WO2014165998A1 - Traitement d'un flux de déchets par l'intermédiaire de la production et de l'utilisation de gaz oxhydrique - Google Patents

Traitement d'un flux de déchets par l'intermédiaire de la production et de l'utilisation de gaz oxhydrique Download PDF

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Publication number
WO2014165998A1
WO2014165998A1 PCT/CA2014/050367 CA2014050367W WO2014165998A1 WO 2014165998 A1 WO2014165998 A1 WO 2014165998A1 CA 2014050367 W CA2014050367 W CA 2014050367W WO 2014165998 A1 WO2014165998 A1 WO 2014165998A1
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Prior art keywords
oxyhydrogen
waste stream
adsorbent
gas
waste
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PCT/CA2014/050367
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English (en)
Inventor
Tyler Lee WILSON
Angella Aileen HUGHES
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Xogen Technologies Inc.
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Publication of WO2014165998A1 publication Critical patent/WO2014165998A1/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
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
    • C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
    • 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
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/04—Treating liquids
    • G21F9/06—Processing
    • G21F9/12—Processing by absorption; by adsorption; by ion-exchange
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/04—Treating liquids
    • G21F9/06—Processing
    • G21F9/16—Processing by fixation in stable solid media
    • G21F9/162—Processing by fixation in stable solid media in an inorganic matrix, e.g. clays, zeolites
    • 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
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
    • 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
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46133—Electrodes characterised by the material
    • 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
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46133—Electrodes characterised by the material
    • C02F2001/46138—Electrodes comprising a substrate and a coating
    • C02F2001/46147—Diamond coating
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/006—Radioactive compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/4616—Power supply
    • C02F2201/46175—Electrical pulses

Definitions

  • This application relates to methods and systems for treating waste streams, such as industrial waste water, municipal waste water and others.
  • Harmful materials found in many waste streams can present a significant risk to the environment and/or human health if left untreated.
  • Government regulations often mandate that various organic, inorganic, chemical, and microbial components of a waste stream must be treated before the waste stream can be discharged to the environment. Examples of such waste streams include industrial and municipal wastewater, chemical processing effluent, animal waste, paper mill effluent, and others.
  • FIG. 1 presents a schematic of a treatment facility illustrative of prior art systems for treating municipal wastewater.
  • wastewater influent 100 enters a primary clarifier 102 of the wastewater treatment facility where raw sludge 104 is separated from the wastewater via flocculation, sedimentation, and other primary settling techniques.
  • the wastewater from the primary clarifier 102 is then transported to an aeration basin 106, in which aerobic microorganisms 108 help treat the wastewater in the presence of air 1 10 that is pumped into the aeration basin 106.
  • the wastewater is then transferred to a secondary clarifier 1 12, in which further settling can occur.
  • Secondary sludge 1 14 is also collected in the secondary clarifier, and the treated wastewater 1 16 is transported to an effluent body of water or other distribution source (sometimes only after being subjected to certain advanced treatment procedures such as disinfection, for example).
  • Some of the secondary sludge 1 14 is recycled 1 18 back into the aeration basin 106 to help perpetuate the aerobic biodegradation process.
  • the remaining secondary sludge 1 14 from the secondary clarifier 1 12 and the raw sludge 104 from the primary clarifier 102 are transported via a digester feed 120 to an anaerobic digester 122.
  • anaerobic microorganisms 124 further degrade the sludge and yield by-product gases 126, such as methane 128.
  • the digested sludge from the anaerobic digester 122 is transferred off as liquid 130 which can be applied directly to agricultural land or can be sent to a dewatering process 132. From the dewatering process, the centrate or liquid fraction 134 is typically returned to the front end of the treatment plant 100 for treatment, and the dewatered sludge cake 136 can be used for incineration, land application, or other appropriate uses.
  • Biosolids are a mixture of water and very small solid particles (primarily bacteria and protozoa). The particles carry a net negative charge that resists flocculation, i.e., the agglomeration of smaller particles into larger composite particles.
  • an organic polyelectrolyte or polymer is typically added to biosolids as a conditioning aid.
  • these polymers are essentially long organic strands or ribbons with many active sites that have a net positive charge.
  • the polymer neutralizes the negative charge on the biosolids and binds a particle to each active site on the polymer.
  • the polymers have a tendency to stick to each other with the net effect that larger particles are created and the result is a porous matrix through which water can drain during the dewatering process.
  • Waste streams may also be treated by incineration.
  • Incineration is one of the few technologies that offers a technically sound solution for the complete destruction of pathogens, viruses, and toxic organics.
  • it has the capability to process biosolids that contain high levels of contaminants, and which are, therefore, unacceptable for agricultural utilization.
  • the high capital cost of a conventional incinerator and the extensive pre-processing (e.g., dewatering) of the biosolids make the process very expensive.
  • incineration has typically been economical only in very large wastewater treatment facilities, in which it is possible to benefit from economy of scale.
  • the biosolids In order to avoid the consumption of prohibitively expensive quantities of imported energy during the combustion process of prior art incineration systems, the biosolids must be dewatered to a cake with approximately 30% solids. At this level of dryness, the cake is a plastic, sticky, semi-solid material that can present significant operational problems related to the transfer of the cake from the dewatering device to the incinerator. Variations in the solids content of the cake and attendant variations in heat demand can also make the combustion process very difficult to control.
  • Stabilization of biosolids is a mandatory prerequisite for agricultural utilization of waste sludge and, depending upon the specific location, may be regulated by federal, state, or provincial authorities.
  • the regulations protect human health and the environment from potential risks associated with pathogens contained in the biosolids.
  • Regulatory bodies typically stipulate which treatment processes are acceptable and/or what levels of specific pathogens are allowable in the treated product.
  • stabilization occurs through one or more of the following processes: biological degradation of organic matter, elevated pH, reduction of moisture, and waste handling according to specific time/temperature regimes. All of these processes are relatively expensive, and may be energy intensive, require large volumes of admixtures, or be difficult to control.
  • digester gas As an energy source. Although it contains a high percentage of methane, digester gas is also saturated with water and contains significant quantities of hydrogen sulfide. This makes digester gas extremely corrosive, and extensive cleaning is required prior to its use.
  • digester gas is only the byproduct of a waste treatment process, as opposed to being a production process in itself.
  • the amount of gas produced is a function of the biosolids stabilization process and cannot be modified to meet changing demands.
  • the combustion of methane-rich biogas also generates significant greenhouse gas emissions.
  • UV ultra-violet
  • the capital and operating costs of both of these systems are relatively high.
  • the capital costs include the construction of the flow-through mechanism, and the multiple UV bulbs (lamps) that are required.
  • the operating costs include power, the replacement of bulbs, and regular cleaning of the bulbs.
  • the major costs for disinfecting with ozone include the ozone generator and the commercial oxygen, which is used as the feed source. When air is used as the feed source, the size of the ozone generator must be approximately doubled, therefore doubling the capital cost.
