Abstract:
A method for treating contaminates includes delivering a stream of a fluid to a directional microporous diffuser that has a sidewall with microscopic openings and has a partitioned interior region to effect discharge of microbubbles from less than the entire sidewall portion of the directional microporous diffuser at any particular interval of time. The directional microporous diffuser described include an elongated member providing the sidewall, the sidewall defining an interior portion of said member and coupled to the first inlet port and a partition member that divides the interior of the elongated member into plural, mutually isolated regions. End caps are disposed to seal ends of the directional microporous diffuser.

Description:
BACKGROUND  
       [0001]     There is a well-recognized need to clean-up contaminants found in ground water, i.e., aquifers and surrounding soil formations. Such aquifers and surrounding soil formations may be contaminated with various constituents including organic compounds such as, volatile hydrocarbons, including chlorinated hydrocarbons such as dichloroethene (DCE), trichloroethene (TCE), and tetrachloroethene (PCE). Other contaminates that can be present include vinyl chloride, 1,1 trichloroethane (TCA), and very soluble gasoline additives such as methyl tertiary butyl ether (MTBE). Other contaminants may also be encountered.  
       SUMMARY  
       [0002]     According to an aspect of this invention, a method includes delivering a stream of a fluid to a directional microporous diffuser that has a sidewall with microscopic openings and has a partitioned interior region to effect discharge of microbubbles from less than the entire sidewall portion of the directional microporous diffuser.  
         [0003]     Other aspects of the invention include the directional microporous diffuser including an elongated member providing the sidewall, the sidewall defining an interior portion of said member and coupled to the first inlet port, a partition member that divides the interior of the elongated member into plural, mutually isolated regions and caps to seal ends of the directional microporous diffuser. The elongated member is a cylinder. The caps support the first inlet port and additional plural inlet ports. The first inlet port and additional plural inlet ports are arranged to be in fluid communication with corresponding ones of the mutually isolated regions of the directional microporous diffuser. A solenoid-controlled distribution valve is coupled to the first inlet ports and additional plural inlet ports. The microporous diffuser can be disposed in a well or injected. The microporous diffuser emits microbubbles having a size in a range of 1 to 200 microns. The partitioning member divides the interior of the elongated member into four quadrants.  
         [0004]     According to a further aspect of this invention, an apparatus includes a distribution arrangement to receive a fluid, a directional microporous diffuser, the directional microporous diffuser including an hollow elongated member having a sidewall with a large plurality of microporous openings, a partitioning member disposed in the interior of the hollow elongated member to divide the interior of the hollow elongated member into mutually isolated regions, with the regions being in fluid communication with the distribution arrangement and a control arrangement to control the distribution arrangement to effect discharge of fluid into selected ones of the mutually isolated regions in the elongated member to cause microbubbles to emanate from correspond portions of the sidewall of the directional microporous diffuser.  
         [0005]     Other aspects of the invention include an ozone generator coupled to the first port of the directional microporous diffuser to deliver ozone and air as the first and second fluids. The elongated member is a cylinder. Microbubbles emanate from less than the entire sidewall portion of the directional microporous diffuser. The apparatus further includes a first pump to deliver a first stream of first fluid to the distribution arrangement and a second pump to deliver a second stream of a second fluid to the distribution arrangement. The directional microporous diffuser emits microbubbles having a size in a range of 1 to 200 microns.  
         [0006]     According to a still further aspect of this invention, apparatus includes an elongated hollow member having a sidewall with a porosity characteristic, a partitioning member disposed within the elongated hollow member to partition the interior of the elongated hollow member into plural, mutually isolated chambers, a first cap with plural inlet ports that are in fluid communication with the plural mutually isolated chambers and an end cap to seal a second end of the directional microporous diffuser.  
         [0007]     The sidewalls of the elongated member have a porosity characteristic of less than 200 microns. The sidewalls of the elongated member have a porosity characteristic of less than 100 microns. The directional microporous diffuser emits microbubbles having a size in a range of 0.5 to 80 microns. The sidewall is comprised of a metal or a plastic. The sidewall is of a hydrophobic material. The sidewall is comprised of sintered fused microscopic particles of plastic.  
