Patent Abstract:
A diffuser useful for sparging to remove contaminant in situ is described. The diffuser includes a first elongated member having a sidewall with a first portion of the length of the sidewall being microporous, and a second portion of the length of the sidewall having well screen sized openings with the first elongated member defining an interior hollow portion of the diffuser, a second elongated member having a second sidewall having a plurality of microscopic openings, said second member being disposed through the hollow region of said first member and a third elongated member having a third sidewall having a plurality of microscopic openings, said third member being disposed coaxial with the first and second members. An end cap is disposed to seal a first end of the third elongated member, and being in contact with the second elongated member forms a chamber. The diffuser has an inlet arrangement disposed at a second end of diffuser for supporting a first inlet fitting to coupled to an peripheral interior portion of the diffuser adjacent the first member, a second fitting to couple to the chamber, and a third fitting coupled to the third member.

Full Description:
BACKGROUND 
   There is a well-recognized need to clean-up contaminants that exist 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 trichloroethene (TCE), tetrachloroethene (PCE). Other contaminates that can be present include vinyl chloride, 1,1 trichloroethane (TCA), and very soluble gasoline additives such as methyltertiarybutylether (MTBE). Other contaminants may also be encountered. 
   SUMMARY 
   According to an aspect of this invention, a diffuser includes a first elongated member having a sidewall with a first portion along the length of the sidewall having microporous openings, and a second portion along the length of the sidewall having well screen sized openings, the first elongated member defining an interior portion of the diffuser. The diffuser includes a second elongated member having a second sidewall having a plurality of microscopic openings, the second member being disposed through the interior region of the first member. The diffuser includes a third elongated member having a third sidewall having a plurality of microscopic openings, the third member being disposed coaxial with the first and second members. The diffuser also has an end cap to seal a first end of the third elongated member, and being in contact with the second elongated member to form a chamber and an inlet arrangement disposed at a second end of diffuser for supporting a first inlet fitting that provides an peripheral interior portion of the diffuser adjacent the first member, a second fitting to couple to the chamber, and a third fitting coupled to the third member. 
   The diffuser has a chamber defined between the first and second elongated members filled with a microporous material. The diffuser has the first, second and third elongated members configured as cylinders, with the third cylinder disposed concentric to the second cylinder, and the second cylinder disposed concentric to the first cylinder. The diffuser has the inlet cap including a first fitting disposed at a peripheral portion thereof that permits a fluid to be injected into a inner peripheral portion of the diffuser, a second fitting disposed to permit a liquid to be injected through the chamber and a third fitting disposed to permit a gas to be injected through the region defined by the third member. Fluid injected through the first fitting is injected under conditions to cause a sheering action on bubbles that exit from sidewalls of the second member, to be carried away through the well-screen sized openings in the second sidewall portion. The diffuser can have a catalyst disposed in glass beads in the chamber with the catalyst containing iron. The second and third members have microscopic openings having a diameter in a range of 0.1 to 200 microns. 
   According to a further aspect of this invention, a method includes delivering a first fluid to a first port of a diffuser and delivering a gas stream to the diffuser and a liquid to a second port of the diffuser to effect production of microbubbles coated with the liquid, the coated microbubbles diffusing towards peripheral portions of the diffuser and being carried away from those peripheral portions by the first fluid stream. 