  • Personal care products can include, for example, prescription and over-the-counter therapeutic drugs, veterinary drugs, fragrances and cosmetics. The removal of these components from a waste stream has become more and more important.
  • Oxidative species that are generated by electrodes placed in an aqueous waste stream are used to oxidize an adsorbent, causing it to coagulate.
  • the coagulated adsorbent can be separated from the aqueous waste stream through, for example, flotation, precipitation, filtration, gravity settling, centrifugation, or any other liquid-solid separation method.
  • the adsorbent is used to adsorb a radioactive isotope from the waste stream.
  • a method for removing a radioactive isotope from a waste stream.
  • the method includes submersing two closely spaced electrodes in the waste stream.
  • the waste stream includes a water component, an adsorbent, and the radioactive isotope.
  • the radioactive isotope is adsorbed on the adsorbent.
  • the electrodes border an interaction zone extending there between.
  • An electrical signal is applied to at least one of the electrodes thereby generating oxyhydrogen-rich gas from the water component.
  • the oxyhydrogen-rich gas which includes oxidative species, oxidizes the adsorbent, causing at least a portion of the adsorbent to coagulate. At least a portion of the coagulated adsorbent is separated from the waste stream.
  • the adsorbent may be, for example, Fe 7 (CN) 18 , a sulfate salt, or a chloride salt.
  • the sulfate salt may be AI 2 (S0 4 ) 3 or Fe 2 (S0 4 ) 3 .
  • the chloride salt may be FeCI 3 .
  • the adsorbent may be added to the waste stream, or generated in the waste stream in-situ. Generating the adsorbent in-situ may include oxidatively generating the adsorbent in-situ through the application of the electrical signal. For example, the electrical signal may oxidize a hexacyanoferrate complex in the presence of a ferrous salt to generate Fe 7 (CN) 18 as the adsorbent. Fe 7 (CN) 8 is also known as Prussian blue.
  • the electrical signal may oxidize a hexacyanoferrate complex in the presence of a ferrous salt to generate Fe 7 (CN) 18 as the adsorbent.
  • Fe 7 (CN) 8 is also known as Prussian blue.
  • hexacyanoferrate complex may be K 4 [Fe(CN) 6 ].
  • the ferrous salt may be Fe 2 (S0 ) 3 .
  • the hexacyanoferrate complex may be in molar excess of the ferrous salt.
  • the ferrous salt may be in molar excess of the hexacyanoferrate complex.
  • the electrical signal may be a pulsed electrical signal or a non-pulsed electrical signal.
  • the electrical signal may be applied at an electric charge of up to about
  • the electrical signal may be applied at an electric charge of between about 900 and about 3500 coulombs/liter.
  • the pulsed electrical signal may be applied at a frequency between about 10 Hz and about 1 gHz, for example between about 10 Hz and about 250 kHz.
  • the pulsed electrical signal may be applied at an electrical current of between about 1 mA/cm 2 and about 100 mA/cm 2 , for example between about 1 and about 20 mA/cm 2 .
  • At least one of the electrodes may be an iron electrode, aluminum electrode, a dimensionally stable electrode, a coated electrode, or a boron doped diamond electrode.
  • the two electrodes may be an anode and an oxygen gas-diffusion cathode, and the method may include providing oxygen gas to the cathode to produce hydrogen peroxide at the cathode.
  • the oxygen gas-diffusion cathode may include at least a coating that includes: platinum, ruthenium, iridium, rhodium, carbon, manganese, silver, nickel, stainless steel, iron, carbon steel, or aluminum.
  • the carbon may be amorphous carbon or glassy carbon.
  • FIG. 1 is a schematic diagram illustrating components of a wastewater treatment facility in accordance with the prior art.
  • FIG. 2 is a schematic diagram illustrating treatment of a waste stream via a waste treatment system in accordance with an embodiment herein.
  • FIG. 3 is a schematic diagram illustrating a waste treatment system in accordance with embodiments in which oxyhydrogen gas generation apparatuses may be used to perform one or more unit processes in a waste treatment system.
  • FIG. 3A is a schematic diagram illustrating a wastewater treatment facility in which an oxyhydrogen gas generation apparatus is incorporated between an anaerobic digester of the facility and a dewatering process for performing conditioning and/or flocculation unit processes.
  • FIG. 3B is a schematic diagram illustrating a wastewater treatment facility utilizing an oxyhydrogen gas generation apparatus in lieu of an anaerobic digester for performing a stabilization unit process.
  • FIG. 3C is a schematic diagram illustrating a wastewater treatment facility utilizing an oxyhydrogen gas generation apparatus for dewatering preliminary to an incineration unit process.
  • FIG. 4 is a schematic diagram illustrating typical secondary uses for oxyhydrogen-rich gas produced by one or more unit processes employing an oxyhydrogen gas generation apparatus according to FIGS. 2, 3A, 3B, 3C, and 5.
  • FIG. 5 is a schematic diagram illustrating an apparatus consistent with the various embodiments and displaying its application in the treatment of wastewater biosolids in a wastewater treatment facility, as in the embodiments of FIGS. 3A, 3B, and 3C, for example.
  • FIG. 2 is a schematic diagram illustrating treatment of a waste stream 202 via a simplified waste treatment system 204 in accordance with a first embodiment.
  • waste stream 202 may comprise an influent waste stream, such as industrial or municipal wastewater (raw sewage which may include pharmaceutical, personal care products and petrochemical products), for example.
  • waste stream 202 may comprise an intermediate waste stream such as supernatant or biosolids, for example, in the context of a larger waste treatment process.
  • waste stream 202 may include chemical processing effluent, animal waste, paper mill effluent, landfill leachate, marine wastewater, storm water runoff, ground water, surface water, in-situ treatment process effluent, and environmental contaminate remediation process effluent, for example. Waste stream 202 may be subjected to preliminary processing steps, such as screening and grit removal, before undergoing a unit process 206, as described below.
  • Screening and grit removal may be particularly important when waste stream 202 comprises raw sewage influent.
  • unit process 206 comprises an oxyhydrogen gas generator 207 (GG1 ) interposed in a flow path 208 between an inlet 210 and an outlet 212 of waste treatment system 204 for generating oxyhydrogen-rich gas 214 from a water component of waste stream 202.
  • Oxyhydrogen-rich gas 214 generated from waste stream 202 preferably bubbles through or otherwise passes through at least a section of flow path 208 to thereby contact at least a portion of waste stream 202.
  • the water component is segregated from the waste stream 207 through use of a semipermeable membrane or other separation technology and the gas generator 207 is immersed in the segregated water component.
  • oxyhydrogen-rich gas may be generated external to flow path 208 and added at unit process 206 to contact at least a portion of waste stream 202.
  • a source of water for the oxyhydrogen gas generator 207 may include tap water, surface water, or a water component that has been separated from the waste stream.
  • Unit process 206 may operate as a one-step wastewater treatment process, in which the concentrations of contaminants, examples of which are: Biochemical Oxygen Demand (BOD), ammonia, phosphorous, suspended solids and pathogens are reduced in waste stream 202.
  • Unit process 206 may additionally operate as a wastewater treatment process in which the concentration of organic, inorganic and chemical contaminants, such as pharmaceutical, personal care products, petrochemical products, and metals, are reduced in waste stream 202.
  • the contaminants to be removed from waste stream 202 using the produced oxyhydrogen-rich gas 214 are generally considered as: (a) contaminants which can be oxidized though contact with the oxidants contained in the oxyhydrogen-rich gas 214 (i.e. they are "oxidizable contaminants"), and (b) contaminants which can be reduced through contact with the hydrogen contained in the oxyhydrogen-rich gas 214 (i.e. they are "reducible contaminants").
  • the contaminants to be removed from waste stream 202 using the produced oxyhydrogen-rich gas 214 can be called reduction-oxidation (“redox”) active ("redox active contaminants”) under the conditions of the process 206.
  • Contaminants are removed from waste stream 202 via operation of the gas generation apparatus in flow path 208.
  • waste stream 202 comprises municipal wastewater
  • organic contaminants such as pharmaceutical, personal care products and petrochemical products, are believed to be oxidized by the oxidizing compounds contained in the oxyhydrogen-rich gas 214.
  • Volatile contaminants which evaporate to varying degrees at normal wastewater processing temperatures, such as ammonia (inorganic) and acetone, toluene, dichloromethane and dichlorobenzene (organic) are stripped (transferred from the liquid phase to the gas phase) from the wastewater through the upward flow of oxyhydrogen-rich gas 214 produced by oxyhydrogen gas generator 207 (GG1 ).
  • Solid-phase contaminants such as suspended solids and phosphorous are removed through the natural flotation mechanism created by oxyhydrogen-rich gas 214 which is produced in the form of micro- bubbles from the oxyhydrogen gas generator 207 (GG1 ).
  • the stripped volatile contaminants are collected at the surface of the unit process 206 in combination with the oxyhydrogen-rich gas 214 and are conveyed to a secondary process module 222 where they may be combusted with the oxyhydrogen-rich gas 220 or separated from the oxyhydrogen-rich gas by processes such as membranes for further treatment (not shown).
  • the solid fraction 216 can be removed from the liquid stream either directly, by skimming the float layer from unit process 206 or by subsequent sedimentation.
  • biological processes are not intended as a component of unit process 206 and therefore the production of biosolids is not intended to occur.
  • the solid fraction in this embodiment is not intended to be biosolids but rather consists of inert, inorganic solids 216 that can be directly disposed of in landfill without further treatment.
  • the treated waste stream is concurrently disinfected of pathogens so that it meets regulatory and industry standards for effluent 218. Thereafter effluent 218 may be released directly to a body of surface water such as a river, for example, or reused in waste treatment system 204.
  • a body of surface water such as a river, for example, or reused in waste treatment system 204.
  • effluent 218 may undergo further processing (not shown) such as tertiary sand filtration after unit process 206 and before release or reuse.
  • exiting amounts of oxyhydrogen-rich gas 220 may be conveyed from unit process 206 to a secondary process module 222 of waste treatment system 204, such as an incineration unit, for example.
  • FIG. 4 described below, illustrates various other secondary uses for oxyhydrogen-rich gas 220 following its utilization in unit process 206.
  • unused oxyhydrogen-rich gas or a by-product 224 of secondary process 222 may be recovered or otherwise conveyed to one or more other process modules 226 for use in tertiary aspect(s) of waste treatment system 204 or external use(s).
  • Oxyhydrogen gas generator 207 may implement a water dissociation technology, such as the kind disclosed in U.S. Pat. Nos. 6,419,815 and 6,126,794 of
  • gas generation apparatuses in accordance with embodiments include electrode "cells" each including two or more spaced-apart electrodes adapted to be immersed in a working fluid including water.
  • the working fluid comprises waste stream 202.
  • the electrodes are preferably made of the same material.
  • One electrode material may be stainless steel for its low cost and durability, but it may be possible to use other conductive metals.
  • the electrodes may be coated or uncoated.
  • the electrodes may be coated with boron doped diamond. Such an electrode may be referred to as a "boron doped diamond electrode”.
  • the electrodes may be coated with a single layer or multiple layers.
  • the coating may include one or more layers of a mixed metal oxide, a conducting metal, a metal alloy, or combinations thereof.
  • the coating may be one or more layers of: Ruthenium Oxide, Iridium Oxide, Platinum, Titanium dioxide, tin oxide, or any combination thereof.
  • the mixed metal oxide, metal or metal alloy may be doped with other metals.
  • a layer that includes a metal doped mixed metal oxide is a layer of antimony doped tin oxide.
  • coated electrodes are available from Denora S.p.A, for example DSATM electrodes which are titanium electrodes coated with a mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum.
  • the anode and the cathode may be the same or different.
  • An equal spacing between the electrodes is maintained and it is preferable to minimize the spacing between the electrodes.
  • the spacing between the electrodes cannot be positioned excessively close because arcing between the electrodes would occur. It has been determined that a spacing of 1 mm or less is optimal spacing for producing oxyhydrogen-rich gas, but an increased spacing of up to approximately 5 mm may work effectively while being less subject to fouling due to accumulation of solids between the electrodes.
  • a spacing above 5 mm may also be feasible, but tends to reduce the output of oxyhydrogen gas and increases power requirements.
  • Electrodes can be almost any shape, but preferably comprise flat or mesh plates closely spaced and parallel to each other.
  • Alternative embodiments may include coaxially aligned cylinders. Insulating spacers can be interposed between adjacent electrodes to maintain equal spacing between the electrodes and to prevent current leakage therebetween.
  • a high- frequency pulsed direct current (DC) electrical signal is applied to the electrodes.
  • the pulsed signal can be almost any waveform and have a variable current level, voltage level, frequency and mark-space ratio (i.e., a ratio of the duration of a single pulse to the interval between two successive pulses).
  • the source of power for the power supply may include a mains 1 10 volts or batteries, such as 12-volt car batteries.
  • the power supply may comprise two 12- volt batteries arranged in series to provide a 24-volt supply.
  • a more complex power supply may be required for generating 24-volt pulsed DC signal having sufficient power to drive the large cells required.
  • multiple smaller electrode cells may be provided for redundancy and spaced apart in a reaction vessel or other reaction zone, in which case the cells may be driven by simpler independent power supplies.
  • a controller is used in conjunction with the batteries or other power source to generate one of a variety of pulsed output waveforms, such as a square wave, a saw tooth wave, or a triangular wave, which can be applied to the electrodes. At present, the best results for producing oxyhydrogen-rich gas have been obtained using a square wave.
  • a pulsed signal has a mark-space ratio of between approximately 1 : 1 and 10: 1 and a pulse frequency of approximately 10Hz-250 kHz.
  • the electrodes After initiation of the pulsed signal from the power supply, the electrodes continuously and almost instantaneously generate bubbles of oxyhydrogen-rich gas from water molecules in an interaction zone that extends between the electrodes and slightly beyond the edges of the electrodes.
