Abstract:
Processes directed to the removal of sulfurous compounds from air are presented herein. The compositions and processes may be able to treat air with H 2 S concentrations of at least 1000 ppm. The processes are used to remove sulfurous compounds from air associated with wastewater systems in various aspects. This Abstract is presented to meet requirements of 37 C.F.R. §1.72(b) only. This Abstract is not intended to identify key elements of the apparatus and processes disclosed herein or to delineate the scope thereof.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 12/340,613 filed 19 Dec. 2008 and entitled “Sulfide Scavenging Media and Associated Methods,” which is hereby incorporated by reference in its entirety herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The production of sulfurous compounds including H 2 S under anaerobic conditions in wastewater systems can result in corrosion problems and noxious odors objectionable to the public. Air with such sulfurous compounds entrained therein can be treated in various ways such as by passing the air through some type of scrubber system that removes the sulfurous compounds. Existing technologies have limitations including the ability to economically remove sulfurous compounds from air at the concentrations that may be found, for example, in air associated with wastewater systems located in warm climates. Accordingly there is a need for improved compositions and methods for the removal of sulfurous compounds from air. 
     BRIEF SUMMARY OF THE INVENTION 
     Improvements and advantages may be recognized by those of ordinary skill in the art upon study of the present disclosure. Methods of scavenging sulfurous compounds from air are disclosed herein. In various aspects, the methods include the step of contacting air with H 2 S entrained therein with a sulfide scavenging media for a retention time of less than about 20 seconds, the sulfide scavenging media comprising a solid substrate impregnated with a sulfur scavenging composition comprising a polymeric amine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates by cut-away view an exemplary implementation of a dry scrubber; 
         FIG. 1B  illustrates by detailed cut-away view the flow of air through portions of the bed of sulfide scavenging media within the dry scrubber of  FIG. 1A ; 
         FIG. 1C  illustrates by detailed cut-away view the flow of air through portions of the bed of amine scavenging media within the dry scrubber of  FIG. 1A ; 
         FIG. 1D  illustrates by detailed cut-away view the flow of air about portions of a particle of sulfide scavenging media within the dry scrubber of  FIG. 1A ; 
         FIG. 2  illustrates by process overview flow chart an exemplary series of process steps for the removal of sulfurous compounds from air; 
         FIG. 3A  illustrates by strip chart the concentration of H 2 S in the inflow air into the bed of sulfide scavenging media during Week 10 of Example 3; and 
         FIG. 3B  illustrates by strip chart the concentration of H 2 S in the outflow air from the bed of sulfide scavenging media during Week 10 of Example 3. 
     
    
    