   According to a further aspect of this invention, apparatus includes a first pump to deliver a first stream of gas, a second pump to deliver a second stream of gas, and a multi-fluid diffuser disposed in the well, the multi-fluid microporous diffuser. The first, second and third inlet ports to allow entry of first second and third fluids to the multi-fluid diffuser. The multi-fluid diffuser includes a first elongated member having a sidewall with a first portion of the length of the sidewall being microporous, and a second portion of the length of the sidewall having well screen sized openings with the first elongated member defining an interior hollow portion of the diffuser, a second elongated member having a second sidewall having a plurality of microscopic openings, said second member being disposed through the hollow region of said first member; a third elongated member having a third sidewall having a plurality of microscopic openings, said third member being disposed coaxial with the first and second members and an end cap to seal a first end of the microporous diffuser. 
   One or more advantages can be provided from the above. 
   A first fluid is introduced through the inlet attached to the third member as a gas mixture such as ozone/air. The second fluid is a liquid such as hydrogen peroxide, which coats bubbles that are produced from the gas delivered to the first inlet. The third fluid is a liquid such as water, which is injected and acts as a shearing flow to shear coated microbubbles off of the sidewall of the second member. By adjusting the velocity of the shearing fluid, microbubbles of very small size can be produced (e.g., sub-micron sized bubble diameters). Adjusting the conditions and porosity characteristics of the materials can produce larger size bubbles. 
   The outer cylindrical member can be terminated by a point member to enable the multi-fluid diffuser to be driven into the ground, with or without a well. The space between the second and third members of multi-fluid diffuser is filled with microporous materials that can be any porous materials such as microbeads with mesh sizes from 20 to 200 mesh, or sand pack, or porous hydrophilic plastic. 
   Further, the chemical oxidation potential can be adjusted to match the type and mass of the organic compounds being oxidized by varying the nature and proportion of the oxidant added. 
   In operation, the multi-fluid diffuser is disposed in a wet soil or an aquifer with or without a well. The multi-fluid diffuser receives three fluid streams. In one embodiment, the first stream that is fed to the inlet is a liquid such as water, whereas second and third streams are hydrogen peroxide and a gas stream of air/ozone. The multi-fluid diffuser can have water in its interior, occasioned by its introduction into the aquifer. 
   The air ozone gas stream enters the multi-fluid diffuser and diffuses through the cylindrical member as trapped microbubbles into the space occupied by the microporous materials where a liquid, e.g., hydrogen peroxide is introduced to coat the microbubbles. The liquid stream through the microporous materials is under a siphon condition occasioned by the introduction of water through the periphery of the multi-fluid diffuser. The flow of water in additional to producing a siphoning effect on the liquid also has a shearing effect to shear bubbles from the microporous sides of the cylindrical member, preventing coalescing and bunching of the bubbles around micro-pores of the cylindrical member. The shearing water flow carries the microbubbles away through the well screen disposed at the bottom of the multi-fluid diffuser, through either continuous or pulsing action. 
   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 
       FIG. 1  is a cross-sectional view showing a sparging treatment system. 
       FIG. 2  is a cross-sectional view showing a sparging treatment system with well screen and a multi-fluid diffuser. 
       FIG. 3  is a longitudinal cross-section view of a multi-fluid diffuser useful in the arrangement of  FIG. 1 . 
       FIG. 4  is a longitudinal cross-section view of an alternative multi-fluid diffuser useful in direct injection into shallow contaminant formations. 
       FIGS. 5A and 5B  are cross-sectional view of sidewalls of the multi-fluid diffuser of  FIG. 3  or  4  showing exemplary construction details. 
   