  • the generated bubbles are not bunched around or on the electrodes and thus readily float to the surface of the fluid in the reactor vessel or other reaction zone. Therefore, there is no need to add a chemical catalyst to assist the conduction of the solution or inhibit bubbles from bunching around or on the electrodes.
  • many different kinds of waste streams can be used as the working fluid, as can other sources of water, such as surface water and ordinary tap water.
  • FIG. 3 is a schematic diagram illustrating a waste treatment system 240 in which oxyhydrogen gas generators GG2, GG3, GG4, and GG5 may be used in the performance of one or more unit processes 242a, 242b, 242c, and 242d (collectively unit processes 242) of waste treatment system 240.
  • Oxyhydrogen gas generators GG2, GG3, GG4, and GG5 may comprise devices similar to those described herein (items 207 and 500) with reference to FIGS. 2 and 5, for example.
  • waste treatment system 240 is embodied as a wastewater treatment plant for treating a waste stream 244 comprising municipal wastewater (raw sewage, which may include pharmaceutical, personal care products and petrochemical products).
  • waste treatment systems may, alternatively, be arranged and configured to treat different types of waste streams, such as industrial wastewater, chemical processing effluent, animal waste, paper mill effluent, landfill leachate, marine wastewater, storm water runoff, ground water, surface water, in-situ treatment process effluent, and environmental contaminate remediation process effluent, for example.
  • Wastewater influent may be treated by use of a primary clarifier 246, aeration basin 248 and final clarifier 250 in accordance with known methods, in which biosolids 252 are removed from waste stream 244 in the forms of raw sludge 254 and waste activated sludge 256.
  • a disinfection process 260 is either replaced or supplemented by an oxyhydrogen gas generator GG2 interposed in the flow path of the treated waste stream, between final clarifier 250 and effluent outlet 258.
  • the pulsed electrical signal applied to oxyhydrogen gas generator GG2 operates to generate oxyhydrogen-rich gas and, by its operation, disinfects treated wastewater.
  • oxyhydrogen-rich gas (H 2 /0 2 ) 262 can then be conveyed to a secondary use within waste treatment system 240, as described below with reference to FIG. 4.
  • an oxygen component of oxyhydrogen-rich gases (H 2 /0 2 ) produced by one or more unit processes 242 other than disinfection unit process 242a can be conveyed to disinfection unit 260 as a feed source for an ozone generator of disinfection process 260, which may result in substantial overall cost savings for effluent disinfection.
  • the oxygen component would need to be separated from the oxyhydrogen-rich gas (H 2 /0 2 ) before use as a feed source for an ozone generator.
  • PSA pressure swing adsorption
  • H 2 /0 2 is used to symbolize oxyhydrogen-rich gas, without limiting to clean oxyhydrogen gas or to a pure gaseous mixture of diatomic hydrogen (H 2 ) and diatomic oxygen (0 2 ).
  • Oxyhydrogen-rich gas is typically composed of gas mixture including predominantly hydrogen and oxygen, but may include at least some oxygen and hydrogen in forms other than diatomic oxygen (0 2 ) and diatomic hydrogen (H 2 ), such as hydroxide radicals, for example.
  • Oxyhydrogen-rich gas may further include measurable amounts of components other than hydrogen and oxygen that may result, for example, from the operation of the oxyhydrogen gas generator in the presence of high concentrations of contaminants or from reactions of the generated oxyhydrogen gas with contaminants in the waste streams.
  • measurable amounts of components other than hydrogen and oxygen may result, for example, from the operation of the oxyhydrogen gas generator in the presence of high concentrations of contaminants or from reactions of the generated oxyhydrogen gas with contaminants in the waste streams.
  • small amounts (e.g., 1 % to 4% mole fraction) of carbon dioxide (C0 2 ) gas may often be present in oxyhydrogen- rich gas generated from wastewater or tap water.
  • Trace amounts of nitrogen may also be present in oxyhydrogen-rich gas, particularly when generated from wastewater, and may indicate breakdown of the nitrogenous compounds present in the wastewater.
  • gas generators GG2- GG5 are typically generated in a stoichiometric ratio of approximately 1 :2, respectively, notwithstanding the lack of an indication of the stoichiometric ratio or other gas components in the shorthand notation "H 2 /0 2 " used herein.
  • biosolids 252 in the form of waste activated sludge 256 may undergo a thickening unit process 242b.
  • a conventional thickening process 264 such as gravity belt filtering, centrifuging, or dissolved air floatation (DAF), for example, is supplemented or replaced by an oxyhydrogen gas generator GG3.
  • Oxyhydrogen gas generator GG3 is preferably interposed in the flow of waste activated sludge between final clarifier 250 and a downstream biosolids treatment process such as stabilization 242c, conditioning 242d, dewatering 266, drying 268 and/or incineration 270, for example.
  • oxyhydrogen gas generator GG3 preferably causes floatation of biosolids and other suspended solids (i.e. collection of solids at the surface of the waste stream), which results in a concentrated floating layer that can be easily removed or separated from the waste stream for further treatment.
  • oxyhydrogen gas generator GG3 is submerged in wastewater contained in a reaction vessel and operated for an interval of from approximately 60 seconds to up to approximately 10 minutes, then power to the gas generator GG3 is shut off. It has been found that after an interval of operation of gas generator GG3, a substantial amount of solids collects on the surface of the wastewater. While a modest amount of solids may collect on the surface of the wastewater during operation of gas generator GG3, a surprisingly large increase in floating solids occurs nearly immediately after de-energizing of gas generator GG3 and stopping of a recycle flow through the reaction vessel (see the description of FIG. 5, below, for details of the recycle flow provided by pump 526). De- energizing of gas generator GG3 and stopping of the recycle flow results in quiescent conditions within the reaction vessel, which allow for unhindered floatation of solids.
  • An extracted gas floatation unit process includes one or more cycles each including the following steps: (1 ) operating the gas generator GG3 (typically by applying a high-frequency pulsed electrical signal) for between approximately 60 seconds and approximately 10 minutes, (2) de-energizing gas generator GG3, (3) waiting until solids collect on the surface of the fluid (typically between approximately 30 seconds and 2 minutes), and (4) removing the solids from the surface (by skimming the surface, for example).
  • the cycles can be repeated continually until a desired amount of solids has been removed from the wastewater.
  • Biosolids 252 that are to be applied to agricultural land must typically be stabilized 242c prior to application to reduce the number and viability of pathogens.
  • an oxyhydrogen gas generator GG4 is utilized for stabilization of the biosolids 252 in waste stream and generation of
  • Gas generator GG4 may be submerged in a reaction vessel 502 (FIG. 3B) wherein the waste stream comes into direct contact with the
  • oxyhydrogen-rich gas 272 produced by gas generator GG4.
  • Utilization of an oxyhydrogen gas generator GG4 for stabilization may require a shorter time of residence than required in a conventional stabilization processes 274 to kill or render innocuous an effective amount of pathogens. Consequently, gas generator GG4 can be immersed directly in a continuous reactor for treating biosolids as they flow through a processing zone of the reactor.
