WO2011057186A2 - Procédé et appareil de retrait d'éléments - Google Patents

Procédé et appareil de retrait d'éléments Download PDF

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Publication number
WO2011057186A2
WO2011057186A2 PCT/US2010/055823 US2010055823W WO2011057186A2 WO 2011057186 A2 WO2011057186 A2 WO 2011057186A2 US 2010055823 W US2010055823 W US 2010055823W WO 2011057186 A2 WO2011057186 A2 WO 2011057186A2
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WIPO (PCT)
Prior art keywords
porous bag
porous
water
metal fibers
fibers
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Application number
PCT/US2010/055823
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English (en)
Other versions
WO2011057186A3 (fr
Inventor
Terrence P. Kane
Steven A. Bouse
Ray Joseph Lovett
Kurt H. Schild
Mark Rak
Alex Krupnik
Original Assignee
Global Material Technologies, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US12/614,204 external-priority patent/US20100147769A1/en
Priority claimed from US12/903,918 external-priority patent/US20110114563A1/en
Application filed by Global Material Technologies, Inc. filed Critical Global Material Technologies, Inc.
Publication of WO2011057186A2 publication Critical patent/WO2011057186A2/fr
Publication of WO2011057186A3 publication Critical patent/WO2011057186A3/fr

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/70—Treatment of water, waste water, or sewage by reduction
    • C02F1/705—Reduction by metals
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH

Definitions

  • the field of the invention is a process and apparatus for the removal of elements from water, and more particularly the removal of contaminants, such as selenium.
  • Selenium is a naturally occurring metalloid element having atomic number 34 and an atomic weight of 78.96. Selenium is widely dispersed in igneous rock. Selenium also appears in large quantities, but in low concentrations, in sulfide and porphyry copper deposits. Moreover selenium is widely associated with various types of sedimentary rock. Inorganic selenium is most commonly found in four oxidation states (Se 6+ , Se 4+ , Se°, and Se 2" ). Selenate (SeC ⁇ 2- , Se(VI)) and selenite (SeCV, Se(IV)) are highly water soluble. Elemental selenium (Se ) is insoluble in water.
  • Selenium is a common water contaminant throughout the United States and the world and represents a major environmental problem. Human related selenium release originates from many sources including mining operations, mineral processing, abandoned mine sites, petroleum processing, and agricultural run-off. The principal sources of selenium in mining are copper and uranium bearing ores and sulfur deposits. Selenium is commonly found in these mining wastewaters in concentrations ranging from a few micrograms per liter up to more than 12 mg/L. In precious metals operations, waste and process water and heap leachate solutions may contain selenium at concentrations up to 30 mg/L.
  • the present invention attempts to solve these problems, as well as others.
  • FIG. 1 is a schematic view of one embodiment of the invention.
  • FIG. 2 is a perspective view of the Zero-Valent Iron Fiber (“ZVIF”) Packing.
  • ZVIF Zero-Valent Iron Fiber
  • FIG. 3 is a light microscope image of view of the ZVIF packing after selenium removal.
  • FIG. 4 is an enlarged perspective view of the metal fiber.
  • FIG. 5 is a schematic displaying the formation of the metal fiber.
  • FIG. 6A is a schematic displaying the formation of the ZVIF packing.
  • FIG. 6B is a schematic displaying the formation of the ZVIF packing.
  • FIG. 7A is a top view of a schematic of one embodiment of the invention
  • FIG. 7B is a top view of a schematic of another embodiment of the invention
  • FIG. 7C a side view of one embodiment of the treatment cell
  • FIG. 7D is a side view of another embodiment of the treatment cell
  • FIG. 7E is a perspective view of the treatment cell with the plurality of porous bag layers
  • FIG. 7F is a perspective view of the porous bag layer
  • FIG. 7G. is a cross sectional side view of another embodiment of the treatment cell including a gas line
  • FIG. 7H. is a cross sectional side view of another embodiment of the treatment cell including a gas line
  • FIG. 7G is a cross sectional side view of another embodiment of the treatment cell including a gas line
  • FIG. 7H is a cross sectional side view of another embodiment of the treatment cell including a gas line
  • FIG. 71 is a cross sectional side view of another embodiment of the treatment cell including three gas lines;
  • FIG. 7J is a top cross-sectional view of the treatment cell showing the gas line and the spacer; and
  • FIG. 7K is a perspective view of a pH control system in accordance with one embodiment.
  • FIG. 8 is a plot of the selenium concentrations entering and leaving the treatment cell over the course of the field test.
  • FIG. 9 is a plot of the fraction of initial Se removed as a function of residence time.
  • FIG. 10 is a plot of the iron removed as a function of the treatment time.
  • FIG. 11 is a plot of the pH of the system showing influent and effluent.
  • FIG. 12 is a plot of the manganese released from the bed over treatment duration.
  • FIG. 13 is a plot of the selenium removal versus the temperature profile.
  • FIG. 14 is a treatment cell in a field test.
  • FIG. 15 is a treatment cell in a field test.
  • FIG. 16 is a treatment cell after 6 weeks of use.
  • FIG. 17 is a perspective view of the bench scale water treatment system.
  • FIG. 18 is a vertical view of the treatment system showing the container, pump and outlet.
  • FIG. 19 is a perspective view of the ZVIF packing after the bench scale experiment.
  • FIG. 20 is a plot of the initial Se removal portion fit to an exponential curve for 0 - 6 hours.
  • FIG. 21 is a plot of the selenium removal for 6 - 12 hours showing linear removal rates.
  • a water treatment cell 100 comprises a container vessel 200, a porous bag 300, and a plurality of Zero Valent Iron Fiber (“ZVIF") packing 400.
  • ZVIF packing 400 A cross- section of the ZVIF packing 400 is shown in FIG. 2, and comprises a plurality of metal fibers 410 with a density D.
  • the metal fibers 410 comprise an average cross- sectional diameter d.
  • the container vessel 200 includes an inlet port 210 and an outlet port 220.
  • the inlet port 210 may be located at the bottom of the container vessel 200 and the outlet port 220 may be located at the top of the container vessel 200 for bottom-in/top-out fluid flow.
  • the inlet port 210 may be located at the top of the container vessel 200, and the outlet port 220 may be located at the bottom of the container vessel 200 for top-in/bottom-out fluid flow. Fluid flow is demonstrated by arrows 212 and 222, whereby a water source containing elements requiring removal enters by way of 212 and exits the treatment cell 100 by way of 222.
  • the porous bag 300 includes a plurality of lift straps 310, a porous bag wall material 320, a porous bottom 330, and a fill 340 of the ZVIF packing 400.
  • the porous bag wall material 320 and the porous bottom 330 includes pores or a mesh cut pattern, such that the fill 340 of the ZVIF packing 400 is maintained and securely held within the porous bag 300 and the fluid flow is transmitted through the porous bag 300.
  • the fill 340 includes a controlled porosity and density D of the ZVIF packing 400 to treat a particular amount of fluid flow rate and allow for a particular contact time of the water of interest with the ZVIF packing 400.
  • the fill 340 may be defined by the density D of the ZVIF packing 400 and the average diameter d of the metal fibers 410.
  • the fill 340 can range in densities from 1 lb/ft 3 , 5 lb/ft 3 , 10 lb/ft 3 , 15 lb/ft 3 , 20 lb/ft 3 , 25
  • the fill 340 may include a variation of densities using the same diameter d of metal fiber from the bottom of the treatment cell 100 to the top of the treatment cell 100 by use of a plurality of porous bag layers 350, as shown in FIG. 7B.
  • the fill 340 may include a plurality of porous bag layers 350 of the same density D of the ZVIF packing 400 with differing metal fiber diameters d ranging from the bottom of the treatment cell 100 to the top of the treatment cell 100.
  • the fill 340 may include a plurality of porous bag layers 350 with differing densities D of the ZVIF packing, whereby each different porous bag layers 350 include differing metal fiber diameters d within each porous bag layer 350.
  • the fill 340 includes a gradient of metal fibers with diameter d in the vertical direction indicated by the z-axis in FIG. 7B, or in the along either horizontal direction indicated by the x-axis and y- axis in FIG. 7B. In all, the density D of the ZVIF packing and the average diameter d of the metal fiber 410 define the total surface area available for selenium removal, further described below.
  • Porosity is the free space in the ZVIF packing 400 in the fill 340 for fluid flow and relates to the maximum fluid flow rate and the volume %.
  • the fluid flow must travel around the metal fibers 410, so the travel path of the fluid flow through the metal fibers 410 is tortuous and decreases the fluid flow rate.
  • Volume % is the percentage of the total volume occupied by ZVIF packing 400 relative to the percentage of open space between the metal fibers 410.
  • the ZVIF packing 400 exceeding 2 volume % may have difficulty sustaining good fluid flow rates.
  • 2 volume % of ZVIF packing 400 has 98% open space in the volume and 2% space occupied by the ZVIF packing 400.
  • the volume percentages of ZVIF packing may be 0.01 volume % to 0.09 volume %, 0.1 volume % to 1 volume %, 1.1 volume % to 1.9 volume %, and the like.
  • One or more pumps may be utilized to facilitate flow through inlet port 210 or outlet port 220.
  • sieve filters may be placed on the inlet port 210 or outlet port 220 to retain solid materials that may plug the medium at the inflow or remove solid reaction products at the outlet port 220.
  • the solid material may include debris, scavenging material, and/or compost that may interact or clog the treatment cell 100.
  • Valves may be located on the inlet port 210 and/or the outlet port 220 to control the flow rate of contaminated water into the treatment cell 100.
  • a top-in/bottom-out fluid flow may include a pipe drain that rises up the side of the tank to below the inlet port 210, such that the container vessel 200 only drains after being filled with contaminated water.
  • the inlet port 210 flow rate may be set to control the residence time.
  • An oxygen trap 600 may be included to remove atmospheric oxygen before the contaminated water enters the treatment cell 100 and at the air/solid interface of the metal fiber 400.
  • the oxygen trap 600 comprises of a replaceable iron cartridge or some commercially available device to reduce the amount of oxygen entering the inlet port 210 or at the air/metal fiber 410 interface.
  • contaminated water flows into the treatment cell 100 through inlet port 210, where the contaminated water flows through the porous bag wall material 320 and contaminants are removed through an interaction with the fill 340 of the ZVIF packing 400.
  • the residence time is the time the contaminated water interacts with the ZVIF packing within the treatment cell 100.
  • the residence time can be roughly determined by calculating the volume in gallons of ZVIF packing 400, and then determining the time it would take to displace that volume at a particular flow rate.
  • the shortest residence times is determined by the permeability of the medium, or fill material 340.
  • contaminated water containing selenium as selenite or selenate contacts the ZVIF packing 400 begins to remove selenium by reduction of selenate and selenite with Fe(0) (which is elemental or zero-valent iron "ZVI"), as shown by the following equations:
  • the reaction products are then immobilized by adherence at the ZVI reaction site or iron reaction products, as shown in FIG. 3.
  • the ZVIF packing 400 ceases to remove selenium and must be replaced.
  • the ZVIF packing 400 may be removed from the treatment cell 100 by slowly lifting the lift straps 310 out of the container vessel 200, allowing the water to drain out into the container vessel 200, and removing the porous bag 300 from the container vessel 200.
  • the removed ZVIF packing 400 is replaced with a new porous bag 300 with new ZVIF packing 400 for additional selenium removal.
  • a suitably designed system using the ZVIF packing 400 effectively removes selenium ions from the neutral or slightly alkaline mine water (pH 6 - 9) to a concentration below 5 ⁇ g/L.
  • a neutral to alkaline pH avoids acid dissolution of iron, and in one embodiment of the invention, the pH may be adjusted to a range of pH 6 to a pH 9.
  • Fe(0) may react with one or more of chromium (as chromate), cobalt ions, arsenic (as arsenate or arsenite), cadmium (as Cd +2 ), copper (as Cu +2 ), cyanide, gold, lead, manganese (as permanganate), molybdenum (as molybdate), nickel, nitrate, selenium (as selenate or selenite), technetium (as TcO "4 ), tin, uranium (as uranyl), vanadium (as vanadyl or other oxy species), radionuclides, pathogens (viruses, bacteria, protozoa), and/or halogenated organics such as chlorinated organics, and derivatives thereof.
  • chromium as chromate
  • cobalt ions arsenic (as arsenate or arsenite)
  • cadmium as Cd
  • Fe(0) may also react with pesticides and herbicides, such that the pesticides and herbicides are adsorbed to the treatment system.
  • the treatment cell 100 serves as an effective clean-up system for mine water or other contaminated water sources to make contaminant removal more controllable.
  • Fe(II) produced by the reduction of selenium and dissolved oxygen is further oxidized to Fe(III), forming iron oxide and hydroxide minerals, as illustrated by the following equations:
  • Equation (4) and (5) shows the formation of various oxyhydroxides of iron, which are colloquially known as "rust" that is associated with ZVI oxidation
  • the porous bag 300 contains most of the rust materials.
  • the porous bag 300 will contain mostly rust and entrained selenium. Clogging is prevented by the formation of small oxyhydroxide particles and sufficient fluid flow to purge them.
  • ferrihydrite and goethite may be the first minerals formed.
  • the ZVIF packing 400 include a plurality of metal fibers 410, as shown in FIG. 4.
  • the metal fibers 410 include an average cross-sectional diameter d, as shown in FIG. 4.
  • the metal fibers 410 comprise an average cross-sectional diameter d ranging between about 10 and 125 microns.
  • a superfine metal fiber includes an average cross-sectional diameter d of 25 microns.
  • An extra fine metal fiber includes an average cross-sectional diameter d of 35 microns.
  • a very fine metal fiber includes an average cross-sectional diameter d of 40 microns.
  • a fine metal fiber includes an average cross-sectional diameter d of 50 microns.
  • a medium metal fiber includes an average cross-sectional diameter d of 60 microns.
  • a medium coarse metal fiber includes an average cross- sectional diameter d of 75 microns.
  • a coarse metal fiber includes an average cross- sectional diameter d of 90 microns.
  • An extra coarse metal fiber includes an average cross- sectional diameter d of 100 microns.
  • the selection of the average cross-sectional diameter d may be dependent on various factors including, but not limited to, concentrations of substances or contaminants of interest, the removal kinetics, and the flow characteristics of various fiber densities, and the like.
  • the average cross- sectional diameter d may include an average fiber width between 10 to 1000 microns.
  • the ZVI fibers include an irregular cross-section and rough outer surfaces with projections 420 and fissures formed along the outer surfaces.
  • the irregular cross-sections vary continuously along the length of the resulting fibers to provide generally asymmetrical metal fibers in the longitudinal and horizontal direction.
  • the nature of the metal fibers provides increased surface area of the metal fiber for interaction with selenium ions.
  • the projections 420 are polycrystalline iron oxides. The increased surface area of the metal fibers increases the rate of reduction of selenium ions for the treatment system and allows for increased removal of selenium, i.e.
  • the surface area of the metal fibers 410 in the treatment cell 100 is one factor that determines the rate of selenium reduction .
  • the increased surface area of the metal fiber 400 functionally increases k because the more reactive collisions with the surface area are possible.
  • Other ions such as chromate, have first order removal kinetics as well.
  • high selenium concentrations and the number of collisions with the metal fiber 400 depends on hoe many selenate molecules are available for collision (first order). As the concentration of selenate falls, the number of collisions with the metal fiber 400 depends on finding fiber, which is zero order in selenate.
  • an exponential curve is fitted to the initial selenium removal for 0 - 6 hours and shows first order removal for the reaction rate. As shown in FIG.
  • metal fiber densities from 0.5 volume % to 2 volume % remove selenium at favorable rates.
  • the metal fibers 400 are produced by shaving a metal wire 1 with a metal member 2 with a succession of serrated blades, as disclosed in commonly assigned U.S. Patents No. 5,972,814 and 6,249,941, which are hereby incorporated by reference.
  • a suitable lubricant such as oil, is preferably applied to the metal member 2 as it is being shaved by the blades in sufficient quantity so that the metal fibers retain on their outer surface a carding-effective amount of the oil or lubricant.
  • Carding-effective amount" of oil or lubricant means that the metal fibers, when blended with the nonmetal fibers, can be carded without substantial breakage or disintegration.
  • the lubricant optionally may be applied after the metal fibers are formed.
  • the carding-effective amount of oil generally may be in the range of about 0.3 to 1.0 wt. % oil, more preferably about 0.4 to 0.7 wt. %, based on the total weight of the metal fibers, although lesser or greater amounts may be used depending on the type and average diameter of the metal fibers.
  • the metal fibers are made from carbon steel, to result in Zero Valent Iron.
  • the metal fibers 410 can also be made from other metals that result in Zero- Valent capabilities, such as copper, silver, palladium, nickel, tin, and the like.
  • the metal fiber 410 may be bimetallic or an alloy of zero-valent metals, such as iron-nickel, iron-palladium, and the like.
  • the metal fibers 400 are oriented as an isotropic mass in a randomized orientation after the metal fiber 400.
  • the isotropic mass may be packed into the ZVIF packing 400 to form the fill 340.
  • the metal fibers 400 are cut into staple lengths using a suitable metal fiber cutting apparatus 26 to give the metal fibers a predetermined length, as shown in FIG. 6A. After cut to the predetermined length, the metal fibers 400 may then be stacked to achieve a unit of isotropic mass.
  • the cut fibers 21 are then fed into conventional textile apparatus which separates and blends the mass of fibers 21 in order to form a homogenous blend of fiber 29, as shown in FIG. 6A.
  • the homogenous fiber mass 29 can then be carded in the garnett 31 to form a fiber web 33, which is readily understood by commonly assigned U.S. Patent No. 6,249,941.
  • the garnett 31 may be any suitable apparatus used in the textile field, with the spacing/ number of the cylinders and the garnett wires depending on the size and strength of the metal fibers 21 being acted upon.
  • the carding process generally imparts a slight "machine direction" to the fibers 21.
  • Sufficient oil or other lubricant is retained on the fibers 21 of the homogenous fiber mass 29 when the web is processed by the garnett 31, to prevent undesirable fracturing or disintegration of the web 29.
  • the fiber web 33 is lapped by suitable textile apparatus 34 to form a multi-layer structure 37.
  • the lapping apparatus 34 changes the orientation of the fiber web 33 as it is being deposited in successive layers. In this way, the orientation of adjacent ones of the layers 39 are rotated out of alignment from each other by a preselected angle, and the direction of the fibers 21 in the fiber web 33 varies between adjacent layers 39 of the resulting multi-layer structure 37 is interwoven may be used as the ZVIF packing 400.
  • the multi-layer structure 37 is then fed through a suitable nip 41 and needled or needle-punched by textile apparatus 45, as shown in FIG. 6B.
  • the needling of the multiple layers 39 interengages the fibers 21 of respective layers 39, giving the resulting ZVIF packing 43 improved strength, fiber density, and fiber distribution characteristics for selenium removal.
  • the needling process causes the fibers 21 to be interengaged not only within respective layers 37 but also between the layers 37 (in the "z" direction relative to the layers).
  • the x-direction is the longitudinal machine direction in which the fabric ply exits the textile apparatus.
  • the y-direction is the transverse machine direction in which the fabric ply exits the textile apparatus.
  • the z-direction is the vertical direction in which the fabric ply exits the textile apparatus.
  • the bias direction is any other direction 0 - 90 degrees between the x, y, or z-direction, and provides an interwoven and interengaged metal fiber 400 mass.
  • the selenium removal process and apparatus includes a plurality of treatment cells 100 and a holding tank 500, as shown in FIG. 7A.
  • the water of interest flows into the holding tank 500 through an inflow port and includes an overflow port.
  • the holding tank 500 is fluidly connected to a manifold 510 by way of valve 512.
  • the manifold 510 includes a plurality of valves 520, which fluidly communicate to a plurality of treatment cells 100.
  • the treatment cells 100 are described as previously indicated, and may include any number of treatment cells, which are designated as treatment cells A, B, C, D, and E in FIG. 7A.
  • FIG. 7A displays the plurality of treatment cells 100 arranged in parallel.
  • sequential treatment cells 100 may be attached to the treatment cells A, B, C, D, and E, as shown in FIG. 7B.
  • Such a distribution between 5 separate treatment cells into a series train may handle 100 galloon/minute fluid flows.
  • a parallel configuration of the treatment cells 100 distribute the flow to allow an adequate residence time in the treatment cells 100.
  • additional treatment cells 100 may be added or shut off by the valve system in the manifold. 510.
  • the treatment cells 100 may be configured in a serial or sequential fashion, one treatment cell 100 is placed in fluid connection with another treatment cell 100, as to give a serial contamination removal processes for additional contaminant removal.
  • FIG. 7C A side view of one embodiment of the treatment cell 100 is shown in FIG. 7C.
  • the inlet port 210 is located on the bottom of the container vessel 200 and fluid flow from the manifold is indicated by arrow 212.
  • a plurality of spacers 230 are located on the bottom of the container vessel 200 to permit the water to flow into the bottom of the container vessel 200.
  • a porous plate 240 separates the spacers 230 and the porous bag 300.
  • the porous bag 300 includes the fill 340 of the ZVIF packing 400 to remove selenium.
  • the treated water then flows out of outlet port 220 by way of fluid flow indicated by arrow 220, to either another treatment cell 100 or discharged consistent with the objectives of the treatment system.
  • the porous bag 300 may include a plurality of porous bag layers 350 of different densities of ZVIF packing 400.
  • the porous bag layers 350 include a plurality of lift straps 370, a porous bag wall material, a porous bottom, and a fill of the ZVIF packing 400.
  • the porous bag layers 350 are discrete and separate layers, where each porous bag layer may include a specific density of ZVIF packing 400.
  • the plurality of porous bag layers may be implemented to accomplish different objectives, such as: (a) ease of maintenance and recharge by decreasing the weight of individual porous bag layers 350; (b) use of porous bag layers containing different densities of ZVIF packing 400 to accomplish more efficient target substance removal; (c) the use of inserts composed of differing average cross-sectional diameter d of the metal fiber 400 to accomplish more efficient target substance removal, and combinations of (b) and (c) to accomplish more efficient target substance removal.
  • the porous bottom on one porous bag layer 350 separates the porous bag layer 350 from each one another.
  • the porous bag layers 350 may include layers 352, 354, 356, 358, 360, and 362, wherein each layer may include different densities of ZVIF packing 400, including, but not limited to, 1 pound cubic foot, 5 lb/ft 3 , 10 lb/ft 3 , 15 lb/ft 3 , 20 lb/ft 3 , 25 lb/ft 3 , to 50 lb/ft 3 .
  • the bottom layer 352 may include a density of 5 lb/ft 3 as to prevent clogging of the bottom layer 352.
  • the middle layers 354, 358, 360, and 362 may have an increased density of 20 lb/ft 3 , to permit increased selenium removal once the contaminated water is within the treatment cell 100.
  • the top layer 364 may include a density of 5 lb/ft .
  • the porous bag layers 350 include metal fibers of any cross- section diameter d at any density.
  • the porous bag layer 350 can be of any thickness and weight, and the stacking of the porous bag layers 350 may be dictated by the system requirements, removal, and the like.
  • FIG. 7E is a cut-away of treatment cell 100 with the plurality of porous bag layers 350.
  • the porous bag layers 350 may be reinforced with straps spanning the diameter of the porous bag layers on the top and side layer.
  • the porous bag layers 350 include the ZVIF packing 400 and are stacked upon each other to allow for replacement and removal of individual porous bag layers 350 as need be.
  • the lift straps 370 are shown in FIG. 7F, as well as the reinforced porous bag material 390.
  • the treatment cell 100 may include a compressed gas line 372 in between one of the layers 352, 354, 356, 358, 360, and 362 to emit a plurality of gas bubbles 374, as shown in FIG. 7G.
  • a space 368 can be created between any (or all) of the porous bag layers and the compressed gas sparge line 372 is inserted in the space 368, as shown in FIG. 7H.
  • the location of the space 368 and insertion of the gas line may be at the bottom layer, as shown in FIG. 7H., or if there are multiple gas lines 372, the gas lines 372 may be placed between multiple porous bay layers, as shown in FIG. 71.
  • the gas sparge line 372 is fit between porous bag layers using a spacer to provide for the space 368, more specifically shown in FIG. 7J.
  • the spacer may include a matrix to provide support for the gas line 372, wherein the spacer could be made of plastic, metal, or any other suitable material.
  • the gas line 372 may include a circular or spiral configuration to provide for sufficient gas to be emitted throughout the porous bag layers, as shown in FIG. 7J. Alternatively, the gas line 372 may be in an "X" configuration with properly sized holes.
  • the gas line 372 may include a air flow meter, an air pressure gauge, and an air regulator to regulate the amount and pressure of the gas being emitted into the treatment cell 100.
  • the location of the gas line 372 may be dependent upon which type of contaminant is to be filtered or removed. In one embodiment, if the contaminant is heavier in water, then the gas line is placed on or close to the bottom layer. Alternatively, the gas line is placed in a layer where the water becomes oxygen depleted due to iron oxidation, and the bottom layer is the layer where the oxygen becomes depleted due to iron oxidation. Alternatively, if the contaminant is lighter in water, the gas line 372 is placed towards the top layer of the treatment cell. The treatment cell may be targeted to remove dissolved contaminants, thus if the contaminants are dissolved and the water is flowing through, buoyancy should not factor into the flow through.
  • the bubble size may be between about 1/100 inch to about 1/2 inch; alternatively, between about 1/50 inch to about 1/3 inch; alternatively between about 1/25 to about 1/4 inch; alternatively, between about 1/16 to about 1/6 inch.
  • the water agitation caused by the compressed air percolating through the ZVIF inserts causes greater contact between the contaminants and the iron in the ZVIF, increasing the chances and rate of the contaminants in reducing to lower valent species and adsorbing to the oxidized iron and/or reducing to elemental species and becoming insoluble.
  • Other types of compressed gases may yield similar or even enhanced contaminant removal benefits, such as nitrogen, oxygen, argon, carbon dioxide.
  • the type of gas may be dependent upon the type of contaminant for removal. For example, if the contaminant is on the same size as Nitrogen gas, then Nitrogen gas increases the contact and bump of the contaminant into the ZVIF inserts.
  • the reduction/adsorption reaction can be altered to yield maximum contaminant removal efficiency.
  • a range in the amount of compressed gas to be delivered may be between about 1 SCFM to about 50 SCFM, alternatively, between about 5 to about 40 SCFM, alternatively, between about 10 to about 30 SCFM, alternatively between about 15 to about 25 SCFM.
  • this range in the amount of compressed gas may be related to the density of the ZVIF inserts, i.e.
  • the amount of compressed gas is between about 10 to 50 SCFM for a ZVIF insert density between about 25 lb/ft 3 to 50 lb/ft 3 .
  • the amount of compressed gas is between about 5 to 20 CFM and the ZVIF insert
  • a range of the gas delivery pressure may be between about 5 to about 100 PSI; alternatively, between about 10 to about 80 PSI; alternatively, between about 15 to about 70 PSI; alternatively, between about 20 to about 60 PSI; alternatively, between about 25 to about 50 PSI; alternatively, between about 30 to about 40 PSI.
  • the gas line can include a plurality of air injection points. In one embodiment, the gas line includes 3 air injection points, as shown in FIG. 7J.
  • the gas delivery pressure may be related to the density of the ZVIF inserts, i.e. higher PSI may be needed for a higher density of the ZVIF inserts.
  • the gas delivery pressure may be between about 1 to about 100 PSI; alternatively, between about 10 to about 80 PSI; alternatively, between about 15 to about 70 PSI; alternatively, between about 20 to about 60 PSI; alternatively, between about 25 to about 50 PSI; alternatively, between about 30 to about 40 PSI.
  • the gas delivery pressure is about 30 PSI with a ZVIF insert density between about 5 to about 25 lb/ft 3 .
  • the flow rate of the water treatment cell may be between about 1 to 50 gallons per minute (GPM), alternatively between about 5 to about 40 GPM, alternatively, between about 10 to about 30 GPM, alternatively, between about 20 to 25 GPM.
  • GPM gallons per minute
  • the flow rate may be increased or decreased depending on the amount of the gas being delivered to the treatment cell.
  • approximately 100% removal of selenium may be achieved in one embodiment.
  • the removal of selenium may be decreased as the rate at which the contaminant is being moved through the treatment cell is at a too high of rate for the ZVIF inserts to remove the selenium, where the removal of selenium may be approximately less than 100%, in one embodiment.
  • a pH control system 700 is placed before the water treatment cell 100 in one embodiment.
  • the acceptable range for the water's pH for selenium removal in ZVI systems is between 6 and 8, and within this range, the lower the pH, the removal of selenium is increased.
  • the ZVIF packings 400 can more readily reduce selenate to selenite and selenite to elemental selenium.
  • One method for lowering the H of water comprises dissolving carbon dioxide (CO2) in a closed system 700 into the influent water 702, thus forming carbonic acid (H 2 CO 3 ) into the influent water and lowering the pH.
  • Acid gas which may be a natural gas or any other gas mixture which contains significant amounts of hydrogen sulfide (H 2 S), carbon dioxide (C0 2 ), or similar contaminants.
  • An acid gas is any gas that contains significant amounts of acidic gases such as carbon dioxide (C0 2 ) or hydrogen sulfide.
  • C0 2 is used below for exemplary purposes.
  • the method comprises using C0 2 to lower the pH before interacting the influent contaminated water 702 with the ZVIF packings 400, which has the advantages of not having to use acidic chemicals with precise measuring and metering systems that respond to changes in influent pH and flow rate.
  • C0 2 has a buffering capability in water; i.e., a constant flow of C0 2 will yield similar pH lowering results across a wider range of flow rates and influent pH.
  • the method comprises infusing regulated, gaseous C0 2 into the influent water 702 (see FIG. 7K) from an enclosed C0 2 regulator 710 via a porous diffuser 712.
  • the influent water 702 is then further blended inline with a static mixer 714 for a maximum effect of mixing the gaseous C0 2 with the influent water 702.
  • the amount of C0 2 required to achieve a particular pH is mainly dependent on the pH of the influent water 702, its alkalinity and the flow rate; other minor factors such as water temperature will also affect the amount of C0 2 required to achieve a target pH.
  • Sensors for the alkalinity, the flow rate, and temperature for the influent water 702 may be placed before the porous diffuser 712, such that the C0 2 regulator 710 may deliver the appropriate amount of C0 2 into the influent water 702.
  • a diffuser 712 consists of a Y-strainer housing that has been retrofit with a length of porous hose. The porous hose is placed inline with the water flow for maximum diffusion of C0 2 in the water stream.
  • a static mixer 714 is operably coupled downstream of the diffuser is which further blends the C02 with the water.
  • the pH control system 700 generally comprises: (1) lowering the pH of water comprising dissolving CO2 in a closed system into the influent water to form carbonic acid and lowering the pH without the use of acidic chemicals coupled with precise measuring and metering systems that respond to changes in influent pH and flow rate; (2) regulating and infusing gaseous CO 2 into the influent water through a porous diffuser comprising a Y strainer housing that is coupled with a length of a porous hose, coupling the porous hose inline with the water flow for maximum diffusion of CO2 in the influent water, and blending the CO2 inline with a static mixer that is downstream of the diffuser to further blend the CO 2 with the influent water; (3) regulating the amount of C0 2 to achieve a target pH between 6 and 8 by testing the pH of the influent water, testing the alkalinity of the influent water, testing the flow rate of the influent water, and testing the water temperature of the influent water; (4) using CO 2 in a closed system to allow more gas to dissolve than in an open system and not
  • FIG. 14 A field demonstration using ZVIF packing with a metal fiber 410 with an average fiber width of 50 ⁇ in a nominal 1850 gallon container vessel 200 was evaluated, as shown FIG. 14.
  • the container vessel 200 was installed at a surface mine and included a top-in inlet port. Piping was attached to divert mine drainage water from a pond into the top of the container vessel.
  • the container vessel 200 was initially filled with 420 pounds of ZVIF packing 400.
  • a container vessel 200 was installed that allowed top inflow and gravity exit of the mine water. The flow was roughly controllable by a valve at the outlet port. The container vessel 200 measured 6.8 feet in diameter and was 6.9 feet high. The container vessel 200 footprint measured 36 square feet.
  • the ZVIF packing was loosely packed in the tank. Initially 420 pounds of ZVIF packing was loaded to a height of 5.5 feet. Over time the fill of the ZVIF packing settled and another 180 pounds was added, which filled the container vessel 200 to a height of 5.7 feet.
  • FIG. 9 shows a general trend towards a higher fraction removed at higher residence time, but there are large fluctuations at low residence times and limitations in the chemical analyses. The conclusion that a greater than 40% of the selenium was removed from the treatment system at residence times longer than five hours is demonstrated.
  • FIG. 10 shows a trend towards lower iron output with increasing time. This may indicate an improved inflow design or some decrease in the access of oxygen to iron, such as might occur if iron oxides coated the fiber particles.
  • FIG. 11 a plot of the pH of the system showing influent and effluent, and drop of pH between the influent and effluent.
  • the pH of the entry water was about 8 (which can support very little dissolved iron).
  • the pH of the solution tends to decrease marginally, from about 8 to 7.5.
  • the oxidation of metallic iron by oxygen, and its subsequent precipitation, produces protons that lower the pH, as in Equations (4) and (5). This is consistent with the generation of protons during the oxidation and precipitation of iron hydroxides in the bed.
  • the generation of manganese during treatment is shown in FIG. 12.
  • the steel wool contains manganese to the level of a percent or more which oxidizes during the treatment process.
  • the mechanism of manganese oxidation is unknown, but the amount released is roughly 1% of the amount of iron released, which is a fair indication that manganese is oxidized with iron.
  • FIG. 13 a plot of the selenium removal versus the temperature profile. The plot shows rate effect of temperature on the selenium removal process.
  • the treatment test has consistently removed selenium from the incoming stream and in most instances to below 5 ⁇ g/L, despite imprecise flow control. Low flow rates and long residence times were consistently effective in removing selenium. Certain higher flow rates and shorter residence times were surprisingly effective, but selenium removal at short residence times in this test was unreliable. On occasion, some low residence times, as shown in FIG. 9, provide 50% removal rates. Treatment at 7 gallons per minute lowered the selenium content to 2 ⁇ g/L. The rate of bed deterioration is slow and manageable. The release of manganese is not substantial. Manganese, if it presents a problem, does have a known treatment chemistry, whereas selenium does not. Efforts to use low manganese source materials maybe the easiest solution. The treatment of selenium with zero-valent iron under field conditions is effective.
  • ZVIF packing 400 Five Fifty five gallon treatment cells 100 of ZVIF packing 400 were installed in a different surface mine, as shown in FIG. 14.
  • the five treatment cells contained a ZVIF packing 400 as follows: (1) 0.5 volume % of metal fibers 410 with a cross-section diameter d of 40 ⁇ ; (2) 1 volume % of metal fibers 410 with a cross-section diameter d of 40 ⁇ ; (3) 2 volume % of metal fibers 410 with a cross-section diameter d of 40 ⁇ ; (4) 1 volume % of metal fibers 410 with a cross-section diameter d of 60 ⁇ ; and (5) 1 volume % of metal fibers 410 with a cross- section diameter of 100 ⁇ .
  • the other removal test contained 0.5 volume % of metal fibers 410 with a cross-section diameter d of 50 ⁇ .
  • the system used consists of a five (5) foot length of 4 inch inside diameter Polyvinyl Chloride ("PVC") drain pipe with a 90 degree bend at both ends, as shown in FIG. 17.
  • the exit end of the pipe also had a straight extension with a three (3) inch reduction output at 90 degrees, as shown in FIG. 18.
  • a 120 gallon-per-hour submersible pump was used to recycle the mine drainage.
  • the effluent was sampled and analyzed for Se and other metals at designed intervals.
  • the rate of selenium removal was 24 ⁇ g of Se/hour for the interval of 0-1 hours; 5.8 ⁇ g of Se hour for the interval of 0-8 hours; 4.9 ⁇ g of Se hour for the interval of 0-12 hours; and 3 ⁇ g of Se hour for the interval of 6-12 hours.
  • the steel wool pads after the bench test are shown in FIG. 19, where the top steel wool pad is a coarse pad and the two bottom steel wool pads are an extra fine pad.
  • FIG. 20 is a plot of the initial Se removal portion fit to an exponential curve for 0 - 6 hours.
  • FIG. 21 is a plot of the selenium removal for 6 - 12 hours showing linear removal rates.
  • the metal fibers 400 may include a helical wound reel configuration, wherein the helical wound reel includes layers of isotropic metal fibers helically wound about a center or core to form a helical wound reel in a cylindrical or puck-like shape.
  • the helical wound reel may then be placed into a PVC tube in a concentric fashion, or alternatively be placed on top each other to form a fluid flow through for treating contaminated water when coupled with a water pump.
  • the metal fibers 400 are produced in an isotropic mass as indicated previously, and then the metal fibers 400 are helically wound into a master helical roll onto a 2" diameter cardboard core.
  • Master helical rolls are approximately about 4" wide x 24" in diameter and weigh about 20 lbs. The approximate densities of the master helical rolls are about 18 lbs per cubic foot.
  • the master helical roll is then taken to a reeling machine to be made into finished helical wound reels including a correct width, tension, weight and diameter.
  • the core of the master helical roll is placed on a shaft at the beginning of the reeling machine and a 1" diameter by 10.5" long PVC core is placed in the reeling machine's bobbin.
  • the ribbon from the master helical roll is threaded through a tensioner, a device that applies a force to an object to maintain it in tension, and hand wrapped onto the 1" PVC core.
  • the tensioner may include a series of polls in which the ribbon may be wrapped around to apply a tension force.
  • An operator uses a foot pedal that starts the reeling machine's bobbin to spin and helically wrap the ribbon of the master helical roll around the PVC core.
  • the reeling machine may operate at a speed of about 50-70 rpm and the reeling machine's speed is controlled by foot pedal as an on/off function.
  • the reeling machine includes a pressure pad on the opposite of the feed side of the reeling machine that is set to about 20-50 psi, which works with the operator to control the tension of the ribbon.
  • the operator guides the ribbon of the master helical roll while adjusting the reeling machine's speed in order to make the helical wound reel to a particular finished specification.
  • the operator stops the reeling machine, cuts the helical wound reel from the master roll, and takes the finished helical wound reel off the bobbin.
  • a 1" diameter plastic plug is placed in one end of the helical wound reel's core to eliminate fluid flow through the core.
  • the specification for the finished helical wound reels is approximately 20 lbs, 10.5" wide x 11.5" in diameter for an approximate density of 32 pounds per cubic foot.
  • the finished helical wound reels can be larger or smaller in diameter and width as well as higher or lower in density in order to adjust for element or selenium removal.
  • the finished helical wound reels may include a range of about 8" to 24" in diameter, 4" to 16" in length, and 15 to 50 pounds per cubic foot in density. There is no minimum or maximum pitch for the helical wound reels; however, the pitch may range from about 1/8" to 3/8".
  • eleven of the 20-lb finished helical reels are loaded into a 12.75" OD x 11.29" ID schedule 80 PVC tube.
  • a complete treatment system would use several PVC tubes either in series or in parallel.
  • the finished helical wound reels may be placed in any type of enclosure with a fluid flow through system, including, but not limited to a tank bale, a pipe, and the like.

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  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
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  • Chemical & Material Sciences (AREA)
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Abstract

Cette invention concerne un procédé et un appareil de retrait d'éléments.
PCT/US2010/055823 2009-11-06 2010-11-08 Procédé et appareil de retrait d'éléments WO2011057186A2 (fr)

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US12/614,204 US20100147769A1 (en) 2008-03-28 2009-11-06 Element removal process and apparatus
US12/614,204 2009-11-06
US12/903,918 US20110114563A1 (en) 2008-03-28 2010-10-13 Element removal process and apparatus
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GB2520775A (en) * 2013-12-02 2015-06-03 Dca Consultants Ltd Multifunctional reactor

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US5298170A (en) * 1993-01-19 1994-03-29 Gunter Woog Effluent neutralization process and chamber
US6249941B1 (en) * 1996-02-23 2001-06-26 Rhodes American Nonwoven metal fabric and method of making same
US20080179256A1 (en) * 2007-01-23 2008-07-31 Purifics Environmental Technologies, Inc. System and method for chemical-free metal particle removal from a liquid media
JP2011502743A (ja) * 2007-10-24 2011-01-27 モット・コーポレーション 焼結繊維フィルタ
US8025800B2 (en) * 2008-03-28 2011-09-27 Global Material Technologies, Inc. Element removal apparatus

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GB2520775A (en) * 2013-12-02 2015-06-03 Dca Consultants Ltd Multifunctional reactor

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