         [0008]     According to a still further aspect of this invention, a directional microporous diffuser includes a first elongated member including at least one sidewall having a plurality of microscopic openings, the sidewall defining an interior hollow portion of said member. The directional microporous diffuser further includes a second elongated member having a second sidewall having a plurality of microscopic openings, the second member being disposed through the hollow region of the first member. The directional microporous diffuser further includes a first partitioning member disposed inside and along a length of the first elongated member to provide a first plurality of isolated chambers and a second partitioning member disposed of the first elongated member and the second elongated member along the length of the first and second elongated members to provide a second plurality of isolated chambers. The directional microporous diffuser further includes an end cap to seal a first end of the directional microporous diffuser and an inlet cap disposed at a second end of directional microporous diffuser for receiving inlet fittings.  
         [0009]     Other embodiments include the directional microporous diffuser having a region defined between the first and second elongated members filled with a catalyst suspension material. The directional microporous diffuser of claim has the first and second partitioning members aligned to provide the first plurality of isolated chambers aligned to the second plurality of isolated chambers. The directional microporous diffuser includes the inlet cap includes multiple inlet fittings, a first portion of the multiple inlet fittings in fluid communication with the corresponding chambers in the first member, and a second portion of the multiple inlet fittings in fluid communication with the corresponding chambers in the second member.  
         [0010]     One or more advantages can be provided from the above.  
         [0011]     While, a non-partitioned microporous diffuser can enlarge its radius of influence (ROI) by placing the non-partitioned microporous diffuser deeper within an aquifer, e.g., a substantial distance below the contaminants, the directional microporous diffuser provides a mechanism that can discharge microbubbles over a broad lateral area while having directional microporous diffuser remain close to contaminated groundwater zones during sparging. The directional microporous diffuser can cover broad lateral areas without diluting its effectiveness, since the oxidant gas emitted from the directional microporous diffuser can be emitted close to the source of contamination. The lateral areas over which the microbubbles are emitted can be larger since all of the microbubbles emitted from the directional microporous diffuser can be directed into one area at a time.  
         [0012]     The partitioning member permits microbubbles to emerge from the surface of the directional microporous diffuser over portions of the directional microporous diffuser in accordance with which of the inlet ports of the directional microporous diffuser receives the fluid stream from the outlet ports of the solenoid-controlled valve. The partition member in the directional microporous diffuser together with the solenoid valve permits a gas stream from the central feed to be directed through one, two, three or all four of the quadrants of the directional microporous diffuser. In general, using a single quadrant at a time permits the microbubbles to exit the directional microporous diffuser and provide a generally elliptical shaped zone of influence in the surrounding soil formation. The zone of influence will extend further in a direction perpendicular from the directional microporous diffuser than tangentially from the sidewalls of the directional microporous diffuser  
         [0013]     The solenoid-controlled valve can be controlled to rotate the pattern of microbubbles emitted from the directional microporous diffuser. Thus, microbubbles exit from only a first quadrant during a first time period, then only from a second quadrant during a second time period, and so forth. The control can be automated or manual. The directional microporous diffuser allows fewer wells and sparging arrangements to be constructed on a site for a given sparging arrangement capacity, since all of the capacity of the pumps and so forth are directed into a single portion, e.g., quadrant of a microporous diffuser at any one time. The directional microporous diffuser can also be used to direct treatment towards especially high concentrations of contaminants while minimizing treatment materials in areas of lower contaminant concentrations.  
         [0014]     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
     
    
     DESCRIPTION OF DRAWINGS  
       [0015]      FIG. 1  is a cross-sectional view showing a sparging treatment example.  
         [0016]      FIG. 2  is a cross-sectional view showing an alternative sparging treatment example.  
         [0017]      FIGS. 3A-3D  are diagrams depicting details of connections of a directional diffuser in the example shown in FIGS.  1  or  2 .  