  • the size of the gas generator GG4 and the residence time required in the processing zone is a function of the level of
  • the finished product must typically have a density of fecal coliform in the biosolids of less than 1000 most probable numbers (MPN) per gram total solids and a "vector attraction reduction” such as a 38 percent reduction in volatile solids content.
  • MPN most probable numbers
  • a "vector attraction reduction” such as a 38 percent reduction in volatile solids content.
  • Two of the approved conventional ways to achieve this are to treat the biosolids by thermophillic aerobic digestion at a temperature of 55° C. to 60° C. for a period of 10 days (240 hours) or under an alternative time/temperature regime of 50° C. for a period of 5 days (120 hours).
  • experimental studies utilizing an oxyhydrogen gas generator GG4 have shown that the stabilization and vector attraction reduction criteria can be met with a processing temperature of 25° C. and a batch residence time of 4 to 6 hours.
  • oxyhydrogen gas generator GG4 Operation of oxyhydrogen gas generator GG4 is believed to create, within a reaction vessel or flow-through processing zone, an atmosphere that is consistent with the conditions required for stabilization.
  • oxyhydrogen-rich gas liberated, the temperature of the contents of the reactor or processing zone increases and can be controlled to achieve necessary temperature requirements for stabilization, in view of a known residence time of a particular system.
  • the time/temperature regime can be customized to meet regulatory requirements and provide the necessary pathogen destruction.
  • the residence time of the liquid can also be controlled independently of the temperature, with the result that any combination of time and temperature can be achieved.
  • the biosolids can either be dewatered for agricultural utilization or utilized directly in a liquid injection program.
  • the oxygen liberated by the gas generator GG4 produces a highly oxidative environment resulting in the oxidation of organic matter, which can, in itself, satisfy stabilization requirements.
  • the combination of these two stabilization approaches in one step offers the potential for an extremely efficient process.
  • the combination of these conditions may be sufficient to qualify as a "Process to Further Reduce Pathogens" as specified in U.S. EPA Regulation 503 and may produce Class A bio solids that can be applied, in liquid form, directly to agricultural land.
  • Treated material may generate fewer odors and attract fewer vectors, such as flies and rodents, during the subsequent handling and reuse operations.
  • a separate conditioning step 242d is performed after stabilization 242c (either conventional 274 or via gas generator GG4) and before dewatering 266.
  • Conventional chemical conditioning 276 involves the addition of polymers or organic polyelectrolytes to facilitate flocculation of solid particles for removal from the waste stream.
  • Conditioning consistent with one embodiment utilizes an oxyhydrogen gas generator GG5 to supplement or replace chemical conditioning 276.
  • Gas generator GG5 generates a highly oxidative and elevated temperature regime that tends to destroy polysaccharide layers around biosolids, which can present a barrier to flocculation of the biosolids.
  • the reduction in polysaccharide alters surface properties of the biosolids to thereby decrease the amount of polymer required or, in some cases, to completely eliminate the need for polymer additives.
  • implementation of the oxyhydrogen gas generator in the conditioning unit process 242d reduces the cost of conditioning, reduces problems of toxicity and odor generation, and concurrently liberates oxyhydrogen-rich gas (H 2 /0 2 ) 278 from a water component of the biosolids waste stream 252.
  • the oxyhydrogen-rich gas 278 can then be recovered and conveyed for secondary uses within waste treatment system 240 or elsewhere.
  • the gas generator GG5 of conditioning process 242d may be immersed in a reaction vessel 502 (FIG.
  • an oxyhydrogen gas generator may allow both stabilization and conditioning to be performed concurrently in a single combined stabilization/conditioning unit process, as discussed below with reference to FIG. 3B.
  • FIGS. 3A-3C represent further illustrative embodiments of wastewater treatment facilities including oxyhydrogen gas generators 500 for processing waste streams including biosolids.
  • reference numerals in the 300-series correlate to 100-series numerals in the corresponding FIG. 1 , described above.
  • the primary clarifier is represented by reference numeral 302, which corresponds to reference numeral 102 for the corresponding unit process of FIG. 1 . Details in FIGS. 3A-3C numbered with 500-series reference numerals are described below in greater detail with reference to FIG. 5.
  • FIG. 5 With respect to FIG.
  • a gas generator 500 is illustrated in operation between the anaerobic digester 322 and the dewatering process 332 for performing conditioning and/or flocculation unit processes.
  • the gas generator 500 is operated in lieu of an anaerobic digester (122 from FIG. 1 ) for purposes of stabilization of the waste stream.
  • the gas generator 500 may also function as a conditioning unit process or a combined stabilization/conditioning unit process, depending on the nature of the waste stream entering reaction vessel 502.
  • the gas generator 500 is operated in lieu of a conventional dewatering process (132 from FIG. 1 ) as part of a combined dewatering and incineration procedure consistent with the embodiments described.
  • Embodiments applied to the treatment of wastewater biosolids are
  • FIG. 5 represents one embodiment of the oxyhydrogen gas generators GG2-GG5 of FIG. 2, and, more specifically, provides additional detail of the implementation of gas generators 500 of FIGS. 3A-3C.
  • gas generator 500 is submerged in a reaction vessel 502 containing a fluid suspension 504 including water and biosolids.
  • Fluid suspension 504 may be dilute, as in influent wastewater, or may be more concentrated, as in activated waste sludge, raw sludge, or thickened sludge.
  • Fluid suspension 504 typically includes a substantial portion of biological floes (biosolids) having an aggregate specific gravity of only slightly greater than 1.0.
  • Gas generator 500 may be mounted on a frame 510 that is hung from a set of floats 522 so that the submergence of the gas generator 500 is maintained at a desired level below the surface of the fluid 504.
  • gas generator 500 may be mounted to a fixed lid or other fixed support for positioning at a fixed height in reaction vessel 502.
  • floats 522 may also serve to seal the top of reaction vessel 502.
  • the frame 510 is adjustable so that the submergence level of the gas generator 500 can be adjusted independent of the depth of fluid 504 in the reaction vessel 502.
  • gas generator 500 is placed on a pedestal or other support so that it is positioned below the middle of the depth of fluid 504 in the reaction vessel 502. Placement of gas generator 500 low in the reaction vessel (or other reaction zone) increases the distance that bubbles of oxyhydrogen-rich gas must rise through fluid 504, thus increasing their residence time and probability of contacting a biosolids particle or other treatable molecule.
  • gas generator 500 is positioned at least slightly above the floor of the reaction vessel 502 to avoid buildup of sediment and sludge between the electrodes of the gas generator 500.
  • Gas generator 500 includes a series of closely-spaced electrode plates that are oriented generally vertically and arranged such that the spaces between adjacent plates are open to the reactor contents at both the top and bottom edges of the plates.
  • a pulsed electrical signal from a power source 505 is provided to the electrode plates via power transmission wires 507.
  • the application of the pulsed electrical signal causes water molecules in the fluid suspension 504 to be dissociated in an interaction zone extending between the plates and slightly beyond the openings between the plates, to thereby form an oxyhydrogen-rich gas including hydrogen and oxygen.