     The Figures are exemplary only and the implementations illustrated therein are selected to facilitate explanation. The number, position, relationship and dimensions of the elements shown in the Figures to form the various implementations described herein, as well as dimensions and dimensional proportions to conform to specific force, weight, strength, flow and similar requirements are explained herein or are understandable to a person of ordinary skill in the art upon study of this disclosure. Where used in the various Figures, the same numerals designate the same or similar elements. Furthermore, when the terms “top,” “bottom,” “right,” “left,” “forward,” “rear,” “first,” “second,” “inside,” “outside,” and similar terms are used, the terms should be understood in reference to the orientation of the implementations shown in the drawings and are utilized to facilitate description thereof. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Disclosed herein is a sulfide scavenging media that removes sulfurous compounds, which may have a noxious odor, from air. In various aspects, the air with sulfurous compounds entrained therein may be contacted with the sulfide scavenging media. As the air contacts the sulfide scavenging media, the sulfurous compounds entrained within the air react with a sulfur scavenging composition included as a part of the sulfide scavenging media, and are, accordingly, removed from the air. Methods for removing sulfurous compounds from air using the sulfide scavenging media are also disclosed herein. 
     The sulfurous compounds include H 2 S, mercaptans, organic sulfides, and other sulfurous compounds and combinations thereof. The air with the sulfurous compounds entrained therein is derived in various aspects from a waste water system such as a sewer, system of sewers, waste water storage facility, storm water tunnel(s), storm water storage reservoir, combined sewer, combinations thereof, or wastewater treatment process(es) such as a settling tank or sludge processing unit associated with a wastewater treatment facility. The quantity of sulfurous compounds entrained in air derived from a waste water system may vary diurnally and may vary seasonally. 
     The reaction between the sulfurous compounds and the sulfur scavenging composition removes the sulfurous compounds from the air by converting the sulfurous compounds into polysulfides that are water soluble and may have a generally liquid form. The polysulfides may be biodegradable and thus could be disposed of by input into the process stream of a wastewater treatment plant. The sulfide scavenging media in various aspects includes a substrate impregnated with the sulfur scavenging composition The substrate may be a generally porous non-reactive material such as pozzolan, calcined pozzolan, diatomaceous earth, zeolites, pumice, volcanic tuff, foamed silica, expanded perlite, vermiculite, Fuller&#39;s earth, and similar porous mineral based materials. As additional examples, the substrate may be a porous ceramic, a porous generally non-reactive polymer, or other such synthetic material. In various aspects the substrate may be a mineral based material or synthetic material including polymers with an absorbency of at least about 50%. 
     In some aspects, the substrate, and hence the sulfide scavenging media formed from the substrate may be in the form of particles that may be aggregated into a bed. Air containing sulfurous compounds may flow through the bed, and sulfurous compounds in the air may react with the sulfide scavenging media and are thus converted into polysulfides. In other aspects, the substrate, and, hence, the sulfide scavenging media formed from the substrate, could be a generally porous material such that air with sulfurous compounds entrained therein flows though the sulfides scavenging media, which allows the sulfurous compounds react with the sulfide scavenging media to be converted into polysulfide thereby. 
     The sulfur scavenging composition includes the reaction product of sterically hindered amines such as selected aliphatic diamines, aliphatic triamines, amino alcohols, and mixtures thereof with aldehydes, aldehyde donors, or the reaction products of lower alkanolamines and lower-aldehydes to form a liquid resin which reacts effectively to convert sulfurous compounds to a water soluble, stable complex. The sulfur scavenging composition, in various aspects, is a reaction product of an effective amount of one or more sterically hindered alkyl diamines with an effective amount of one or more monoaldehydes and dialdehydes having from 1 to 6 carbon atoms. Further details of the formation and properties of the sulfur scavenging composition may be found in Gatlin, U.S. Pat. No. 5,488,103 entitled “Hydrogen Sulfide Converter,” which is hereby incorporated herein by reference in its entirety for any and all purposes. 