         [0018]      FIGS. 4A and 4B  are cross-sectional view of sidewalls of the directional microporous diffusers of  FIGS. 3A, 3B  showing exemplary construction details.  
         [0019]      FIGS. 5A and 5B  are longitudinal cross-section and plan cross-sectional views of a directional microporous diffuser useful in the arrangement of  FIG. 1 .  
         [0020]      FIG. 6  is a cross-sectional view showing a sparging treatment example. 
     
    
     DETAILED DESCRIPTION  
       [0021]     Referring now to  FIG. 1 , a sparging arrangement  10  for treating plumes, sources, deposits or occurrences of contaminants, is shown. The arrangement  10  is disposed in a well  12  that has a casing  14  with an inlet screen  14   a  and outlet screen  14   b  to promote a re-circulation of water into the casing  14  and through the surrounding ground/aquifer region  16 . The casing  14  supports the ground about the well  12 . Disposed through the casing  14  are one or more directional microporous diffusers  50  (discussed in  FIGS. 3A-3C ).  
         [0022]     The arrangement  10  also includes a first air compressor/pump  22  and a compressor/pump control mechanism  27  to feed a first fluid, e.g., air into a two port mixing valve  23  and a second pump  26  and coupled to a second source, e.g., a ozone generator  28  to feed ozone (O 3 ) to the mixing valve  23 . Other arrangements are possible.  
         [0023]     The mixing valve  23  is coupled via a check valve  25  to an inlet port of a solenoid-controlled valve  30 . Solenoid-controlled valve  30 , as shown in  FIG. 3D , has a common inlet port  31  and here four branch or outlet ports  32   a - 32   d.  A control arrangement  35  controls the solenoid-controlled valve  30 . The control arrangement  35  can be a series of switches to actuate the solenoids, via lines  35   a,  or could be more complicated schemes. The gas mixture from the central mixing valve  23  is distributable to each of the outlet ports  32   a - 32   d  of the solenoid-controlled valve  30 .  
         [0024]     The directional microporous diffuser  50  is fitted tightly inside the casing and in some embodiments the casing itself can be partitioned (not shown). For the embodiments where the casing is partitioned, the directional microporous diffuser  50  is aligned in the casing such that quadrants in the directional microporous diffuser  50  are aligned with quadrants in the casing. In some embodiments, packing material, e.g., sand may be disposed around the directional microporous diffuser  50 . In other embodiments, grooves and rails (not shown) can be provided on the casing and directional microporous diffuser respectively, to allow the directional microporous diffuser to slide down the casing in alignment with partitions in the casing. The grooves and rails (not shown) in addition to providing alignment also provide an inherent isolation of the quadrants of the directional microporous diffuser  50  when inserted in the casing  14 .  
         [0025]     A non-partitioned microporous diffuser can enlarge its radius of influence (ROI) by placing the microporous diffuser deeper within an aquifer, e.g., a substantial distance below the contaminants. However, this approach dilutes the effectiveness of such a microporous diffuser since the oxidant gas emitted from the non-partitioned microporous diffuser travels vertically for some distance in order to reach the contaminants. Along the way some of the oxidant can dissolve or is absorbed or otherwise become ineffective. The directional microporous diffuser  50  provides a mechanism that can cover broad laterally areas while staying close to contaminated groundwater zones.  
         [0026]     Referring now to  FIG. 2 , an alternative sparging arrangement  100  for treating plumes, sources, deposits or occurrences of contaminants, is shown. The arrangement  100  includes one or more directional microporous diffusers  50  (discussed in  FIGS. 3A-3C ) disposed directly through a surrounding ground/aquifer region  16 . As shown in  FIG. 2 , the directional microporous diffusers  50  are of a type that has a pointed member  51  on an end thereof to allow the pointed member to be driven or injected into the ground without the need for a well or casing as in  FIG. 1 .  