  • the oxyhydrogen-rich gas collects in the interaction zone to form bubbles that rise through the fluid suspension 504 between the plates and can then be collected at the surface of the fluid suspension 504 under a gas containment lid 524.
  • the rising bubbles may transport the floes upward and into contact with the oxygen and hydrogen in the liberated gas bubbles and/or the atmosphere collected under the containment lid 524.
  • the recirculation loop may also provide a degree of positive mixing in the reaction vessel 502 to help keep the bio solids in suspension and thus in a position to be transported upwards toward the surface of the fluid suspension 504 or another contact zone where the biosolids are more likely to contact oxyhydrogen-rich gas.
  • Sample ports 508 may be provided in the recirculation line to allow samples of the biosolids to be collected and analyzed for various parameters in order to determine the degree of treatment that has been achieved at any point in time.
  • Unit process applications for gas generator 500 in the context of municipal or industrial wastewater treatment may include disinfection, thickening, conditioning, dewatering, and stabilization, for example, as described herein.
  • the combination of operating parameter levels can be optimized for each kind of unit process and may be unique for each application and for each waste stream source.
  • Some of the operating parameters, which can be independently varied, include the submergence depth of the gas generator 500, the magnitude of the power provided to gas generator 500 via power supply 505, the
  • Characteristics of the pulsed electrical signal that may be controlled by power supply 505 include pulse frequency, amplitude, pulse duration, mark: space ratio, waveform (i.e., square wave, saw tooth wave, etc.), and voltage relative to ground. Other applications and corresponding operating parameters may also be evident to those skilled in the art.
  • Conditioning destroys or degrades the natural polysaccharide layers that are present on the surface of biological floes and act as a deterrent to dewatering.
  • the floes are drawn upwards by the rising bubbles of oxyhydrogen-rich gas, they are brought into direct contact with the hydrogen and/or oxygen in bubbles produced by the gas generator in a highly-oxidative contact zone.
  • the polysaccharide layers represent the outermost boundary of the floe particles, these layers will be preferentially degraded. This removal of a substantial fraction of the polysaccharide layer has the effect of reducing or completely eliminating the need for polymer addition in subsequent conventional dewatering processes.
  • the conditioned biosolids can be transported directly to a conventional dewatering device and the dewatered cake can be disposed of or utilized in any conventional manner known in the art.
  • the final solids concentration of the biosolids released to incinerator 512 is relatively unimportant because the incineration process 512 includes combustion of the biosolids particles and vaporization of the remaining free water.
  • electrical power is provided to the gas generator 500, water from the reaction vessel is liberated into oxyhydrogen-rich gas and the degree of dewatering achieved will be in direct proportion to the amount of oxyhydrogen gas produced. In this approach the amount of gas produced is more important than the final solids concentration in the reaction vessel 502. It is expected that only a small fraction of water need be converted to gas to provide sufficient energy to incinerate the remaining contents of the reactor.
  • the generation of a sufficient amount of oxyhydrogen gas via gas generator 500 is expected to cause a corresponding 10% increase in the solids concentration, from approximately 3.0% solids to approximately 3.3% solids, for example.
  • the solids concentration may be increased to approximately 10% or 20% solids concentration before incineration using oxyhydrogen gas. Because the fuel for the incineration process 512 (i.e., the oxyhydrogen gas) can be generated internally, the demand for imported fuel can be reduced or eliminated.
  • Biosolids are also incinerated in the form of a liquid suspension, rather than cake form, which may eliminate the need for conventional dewatering as a pre-processing step and the attendant material handling problems associated with the transfer of a semi-solid or plastic cake to the incinerator 512.
  • the ability to incinerate biosolids in the form of a liquid suspension also offers the potential for using non-conventional incinerator technology, which in turn may reduce the costs such that incineration becomes economically attractive for use at smaller installations.
  • Incineration may also eliminate the need and the cost for both stabilization and conventional dewatering, which may make the incineration of liquid biosolids economically competitive with other management alternatives.
  • an energy-rich gas will be produced. As shown in FIG. 5, this gas can be used as fuel for incineration 512, power generation 514, or as a feed source for the production of ozone 516 (with oxygen separated from the gas mixture).
  • FIG. 4 is a schematic diagram illustrating several secondary uses for oxyhydrogen-rich gas (e.g. , 220, 262, 272, 278) produced by one or more unit processes employing oxyhydrogen gas generators in accordance with FIGS. 2, 3A, 3B, 3C and/or 5.
  • oxyhydrogen-rich gas may be used as a fuel for (A) incineration of sludge or biosolids, (B) power generation (and subsequent heat recovery for in-plant use), and (C) hot gas generation (for drying or other hot processing).
  • Oxyhydrogen-rich gas may also be separated into its hydrogen and oxygen components for use in one or more secondary processes or uses (D).
  • an oxygen component of the oxyhydrogen-rich gas may be supplied to an ozone generator of a disinfection process or pumped into an aeration basin.
  • the hydrogen component can be conveyed to a different secondary use, such as combustion for incineration, power generation, or drying, for example.
  • the gas produced by embodiments of the present invention is an
  • oxyhydrogen-rich gas that can be combusted with minimal greenhouse gases as byproducts.
  • the gas does not require extensive cleaning and the quantity of gas produced can be adjusted to match the demand for power.
  • the production of power within the treatment plant utilizing the produced gas will result in long-term lower electrical costs and provide a secure supply of electricity that is independent of external market conditions.
  • the principal products of combustion of oxyhydrogen gas are heat and water vapor.
  • the hot combustion exhaust may be condensed in a condensing process 518 to recover high-quality water that can be stored 520 for use within the wastewater treatment facility for a variety of uses.
  • many of these uses do not require potable water quality but they do require a higher quality than is available as secondary effluent. Examples of these uses would include flushing of toilets and urinals, dilution water for polymer solutions and preparing other chemical solutions.
  • water condensed 518 from combustion exhaust can replace water otherwise purchased from a municipal water supply for uses where potable water is not a requirement, thereby reducing operating costs.
  • Acetaminophen inflammatory 61 (M9/L) ⁇ 0.01 (M9/L) 99.98
  • Toluene Organic solvent 263 (mg/L) ⁇ 0.0005 (mg/L) 100.00
  • Tables 2 and 3 detail the results of the testing of municipal waste water from a different source than the waste water used in Table 1.
  • "ND" is an abbreviation for "Not detected”.
  • Each sample was exposed to an initial treatment in a stainless steel reactor for a time of approximately 10 minutes, a second treatment in an aluminum reactor for a time of approximately 2 minutes, and finally effluents were polished by granular activated carbon column.
  • LCS Laboratory Control Sample.
  • the LCS is a "sample” (always a clean water or solid) that is spiked with the contaminant, to determine the efficiency of the extraction process and detection.
  • MS refers to the Matrix Spike, which is an actual sample that is spiked as an LCS, but this verifies that the contaminant can be extracted and detected in an actual sample or slightly different matrix than the MS.