     The sulfide scavenging media may be formed by soaking the substrate in the sulfur scavenging composition or otherwise impregnating the substrate with the sulfur scavenging composition. In various aspects, the sulfur scavenging composition is diluted with a solvent such as water or alcohol, and the substrate impregnated with the sulfur scavenging composition so diluted. When the sulfide scavenging media is formed by soaking the substrate in the sulfur scavenging composition, the substrate is generally immersed in the sulfur scavenging composition until the sulfur scavenging composition is absorbed by the substrate. The porous nature of the substrate in various aspects may enhance the ability of the substrate to absorb the sulfur scavenging composition. After the substrate is generally saturated with the sulfur scavenging composition to form the sulfide scavenging media, any excess sulfur scavenging composition is drained away. The resulting sulfide scavenging media includes the substrate now impregnated with the sulfur scavenging composition, which may or may not be diluted by various solvents. 
     As noted in Gatlin, in theory about 1 ppm (part per million) to about 2 ppm of the sulfur scavenging composition may convert about 1 ppm of H 2 S. However, about 2 ppm to about 4 ppm of sulfur scavenging composition may be required to convert about 1 ppm of H 2 S when the sulfur scavenging composition is injected as a fluid into a stream of gas or liquid containing H 2 S as the result of incomplete contact between the sulfur scavenging composition and the H 2 S in the stream of gas or liquid. By incorporating the sulfur scavenging composition onto a substrate to produce the sulfide scavenging media and then contacting air with sulfurous compounds entrained therein with the sulfide scavenging media, the effectiveness of the contact between the air with sulfurous compounds entrained therein and the sulfur scavenging composition may be enhanced. Accordingly, the amount of sulfur scavenging composition required to convert, for example, about 1 ppm of H 2 S to polysulfide may approach the theoretical value of about 1 ppm to about 2 ppm of sulfur scavenging composition, as the sulfur scavenging composition impregnated into the sulfur scavenging composition is consumed only upon reaction with the sulfurous compounds. 
     The Figures referenced herein generally illustrate various exemplary implementations of the sulfide scavenging media and methods for removing sulfurous compounds from air using the sulfide scavenging media. These illustrated implementations are not meant to limit the scope of coverage, but, instead, to assist in understanding the context of the language used in this specification and in the claims. Accordingly, variations of the compositions and methods that differ from these illustrated implementations may be encompassed by the appended claims. 
       FIG. 1A  illustrates an implementation of dry scrubber  100  to remove sulfurous compounds entrained in air that includes bed  12  of sulfide scavenging media  10  and bed  52  of amine scavenging media  50 . The dry scrubber  100 , as illustrated, includes a scrubber housing  411  and divider wall  418  that in combination define chamber  416  and plenum  406 . The scrubber housing  411  defines inlet  402  to admit air  64  that may have sulfurous compounds entrained therein into the plenum  406 . The divider wall  418 , in this implementation, is formed with apertures (not shown) to pass air  64  from the plenum  406  into chamber  416 . For example, the divider wall  418  may be formed as a grated structure or as a metal sheet with holes disposed thereabout. The housing  411  and the divider wall  418  may be composed of metal such as steel, aluminum, fiberglass, various polymers or of other suitable materials and combinations of materials that may be corrosion resistant or covered with corrosion resistant materials as would be recognized by those of ordinary skill in the art upon study of this disclosure. 
     As illustrated in  FIG. 1A , sulfide scavenging media  10  is formed into bed  12  within chamber  416 , and bed  12  rests upon the divider wall  418 . Bed  52  of amine scavenging media  50  rests upon bed  12  of sulfide scavenging media  10  within chamber  416  in this implementation. Air  65  with sulfurous compounds generally removed therefrom by the bed  12  of sulfide scavenging media  10  may flow from the bed  12  of sulfide scavenging media  10  into bed  52  of amine scavenging media  50 . Polysulfide  88  formed within the bed  10  by conversion of sulfurous compounds. The polysulfide  88  may be generally liquid in some implementations and, thus, a portion of the polysulfide  88  may flow out of the bed  12 , as illustrated, generally into the plenum  406  under the influence of gravity. The polysulfide  88  could be collect from the plenum  406  or otherwise collected from dry scrubber  100  for disposal. The flow of polysulfide  88  out of the bed  12  may prevent or at least mitigate clogging of bed  12  by the buildup of polysulfide  88  within the bed. 
