Abstract:
An effective ethanol emission treatment system usable at buildings such as spirit aging warehouses which biologically removes ethanol prior to air escaping to the atmosphere is disclosed. The system can be used either with or without imparting negative pressure on the building to draw the ethanol vapors into the treatment system. The system provides efficient removal of ethanol from large volumes of air having relatively low ethanol concentrations.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/292,011 filed Feb. 5, 2016, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to treatment of ethanol emissions, and more particularly relates to apparatus and methods for treating and reducing ethanol emissions from distilled spirits aging and storage facilities. 
       BACKGROUND INFORMATION 
       [0003]    The process of creating desirable tastes of many distilled spirits includes aging in wooden barrels. Such aging processes generate significant amounts of ethanol due to evaporation through the wooden barrels. This loss of ethanol is known in the industry as the “angels&#39; share”. These ethanol emissions can be very significant depending on the size of the warehouse, and they cannot easily be controlled since the aging warehouses are typically not climate controlled and are generally open to the outside atmosphere. Ethanol is a volatile organic compound (VOC), and emissions thereof can lead to photochemical production of ground-level ozone, one of the Criteria Pollutants monitored and controlled by the United States Environmental Protection Agency. 
         [0004]    In many cases, angels&#39; share ethanol loss is the suspected cause of impacts to surrounding properties associated with the growth of a black fungus such as  Baudoinia compniacensis,  which is sometimes referred to as “whiskey fungus”.  Baudoinia  species use ethanol, among other sources, for carbon nutrition and can withstand high temperatures. Ethanol in the vapor phase is also shown to accelerate the growth of the fungus and stimulate the germination of spores. 
         [0005]    Cosmetic and other aesthetic impacts caused by  Baudoinia  have caused regulators to consider ethanol emission controls for spirit aging warehouses, even though these emissions have heretofore been considered fugitive emissions. A regenerative thermal oxidizer (RTO) has been developed in an attempt to control ethanol emissions. Although RTO technology may provide an effective method of controlling high concentration VOC emissions, the technology requires heating of air flowing through a control device and works best when high concentrations of VOCs are present. Large amounts of supplemental heat are required if the concentrations of VOCs are not high enough, especially when large volumes of air need to be treated. Because of the method of aging in the barrels and the design of the existing warehouses, it is impractical to design a method of collecting high concentration VOC vapors to feed an RTO. Therefore, any application of RTO technology to existing warehouses would likely be very expensive in terms of both capital and operating costs. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides an effective treatment system usable at buildings such as spirit aging warehouses to duct vapors through an apparatus for biological removal of ethanol prior to air escaping to the atmosphere. The system can be used either with or without imparting negative pressure on the building to draw the ethanol vapors. The system provides efficient removal of ethanol from large volumes of air having relatively low ethanol concentrations. Ethanol vapors may be removed with a low energy demand. 
         [0007]    An aspect of the present invention is to provide an ethanol emission treatment system for reducing levels of ethanol generated from a building, the system comprising an enclosure comprising at least one inlet opening structured and arranged to provide flow communication with an interior of a building and at least one outlet opening, and multiple air-permeable microbial support media trays in the enclosure, wherein the multiple support media trays are structured and arranged in the enclosure to hold the microbial support media while allowing airflow through the support media trays from the inlet opening to the outlet opening of the enclosure. 
         [0008]    Another aspect of the present invention is to provide a method of reducing ethanol emissions from a building, the method comprising drawing ethanol-containing air from a building into a treatment system comprising an enclosure and at least one support media tray containing microbial support media; passing the ethanol-containing air through the at least one support media tray to contact at least a portion of the ethanol with microorganisms in the microbial support media to thereby allow the microorganisms to oxidize the ethanol; and exhausting air from the enclosure containing a lower level of ethanol than an ethanol level of the ethanol-containing air drawn into the enclosure. 
         [0009]    A further aspect of the present invention is to provide microbial support media inoculated with ethanol-oxidizing microorganisms for use in ethanol emission treatment systems and methods as described above. 
         [0010]    These and other aspects of the present invention will be more apparent from the following description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a partially schematic side view of an ethanol effluent treatment system installed adjacent to a building in accordance with an embodiment of the present invention. 