   DETAILED DESCRIPTION 
   Referring now to  FIG. 1 , a sparging arrangement  10  for use with 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 multi-fluid diffusers, e.g.,  50 ,  50 ′ (discussed in  FIGS. 3 and 4 ). 
   The arrangement  10  also includes a first pump or compressor  22  and a pump or compressor control  24  to feed a first fluid, e.g., a gas such as an ozone/air or oxygen enriched air mixture, as shown, or alternatively, a liquid, such as, hydrogen peroxide or a hydro-peroxide, via feed line  38   a  to the multi-fluid diffuser  50 . The arrangement  10  includes a second pump or compressor  26  and control  27  coupled to a source  28  of a second fluid to feed the second fluid via feed line  38   b  to the multi-fluid diffuser  50 . A pump  30 , a pump control  31 , and a source  32  of a third fluid is coupled via a third feed  38   c  to the multi-fluid diffuser  50 . 
   The arrangement  10  can supply 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. 
   The arrangement  10  makes use of a laminar multi-fluid diffuser  50  ( FIG. 3  or  FIG. 4 ). The laminar multi-fluid diffuser  50  allows introduction of multiple, fluid streams, with any combination of fluids as liquids or gases. The laminar multi-fluid diffuser  50  has three inlets. One of the inlets introduces a first gas stream within interior regions of the multi-fluid diffuser, a second inlet introduces a fluid through porous materials in the laminar multi-fluid diffuser  50 , and a third inlet introduces a third fluid about the periphery of the laminar multi-fluid diffuser  50 . The fluid streams can be the same materials or different. 
   In the embodiment described, the first fluid stream is a gas such as an ozone/air mixture, the second is a liquid such as hydrogen peroxide, and the third is liquid such as water. The outward flow of fluid, e.g., air/ozone from the first inlet  52   a  results in the liquid, e.g., the hydrogen peroxide in the second flow to occur under a siphon condition developed by the flow of the air/ozone from the first inlet  52   a.    
   Alternatively, the flows of fluid can be reversed such that, e.g., air/ozone from the second inlet  52   a  and the liquid, e.g., the hydrogen peroxide flow from first inlet, to have the ozone stream operate under a siphon condition, which can be used to advantage when the arrangement is used to treat deep deposits of contaminants. The ozone generator operating under a siphon condition is advantageous since it allows the ozone generator to operate at optimal efficiency and delivery of optimal amounts of ozone into the well, especially if the ozone generator is a corona discharge type. In this embodiment, the third fluid flow is water. The water is introduced along the periphery of the multi-fluid diffuser  50  via the third inlet. 
   Referring to  FIG. 2 , an alternate arrangement  40  to produce the fine bubbles is shown. A well casing  41  is injected or disposed into the ground, e.g., below the water table. The casing  41  carries, e.g., a standard 10-slot well-screen  43 . A laminar microporous diffuser  45  is disposed into the casing  41  slightly spaced from the well screen  43 . A very small space is provided between the laminar microporous diffuser  45  and the 10-slot well screen. In one example, the laminar microporous diffuser  45  has an outer diameter of 2.0 inches and the inner diameter of the well casing is 2.0 inches. The laminar microporous diffuser  45  is constructed of flexible materials (described below) and as the laminar microporous diffuser  45  is inserted into the casing  41  it flexes or deforms slightly so as to fit snugly against the casing  41 . In general for a 2 inch diameter arrangement a tolerance of about +/−0.05 inches is acceptable. Other arrangements are possible. The bottom of the casing  41  is terminated in an end cap. A silicon stopper  47  is disposed over the LAMINAR SPARGEPOINT® type of microporous diffuser available from KV-Associates, Inc. and also described in U.S. Pat. No. 6,436,285. The silicone stopper  47  has apertures to receive feed lines from the pumps (as in  FIG. 1 , but not shown in  FIG. 2 ). 
   Exemplary operating conditions are set forth in TABLE 1. 
   