     The plenum  406  generally allows the pressure of the air  64  to equilibrate after passage through inlet  402  in order to distribute air  64  relatively uniformly over the bed  12  of sulfide scavenging media  10  from the plenum  406  through the divider wall  418 , and, in turn, distributes air  65  relatively uniformly over bed  52  of amine scavenging media  50 . 
     Fan  415  is provided to draw the air  64  into the plenum  406  through inlet  402  and thence into the bed  12  of sulfide scavenging media  10  in this implementation. The fan  415 , as illustrated in  FIG. 1A , draws air  65  from the bed  12  of sulfide scavenging media  10  into bed  52  of amine scavenging media  50 . Air  66  contains (i) sulfurous compounds removed therefrom by the bed  12  of sulfide scavenging media  10  and (ii) amines volatilized from the bed  12  of sulfide scavenging media  10  removed therefrom by bed  52  of amine scavenging media  50 . Air  66  is ejected from the chamber  416  into the ambient environment through outlet  404  by fan  415 . In this implementation, the fan  415  is oriented such that the intake side of the fan  415  draws air  64  into the plenum  406  and thence chamber  416 . In other implementations (not shown), the fan  415  could be oriented such that air  64  is propelled from the discharge side of the fan  415  into the plenum  406  and thence chamber  416 . In still other implementations, thermal convection may flow the air  64  into the bed  12  of sulfide scavenging media  10  and thence air  65  into bed  52  of amine scavenging media  50 , or other motive forces and/or mechanisms may be employed. In this implementation, bed  12  and bed  52  are fixed and bed  52  rests upon bed  12  in a single chamber  416 . In other implementations (not shown) bed  12  and bed  52  may be in separate chambers, may be fluidized, or may be formed in various other ways. 
     Amine scavenging media  52  generally removes amines from air  65  that may be volatilized into air  65  from bed  12  of sulfide scavenging media  10  as the air  65  passes through the bed  52  of amine scavenging media  50 . In various implementations, the amine scavenging media may be activated carbon such as activated carbon derived from coconut shells. 
       FIG. 1B  illustrates a detail of bed  12  of sulfide scavenging media  10 . As illustrated in  FIG. 1B , the sulfide scavenging media  10  is formed as particles with particle size  13 . The particle size  13  of the particles of sulfide scavenging media  10  may be chosen such that air  64  may flow through bed  12  and contact the sulfide scavenging media  10 . In various implementations, the particle size  13  may range from about ⅜ inch to about ½ inch. Interstitial region  87  is a void space between particles of sulfide scavenging media  10 , and the interstitial region  87  is generally filled with air  64  as the air passes through the bed  12 . The interstitial region  87  is generally devoid of liquids other than polysulfide  88  ( FIG. 1A ) formed by conversion of the sulfurous compounds by the sulfide scavenging media. 
     As illustrated in  FIG. 1C , the amine scavenging media  50  may be formed as particles having a particle size  53  chosen such that air  65  may flow through the bed  52  and contact the amine scavenging media  50 . In various implementations, the particle size  53  may range from 4×8 mesh. 
       FIG. 1D  illustrates a portion of the sulfide scavenging media  10  that includes substrate  22  impregnated with sulfur scavenging composition  16 . As illustrated in  FIG. 1D , the sulfide scavenging media  10  includes pore  14  defined by surface  13 . Sulfur scavenging composition  16  is retained in the pore  14  with a portion of the sulfur scavenging composition  16  exposed at pore entrance  19  of pore  14 . Various forces such as capillary forces, adsoptive forces, and/or absorptive forces may retain the sulfur scavenging composition  16  within the pore  14  or otherwise retain the sulfur scavenging composition  16  about substrate  22  and prevent volatilization or other losses of the sulfur scavenging composition  16  from the substrate  22 . The sulfur scavenging composition  16  may be retained about the substrate  22  in ways other then that illustrated in  FIG. 1D  in various implementations. 
     As air  64  passes proximate surface  13  as illustrated in  FIG. 1D , the air  64  contacts the sulfur scavenging composition  16  generally proximate the pore entrance  19 , which allows sulfurous compounds entrained in the air  64  to react with the sulfur scavenging composition  16  to be converted into polysulfide  88 . As sulfur scavenging composition  16  generally proximate surface  13  is consumed by reaction with sulfurous compounds, a concentration gradient may be produced that may cause sulfur scavenging composition  16  within the substrate  22  to diffuse to the surface  13  to replenish the sulfur scavenging composition  16  so consumed. For example, as the sulfur scavenging composition  16  proximate the pore entrance  19  in  FIG. 1D  is consumed by reaction with sulfurous compounds, additional sulfur scavenging composition  16  may diffuse generally to the pore entrance  19  from within the pore  14  to provide additional sulfur scavenging composition  16  for reaction with sulfurous compounds in air  64 . Accordingly, the consumption of the sulfur scavenging composition  16  is regulated by contact with the sulfurous compound(s) entrained in the air, which may allow the sulfide scavenging media to respond to variations in the quantity of sulfurous compounds in the air. A bed of sulfide scavenging media may be capable of treating air with an H 2 S concentration of at least 1,000 ppm in various implementations with generally complete removal of the H 2 S from the air. 
     Returning to  FIG. 1A , in operation, fan  415  draws air  64  with sulfurous compounds entrained therein into plenum  406  through inlet  402 . The air  64  is then drawn from the plenum  406  through divider wall  418  into bed  12  of sulfide scavenging media  10 . The sulfurous compounds react with the sulfur scavenging composition  16  impregnated into the sulfide scavenging media  10  and are converted thereby into a water soluble polysulfide  88  that may be generally liquid. The polysulfide  88  in some implementations may be retained, at least in part, within the bed  12 . In some implementations, at least a portion of the polysulfide  88  may be eluded as a liquid from the bed  12 , and may be withdrawn from the dry scrubber  100  and disposed of as illustrated in  FIG. 1A . 
     Amines may be volitilized from the bed  12  particularly during initial operation of the bed  12 . Air  65  that may have amines entrained therein flows from bed  12  into bed  52  of amine scavenging media  50 . Amines, if any, entrained within the air  65  are generally adsorbed by the bed  52 . In some implementations, the bed  52  may adsorb sulfurous compounds that pass through bed  12 . Air  66  with sulfurous compounds generally removed therefrom and with amines generally removed therefrom may be discharged through outlet  404  into, for example, the ambient environment. Exiting air  66  may be generally devoid of the noxious odors of sulfurous compound and the noxious odors of amines. 
       FIG. 2  illustrates by process overview flow chart an exemplary series of process steps for the removal of sulfurous compounds from air. In step  1002 , air with sulfurous compounds entrained therein is contacted with sulfide scavenging media such as sulfide scavenging media  12 . In Step  1004 , the sulfide scavenging media converts the sulfurous compounds into polysulfide such as polysulfide  88 . The sulfide scavenging media may release amines into the air as indicated by step  1006 . The air is then contacted with an amine scavenging media such as amine scavenging media  52  as indicated in step  1008 . In various aspects, the methods may include the step (not shown) of draining at least a portion of the polysulfides from the sulfide scavenging media. 
     EXAMPLES 
     These Examples are provided for illustrative purposes only and are not to be considered as limiting except where expressly so stated. 
     Example 1 
     In Example 1, the sulfide scavenging media was formed from SULFA CLEAR® 8640 as the sulfur scavenging composition in combination with calcined pozzolan as the substrate. SULFA CLEAR® 8640 is a polymeric amine as described in Gatlin and produced by Weatherford Inc., Houston, Tx. The SULFA CLEAR® 8640 was diluted with water at a 1:1 ratio by volume, i.e. 1 gallon of SULFA CLEAR® 8640 was mixed with 1 gallon of water in this Example. The resulting SULFA CLEAR® 8640-water mixture weighted between 8.58 and 8.71 pounds per gal. The substrate in Example 1 was calcimined pozzolan distributed under the name Absorbs-All® by Western Pozzolan Corp., Lassen Calif. The dry calcined pozzolan was in the form of particles with particle size ranging generally from about ⅜ inch to about ½ inch. The dry calcined pozzolan weighted between about 41 lbs to 45 lbs/ft 3  so that 40 ft 3  of calcined pozzolan weighed generally between about 1700 lbs and about 1800 lbs. 
     In order to form the sulfide scavenging media, about 220 gal. of the SULFA CLEAR® 8640-water mixture was combined with about 40 ft 3  of generally dry calcined pozzolan substrate in an open vat such that the calcined pozzolan substrate was completely submerged by the SULFA CLEAR® 8640-water mixture. After allowing the calcined pozzolan substrate to soak for about 20 minutes, any excess SULFA CLEAR® 8640-water mixture was drained from the vat and hence from the calcined pozzolan substrate. The resulting sulfide scavenging media is the calcined pozzolan substrate combined with the portion of the SULFA CLEAR® 8640-water mixture absorbed by the calcined pozzolan—i.e. the portion of the SULFA CLEAR® 8640-water mixture that does not freely drain from the calcined pozzolan by gravity. 