  • the R 2 refers to the recovery of the contaminant from the sample.
  • RL shows the reporting limits. These results show the lowest limit that may be detected within the confidence level. The provided confidence levels range from 95% to 99.5%.
  • the systems and methods reduce the concentration of organic contaminants, such as pharmaceuticals, personal care products and petrochemical products, in the waste stream. This feature may be advantageous in treating municipal waste water where these contaminants may be incorporated within the waste water but where traditional treatment processes may not eliminate them.
  • the steel electrodes appear to be effective at reducing the concentrations.
  • the addition of a set of aluminum electrodes adds to the reduction. It will be understood that other metals and or combinations of metals used in the electrodes and in a different order may have the same or improved results depending on the target contaminants.
  • the systems and methods for removing contaminants from a waste stream can be used to reduce the concentration of metals in the waste stream.
  • a metal which may be removed from the waste stream is a fission product. Fission products are also referred to as radioactive isotopes or metals. Examples of fission products which may be found in a waste stream include: 37 Cs, 60 Co, 65 Zn, 54 Mn, 44 Ce, 226 Ra, 232 Th, and 238 U.
  • the fission products are removed from the waste stream by flocculation (also known as coagulation).
  • the flocculated fission products may be separated from the waste stream by, for example: flotation, precipitation, filtration, gravity settling, centrifugation, or any other liquid-solid separation method.
  • the oxyhydrogen gas generator includes an anode and a cathode.
  • the anode material will electrochemically corrode due to oxidation, while the cathode will be subjected to passivation.
  • Consumable metal plates for example iron or aluminum, may be used as sacrificial electrodes and continuously release ions into the water. The released ions may neutralize the charges of suspended radioactive isotopes and thereby initiate coagulation.
  • One electrode material may include stainless steel for its low cost and durability, but it may be possible to include other conductive metals.
  • the electrodes may be coated or uncoated. Coated electrodes may be, for example, coated metal, coated plastic, coated glass, or another coated substrate. The electrodes may be coated with a single layer or multiple layers.
  • the coating may include one or more layers of a mixed metal oxide, a conducting metal, a metal alloy, or combinations thereof. For example, the coating may be one or more layers of: Ruthenium Oxide, Iridium Oxide, Platinum, Titanium dioxide, tin oxide, or any combination thereof.
  • the mixed metal oxide, metal or metal alloy may be doped with other metals.
  • a layer that includes a metal doped mixed metal oxide is a layer of antimony doped tin oxide.
  • coated electrodes are available from Denora S.p.A, for example DSATM electrodes which are titanium electrodes coated with a mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum.
  • Other examples of coated electrodes include coatings applied to titanium coated plastic.
  • the oxyhydrogen gas generator may include a gas-diffusion cathode that produces hydrogen peroxide, an oxidative species, with the addition of oxygen gas.
  • the gas- diffusion cathode may include at least a coating that includes: platinum, ruthenium, iridium, rhodium, carbon, manganese, silver, nickel, stainless steel, iron, carbon steel, or aluminum.
  • the gas-diffusion cathode may be connected to a source of oxygen gas or a source of a mixture of gases that contains oxygen gas.
  • oxygen gas should be understood to include both pure oxygen gas as well as a mixture of gases that contains oxygen gas. One example of such a mixture of gases is air.
  • the mixture of gases should include substantially no corrosive gases, such as fluorine, chlorine and iodine.
  • the oxygen gas is applied at a pressure such that the partial pressure of the oxygen gas is high enough to provide oxygen to reaction sites on the cathode.
  • the oxygen reacts with the H + and e " , producing the hydrogen peroxide.
  • Increasing the amount of oxygen provided to the cathode may increase the production of hydrogen peroxide by increasing the number of reaction sites occupied by oxygen, until such point as all of the available reaction sites on the cathode are occupied. Once all of the available reaction sites are occupied, providing additional oxygen to the cathode does not increase the production of hydrogen peroxide, but is not detrimental to the production of the hydrogen peroxide.
  • the term "applied pressure” should be understood, in the context of the present application, to refer to the pressure of the pure oxygen gas or the mixture of gases that contains oxygen gas.
  • the applied pressure may depend on whether the oxygen gas is supplied as a pure gas or in a mixture of gases.
  • the applied pressure may be, for example, atmospheric pressure or greater than atmospheric pressure.
  • the gas-diffusion cathode may be constructed of any number of metals.
  • the gas diffusion cathode may be coated with a catalyst such as platinum, ruthenium, iridium, rhodium, carbon, manganese, silver, nickel, stainless steel, iron, carbon steel, or aluminum.
  • the catalyst may include amorphous carbon, glassy carbon, or both.
  • the gas-diffusion cathode is not sacrificial to ensure the current at the gas-diffusion cathode is generating as much hydrogen peroxide as possible.
  • An adsorbent in the waste stream adsorbs at least a portion of the isotopes and increases the amount of suspended radioactive isotopes removed from the waste stream.
  • the adsorbent may be generated in-situ, or may be added to the waste stream. Oxidation, for example at an electrode and/or through reaction with the produced
  • oxyhydrogen gas may be used to generate the adsorbent in situ from one or more chemicals that are added to the waste stream.
  • the in situ generated adsorbent may be formed when an electrochemical cell is run under current control, voltage control, or both.
  • the cell may be subjected to a current having a frequency between about 10 Hz and about 1 GHz.
  • the current may have a frequency between about 10 Hz and about 10 MHz, for example between about 10 Hz and about 1 MHz, or between about 10 Hz and about 250 kHz.
  • the current may have a current density between about 1 mA/cm 2 and about 100 mA/cm 2 , for example between about 1 mA/cm 2 and about 20 mA/cm 2 .
  • the cell may be subjected to an electrical signal at an electrical charge of up to about 100,000 coulombs/liter, for example between about 100 and about 10,000 coulombs/liter. In a particular example, the cell may be subjected to an electrical signal at an electrical charge of about 900 and about 3500 coulombs/liter.
  • Prussian blue (Fe 7 (CN) 18 ).
  • Prussian blue may be formed from the oxidation of hexacyanoferrate complexes in the presence of ferrous salts, for example oxidation of K4[Fe(CN) 6 ] in the presence of Fe 2 (S0 4 ) 3 .
  • Prussian blue may be formed when an electrochemical cell that includes an aqueous mixture of K4[Fe(CN) 6 ] and Fe 2 (S0 4 ) 3 is run under current control at 90% duty cycle and is subjected to a current having a frequency between about 10 Hz and about 250 kHz, with the current having a current density between 1 mA/cm 2 and about 20 mA/cm 2 .
  • the aqueous mixture may include a molar excess of K 4 [Fe(CN) 6 ] or Fe 2 (S0 4 ) 3 .
  • Adsorbents that are not generated in situ may be added to the waste stream. These non-/n situ generated adsorbents may increase the amount of suspended radioactive isotopes removed from the waste stream. Examples of non-/>? situ generated adsorbents which may be added to the waste stream include, for example, Prussian blue (when generated before being added to the waste stream), and sulfate or chloride salts that form double sulfate salts or double chloride salts having reduced solubility.
  • the sulfate salts may form double sulfate salts with the general formula A 2 S0 4 'B2(S0 4 )3'2 H 2 0, which are known to be low solubility salts; where A is a monovalent cation, such as cesium, and B is a trivalent metal ion such as aluminum or iron(lll). These sulfate salts may be used according to the present disclosure to adsorb monovalent radioactive monovalent cations.
  • the chloride salts may form double chloride salts with antimony or iron (such as CsSbCI 4 and CsFeCI ), which are also poorly soluble. These chloride salts may be used according to the present disclosure to adsorb monovalent radioactive monovalent cations.
  • At least a portion of the adsorbed radioactive material is removed by oxidizing at least a portion of the adsorbent.
  • the oxidized adsorbent coagulates, and may then be removed by flotation, precipitation, filtration, gravity settling, centrifugation, or any other liquid-solid separation method.
  • Sodium ions may be removed from the waste stream along with the suspended fission products.
  • Aqueous solutions of CsCI were prepared to simulate radioactive metal contaminated water. Solutions (700 mL) were prepared at 1.0 ppm of CsCI, with 250 mg/L of NaCI. Different parameters of the method were tested.
  • Double sulfates with the general formula A 2 S0 4 B2(S0 4 )3-24H 2 0, are known to be low solubility salts; where A is a
  • B is a trivalent metal ion such as aluminum or iron(lll).
  • Double salt chlorides with antimony or iron (such as CsSbCI 4 and CsFeCI 4 ) are also poorly soluble.
  • the parameters for testing three adsorbents are shown in Tables 4-8.
  • the initial concentration of CsCI and NaCI were 1 and 250 mg/L, respectively.
  • the three exemplary adsorbents were AI 2 (S0 4 ) 3 , FeCI 3 and Fe 2 (S0 4 ) 3 tested at concentrations of 50, 100 or 200 mg/L, though other concentrations could alternatively be used.
  • the pH was tested at about 7, about 9 and about 10.
  • the temperature of the solution was measured to be between 19 and 22 °C. Electric current and charge values were as noted.
  • the solutions were tested in a reactor having a dimensionally stable anode (DSA) electrdoes, Iron electrodes or Aluminum electrodes. The solutions were treated for 30 minutes.
  • DSA dimensionally stable anode
  • Table 6 Tests with DSA Reactor and FeCI 3
  • Table 8 Test with Na 2 S0 4 (200 m /L)
  • test cell In testing the current, voltage, duty cycle and frequency applied to the electrodes, the test cell was operated under current control, 90% duty cycle, 10 Hz, and up to 20 mA/cm 2 .
  • ferrocyanide trihydrate were added to an aqueous solution in an electrochemical cell.
  • the electrochemical cell was subjected to one of three different electrical settings for 3.5 minutes.
  • the resulting coagulated material was removed by filtration and the effluent was analyzed for cesium chloride.
  • condition "A” corresponds to the cell being subjected to a current of about 19 A and an electric charge of about 3400-3600 coulombs
  • condition "B” corresponds to the cell being subjected to a current of about 9.5 A and an electric charge of about 1800-1900 coulombs
  • condition "C” corresponds to the cell being subjected to a current of about 4.7 A and an electric charge of about 890-940 coulombs
  • the cell was operated under current control, 90% duty cycle, 10 Hz, and up to 20 mA/cm 2 .

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Abstract

L'invention concerne des procédés et des systèmes pour réduire un isotope radioactif dans un flux de déchets dans un système de traitement de flux de déchets, consistant à mettre en œuvre un traitement unitaire dans le système de traitement des déchets par adsorption de l'isotope radioactif dans le flux de déchets avec un adsorbant, puis à mettre en contact l'adsorbant avec un gaz riche en gaz de Brown généré sur place par un générateur de gaz oxhydrique qui utilise la technologie de dissociation par l'eau. Dans le générateur de gaz oxhydrique, un signal électrique est appliqué à une série d'électrodes étroitement espacées qui sont submergées dans le flux de déchets pour produire un gaz riche en gaz de Brown à partir d'un composant à base d'eau du flux de déchets. Le fonctionnement du générateur de gaz oxhydrique dans le flux de déchets peut réaliser un ou plusieurs processus unitaires pour le traitement des déchets, tels que l'oxydation, le lavage, la flottation, la désinfection, le conditionnement, la stabilisation, l'épaississement et l'assèchement, entre autres.
PCT/CA2014/050367 2013-04-10 2014-04-10 Traitement d'un flux de déchets par l'intermédiaire de la production et de l'utilisation de gaz oxhydrique WO2014165998A1 (fr)

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WO2016187649A1 (fr) * 2015-05-25 2016-12-01 Micromet Pty Ltd Électrode sacrificielle à alimentation en courant pulsé
CN113371892A (zh) * 2021-05-28 2021-09-10 广东工业大学 一种利用电化学法去除废水中重金属的装置及其实现方法
US11401181B1 (en) 2021-03-02 2022-08-02 Phosphorus Free Water Solutions, Llc Galvanic process for treating aqueous compositions

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7795332B2 (en) * 2005-07-15 2010-09-14 3M Innovative Properties Company Method of removing fluorinated carboxylic acid from aqueous liquid
US20110215001A1 (en) * 2008-08-29 2011-09-08 The Regents Of The University Of California Electrochemical Removal of Arsenic
US20130341267A1 (en) * 2010-09-28 2013-12-26 General Electric Company Treatment for molasses spent wash and other wastewaters

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7795332B2 (en) * 2005-07-15 2010-09-14 3M Innovative Properties Company Method of removing fluorinated carboxylic acid from aqueous liquid
US20110215001A1 (en) * 2008-08-29 2011-09-08 The Regents Of The University Of California Electrochemical Removal of Arsenic
US20130341267A1 (en) * 2010-09-28 2013-12-26 General Electric Company Treatment for molasses spent wash and other wastewaters

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104773919A (zh) * 2015-04-08 2015-07-15 常州大学 一种制药废水深度处理系统
CN104773919B (zh) * 2015-04-08 2016-06-29 常州大学 一种制药废水深度处理系统
CN104787972A (zh) * 2015-04-10 2015-07-22 常州大学 一种煤焦化废水处理系统
CN104787972B (zh) * 2015-04-10 2016-08-17 常州大学 一种煤焦化废水处理系统
WO2016187649A1 (fr) * 2015-05-25 2016-12-01 Micromet Pty Ltd Électrode sacrificielle à alimentation en courant pulsé
US11401181B1 (en) 2021-03-02 2022-08-02 Phosphorus Free Water Solutions, Llc Galvanic process for treating aqueous compositions
CN113371892A (zh) * 2021-05-28 2021-09-10 广东工业大学 一种利用电化学法去除废水中重金属的装置及其实现方法
CN113371892B (zh) * 2021-05-28 2022-05-17 广东工业大学 一种用于实现电化学法去除废水中重金属的方法

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