         [0027]     The arrangement  100  also includes the first air compressor/pump  22 , the compressor/pump control mechanism  27 , two port mixing valve  23 , the second pump  26 , ozone generator  28  and so forth as discussed above. The mixing valve  23  is coupled via a check valve  25  to an inlet port of a solenoid-controlled valve  30  controller via the control arrangement  35 , as also discussed above.  
         [0028]     In either arrangement  10  or  100 , the outlet ports of the solenoid-controlled valve  30  are controlled by solenoids that selectively open and close the outlet ports  32   a - 32   d  permitting fluid to escape from one or more of the outlet ports  32   a - 32   d.  The outlet ports  32   a - 32   d  are coupled to feed lines generally  33  that are coupled to inlet fittings on a cap of the directional microporous diffuser  50 . The directional microporous diffuser  50  allows microbubbles to be directed in selected directions into a surrounding soil formation  16 , as discussed below.  
         [0029]     In the embodiment described, a gas stream of ozone and air is delivered to the directional microporous diffuser  50 . Other fluid streams could be used including, air, air enhanced with oxygen, a gas and liquid, e.g., hydrogen peroxide, air/ozone enhanced with hydrogen peroxide, or a hydro peroxide and so forth.  
         [0030]     In the illustrated embodiment, microbubbles of air and ozone exit from walls of the directional microporous diffuser  50 . The microbubbles of air/ozone affect substantial removal of below-mentioned or similar types of contaminants. The arrangement  10  can also include a pump (not shown) that supplies nutrients such as catalyst agents including iron containing compounds such as iron silicates or palladium containing compounds such as palladized carbon. In addition, other materials such as platinum may also be used.  
         [0031]     The microbubbles promote rapid gas/gas/water reactions with volatile organic compounds, in which a substrate (catalyst or enhancer) participates in, instead of solely enhancing dissolved (aqueous) disassociation and reactions. The production of microbubbles and selection of appropriate size distribution is provided by using microporous material and a bubble chamber for optimizing gaseous exchange through high surface area to volume ratio and long residence time within the liquid to be treated. The equipment promotes the continuous production of microbubbles while minimizing coalescing or adhesion.  
         [0032]     The injected air/ozone combination moves as a fluid into the material to be treated. The use of microencapsulated ozone enhances and promotes in-situ stripping of volatile organics and simultaneously terminates the normal reversible Henry s reaction. The process involves promoting simultaneous volatile organic compounds (VOC) in-situ stripping and gaseous decomposition, with moisture (water) and substrate (catalyst or enhancer). The basic chemical reaction mechanism of air/ozone encapsulated in micron-sized bubbles is further described in several of my issued patents such as U.S. Pat. No. 6,596,161 “Laminated microporous diffuser”; U.S. Pat. No. 6,582,611 “Groundwater and subsurface remediation”; U.S. Pat. No. 6,436,285 “Laminated microporous diffuser”; U.S. Pat. No. 6,312,605 “Gas-gas-water treatment for groundwater and soil remediation”; and U.S. Pat. No. 5,855,775, “Microporous diffusion apparatus” all of which are incorporated herein by reference.  
         [0033]     The compounds commonly treated are HVOCs (halogenated volatile organic compounds), PCE, TCE, DCE, vinyl chloride (VC), EDB, petroleum compounds, aromatic ring compounds like benzene derivatives (benzene, toluene, ethylbenzene, xylenes). In the case of a halogenated volatile organic carbon compound (HVOC), PCE, gas/gas reaction of PCE to by-products of HCl, CO2 and H2O accomplishes this. In the case of petroleum products like BTEX (benzene, toluene, ethylbenzene, and xylenes), the benzene entering the bubbles reacts to decompose to CO2 and H2O.  
         [0034]     Also, pseudo Criegee reactions with the substrate and ozone appear effective in reducing saturated olefins like trichloro alkanes (1,1,1,-TCA), carbon tetrachloride (CCl 4 ), chloroform methyl chloride, and chlorobenzene, for instance.  
