracket  116 . The exhaust air is directed downward through the porous media containment tray  100 . An access door  106 , is placed at the end of the applicator to allow access to the IPC. The pressure sensor  109 , is placed inside the transparent enclosing structure  108 , and connected to a triggering device and system operation and maintenance control module  102 . This sensor can be preset to identify predetermined ventilation thresholds. A stirring rake  114 , can move across the top of the media to mechanically mix and blend the media reducing the ventilation compromise. This stirring rake  114 , may spin, turn, roll, vibrate or move slowly across the media. Tracks  115 , for guiding the stirring rake  114 , are added to the sides of the containment tray. The media may also be manually stirred or mixed with the use of a garden rake or similar device. 
         [0032]    Spray nozzles  113 , are placed only above the porous media containment tray  100 . This applicator setting creates the IPC to be on the top of the media eliminating the need for spray nozzles  113 , to be placed below the porous media containment tray  100 . The spray nozzles  113 , are attached to the support beams  111 , by use of a bracket and bolt. The spray nozzles  113 , are interconnected and placed in a way to cover the entire media bed equally. The spray nozzles  113 , can be 1 gallon per minute full cone nozzles or other suitable volume and pattern nozzles. The entire spraying system is then attached to a water source and hydration system controller  107 . In every applicator setting, the operator of the system has physical access to the IPC where maintenance and inspection can easily occur. 
         [0033]    Note that various electrical signal wires between the various components which could receive or provide information to and from the triggering device and system operation and maintenance control module  102 , and a water source and hydration system controller  107 , have been omitted for clarity. Such wires should be easily understood to exist where helpful. Also wireless communication and battery powered control components are not shown, but are intended to be included in any of the means for controlling hydration and/or means for controlling ventilation through the IPC. 
       DEFINED TERMS 
       [0034]    The term meant for electronically controlling physical characteristics of the initial point of contact shall specifically include any of the hydration system controller, any electrically controlled valves, humidity sensors; system operation and maintenance control module, air pressure sensor electrically controlled stirring rake or any other device or system configured to change physical characteristics of said initial point of contact; however such term shall specifically exclude any electronic or other control of an exhaust fan.