           [0012]      FIG. 2  is a partially schematic isometric view of an ethanol effluent treatment system in accordance with an embodiment of the present invention. 
           [0013]      FIG. 3  is a partially schematic top view of an ethanol effluent treatment system installed adjacent to a building in accordance with an embodiment of the present invention. 
           [0014]      FIG. 4  is an isometric view and 
           [0015]      FIG. 5  is a top view of a support media tray for use in a treatment system in accordance with an embodiment of the present invention. 
           [0016]      FIG. 6  is a partially schematic front view of an ethanol effluent treatment system and ductwork in accordance with an embodiment of the present invention. 
           [0017]      FIG. 7  is a partially schematic isometric view of an ethanol effluent treatment system including an inlet duct in accordance with an embodiment of the present invention. 
           [0018]      FIG. 8  is a partially schematic isometric view of an ethanol effluent treatment system including another inlet duct in accordance with an embodiment of the present invention. 
           [0019]      FIG. 9  is a photograph of wood chips that may be used as microbial support media in a treatment system in accordance with an embodiment of the present invention. 
           [0020]      FIG. 10  is a photograph of wood chips that have been inoculated with ethanol-oxidizing microbial populations for use in a treatment system in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]      FIGS. 1-8  illustrate embodiments of ethanol effluent treatment systems  10  in accordance with embodiments of the present invention. As shown in  FIG. 1 , the treatment system  10  may be installed adjacent to a building  5  containing airborne ethanol, such as a distilled spirits warehouse or storage facility. The treatment system  10  is in gas flow communication with the ethanol-generating building  5  via an air duct  8  which transports airborne ethanol from the building  5  to the treatment system  10 . 
         [0022]    As shown most clearly in  FIGS. 1 and 2 , the treatment system  10  includes an enclosure  12 , base  14  and top panel  16 . An inlet opening  18  is provided in a lower portion of the enclosure  12  near the base  14  to allow airflow through the duct  8  into the enclosure  12 . An array of stacked trays  20  is provided in the treatment system  10 , including individual support media trays  22 . 
         [0023]    The treatment system  10  of the present invention may be installed in warehouse to duct vapors from existing vents through a specially designed control device using biological removal of ethanol prior to any air escaping to the atmosphere. 
         [0024]    As shown in  FIG. 2 , the treatment system  10  includes a water delivery and spray system  30  comprising four water spray heads  32  connected to a water supply line  34 . As more fully described below, water delivered through the supply line  34  to the spray heads  32  is used to maintain a moist atmosphere inside the enclosure  12 . The spray heads  32  may be provided with a timer (not shown) to maintain a desired moisture level in support media contained on the trays  22 . Timer settings for the water spray can be adjusted based on parameters such as the relative moisture in the air that is venting. 
         [0025]    As further shown in  FIGS. 1, 2 and 6 , the treatment system  10  may optionally include a top vent  42  on each side of the enclosure  12  and/or bottom vents  44  on the front panel of the enclosure  12 . The top and bottom vents  42  and  44  may be dampered for selective opening and closing of the vents during operation of the treatment system. For example, the bottom vents  44  may be standard one-way vents that allow ambient air to be drawn into the enclosure  12 . In certain embodiments, the exhaust fan  46  may run constantly, or the exhaust fan  46  may run intermittently, e.g., to draw a desired volume of ethanol-containing air into the enclosure and hold the air inside for a selected dwell time. In certain embodiments, the top and bottom vents  42  and  44  may be permanently dampered or eliminated. 
         [0026]    As shown in  FIG. 2 , the treatment system  10  includes an exhaust fan  46  on the top panel  16 . The exhaust fan  46  may be used to draw ethanol-containing air through the duct  8  from inside the building  5 . In certain embodiments, the duct  8  may be provided with at least one conventional one-way vent  45  that permits ambient air outside the building  5  to be drawn into the duct and into the enclosure  12  of the treatment system  10 . Such one-way vent(s) prevent air from escaping the duct  8  while allowing ambient air to enter. In certain embodiments, if the exhaust fan  46  is not in use, it can be closed or dampered in order to prevent the escape of air through the top panel  16  of the enclosure  12 . However, as described above, the exhaust fan  46  may constantly run to draw ethanol-containing air from inside the building  5  and/or to draw fresh air from outside the building into the enclosure  12  of the treatment system  10 . 