         [0035]     Other contaminants that can be treated or removed include hydrocarbons and, in particular, volatile chlorinated hydrocarbons such as tetrachloroethene, trichloroethene, cisdichloroethene, transdichloroethene, 1-1-dichloroethene and vinyl chloride. In particular, other materials can also be removed including chloroalkanes, including 1,1,1 trichloroethane, 1,1, dichloroethane, methylene chloride, and chloroform. Also, aromatic ring compounds such as oxygenates such as O-xylene, P-xylene, naphthalene and methyltetrabutylether (MTBE), ethyltetrabutylether, and tertiaryamyltylether can be treated.  
         [0036]     Ozone is an effective oxidant used for the breakdown of organic compounds in water treatment. The major problem in effectiveness is that ozone has a short lifetime. If ozone is mixed with sewage containing water above ground, the half-life is normally minutes. Ozone reacts quantitatively with PCE to yield breakdown products of hydrochloric acid, carbon dioxide, and water.  
         [0037]     To offset the short life span, the ozone is injected with directional microporous diffusers, enhancing the selectiveness of action of the ozone. By encapsulating the ozone in fine bubbles, the bubbles would preferentially extract a vapor phase fraction of the volatile compounds organic compounds they encountered. With this process, a vapor phase according to a partition governed by Henry&#39;s Law, of the volatile organics are selectively pulled into the fine air-ozone bubbles. The gas that enters a small bubble of volume (4πr3) increases until reaching an asymptotic value of saturation. The ozone in the bubbles attacks the volatile organics, generally by a Criegee or Criegee like reaction.  
         [0038]     The following characteristics of the contaminants appear desirable for reaction:  
                                                       Henry&#39;s Constant:   10 −2  to 10 −4  m 3  atm/mol           Solubility:   10 to 20,000 mg/l           Vapor pressure:    1 to 3000 mmhg           Saturation concentration:    5 to 9000 g/m 3                        
 
         [0039]     The production of microbubbles and selection of appropriate size distribution are selected for optimized gas exchange through high surface area to volume ratio and long residence time within the area to be treated.  
         [0040]     Referring now to  FIGS. 3A-3D , exemplary details of an arrangement of the directional microporous diffuser  50  associated piping and the solenoid-controlled valve  30  is shown. The directional microporous diffuser  50  includes a first cylindrical member  56  that provides an outer cylindrical shell for the directional microporous diffuser  50 . The cylindrical member  56  has a sidewall  56   a  comprised of a large plurality of micropores. A partitioning member  60  is coaxially disposed within the cylindrical member  56  and generally affixed, e.g., bonded or otherwise affixed to the inner portions of sidewall  56   a  by e.g., ridges and groves. Alternatively, the partitioning member is formed with the cylindrical member by being extruded with the cylindrical member, and so forth). The partitioning member  60 , as illustrated, is comprised of two planar members that intersect each other at the center of the members, and which divides the cylindrical member into four, mutually isolated interior chambers  60   a - 60   d  along the length of the member  60 , and which is particularly shown in the views of  FIGS. 3B and 3C . Other configurations of fewer or more isolated chambers are possible.  
         [0041]     The partitioning member  60  permits microbubbles to emerge from the surface of the directional microporous diffuser  50  over four, here equally sized quadrants. The microbubbles emerge from the quadrants in accordance with which on the inlet ports  52   a - 52   d  of the directional microporous diffuser  50  receives the fluid stream from the outlet ports  32   a - 32   d  of the solenoid-controlled valve  30 .  FIG. 3D  shows in pictorial detail the solenoid-controlled valve  30  including inlet  31  and the outlet ports  32   a - 32   d.    