     
       
             
             
             
             
             
             
             
             
           
             
             
             
             
             
             
             
             
             
           
         
             
               TABLE 1 
             
             
                 
             
             
                 
                 
                 
                 
                 
                 
               Laminar 
                 
             
             
                 
                 
                 
               Hydro- 
               Water 
                 
               microporous 
               Operating 
             
             
                 
                 
               Ozone 
               peroxide 
               Flow 
               Recirculation 
               diffuser 
               pressure 
             
             
               Unit 
               Air 
               gm/day 
               gal/day 
               gal/min 
               Wells 
               with screen 
               (psi) 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               Wall mount 
               3–5 
               cfm 
               144–430 
                5–50 
               1–3 
               1–4 
               1–8 
               0–30 
             
             
               Palletized 
               10–20 
               cfm 
               300–1000 
               20–200 
               1–10 
               1–8 
               1–16 
               0–100 
             
             
               Trailer 
               20–100 
               cfm 
               900–5000 
               60–1000 
               1–50 
               1–20 
               1–40 
               0–150 
             
             
                 
             
           
        
       
     
   
   Flow rates are adjusted to a pressure that offsets groundwater hydraulic head and formation backpressures. In general, pressures of, e.g., above 40 psi ambient are avoided so as to prevent fracture or distortion of microscopic flow channels. The percent concentration of hydroperoxide in water is typically in a range of 2–20 percent, although other concentrations can be used. The flow is adjusted according to an estimate of the total mass of the contaminants in the soil and water. If high concentrations (e.g., greater than 50,000 parts per billion in water or 500 mg/kg in soil) of the contaminants are present, sufficient hydroperoxides are added to insure efficient decomposition by a Criegee or a pseudo Creigee or hydroxyl-radical reaction mechanism. 
   Fine bubbles from an inner surface of the microporous gas flow and water (including a hydroperoxide, e.g., hydrogen peroxide) are directed by lateral laminar flow through the porous material or closed spaced plates ( FIG. 2 ). The gas to water flow rate is held at a low ratio, e.g., sufficiently low so that the effects of coalescence are negligible and the properties of the fluid remain that of the entering water. 
   Alternatively, the water flow is oscillated (e.g., pulsed), instead of flowing freely, both to reduce the volume of water required to shear, and maintain the appropriate shear force at the interactive surface of the gas-carrying microporous material. John San et al., Separation Science and Technology, 17(8), pp. 1027–1039, (1982), described that under non-oscillating conditions, separation of a bubble at a microporous frit surface occurs when a bubble radius is reached such that drag forces on the bubble equal the surface tension force (π D γ), as: 
   
     
       
         
           
             
               C 
               D 
             
             · 
             
               
                 
                   PU 
                   0 
                   2 
                 
                 ⁢ 
                 
                   A 
                   P 
                 
               
               2 
             
           
           = 
           
             Π 
             ⁢ 
             
                 
             
             ⁢ 
             D 
             ⁢ 
             
                 
             
             ⁢ 
             Υ 
           
         
       
     
   
   Where P is the fluid density, U 0   2  is the fluid velocity, A p  is the projected bubble area, γ is the gas-water surface tension, and D is the pore diameter of the frit. A bubble is swept from the microporous surface when the bubble radius is reached such that the dynamic separating force due to drag equals the retention force due to surface tension. Bubble distributions of 16 to 30 μm (micron) radius and 1 to 4×10 6  bubbles/min can be produced with a gas flow rate of 8 cm 3 /min and water flow rates of 776 cm 3 /min across a microporous surface of μm (micron) pore size with a 3.2 cm diameter surface area. If the flow of liquid is directed between two microporous layers in a fluid-carrying layer, not only is a similar distribution of microbubble size and number of microbubbles produced, but, the emerging bubbles are coated with the liquid which sheared them off. 
   Instead of using a continual flow of fluid to shear the surface, the liquid can be oscillated (pulsed) at a frequency sufficient to allow for fluid replacement in the microporous diffuser, for the volume of liquid removed as coatings on the bubbles, but not allowing interruption of the liquid/bubble column on its way to the surface (or through a slit, e.g., well screen slot). To avoid coalescing of the microbubbles, a continual stream of microbubbles, coated with the peroxide liquid is emitted from the surface of the laminated material. 
   Some examples of gas flows and liquid volumes are listed below for each of the examples described in  FIGS. 1 and 2 . 
   
     
       
             
           
             
             
             
             
           
             
             
             
             
             
           
         
             
               TABLE II 
             
           
           
             
                 
             
             
               Per 8 cm surface area, (5 μm (micron) porosity) 
             
           
        
         
             
               Water Flow 
                 
                 
               Rotative 
             
             
               rates 
               Mean Bubble 
               Bubble size 
               Frequency 
             
             
               10 cm 3 /min gas 
               size (μm) 
               range (μm) 
               bubbles/min 
             
             
                 
             
           
        
         
             
               250 
               cm 3 /min 
               30 
               16–60 
                4 × 10 6   
             
             
               500 
               cm 3 /min 
               20 
               16–50 
                7 × 10 6   
             
             
               800 
               cm 3 /min 
               15 
                8–30 
               15 × 10 6   
             
             
               1500 
               cm 3 /min 
               10 
                5–15 
               30 × 10 6   
             
             
               3000 
               cm 3 /min 
               5 
                   .5–10     
               50 × 10 6   
             