         [0027]    As shown in  FIG. 3 , each support media tray  22  may be removed from the enclosure  12  by sliding the tray  22  sideways. In the embodiment shown, opposing doors  17  are provided on opposite sides of the enclosure  12  to allow such tray removal. The doors  17  allow support media trays  22  to be changed one level at a time or levels can be moved to assure that active cultures are not lost at time of support media change. 
         [0028]    As shown in  FIGS. 3-5 , each support media tray  22  includes a bottom panel  24  including an air permeable mesh material  26  capable of holding microbial support media  29  while allowing air and vapor flow through the bottom panel  24 . Each tray  22  includes sidewalls  28  which help to contain the microbial support media  29  contained in the tray  22 . Each tray  22  may have a height, width and depth selected to house the support media within the enclosure  12 . The specific dimensions may vary according to the particular application. 
         [0029]    During operation of the treatment system  10 , the arrangement of the support media trays  22  may be varied, e.g., to move lower trays to upper positions within a vertical stack and vice versa in order to change the order in which the air flowing through the enclosure contacts the support media trays  22 . 
         [0030]      FIGS. 3 and 6-8  illustrate air duct configurations in accordance with embodiments of the present invention. In the embodiment shown, a first air duct  8   a  communicates with a first inlet opening  18   a,  while a second air duct  8   b  communicates with a second inlet opening  18   b.  In the embodiment shown, the first air duct  8   a  exits the building  5  at a relatively high elevation, while the second air duct  8   b  exits the building  5  at a relatively low elevation, e.g., in order to match an existing exhaust duct structure of the building  5 . Ducting to the treatment system may be adjusted specific to each facility, specific vent locations and the location where the tray unit can best be located. In order to optimize the capture of ethanol emissions, it is desirable to attach all atmospheric vents of a building  5  to the treatment system  10 . 
         [0031]    Embodiments of the treatment system of the present invention can be used either with or without imparting negative pressure on the building  5  to draw ethanol vapors into the treatment system  10 . The treatment system  10  may be designed such that it can be attached to existing atmospheric vents at any distilled beverage aging warehouse. Such treatment reduces the total ethanol emissions from these warehouses, thereby reducing contribution to ground level ozone and avoiding the potential for contributing to black mold growth. The present treatment system  10  allows significant air to flow, and can be applied with a slight negative pressure, but no negative pressure is necessary to allow treatment of vapors that exhaust through the atmospheric vents. This control of vent gas without drawing negative pressure is advantageous in order to allow the aging process to continue while effectively controlling the ethanol emissions. This balance of flow may be accomplished through the use of the dampered vents in the top end of the tray enclosure. If negative pressure is imparted on the warehouse, ventilation may be improved by installing one-way gravity vents to allow make-up air to enter the warehouse. 
         [0032]      FIGS. 9 and 10  are photographs of microbial support media  29  in the form of wood chips that may be loaded into the support media trays  12  in accordance with embodiments of the present invention. The wood chips  29  shown in  FIG. 9  have been inoculated with active microbial cultures, while the inoculated wood chips  29  shown in  FIG. 10  have been used in a treatment system of the present invention for several days to capture and oxidize ethanol with the microbes present on the wood chips. 
         [0033]    The enclosure  12  of the treatment system  10  may have a height, width and depth selected to house the support media trays  22  and other components of the treatment system  10 . The enclosure  12  includes levels of support media trays  22  that hold support media within the enclosure  12 . In the embodiment shown, there are eight levels of trays  22 , but any other suitable number of levels of trays may be used. For example, there may be one, two, four, six, ten or more levels of trays. It has been found that, with eight levels of trays, removal of ethanol from air venting through the system  10  with active cultures may be in excess of 99% efficient. In the embodiment shown, there are four individual trays  22  on each of the eight levels of trays  22 , but any other suitable number of trays may be used on each level to provide the required air flow rates and desired maximum system pressure drop. For example, one, two, three, five or more trays may be used on each level of trays. 
         [0034]    Each tray  22  may be made of structurally supported stainless steel mesh  26 , capable of holding up to 300 pounds of support media including moisture and active culture. However, it is to be understood that any other suitable material, such as plain steel, galvanized steel, aluminum and the like may be used to make the tray. In certain embodiments, the entire enclosure  12  may hold up to 9,600 pounds or more of support media. In an embodiment of the present invention, the support media may be wood chips between 1 to 3 inches in size. However, it is to be understood that any other suitable size of wood chips may be used. In addition, any other suitable support media may be used. For example, wheat straw, compost, peels, synthetic materials, polymeric spheres, rocks, volcanic rocks or combinations of such materials and the like may be used to provide the support media of the treatment system  10 . 
         [0035]    An active culture is provided on the support media and includes one or a variety of microorganisms. In an embodiment of the invention, in an existing facility, moist wood chips may be populated with a naturally occurring mix of fungi and bacteria that will adequately oxidize ethanol from the treatment air. In an embodiment of the invention, in new facilities or where sufficient colonization has not occurred within a reasonable time, e.g., 14 days of system operation, the support media in one or more of the trays may be inoculated with microorganisms known to be actively degrading ethanol, e.g., the support media placed in the bottom tray and/or top tray may contain inoculated support media. The microorganisms may be grown on the support media by any suitable technique, such as immersion or spraying with a liquid containing ethanol-utilizing microbes as described in the example below. 
         [0036]    In an embodiment of the present invention, effluent gas from the building  5  flows into the enclosure  12  of the treatment system  10  and is at least partially absorbed into moisture on the media so that it can come into contact with the active culture. The VOCs contained in the effluent gas, including ethanol, are absorbed into the active culture and are degraded by the microorganisms. The VOCs may be first oxidized by the microorganisms, and then may be broken down to various reaction products. The operating conditions of the enclosure  12  of the treatment system  10  may be controlled to maintain active cultures, while providing the microorganisms with sufficient nourishment and ensuring that the adequate amount of VOCs are being removed from the effluent gas. The flow rate of air through the enclosure and out through the exhaust fan  46  may be controlled to provide sufficient dwell time in the enclosure to achieve the desired biological oxidation of ethanol. For example, exhaust flow rates of from zero to 10,000 cfm may be used, or from 0.1 to 5,000 cfm, or from 0.5 to 2,500 cfm. The exhaust flow rate may be held constant, or may be varied as desired. In certain embodiments, the flow rate may be reduced or stopped periodically to increase dwell time of the air inside the enclosure, e.g., for batch processing of selected volumes of air. 
         [0037]    Bacteria then may be inoculated onto the support media, or which may grow on the support media during operation of the treatment system 10, in accordance with embodiments of the present invention may include the following groups (in addition to fungi, algae, protozoa, rotifers and other aerobic and anaerobic microbial populations): the spirochetes; aerobic/microaerophilic, motile, helical/vibroid, and gram-negative bacteria; nonmotile (or rarely motile), gram-negative bacteria; gram-negative aerobic/microaerophilic rods and cocci; facultatively anaerobic gram-negative rods; gram-negative, anaerobic, straight, curved, and helical bacteria; dissimilatory sulfate- or sulfur-reducing bacteria; anaerobic gram-negative cocci; anoxygenic phototrophic bacteria; oxygenic phototrophic bacteria; aerobic chemolithotrophic bacteria and associated organisms; budding and/or appendaged bacteria; sheathed bacteria; nonphotosynthetic, nonfruiting gliding bacteria; the fruiting, gliding bacteria and the myxobacteria; gram-positive cocci; endospore-forming gram-positive rods and cocci; regular, nonsporing, gram-positive rods; irregular, nonsporing, gram-positive rods; the mycobacteria; the actinomycetes; nocardioform actinomycetes; genera with multiocular sporangia; actinoplanetes; streptomycetes and related genera; maduromycetes; thermomonospora and related genera; thermoactinomycetes; genus  glycomyces,  genus  kitasatospira  and genus  saccharothrix;  the mycoplasmas—cell wall-less bacteria; the methanogens; archaeal sulfate reducers; extremely halophilic, archaeobacteria (halobacteria); cell wall-less archaeobacteria; and extremely thermophilic and hyperthermophilic SO-metabolizers. 
         [0038]    In addition to the above-listed bacteria examples, facultative anaerobes and microaerophilics, which are bacteria capable of surviving at low levels of oxygen, may also be used in accordance with embodiments of the present invention. They may not require strict anaerobic conditions such as the obligate anaerobes. Examples include acidophilic, alkaliphilic, anaerobe, anoxygenic, autotrophic, chemolithotrophic, chemoorganotroph, chemotroph, halophilic, methanogenic, neutrophilic, phototroph, saprophytic, thermoacidophilic and thermophilic bacteria. 
         [0039]    Representative fungi that may be used in accordance with embodiments of the present invention include: phylum ascomycota, class neolectomycetes, class pneumocystidomycetes, class schizosaccharomycetes, and class taphrinomycetes; subphylum pezizomycotina, class arthoniomycetes, class dothideomycetes (genus  baudoinia ), class geoglossomycetes, class eurotiomycetes, and class laboulbeniomycetes; class lecanoromycetes, subclass acarosporomycetidae, subclass lecanoromycetidae, and subclass ostropomycetidae; class leotiomycetes; class lichinomycetes; class orbiliomycetes; class pezizomycetes; class sordariomycetes, subclass hypocreomycetidae, subclass sordariomycetidae, and subclass xylariomycetidae; subphylum saccharomycotina, class saccharomycetes; phylum basidiomycota, subphylum agaricomycotina, class agaricomycetes, class dacrymycetes, class tremellomycetes, subphylum pucciniomycotina, class agaricostilbomycetes, class attractiellomycetes, class classiculomycetes, class cryptomycocolacomycetes, class cystobasidiomycetes, class microbotryomycetes, class mixiomycetes, class pucciniomycetes, subphylum ustilaginiomycotina, class ustilaginomycetes, and class exobasidiomycetes; phylum chytridiomycota; phylum glomeromycota, class glomeromycetes; and phylum zygomycota, class trichomycetes, and class zygomycetes. 
         [0040]    The following example is intended to illustrate various aspects of the present invention, and are not intended to limit the scope of the invention. 
       EXAMPLE 
       [0041]    A test chamber was constructed using a prefabricated rack made of welded aluminum. The rack was designed to hold up to 20 trays weighing as much as 100 pounds each. A total of eight galvanized steel trays containing screened bottoms (16-gauge, 1-inch by 0.5-inch) were installed. The weights of these trays ranged from approximately 5.5 to 6.0 pounds each. The rack was enclosed and made air-tight on all four sides using gasketed doors and silicone-sealed seams. A dosing chamber was installed at the bottom of the assembly, and an inline fan was installed within a six-inch exhaust duct to draw the air through the testing unit. Small holes were drilled at the base on the unit, between the four lower trays and four upper trays, and at the top of the assembly prior to the exhaust duct. These holes were installed for the collection of midfluent ethanol concentration data, and for spraying the treatment media with water to maintain the desired humidity levels within the test unit. 
         [0042]    The treatment media used for pilot testing consisted of hardwood chips coated with bacterial, fungal, and protozoan cultures. To prepare this media, a broad spectrum biological liquid sludge culture was used. The sludge was kept aerated prior to testing and was introduced to ethanol as its sole food source to stimulate microbes that are able to utilize ethanol as a source of nutrition. This culture had been maintained on an ethanol food supply for several weeks at the time of inoculation. The wood chips utilized, which were thoroughly moistened with water prior to the initiation of testing, were a mixture of oak, maple and walnut with sizes of approximately 1-inch by 1.5 inches by 0.25 inches. 
         [0043]    Day No. 1 the test was initiated. The eight trays were filled with the moistened wood chips until the weight of each tray was measured to be 20 pounds (approximately 14 to 14.5 pounds of wood chips per tray). Approximately 25 ounces of the activated microbial culture were then added to each tray, after which the unit was sealed and the testing commenced. A 95% ethanol solution was added continuously to the dosing chamber at the bottom of the assembly using a liquid dripper similar to the type used for dripping water into animal cages. During testing, the drip rate was varied such that the ethanol solution was added at rates between approximately 0.5 and 4.2 grams per minute. The humidity of the air stream inside the exhaust duct was measured to be 77%. Variations in the humidity level throughout the pilot testing were measured. 
         [0044]    During the initial stages of testing, the air flow rate was measured to be 305 feet per minute (fpm) at the test unit inlet. It was identified that the flow was not uniform at the outlet, with flow rates ranging from 310 fpm (4 inches into the exhaust duct) to 820 fpm (1 inch into the duct). A vertical straightener was installed within the exhaust duct to reduce the cyclonic nature of the effluent air flow, and the damper for the fan was partially closed. The subsequent air flow rates at the outlet ranged from 250 fpm (five inches into the duct) to 660 fpm (one inch into the duct). The average effluent flow rate of 442 fpm was used to determine the volumetric flow rate, which was calculated to be approximately 86.6 cubic feet per minute (cfm) based on the 6-inch-diameter of the exhaust duct. Since the internal volume of the test chamber was 17.3 cubic feet (CF), the detention time in the chamber was 12 seconds. Since there was an average of approximately 3.5-inches of wood chips in each tray, there was about 7.5 CF of media, so the contact time with the media itself was approximately 5 seconds. 
         [0045]    Ethanol concentrations were measured using a photoionization detector (PID) on Day Nos. 1 and 3, and were measured using a flame ionization detector (FID) on Day Nos. 6 through 9. Based on available industry literature and field calibration data, the PID readings were multiplied by a factor of 5.0 to obtain the actual ethanol concentrations in units of parts per million by volume (ppmv). With regard to the FID, per information provided by the equipment vendor, the collected readings were multiplied by a factor of 5.2 to obtain the ethanol concentrations in units of ppmv. The PID/FID readings are summarized in the following table. The response of the FID was more rapid and steady than those of the PID, so the FID results are the preferred readings. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Ethanol Concentrations and Removal 
               
               
                 Efficiency Day Nos. 1, 3 and 6-9 
               
             
          
           
               
                   
                   
                   
                   
                 Ambient/ 
                   
               
               
                   
                   
                 Inlet 
                 Outlet 
                 Room 
               
               
                   
                   
                 Ethanol 
                 Ethanol 
                 Ethanol 
               
               
                   
                   
                 Concen- 
                 Concen- 
                 Concen- 
                 Removal 
               
               
                   
                   
                 tration 
                 tration 
                 tration 
                 Efficiency 
               
               
                 Day No. 
                 Time 
                 (ppm) 
                 (ppm) 
                 (ppm) 1   
                 (percent) 2   
               
               
                   
               
             
          
           
               
                 1 
                 2:40 
                 PM 
                 18.0 
                 8.0 
                 5.0 
                 83.3 
               
               
                 1 
                 2:54 
                 PM 
                 28.5 
                 8.0 
                 4.5 
                 87.7 
               
               
                 1 
                 3:00 
                 PM 
                 48.0 
                 11.0 
                 5.5 
                 88.5 
               
               
                 1 
                 3:08 
                 PM 
                 73.0 
                 12.5 
                 7.0 
                 92.5 
               
               
                 1 
                 3:21 
                 PM 
                 112 
                 20.5 
                 — 
                 81.7 
               
               
                 1 
                 3:30 
                 PM 
                 144 
                 35.0 
                 — 
                 75.7 
               
               
                 1 
                 3:49 
                 PM 
                 137 
                 43.0 
                 — 
                 68.6 
               
               
                 3 
                 10:52 
                 AM 
                 28.5 
                 &lt;2.5 
                 &lt;2.5 
                 100 
               
               
                 3 
                 11:19 
                 AM 
                 56.0 
                 12.0 
                 — 
                 78.6 
               
               
                 3 
                 11:39 
                 AM 
                 46.5 
                 19.5 
                 — 
                 58.1 
               
               
                 6 
                 1:56 
                 PM 
                 172 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 2:02 
                 PM 
                 97.8 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 2:07 
                 PM 
                 281 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 2:15 
                 PM 
                 291 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 2:25 
                 PM 
                 276 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 2:36 
                 PM 
                 333 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 3:55 
                 PM 
                 619 
                 14.6 
                 — 
                 97.6 
               
               
                 6 
                 4:08 
                 PM 
                 572 
                 &lt;2.6 
                 — 
                 100 
               
               
                 6 
                 4:20 
                 PM 
                 588 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 4:35 
                 PM 
                 494 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 6 
                 4:48 3   
                 PM 
                 73.0 
                 13.5 
                 7.0 
                 91.9 
               
               
                 6 
                 4:48 4   
                 PM 
                 468 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 7 
                 8:24 
                 AM 5   
                 78.0 
                 44.7 
                 5.7 
                 50.0 
               
               
                 7 
                 8:29 
                 AM 5   
                 63.4 
                 36.4 
                 &lt;2.6 
                 42.6 
               
               
                 7 
                 8:34 
                 AM 
                 60.3 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 7 
                 8:39 
                 AM 
                 78.0 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 7 
                 1:21 
                 PM 
                 156 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 7 
                 1:28 
                 PM 
                 172 
                 &lt;2.6 
                 &lt;2.6 
                 100 
               
               
                 8 
                 12:30 
                 PM 
                 1,144 
                 101 
                 13.5 
                 92.4 
               
               
                 8 
                 12:38 
                 PM 
                 1,352 
                 130 
                 &lt;2.6 
                 90.4 
               
               
                 8 
                 12:46 
                 PM 
                 1,684 
                 166 
                 3.1 
                 90.3 
               
               
                 8 
                 12:53 
                 PM 
                 1,773 
                 192 
                 &lt;2.6 
                 89.2 
               
               
                 8 
                 1:06 
                 PM 
                 1,888 
                 203 
                 &lt;2.6 
                 89.2 
               
               
                 8 
                 1:16 
                 PM 
                 2,163 
                 231 
                 &lt;2.6 
                 89.3 
               
               
                 8 
                 1:22 
                 PM 
                 1,945 
                 250 
                 &lt;2.6 
                 87.1 
               
               
                 8 
                 1:27 
                 PM 
                 1,498 
                 224 
                 &lt;2.6 
                 85.0 
               
               
                 8 
                 1:40 
                 PM 
                 2,194 
                 250 
                 &lt;2.6 
                 88.6 
               
               
                 8 
                 1:44 
                 PM 
                 1,659 
                 244 
                 &lt;2.6 
                 85.3 
               
               
                 8 
                 1:53 
                 PM 
                 1,602 
                 244 
                 &lt;2.6 
                 84.8 
               
               
                 8 
                 2:05 
                 PM 
                 1,118 
                 187 
                 &lt;2.6 
                 83.3 
               
               
                 8 
                 2:15 
                 PM 
                 894 
                 166 
                 &lt;2.6 
                 81.4 
               
               
                 8 
                 2:26 
                 PM 
                 894 
                 139 
                 &lt;2.6 
                 84.5 
               
               
                 8 
                 2:35 
                 PM 
                 806 
                 131 
                 &lt;2.6 
                 83.7 
               
               
                 8 
                 2:46 
                 PM 
                 582 
                 107 
                 &lt;2.6 
                 81.6 
               
               
                 8 
                 3:30 
                 PM 
                 414 
                 89.4 
                 &lt;2.6 
                 78.4 
               
               
                 8 
                 3:40 
                 PM 
                 371 
                 77.5 
                 &lt;2.6 
                 79.1 
               
               
                 8 
                 3:50 
                 PM 
                 282 
                 68.1 
                 &lt;2.6 
                 75.9 
               
               
                 8 
                 4:00 
                 PM 
                 268 
                 62.4 
                 &lt;2.6 
                 76.7 
               
               
                 8 
                 4:10 
                 PM 
                 245 
                 56.2 
                 &lt;2.6 
                 77.1 
               
               
                 8 
                 4:20 
                 PM 
                 239 
                 45.8 
                 &lt;2.6 
                 80.8 
               
               
                 8 
                 4:30 
                 PM 
                 204 
                 43.2 
                 &lt;2.6 
                 78.8 
               
               
                 9 
                 7:30 
                 AM 
                 1,331 
                 398 
                 133 
                 80.1 
               
               
                 9 
                 7:40 
                 AM 
                 1,206 
                 357 
                 85.3 
                 77.5 
               
               
                 9 
                 7:50 
                 AM 
                 562 
                 249 
                 68.6 
                 67.9 
               
               
                 9 
                 8:00 
                 AM 
                 323 
                 213 
                 31.7 
                 43.9 
               
               
                   
               
               
                   1 No reading was collected at this time. 
               
               
                   2 If ambient air ethanol readings were detected above the instrument detection limit of 0.5 ppmv, the detected concentrations were subtracted from the outlet concentrations prior to calculating the removal efficiency. 
               
               
                   3 This reading was collected using the PID. 
               
               
                   4 This reading was collected using the FID. 
               
               
                   5 It is believed that the instrument was not yet fully started (i.e. “warmed up”) during the collection of these two readings. 
               
             
          
         
       
     
         [0046]    Based on the data collected, there is no definitive relationship between the inlet concentration and the treatment system removal efficiency. However, there is a slight trend for the removal efficiency to be higher with increased inlet concentrations. 
         [0047]    The average measured removal efficiency was 85.4%. For typical spirit aging warehouses, it is expected that the ambient air ethanol concentration will be in the range of 200 milligrams per cubic meter (mg/m 3 ), which is equivalent to approximately 106 ppmv based on the molecular weight of ethanol. Based on the data collected during the test, this concentration can be reduced to levels of approximately 15 ppmv or lower using the technology described herein. It is also noted that the primary organic component of the ethanol, which is suspected to stimulate the growth of the  Baudoinia  fungus, is believed to be largely or wholly removed by the activated culture during the treatment process. Testing is currently ongoing to improve the average removal efficiency rate. 
         [0048]    The humidity level in the test unit ranged from 33% to 78%. In particular, on the final day of testing (Day No. 9), the lowest humidity level of 33% was recorded and the corresponding removal efficiencies were limited to values between 43.9% and 80.1%. As such, the moisture level appears to play a significant role in the ability of the activated culture to remove ethanol from the vapor stream. The establishment of the activated culture resulted in a predominantly black-colored growth on the surface of the wood chips. It is noted that a supply bin containing spare moist wood chips also grew an apparent microbial layer (similar visual appearance) after this bin was used to catch drips from the introduction of the sludge to the eight treatment trays, which suggests that the culture is durable even in nutrient-limited conditions. 
         [0049]    Based on a conservative influent concentration of 500 ppmv ethanol this test unit would remove approximately 0.31 pounds of ethanol per hour. This is for a media bed of 7.5 cubic feet, yielding a removal rate of 0.041 pounds/hour/CF of media. 
         [0050]    It is expected that when moisture can be maintained at more consistent levels and a greater thickness of biofilm is allowed to accumulate on the media, the treatment system will be able to consume a greater mass loading rate of ethanol. The ductwork and dampers on the treatment unit may be designed such that air can passively flow into the warehouse, but any exiting air must pass through the media trays. Fans may be used to keep air flowing through the media, but since air may be allowed to enter the ducts through one-way valves outside the warehouse, there may be no negative pressure exerted on the warehouse. 
         [0051]    For a full scale unit containing 320 CF of media, at removal rates estimated during this test, a removal rate of about 13 pounds of ethanol per hour for each unit may be achieved. A full size unit may thus be capable of handling the angels&#39; share emissions from up to several thousand barrels depending on specific warehouse configuration and air flows. 
         [0052]    The removal efficiency generally ranged from 80% to 100% with inlet air concentrations of from 200 to 2,000 ppmv with a media contact time of approximately 5 seconds. Observations indicated that a biofilm was growing on the media, seen as darkened areas in  FIG. 10 . Since this testing was conducted for a period of less than two full weeks, a more mature system is expected to have a thicker biofilm and will respond much better with higher removal efficiencies and faster response times when subjected to increasing ethanol concentrations. 
         [0053]    The removal efficiencies are very high at low concentrations (generally at or near 100% below 500 ppm) and respond well to periods when concentrations are increasing. Removal efficiencies decrease when the media begins to dry, so it is important to keep moisture levels high through frequent spraying of water on the media. It is therefore desirable to monitor moisture levels in an operating system. Although removal efficiencies were near 90% even with inlet concentrations of ethanol up to 2,000 ppmv, removal efficiencies are not high when the system is recovering from very high inlet concentrations (over 1,500 ppmv). A properly cultured and established system that is kept moist in accordance with embodiments of the present invention should consistently remove greater than 90% of the ethanol with influent ethanol concentrations up to 800 ppmv as long as inlet concentrations are not allowed to exceed 1,500 ppmv. Since the present invention utilizes a biological treatment process, the most biologically available form of ethanol that is most likely to cause blackening will be effectively destroyed using the treatment systems of the present invention. 
         [0054]    Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.