         [0042]     Proximate ends of the cylindrical members  56  are coupled to inlet ports generally denoted as  52   a.  The inlet ports  52   a  are supported on an inlet cap  52  that seals one end of the cylindrical member  56 . The inlet ports  52   a  are arranged in relation to the four mutually isolated chambers  60   a - 60   d  provided within the directional microporous diffuser  50  such that the inlet ports  52   a  allow a fluid delivered to the inlet ports  52   a  to enter the respective chamber in the interior of the directional microporous diffuser. In one embodiment, the fluid delivered to the inlet ports  52   a  is a mixture of air and ozone, as described above. At the opposite end of the directional microporous diffuser  50  an end cap  54  covers the second, distal end of cylindrical member  56 . Together end cap  54  and cap  52  seal the ends of the directional microporous diffuser  50 . While, the cylindrical member  56  is disclosed as being cylindrical in shape, in general the configuration could have other shapes. The partitioning member  60  can extend beyond the length of the cylindrical member such that ends of the partitioning member  60  sit in grooves provided in caps  52  and  54 .  
         [0043]     The cylindrical member  56  has a plurality of microscopic openings constructed through sidewalls  56   a.  The openings generally have a pore sizes matched to a surrounding ground formation so as to be effective for inducing gas/gas reactions with introduction of the microbubbles. Sidewalls of each of the cylindrical members can have a pore diameter in a range of 1-200 microns, preferably 1-80 microns and more preferably 1-20 microns. The combination of the inlet cap  52  and end cap  54  seals the directional microporous diffuser  50  permitting the microbubbles to escape only via the porous construction of the sidewalls of the directional microporous diffusers.  
         [0044]     The partition member  60  in the directional microporous diffuser  50  together with the solenoid valve  30  permits a gas stream from the central feed to be directed through one, two, three or all four of the quadrants of the directional microporous diffuser  50 . Thus, the pattern of the gas stream that exits from the directional microporous diffuser can be adjusted. In general, using a single quadrant at a time permits the bubbles to exit the directional microporous diffuser and have a generally elliptical shaped zone of influence in the surrounding soil formation, that is the zone of influence will extend further in a direction perpendicular from the directional microporous diffuser  50  that tangentially from the sidewalls of the directional microporous diffuser  50 . The treatment zone has a longer radius perpendicular to the surface of the directional microporous diffuser than the treatment zone that could be provided were the arrangement used with a non partitioned, non directional microporous diffuser.  
         [0045]     The solenoid-controlled valve  30  can be controlled to rotate the pattern of microbubbles emitted from the directional microporous diffuser  50  by permitting microbubbles to exit from only a first quadrant, then only a second quadrant, and so forth. The control can be automated or manual. The directional microporous diffuser  50  allows fewer wells and sparging arrangements  10  to be constructed on a site for a given sparging arrangement capacity by directing all of the capacity of the pumps and so forth into a single quadrant of a directional microporous diffuser at any one time. The directional microporous diffuser  50  can also be used to direct treatment towards especially high concentrations of contaminants while minimizing treatment materials in areas of lower contaminant concentrations. Once a first region is treated, the solenoid can be activated to close the outlet that feeds the first quadrant that treated the first region and open a second outlet of the solenoid to feed a second, different quadrant and treat a second different region.  
         [0046]     Referring now to  FIGS. 4A, 4B  details of sidewalls of the directional microporous diffusers  50  are shown.  FIG. 4A  shows that sidewalls of the members can be constructed from a metal or a plastic support layer  91  having large (as shown) or fine perforations  91   a  over which is disposed a layer of a sintered i.e., heat fused microscopic particles of plastic. The plastic can be any hydrophobic material such as polyvinylchloride, polypropylene, polyethylene, polytetrafluoroethylene, high-density polyethylene (HDPE) and ABS. The support layer  91  can have fine or coarse openings and can be of other types of materials. Other materials are possible such as porous stainless steel and so forth.  
         [0047]      FIG. 4B  shows an alternative arrangement  94  in which sidewalls of the members are formed of a sintered i.e., heat fused microscopic particles of plastic. The plastic can be any hydrophobic material such as polyvinylchloride, polypropylene, polyethylene, polytetrafluoroethylene, high-density polyethylene (HDPE) and alkylbenzylsulfonate (ABS).  