             
                 
             
           
        
       
     
   
   For an equivalent LAMINAR SPARGEPOINT® type of microporous diffuser available from Kerfoot Technologies, Inc. (formally KV-Associates (2 INCH OUTER DIAMETER) 
   For Laminar Spargepoint® 
   Porous Surface Area is 119 sq. in. (771 sq. cm.) 
   Gas flow 25000 cm 3 /min (25 l/min) or (0.8825 cu. ft/min)=52.9 cu. ft./hr. 
   (20 cfm)=1200 cu. ft./hr 
   (L×0.264=gallons) 
   Liquid flow 
   If continuous: 625 l/min (165 gallons/min) or 2000 gallons/day 
   If oscillate: 5 gallons/day 
   The liquid is supplied with a Pulsafeeder® pulsing peristaltic pump to oscillate the liquid (5 psi pulse/sec) and to deliver an adjustable 0.1 to 10 liters/hour (7 to 60 gallons/day). 
   
     
       
             
           
             
             
             
             
           
             
             
             
             
             
           
         
             
                 
             
             
               TWO LAMINAR MICROPOROUS MATERIALS 
             
             
               OSCILLATING GAS 
             
           
        
         
             
                 
               WATER FLOW 
                 
                 
             
             
               GAS FLOW 
               200–800 
               BUBBLE SIZE 
               FREQUENCY 
             
             
               50 scf 
               ccm/min 
               (μm) 
               Bubbles/min. 
             
             
                 
             
           
        
         
             
               1 
               cfm 
               1 L/min (.26 
               20 μm 
               10 × 10 8   
             
             
                 
                 
               gallons/min 
             
             
               3 
               cfm 
               3 L/min (.78 
               20 μm 
               10 × 10 8   
             
             
                 
                 
               gallons/min 
             
             
               30 
               cfm* 
               30 L/min (7.8 
               20 μm 
               10 × 10 8   
             
             
                 
                 
               gallons/min 
             
             
                 
             
             
               (2 inch 800 sq. cm. LAMINAR SPARGEPOINT ® type of microporous diffuser available from Kerfoot Technologies, Inc. 1   
             
             
                 1 Would require ten (10) LAMINAR SPARGEPOINT ® type of microporous diffuser for operation, or increase length or diameter of the microporous diffuser). 
             
           
        
       
     
   
   For insertion of the LAMINAR SPARGEPOINT® type of microporous diffuser into well screens or at depth below water table, the flow of gas and liquid is adjusted to the back pressure of the formation and, for gas reactions, the height (weight) of the water column. At ambient conditions (corrected for height of water column), the liquid fraction is often siphoned into the exiting gas stream and requires no pressure to introduce it into the out flowing stream. The main role of an oscillating liquid pump is to deliver a corresponding flow of liquid to match a desired molar ratio of ozone to hydrogen peroxide for hydroxyl radical formation as:
 
2O 3 +H 2 O 2  2OH+3O 2 
 
   Set out below are different operating conditions for different types of systems available from Kerfoot Technologies, Inc. (formally KV-Associates, Inc.) Mashpee Mass. Other systems with corresponding properties could be used. 
   Wallmount Unit 
   Pressure range, injection: 10 to 40 psi 
   Gas flow: 1-Scfm (50 to 350 ppmv ozone) 
   Liquid range: 0.03–0.5 gallons/hr. (55 gallon tank) (3 to 8% peroxide). 
   Shearing fluid (water) 
   Palletized Units 
   Pressure range-injection: 10 to 100 psi 
   Gas flow: 0–20 cfm (50 to 2000 ppmv ozone) 
   Liquid range: 0–5 gallons/hr (3 to 9% peroxide) 
   Shearing fluid (water) 
   Trailer Units 
   Pressure range-injection: 10 to 150 psi 
   Gas flow: 0–100 cfm (50 to 10,000 ppmv ozone) 
   Liquid range: 0–20 gallons/hr (3 to 9% peroxide) 
   Shearing fluid (water) 
   The process involves generation of extremely fine microbubbles (sub-micron in diameter up to less than about 200 microns in diameter) that promote rapid gas/gas/water reactions with volatile organic compounds. The production of microbubbles and selection of appropriate size distribution optimizes gaseous exchange through high surface area to volume ratio and long residence time within the material to be treated. The equipment promotes the continuous or intermittent production of microbubbles while minimizing coalescing or adhesion. 
   The injected air/ozone combination moves as a fluid of such fine bubbles 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 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. 
   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. 
   Also, pseudo Criegee reactions with the substrate and ozone appear effective in reducing saturated olefins like trichloro ethane (1,1,1-TCA), carbon tetrachloride (CCl 4 ), chloroform and chlorobenzene, for instance. 
   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, O-xylene, P-xylene, naphthalene and methyltetrabutylether (MTBE). 
   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. To offset the short life span, the ozone is injected with multi-fluid diffusers  50 , enhancing the selectiveness of action of the ozone. By encapsulating the ozone in fine bubbles, the bubbles would preferentially extract volatile compounds like PCE from the mixtures of soluble organic compounds they encountered. With this process, volatile organics are selectively pulled into the fine air bubbles. The gas that enters a small bubble of volume (4πr3) increases until reaching an asymptotic value of saturation. 
   The following characteristics of the contaminants appear desirable for reaction: 
   Henry&#39;s Constant: 10 −1  to 10 −4  m3 atm/mol 
   Solubility: 10 to 20,000 mg/l 
   Vapor pressure: 1 to 3000 mmHg 
   Saturation concentration: 5 to 9000 g/m 3    
   The production of microbubbles and 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. 
   Referring now to  FIG. 3 , a multi-fluid diffuser  50  is shown. The multi-fluid diffuser  50  includes inlets  52   a – 52   c , coupled to portions of the multi-fluid diffuser  50 . An outer member  55  surrounds a first inner cylindrical member  56 . Outer member  55  provides an outer cylindrical shell for the multi-fluid diffuser  50 . First inner cylindrical member  56  is comprised of a hydrophobic, microporous material. The microporous material can has a porosity characteristic less than 200 microns in diameter, and preferable in a range of 0.1 to 50 microns, most preferable in a range of 0.1 to 0.5 microns to produce nanometer or sub-micron sized bubbles. The first inner member  56  surrounds a second inner member  60 . The first inner member  56  can be cylindrical and can be comprised of a cylindrical member filled with microporous materials. The first inner member  56  would have a sidewall  56   a  comprised of a large plurality of micropores, e.g., less than 200 microns in diameter, and preferable in a range of 0.1 to 50 microns, most preferable in a range of 0.1 to 0.5 microns to produce nanometer or sub-micron sized bubbles. 
   A second inner member  60  also cylindrical in configuration is coaxially disposed within the first inner member  56 . The second inner member  60  is comprised of a hydrophobic material and has a sidewall  60   a  comprised of a large plurality of micropores, e.g., less than 200 microns in diameter, and preferable in a range of 0.1 to 50 microns, most preferable in a range of 0.1 to 0.5 microns to produce nanometer or sub-micron sized bubbles. In one embodiment, the inlet  52   a  is supported on an upper portion of the second inner member  60 , and inlets  52   b  and  52   c  are supported on a top cap  52  and on a cap  53  on outer member  55 . A bottom cap  59  seals lower portion of outer member  55 . 
   Thus, proximate ends of the cylindrical members  56  and  60  are coupled to the inlet ports  52   b  and  52   a  respectively. At the opposite end of the multi-fluid diffuser  50  an end cap  54  covers distal ends of cylindrical members  56  and  60 . The end cap  54  and the cap  52  seal the ends of the multi-fluid diffuser  50 . Each of the members  55 ,  56  and  60  are cylindrical in shape. 
   Member  55  has solid walls generally along the length that it shares with cylindrical member  60 , and has well screen  57  (having holes with diameters much greater than 200 microns) attached to a lower portion of the outer member  55 . Outer member  55  has an end cap  59  disposed over the end portion of the well-screen  57 . The multi-fluid diffuser  50  also has a member  72  coupled between caps  54  and  57  that provide a passageway  73  along the periphery of the multi-fluid diffuser  50 . Bubbles emerge from microscopic openings in sidewalls  60   a  and  56   a , and egress from the multi-fluid diffuser  50  through the well screen  57  via the passageway  73 . 
   Thus, a first fluid is introduced through first inlet  52   a  inside the interior  75  of third member  60 , a second fluid is introduced through the second inlet  52   b  in region  71  defined by members  56  and  60 , and a third fluid is introduced through inlet  52   c  into an outer passageway  73  defined between members  53 ,  55 ,  56 , and  59 . In the system of  FIG. 1 , the first fluid is a gas mixture such as ozone/air that is delivered to the first inlet through central cavity  75 . The second fluid is a liquid such as hydrogen peroxide, which coats bubbles that arise from the gas delivered to the first inlet, and the third fluid is a liquid such as water, which is injected through region  73  and acts as a shearing flow to shear bubbles off of the sidewall  56   a . By adjusting the velocity of the shearing fluid, bubbles of very small size can be produced (e.g., sub-micron size). Of course adjusting the conditions and porosity characteristics of the materials can produce larger size bubbles. 
   Referring to  FIG. 4 , an alternative embodiment  50 ′ has the cylindrical member  56  terminated along with the member  60  by a point member  78 . The point member  78  can be used to directly drive the multi-fluid diffuser into the ground, with or without a well. The point member can be part of the cap  59  or a separate member as illustrated. 
   The multi-fluid diffuser  50  or  50 ′ is filled with a microporous material in the space between members  56  and  60 . The materials can be any porous materials such as microbeads with mesh sizes from 20 to 200 mesh or sand pack or porous hydrophilic plastic to allow introducing the second fluid into the space between the members  56  and  60 . 
   In operation, the multi-fluid diffuser  50  is disposed in a wet soil or an aquifer. The multi-fluid diffuser  50  receives three fluid streams. In one embodiment, the first stream that is fed to the inlet  52   a  is a liquid such as water, whereas second and third streams that feed inlets  52   b  and  52   c  are hydrogen peroxide and a gas stream of air/ozone. The multi-fluid diffuser  50  has water in its interior, occasioned by its introduction into the aquifer. The air ozone gas stream enters the multi-fluid diffuser  50  and diffuses through the cylindrical member  56  as trapped microbubbles into the space occupied by the microporous materials where a liquid, e.g., hydrogen peroxide is introduced to coat the microbubbles. The liquid stream through the microporous materials is under a siphon condition occasioned by the introduction of water through the periphery of the multi-fluid diffuser  50 . The flow of water in additional to producing a siphoning effect on the liquid introduced through inlet  52   b  also has a shearing effect to shear bubbles from the microporous sides of the cylindrical member  60 , preventing coalescing and bunching of the bubbles around micropores of the cylindrical member  60 . The shearing water flow carries the microbubbles away through the well screen disposed at the bottom of the multi-fluid diffuser  50 . 
   Referring now to  FIGS. 5A ,  5 B, exemplary construction details for the elongated cylindrical members of the multi-fluid diffusers  50  or  50 ′ and the laminar microporous diffuser  45  are shown. As shown in  FIG. 5A , 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 to provide the micropores. 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. 
     FIG. 5B  shows an alternative arrangement  94  in which sidewalls of the members are formed of a sintered i.e., heat fused microscopic particles of plastic to provide the micropores. The plastic can be any hydrophobic material such as polyvinylchloride, polypropylene, polyethylene, polytetrafluoroethylene, high-density polyethylene (HDPE) and alkylbenzylsulfonate (ABS). Flexible materials are desireable if the laminar microporous diffuser  45  is used in an arrangement as in  FIG. 2 . 
   The fittings (i.e., the inlets in FIG.  2 ,) can be threaded and/or 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 thus are securely attached to the multi-fluid diffuser  50   s  in a manner that insures that the multi-fluid diffuser  50   s  can handle pressures that are encountered with injecting of the air/ozone. 
   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.

Technology Classification (CPC): 4