     The porosity of the calcined pozzolan in this Example is roughly about 70%. Generally, per this Example, 1750 lbs. of calcined pozzolan absorbed about 975 pounds of SULFA CLEAR® 8640-water mixture or about 56% by weight. Thus, 1 ft 3  foot of the sulfide scavenging media in this example weighs about 67 lbs, which is apportioned as 43 lbs of calcined pozzolan and 24 lbs of SULFA CLEAR® 8640-water mixture. 
     Example 2 
     In Example 2, the sulfide scavenging media was formed from SULFA CLEAR® 8640 as the sulfur scavenging composition in combination with diatomaceous earth as the substrate. The SULFA CLEAR® 8640. The SULFA CLEAR® 8640 was diluted with water at a 1:1 ratio by volume, i.e. 1 gallon of SULFA CLEAR® 8640 was mixed with 1 gallon of water in this Example. The diatomaceous earth substrate was Celatom 2S51C manufactured by Eagle Picher Corp., Dearborn, Mi. The dry diatomaceous earth substrate weighted approximately 25 lbs/ft 3  and was formed into particles with particle size ranging generally from about ¼ inch to about ⅜ inch. 
     In order to form the sulfide scavenging media, about 220 gal. of SULFA CLEAR® 8640-water mixture was combined with about 40 ft 3  of generally dry diatomaceous earth substrate in an open vat such that the diatomaceous earth substrate was completely submerged by the SULFA CLEAR® 8640-water mixture. After allowing the diatomaceous earth substrate to absorb the SULFA CLEAR® 8640-water mixture for about 20 minutes, any excess SULFA CLEAR®8640-water mixture was drained from the vat and, hence, from the diatomaceous earth substrate. The resulting sulfide scavenging media in this Example is the diatomaceous earth substrate combined with the portion of the SULFA CLEAR® 8640-water mixture absorbed by the diatomaceous earth substrate—i.e. the portion of the SULFA CLEAR® 8640-water mixture that does not freely drain from the diatomaceous earth substrate by gravity. 
     Generally, per this Example, 1000 lbs. of diatomaceous earth absorbed about 975 pounds of SULFA CLEAR® 8640-water mixture or about 98% by weight. Thus, 1 ft 3  foot of the sulfide scavenging media of Example 2 weighed about 49 lbs, which is apportioned as 25 lbs of diatomaceous earth and 24 lbs of SULFA CLEAR® 8640-water mixture. 
     Example 3 
     An in situ test of the sulfide scavenging media generally described in Example 1 above was conducted. This in situ test was conducted on a wastewater system located in the Southwestern United States. 
     A bed was formed of the sulfide scavenging media. The bed was generally cylindrical in shape with a diameter of approximately 22 inches and a thickness measured along the cylindrical axis of approximately 30½ inches. The bed contained approximately 6.4 ft 3  of sulfide scavenging media. 
     Air flowed through the bed generally parallel to the cylindrical axis. The source of the air was a wastewater system, and the air included sulfurous compounds generally in the form of H 2 S. The sulfurous compounds were likely generated by anaerobic activity generally within the wastewater system. Some results obtained from this in situ test are given in Table 1. In this Table, the flow rate is the flow rate in cubic feet per minute (cfm) of air delivered to the bed of sulfide scavenging media. The retention time is the time period over which the air is in contact with the sulfide scavenging media. The retention time in seconds (s) is calculated as the bed volume divided by the flow rate. The concentration of H 2 S in the air delivered to the bed of sulfide scavenging media (inflow) and the concentration of the H 2 S in the air effluent from the bed of sulfide scavenging media (outflow) are given in parts per million (ppm). 
     Two different methods were used to determine the H 2 S concentration. The first method utilized a Model AP-20S is gas detection pump kit manufactured by Sensidyne LP of Clearwater, Fla. The tubes used in conjunction with this pump kit (which were manufactured by Sensidyne) measured H 2 S over a range generally between 25 ppm and 2000 ppm with a sensitivity of 0.05 ppm. The second method employed an Odalog Model Type 1 manufactured by App-Tek, Pine Rivers Shire, Queensland, Australia. The Odalog Model Type 1 measured H 2 S over a range generally between 0 ppm and 1000 PPM with sensitivity of 0.001 ppm. 
     The ammonia concentration and the amine concentration in the outflow air as given in Table 1 were measured with the Sensidyne Model AP-20S pump kit and with ammonia and amine tubes with Ranges of 1 to 20 ppm with sensitivity of 0.05 ppm. Amine and ammonia were generally not detected in the inflow air. 
     
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Flow 
                 Retention 
                 H 2 S in 
                 H 2 S in 
                 Removal 
                 Ammonia 
                 Amine 
               
               
                   
                 Rate (cfm) 
                 time(s) 
                 Inflow (ppm) 
                 Outflow (ppm) 
                 (%) 
                 (ppm) 
                 (ppm) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Week 1 
                 25 
                 15.4 
                 700 †   
                 0 †   
                 100 †   
                 — 
                 — 
               
               
                 Week 2 
                 50 
                 7.68 
                 329 §   
                 3 §   
                  99 §   
                 — 
                 — 
               
               
                   
                   
                   
                 200 †   
                 0 †   
                 100 †   
               
               
                 Week 3 
                 75 
                 5.12 
                 312 §   
                 0 §   
                 100 §   
                 — 
                 — 
               
               
                   
                   
                   
                 350 †   
                 0 †   
                 100 †   
               
               
                 Week 4 
                 75 
                 5.12 
                 157 §   
                 1 §   
                  99 §   
                 — 
                 — 
               
               
                   
                   
                   
                 175 †   
                 0 †   
                 100 †   
               
               
                 Week 5 
                 58 
                 6.61 
                 138 §   
                 0 §   
                 100 §   
                 5 
                 5 
               
               
                   
                   
                   
                  81 †   
                 0 †   
                 100 †   
               
               
                 Week 6 
                 67 
                 5.73 
                 173 §   
                 1 §   
                  99 §   
                 8 
                 10 
               
               
                 Week 7 
                 78 
                 4.92 
                 236 §   
                 3 §   
                  99 §   
                 8 
                 3 
               
               
                 Week 8 
                 78 
                 4.92 
                 161 §   
                 4 §   
                  98 §   
                 18 
                 10 
               
               
                 Week 9 
                 78 
                 4.92 
                 222 §   
                 4 §   
                  98 §   
                 — 
                 1 
               
               
                   
               
               
                   § Odalog Model Type 1 [average value] 
               
               
                   † Sensidyne test [spot test] 
               
             
          
         
       
     
     As indicated in Table 1, the bed of sulfide scavenging media was able to remove to generally detectible limits sulfurous compounds in the form of H 2 S from the inflow air at concentrations in excess of 300 ppm with retention times less than or equal to about 15 seconds. For example, the bed converted H 2 S with an inflow concentration of 329 ppm at a retention time of 7.68 seconds as indicated by the data for Week 2 in Table 1. The small amounts of H 2 S in the outflow air measured at Weeks 7, 8, and 9 in Table 1 may be the result of incomplete conversion of the H 2 S in the sulfide scavenging media due to the relatively short retention time of 4.92 seconds in combination with H 2 S concentration in excess of 150 ppm, and not the result of column break through or exhaustion of the sulfide scavenging media. Based on analysis of these results, it was estimated that 1 ft 3  of sulfide scavenging media converted 12.1 lbs of H 2 S during the 70 day period of this Example—see Appendix 1. 
     In general, for an H 2 S concentration of less than about 50 ppm, retention time of between about 5 seconds and about 10 seconds is preferred in order to ensure complete conversion of the H 2 S. For an H 2 S concentration between about 50 ppm and about 150 ppm, it is preferred that the retention time should be generally within the range of from about 10 seconds to about 15 seconds. For an H 2 S concentration between about 150 ppm and about 1000 ppm, it is preferred that the retention time should be generally in the range of from about 15 seconds to about 20 seconds. 
     Peak (maximum) values for H 2 S for the inflow air into the bed and the outflow air from the bed as measured using the Odalog Model Type 1 for Example 3 are presented in Table 2. 
     
       
         
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Peak H 2 S in 
                   
               
               
                   
                 Peak H 2 S in 
                 Outflow 
                   
               
               
                   
                 Inflow (ppm) 
                 (ppm) 
                 Removal % 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Week 1 
                 — 
                 — 
                 — 
               
               
                   
                 Week 2 
                 816 
                 74 
                 90 
               
               
                   
                 Week 3 
                 878 
                 1 
                 100  
               
               
                   
                 Week 4 
                 755 
                 22 
                 97 
               
               
                   
                 Week 5 
                 299 
                 3 
                 99 
               
               
                   
                 Week 6 
                 594 
                 10 
                 98 
               
               
                   
                 Week 7 
                 1000* 
                 32 
                 97 
               
               
                   
                 Week 8 
                 996 
                 34 
                 97 
               
               
                   
                 Week 9 
                 398 
                 48 
                 88 
               
               
                   
                 Week 10 
                 1000* 
                 16 
                 98 
               
               
                   
                   
               
               
                   
                 *the maximum measurable value using the Odalog Model Type 1 
               
               
                   
                 — the actual value may exceed 1000 ppm. 
               
             
          
         
       
     
     As indicated by the results in Table 2, the bed of sulfide scavenging media is generally able to convert and thus generally remove H 2 S from the influent air at H 2 S concentrations approaching or exceeding 1000 ppm without breakthrough or exhaustion over the indicated time period. By increasing the retention time of the air in the bed of sulfide scavenging media, it is posited that the removal may reach about 100% at H 2 S concentrations of 1000 ppm or more. 
       FIGS. 3A and 3B  illustrates measured inflow and outflow concentrations of H 2 S during Week 10.  FIG. 3A  illustrates graphically the measured H 2 S concentration in ppm of the inflow air into the bed as a function of time during Week 10 of Example 3 as measured using the Odalog Model Type 1. The H 2 S concentration in the inflow air is characterized by spikes about the average H 2 S concentration, as illustrated. The temperature in degrees Fahrenheit of the inflow air is also shown in  FIG. 3A . Note that the Odalog Model Type 1 measures H2S concentrations up to 1000 ppm so that the 1000 ppm spike in  FIG. 3A  could be indicative of an H 2 S concentration greater than 1000 ppm. Also, the bed of sulfide scavenging media has not been recharged during the 10 week period covered by this Example. No substantial reductions in air flow through the bed were noted during the 10 week period encompassed by this example such as might be caused by build up of polysulfide in the bed. 
       FIG. 3B  illustrates graphically the corresponding measured H 2 S concentration in ppm of the outflow air from the bed as a function of time during Week 10 of Example 3 as measured using the Odalog Model Type 1.  FIG. 3B  also shows the temperature in degrees Fahrenheit of the outflow air from the bed. In general, the bed of sulfide scavenging media is able to respond to the spikes of H 2 S concentration in the inflow so that the H 2 S is generally removed from the outflow air, as indicated by  FIG. 3B . 
     APPENDIX 1 
     Average H 2 S concentration into the bed=264 ppm
         Average H 2 S concentration out of the bed=2 ppm
           Time period=70 d.   
           Average flow rate=63 ft 3 /min
           Temperature≈20° C.=293K
 
The mass of H 2 S retained in the bed can then be calculated by:
 
262 ppm×[34 g/mole]/[(0.0825 atm l/mole K)(293 K)]=368 mg/m 3 →3.68×10 −4  kg/m 3  
 
63 ft 3 /min×60 min/hr×24 h/d×70 d=6.35×10 6  ft 3 =1.80×10 5  m 3  
 
3.68×10 −4  kg/m 3 ×1.80×10 5  m 3 =66.2 kg=145.7 lbs
   
           Bed volume=6.4 ft 3 =0.1812 m 3  
 
The mass of H2S retained in the bed is then 66.2 kg/0.1812 m 3 =365 kg/m 3 =22.6 lb/ft 3  
       

     The foregoing along with the accompanying Figures discloses and describes various exemplary implementations. Upon study thereof, one of ordinary skill in the art may readily recognize that various changes, modifications and variations can be made therein without departing from the spirit and scope of the inventions as defined in the following claims.