         [0048]     The fittings (e.g., the inlets in  FIGS. 3A-3D ) can be threaded and are attached to the inlet cap members by epoxy, heat fusion, solvent or welding with heat treatment to remove volatile solvents or other approaches. Standard threading can be used for example NPT (national pipe thread) or box thread e.g., (F480). The fittings are securely attached to the directional microporous diffusers in a manner that insures that the directional microporous diffusers can handle pressures that are encountered with injecting of the air/ozone.  
         [0049]     Referring now to  FIGS. 5A and 5B , an alternate embodiment  70  of a directional microporous diffuser is shown. The directional microporous diffuser  70  includes an outer cylindrical member  76  having a sidewall  76   a  within which is disposed an inner cylindrical member  78  having a sidewall  78   a.  The inner cylindrical member  78  is spaced from the sidewall  78   a  of the outer cylindrical member. The space  77  between the inner and outer cylindrical members  76 ,  78  is filled with a packing material comprised of glass beads or silica particles (silicon dioxide) or porous plastic that is hydrophilic. A first partitioning member  71  is disposed within the inner cylindrical member  78  and a second partitioning member  73  generally aligned with the first partitioning member  71  is disposed between inner portions of the sidewall  76   a  of the outer cylindrical member  76  and the outer portions of the sidewall  78   a  of the inner cylindrical member  78 . The space  77  is coupled to input ports generally  72   b.    
         [0050]     The directional microporous diffuser  70  has the inner cylindrical member  76  disposed coaxial or concentric to cylindrical member  78 . Sidewalls of each of the cylindrical members  76 ,  78  can have a pore diameter in a range of 1-200 microns, preferably 1-5.0 microns and more preferably 5-20 microns. A proximate end of the inner cylindrical member is coupled to inlet ports  72   a,  which are fed an air ozone mixture from the first solenoid valve  30 . The directional microporous diffuser also includes an end cap  74 , which secures distal ends of the cylinders  76  and  78 . The combination of the inlet cap  72  and end cap  74  seals the directional microporous diffuser permitting liquid and gas to escape by the porous construction of sidewalls of the directional microporous diffusers.  
         [0051]     The partition members  71  and  73  in the directional microporous diffuser  70  together with the solenoid valve  30  permit a gas stream to be directed through one, two, three or all four of the quadrants of inner member  78 . The gas stream that exits from inner member  78  enters outer quadrants between the inner and outer members where it mixes with, e.g., liquid to coat the microbubbles with a liquid coating of, e.g., water or hydrogen peroxide or a hydro peroxide. In general, using a single quadrant at a time permits the coated microbubbles to exit the directional microporous diffuser  70  over the sidewall surface of a single quadrant. The coated microbubbles cover a generally elliptical shaped zone of influence in the surrounding soil formation, as discussed above for directional microporous diffuser  50 .  
         [0052]     Referring to  FIG. 6  an example of a sparging arrangement  120  using the directional microporous diffuser  70  is shown. The sparging arrangement  120  includes a source  123  (of liquid and catalysts, and/or nutrients) and a pump  122  coupled to a check valve  125  and a second solenoid-controlled valve  130 . The second solenoid-controlled valve  130  has outlets (not numbered) coupled to a second set of feed lines  133  that are coupled to input ports  72   b  of the directional microporous diffuser  70 . The directional microporous diffuser  70  receives liquid, catalysts, and/or nutrients, which mixes in the directional microporous diffuser  70  with the gaseous stream provided via feed lines  33  to effect coated microbubbles and so forth, as in the patents mentioned above, e.g., U.S. Pat. Nos. 6,582,611 or 6,436,285 for instance. Otherwise, the arrangement  120 , as shown in  FIG. 6 , is analogous to the arrangements  10 ,  100  shown in FIGS.  1  or  2  but for the addition of the pump  122 , source  123 , check valve  125 , the second set of feed lines  133  and the second solenoid-controlled valve  130 . The control arrangement  35  is shown controlling both solenoid-controlled valves  30  and  130 .  
         [0053]     A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention.