EP4673405A1 - Système et procédé de piégeage d'oxyde nitreux - Google Patents

Système et procédé de piégeage d'oxyde nitreux

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Publication number
EP4673405A1
EP4673405A1 EP24713544.5A EP24713544A EP4673405A1 EP 4673405 A1 EP4673405 A1 EP 4673405A1 EP 24713544 A EP24713544 A EP 24713544A EP 4673405 A1 EP4673405 A1 EP 4673405A1
Authority
EP
European Patent Office
Prior art keywords
lumen
membrane
exhaust gas
gas
treatment
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
EP24713544.5A
Other languages
German (de)
English (en)
Inventor
Jeff PEETERS
Daniel COUTTS
Matthew REEVE
Robert Hacking
Giuseppe GUGLIELMI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BL Technologies Inc
Original Assignee
BL 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
Application filed by BL Technologies Inc filed Critical BL Technologies Inc
Publication of EP4673405A1 publication Critical patent/EP4673405A1/fr
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456—Removing acid components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/006—Regulation methods for biological treatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/10—Packings; Fillings; Grids
    • C02F3/102—Permeable membranes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes
    • C02F3/1236—Particular type of activated sludge installations
    • C02F3/1268—Membrane bioreactor systems
    • C02F3/1273—Submerged membrane bioreactors
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/30—Aerobic and anaerobic processes
    • C02F3/302—Nitrification and denitrification treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
    • B01D2252/10—Inorganic absorbents
    • B01D2252/103—Water
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/207—Transition metals
    • B01D2255/20707—Titanium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/40—Nitrogen compounds
    • B01D2257/402—Dinitrogen oxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/80—Employing electric, magnetic, electromagnetic or wave energy, or particle radiation
    • B01D2259/804—UV light
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/14—Pressure control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/16—Flow or flux control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/26—Further operations combined with membrane separation processes
    • B01D2311/2661—Addition of gas
    • B01D2311/2665—Aeration other than for cleaning purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/26—Further operations combined with membrane separation processes
    • B01D2311/2688—Biological processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/02—Biological treatment
    • C02F11/04—Anaerobic treatment; Production of methane by such processes
    • 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
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • 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
    • C02F2209/003—Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process
    • 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
    • C02F2209/03—Pressure
    • 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
    • C02F2209/22—O2
    • C02F2209/225—O2 in the gas phase
    • 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
    • C02F2209/24—CO2
    • C02F2209/245—CO2 in the gas phase
    • 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
    • C02F2209/34—N2O
    • 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
    • C02F2209/38—Gas flow rate
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/04—Flow arrangements
    • C02F2301/043—Treatment of partial or bypass streams
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/04—Flow arrangements
    • C02F2301/046—Recirculation with an external loop
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

  • the present invention relates to wastewater treatment processes and systems for reducing or eliminating nitrous oxide emissions from wastewater treatment systems.
  • N2O nitrous oxide
  • International Patent Application WO 2022/184829 discloses a method to reduce or minimize N 2 O emissions in the exhaust gas from a membrane aerated biofilm reactor (MABR) by monitoring one or more parameters of the wastewater and/or the exhaust gas and/or the feed gas and modulating the supply of feed gas to the membrane based on the one or more parameters in order to minimize or eliminate the N2O in the exhaust gas.
  • MABR membrane aerated biofilm reactor
  • a method according to this disclosure comprises operating an MABR in an anoxic zone of a wastewater treatment plant such that N2O produced in the biofilm is preferentially driven into the lumen of the membrane and concentrated in exhaust gas.
  • N 2 O may be preferentially driven into the lumen of the membrane, for example, driven to a relatively greater extent into the lumen of the membrane relative to N 2 O driven into the bulk liquid, by adjusting the partial pressure of components in a process gas inputted to the membrane.
  • the exhaust gas comprising N 2 O is not returned to the bulk liquid, for example as a mixing or scrubbing gas.
  • the exhaust gas may be repurposed to another point in the wastewater treatment line or to another process within the same or another treatment facility, upstream or downstream of the MABR, scrubbed by other means, or otherwise treated, to use or reduce or eliminate N 2 O in the gas.
  • a system according to this disclosure comprises an MABR with a gas- permeable membrane capable of supporting a counter diffusional biofilm.
  • the MABR may be equipped with an exhaust valve for controlling the pressure of a process feed gas or the partial pressure of components of a process gas fed into the lumen of the membrane.
  • the partial pressure of the components of the gas inside the lumen may be adjusted to promote or encourage N 2 O to diffuse towards the interior of the lumen as opposed to diffusing into the bulk liquid.
  • some N 2 O may diffuse into the bulk liquid so long as the denitrification capacity in the bulk liquid is sufficient to prevent N 2 O emissions in off-gas from the bulk liquid.
  • FIG. 1 provides a schematic representation of a counter-diffusional biofilm.
  • FIG. 2 shows an example membrane for use in a membrane aerated biofilm reactor.
  • the present invention provides a system and method for reducing or eliminating N 2 O emissions from a wastewater treatment plant, for example to assist in reducing the overall carbon footprint for wastewater treatment.
  • the method and system disclosed herein comprise scavenging N 2 O in a lumen of the membrane of a membrane aerated biofilm reactor and, in another aspect, reusing the N 2 O in upstream or downstream processes of the wastewater treatment plant or treating the N2O downstream of the MABR.
  • the method comprises operating a membrane aerated biofilm reactor (MABR) in an unaerated zone, such as an anaerobic and preferably an anoxic zone, of a wastewater treatment system (WWTS).
  • the unaerated zone may be for example an anoxic part of an activated sludge process with an elevated ammonia concentration in the bulk liquid.
  • the elevated ammonia concentration may be 7 mg-N/L or more.
  • the increased ammonia concentration can provide higher nitrification activity in the MABR and can produce more N 2 O.
  • the increased concentration of N 2 O may be scavenged for reuse or additional treatment as further described herein.
  • the system and method as disclosed herein may be used for high-strength nitrogen removal, for example in mainstream or sidestream wastewater treatment.
  • Minimizing airflow for post- treatment may be easier to do in sidestream as compared to mainstream environments.
  • use of anammox pathways may decrease the oxygen requirement for ammonia oxidation by approximately half.
  • the sidestream ratio of oxygen demand to nitrogen load can be much lower than in the mainstream.
  • MABR may further facilitate post-treatment of N 2 O emissions by operating at very high oxygen transfer efficiencies, even exceeding 95% which can result in less airflow required to transfer the same amount of oxygen, and the airflow volume requiring posttreatment for removal of N 2 O may be minimized.
  • the system and method disclosed herein may be used for treating centrate from digested sludge (i.e. after dewatering of aerobically or anaerobically digested sludges), or any high ammonia waste streams such as food and industrial wastes, with low carbon.
  • the MABR may be operated for short cut nitrogen removal processes to treat low carbon to nitrogen ratio wastewaters.
  • the membrane aerated biofilm reactor comprises a counter-diffusional biofilm.
  • a counter diffusional biofilm may be, for example, grown on a gas-permeable membrane wherein electron acceptor and electron donor substrates are supplied from opposite sides of the biofilm (i.e. from the bulk liquid and from the lumen of the membrane).
  • co- diffusional biofilms grow on non-permeable substrates, where both electron donor and acceptor substrates are supplied from the bulk liquid.
  • Figure 1 provides a representative counter-diffusional biofilm 100 comprising an aerobic/nitrifying layer 102 and an anoxic/denitrifying layer 104, showing substrate movement into and out of the biofilm.
  • Figure 1 also shows the partitioning of N 2 O produced in the biofilm, for example, N 2 O may diffuse towards the membrane lumen 106 comprising the exhaust gas or to the bulk liquid 108.
  • oxygen diffuses from the membrane lumen 106 through the membrane wall 110 to the aerobic/nitrifying layer 102 of the biofilm.
  • N 2 O produced in the nitrification process flows from the aerobic layer 102 back towards membrane lumen 106, and towards the bulk liquid 108 (which is also anoxic and provides denitrification).
  • NH 4 may move towards the aerobic biofilm layer from the bulk liquid while COD moves toward the anoxic biofilm layer.
  • NO X from the aerobic layer moves to the anoxic biofilm layer and N 2 from the anoxic biofilm layer moves into the bulk liquid.
  • FIG. 2 shows an example membrane 202 that may be used in an MABR.
  • a process feed air may be inputted at a first end of the membrane into the lumen 204 of the membrane and an exhaust air may be expelled from a second end.
  • the second end of the membrane may be, for example, at an end of the membrane that is opposite the input end of the membrane.
  • the process feed gas may include oxygen, nitrogen and/or other components.
  • the process feed gas may be air.
  • the MABR comprising the membrane is preferably located in an anoxic zone of the reactor but may be located in an anaerobic or other unaerated zone.
  • the oxygen depleted zone drives oxygen from the lumen of the membrane towards the bulk liquid where oxygen is not available.
  • the biofilm may comprise several layers, including both an aerobic layer closest to the membrane wall and an anoxic layer closest to the bulk liquid. This type of biofilm may promote both nitrification and denitrification pathways in the aerobic and anoxic layers, respectively.
  • N 2 O is a byproduct of secondary wastewater treatment that may be formed in the nitrification and denitrification pathways in the biofilm. The N 2 O can diffuse out of the biofilm towards the lumen or towards the bulk liquid.
  • other greenhouse gases such as CO 2 for example, may be created and may diffuse out of the biofilm in a similar manner to N 2 O.
  • Driving N 2 O into the lumen of the membrane from the biofilm may comprise using a process feed gas with little or no N 2 O, for example using a process feed gas such as ambient air pressurized by a blower without N 2 O, or another gas with less than 25ppm N 2 O.
  • a process feed gas such as ambient air pressurized by a blower without N 2 O, or another gas with less than 25ppm N 2 O.
  • the lumen of the membrane may be operated with a lower concentration of N 2 O than the biofilm such that N2O moves from a high concentration where it is being produced in the biofilm to an area of low concentration of N2O in the lumen of the membrane.
  • the lumen may have a feed gas or be fed a feed gas with a lower concentration of N 2 O than the biofilm.
  • N 2 O may be permitted to flow from the biofilm to the bulk liquid where it may be denitrified if sufficient readily biodegradable carbon is present.
  • some N2O that diffuses toward the bulk liquid may also be reduced to N2 in the biofilm, for example in anoxic outer layers of the biofilm. If sufficient denitrification capacity is not present, the N2O may be stripped to the atmosphere by bulk liquid aeration which is not desirable.
  • N 2 O and/or other components such as CO2 may be driven into the lumen by selecting a feed or input gas (i.e. the process gas) that is low or absent that component.
  • the partial pressure of N 2 O, and/or CO2 in the process gas may be selected or adjusted to be less than the partial pressure of N2O, and/or CO2 in the bulk liquid.
  • the process feed gas is selected such that it is absent N2O and/or CO2.
  • Some greenhouse gases such as N2O or CO2 may flow into the bulk liquid, particularly as the pressure differential between the biofilm and the lumen membrane approaches equilibrium. Some N 2 O or CO 2 flowing into the bulk liquid is acceptable so long as there is enough denitrification capacity to remove the N 2 O from the bulk liquid before it is emitted into the environment.
  • the partial pressure of N2O at a second end of the lumen i.e. the end where the exhaust gas is expelled), may be adjusted by reducing the partial pressure of O2 in the process feed gas.
  • the partial pressure of oxygen may be reduced just enough to balance a limit in the nitrification and denitrification reactions in the biofilm to produce less N 2 O with maintaining an efficient MABR system.
  • the partial pressure of N 2 O at the input end of the lumen is smallest or non-existent, and highest, for example to the point of equilibrium between the lumen and the biofilm, at an exhaust end of the lumen.
  • the exhaust gas may be expelled from the lumen at its maximum capacity for the greenhouse gas, while limiting the amount of N 2 O that back diffuses into the bulk liquid.
  • the concentration of N 2 O along the length of the membrane may vary. For example, a higher concentration of N2O may exist closer to a second end of the lumen, closest to where the exhaust gas is expelled.
  • a process according to the present disclosure may include monitoring components in the exhaust gas such as N2O, CO2 and O2, and based on these parameters, controlling the process by adjusting the pressure of the process feed gas or the backpressure into the lumen.
  • the pressure of the process feed gas into the lumen of the membrane may be adjusted. Increasing the pressure of the feed gas may be used to lower diffusion of greenhouse gases into the lumen of the membrane while decreasing pressure may increase diffusion of greenhouse gases into the lumen of the membrane.
  • N2O in the exhaust gas may be measured or monitored, to determine what adjustments, if any, need to be made to the process feed gas. For example, if N2O in the exhaust gas increases above an upper threshold value, the process feed gas flowrate may be reduced. A reduced flowrate of process feed gas into the lumen of the membrane reduces the O2 availability in the biofilm and increases the opportunity for reduction of N 2 O to N 2 via denitrifiers in the biofilm. When the N 2 O measurement or monitoring shows a reduced N2O concentration in the exhaust gas, for example lower than a lower threshold value, the process feed gas flowrate may be increased such that the O2 concentration in the biofilm is increased to promote more nitrification.
  • Process feed gas that has not diffused through the membrane walls towards the bulk liquid and any components that have diffused into the lumen of the membrane from the biofilm may be concentrated in the lumen as an exhaust gas.
  • the exhaust gas will have a higher N2O concentration as compared to the process feed gas.
  • the exhaust gas may comprise N2O and other components that diffuse from the bulk liquid, and/or the biofilm into the lumen of the membrane.
  • the exhaust gas may be sent for additional treatment, or redirected to another part of the wastewater treatment system. In an example, redirecting the exhaust gas may be used to leverage denitrification capacity in the bulk liquid around the MABR.
  • N2O in the exhaust gas may be used as a means of determining an anoxic zone’s capacity to denitrify any N2O that is produced by the MABR and diffused to the bulk liquid.
  • the denitrification capacity in the anoxic zone of the bulk liquid may be used to determine the N 2 O denitrification capacity.
  • the N 2 O in the exhaust gas may indicate the driving force of N 2 O into the lumen of the membrane, wherein the higher the driving force of N2O into the lumen, the higher the N2O concentration is in the bulk liquid.
  • the higher concentration of N2O in the bulk liquid may be tied to nitrates and nitrites, for example as a consequence of excessive nitrates and nitrites, being returned to the anoxic zone.
  • a target exhaust N2O band (for example to define an upper limit) may be selected such that if the N2O exceeds the upper limit, the MABR system may be controlled to target one or more of i) a lower percent of internal mixed liquor recycle, ii) the addition or adjustment of an intermittent aeration regime in the bulk liquid, and iii) a percent increase of carbon addition to the bulk liquid.
  • N 2 O enriched exhaust gas may be directed to downstream treatment.
  • Downstream treatment may include a wet scrubber, which may for example be used with raw sewage or primary effluent as a liquid source, or in cases where carbon is not available such as some food waste applications, may be used with supplemental carbon, for example in the form of acetate or methanol.
  • Other downstream treatments may include N 2 O abatement or reduction treatments, catalysis, N 2 O absorption and N 2 O adsorption.
  • the N2O enriched exhaust gas may be used to enhance energy production through combustion.
  • the fuel-to-air ratio may be adjusted to minimize nitrogen oxide emissions associated with N2O from wastewater treatment processes.
  • treatment of the exhaust gas may be effected by adsorption, such as by using titanium coated carbon with UV light (for example, from the sun) to treat the N2O or in another example, using a catalyst and heating the exhaust gas up to 200+ 0 C.
  • the exhaust gas may be diffused into a denitrifying submerged biological process, such as for example a fixed bed, or denitrification filter.
  • the exhaust gas enriched in N 2 O may be used to control the bulk liquid in the anoxic zone, aerobic zone and/or other zones in the wastewater treatment system.
  • the exhaust gas may be used to control return activated sludge recycle rates or internal mixed liquor recycle rates.
  • the exhaust gas enriched with N2O may be used to control oxidation-reduction potential (ORP) in the anoxic zone of the wastewater treatment system or to control intermittent aeration in the aerobic zone.
  • ORP oxidation-reduction potential
  • the N 2 O enriched exhaust gas may be used to control the target effluent nitrate/nitrite at the end of either the aerobic zone or plant effluent such as to try to limit the amount of nitrogen oxides being returned in return activated sludge.
  • Leveraging the potential of the N2O in the exhaust gas may also be beneficial to maintaining the denitrification capacity of the bulk liquid, for example to treat any N 2 O flowing from the biofilm into the bulk liquid (rather than into the lumen of the membrane).
  • the denitrification capacity in the bulk liquid may be maintained by controlling the mixed liquor recycle, ORP, and dissolved oxygen in the anoxic and/or aerobic zones of the wastewater treatment plant.
  • exhaust gas is de-coupled from the scouring or mixing gas dedicated for the MABR operation, for example scouring or mixing gas directed at the bulk liquid.
  • N 2 O or CO 2 or other greenhouse gases driven into the lumen of the membrane are not returned to the liquid phase of the system.
  • the exhaust gas enriched with undesirable greenhouse gases may be removed from the system and/or treated or reused to leverage the potential of N 2 O, for example as described herein.
  • the mixing or scouring gas may be received from an alternative source. In this way the denitrification capacity of the bulk liquid only needs to account for the N 2 O diffusing from the biofilm into the bulk liquid, and not from N 2 O being reintroduced via the bulk liquid aeration (i.e. mixing or scouring) system.
  • the intensity or frequency of scouring or mixing gas in bulk liquid may be controlled to manage biofilm thickness.
  • a thicker biofilm may provide for larger anoxic and aerobic layers that may be used to directly treat N 2 O in the biofilm, which may help to reduce the total amount of N 2 O flowing out of the biofilm (in either direction).
  • the frequency or intensity of scouring or mixing gas may be adjusted to encourage substrate renewal in the liquid phase to promote further growth of the biofilm.
  • a method of reducing or eliminating N 2 O emission from a wastewater treatment system may comprise operating an MABR in a location within a wastewater treatment plant where the ammonia concentration is high or highest, for example in an anoxic zone upstream of an aerobic zone or in sidestream treatment of centrate from dewatered digester digestate.
  • the MABR membranes comprise a hollow interior lumen with an inlet for introducing a process gas as a feed gas to the system and an outlet for expelling an exhaust gas.
  • the feed gas may provide, for example, oxygen, that diffuses through the walls of the lumen to the opposite side of the membrane walls where a biofilm forms.
  • the biofilm may comprise both anoxic and aerobic zones that promote both nitrification and denitrification.
  • the nitrification and denitrification pathways produce N 2 O.
  • the feed gas is low and preferably completely depleted of N2O.
  • N2O may be driven by partial pressure adjustments into the lumen of the membrane. Some N2O may flow into the bulk liquid.
  • N 2 O driven into the exhaust gas may be reused in the wastewater treatment system to maintain or leverage sufficient denitrification capacity in the bulk liquid, as previously described herein.
  • This recycle may be used to address any N 2 O flowing into the bulk liquid before N2O diffuses into the atmosphere, such as in off-gas from bulk aeration.
  • N2O enriched exhaust gas may alternatively or additionally be treated to reduce or eliminate the N2O, for example by using a wet scrubber, by adsorption or using other submerged biological processes.
  • a system for scavenging N 2 O from a wastewater treatment plant comprises a membrane aerated biofilm reactor adapted to grow a counter-diffusional biofilm that produces N2O in nitrification and/or denitrification pathways.
  • the membranes used in the MABR comprise a lumen and permeable membrane walls, for example the membranes may be hollow fiber membranes.
  • the lumen may be used to concentrate N 2 O diffusing into the lumen from biofilm grown on the outer membrane walls.
  • the lumen may comprise a process feed gas input end and an exhaust gas output end.
  • the exhaust gas output end may be connected to a downstream N2O treatment step or a recycle stream to redirect the exhaust gas to another part of the wastewater treatment system.
  • the MABR comprises an exhaust valve for controlling the partial pressure of components of the process feed gas being introduced into the lumen of the membrane.
  • the partial pressure of the components may be adjusted to promote diffusion of N2O from a high concentration of N2O in the biofilm to a low partial-pressure environment in the lumen of the membrane.
  • the N2O partial pressure in the lumen may be adjusted such that the driving pressure of N2O from the bulk liquid is maintained or elevated.
  • the process gas being introduced into the lumen is completely depleted of N 2 O.
  • the lumen of the membrane may comprise a partial pressure gradient with a partial pressure of N 2 O being lowest at the input end of the lumen and highest at the output end.
  • Downstream N2O treatment may comprise treatment with a wet scrubber such as with raw sewage or primary effluent as a liquid source, or with supplemental carbon.
  • treatment of the exhaust gas comprising N 2 O may be achieved by adsorption or by diffusing the exhaust gas into a denitrifying submerged biological process.
  • Analyzing the N2O enriched exhaust gas may comprise a recycle control system that manipulates the performance of the activated sludge process to have lower N2O concentrations in the bulk liquor.
  • Recycle or re-use of the N 2 O enriched exhaust gas may comprise a recycle conduit such as to allow the exhaust gas to be used to i) control return activate sludge rates or internal mixed liquor recycle rates, ii) control ORP in the anoxic or aerobic zones, iii) control aeration in an aerobic zone and/or iv) control target effluent nitrate/nitrite at the end of either an aerobic zone or plant effluent to limit the amount of nitrogen oxides being returned in return activated sludge.
  • a system and method for driving N 2 O that is produced in the biofilm into the MABR lumen to facilitate downstream treatment.
  • the system and method further provide for re-use of N 2 O in various processes.
  • the invention as disclosed herein may therefore be beneficial in limiting the greenhouse gas emissions from the wastewater industry while also promoting more efficient processes within the wastewater industry.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Organic Chemistry (AREA)
  • Water Supply & Treatment (AREA)
  • Hydrology & Water Resources (AREA)
  • Microbiology (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Molecular Biology (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
  • Activated Sludge Processes (AREA)

Abstract

L'invention concerne un système et un procédé de piégeage de N20 dans un processus de traitement des eaux usées. Le procédé comprend le fonctionnement d'un réacteur à biofilm aéré par membrane (RBAM) dans un processus de boues activées à forte concentration d'ammoniac et la collecte de N20 dans la lumière de la membrane du RBAM. Le N20 est poussé dans la lumière des membranes par des ajustements de pression. Les ajustements de pression comprennent la pression totale d'un gaz de traitement et les ajustements de pression partielle des composants d'un gaz de traitement. Le N20 collecté peut être recyclé dans le système de traitement des eaux usées ou traité en aval du RBAM.
EP24713544.5A 2023-02-27 2024-02-12 Système et procédé de piégeage d'oxyde nitreux Pending EP4673405A1 (fr)

Applications Claiming Priority (2)

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IT102023000003423A IT202300003423A1 (it) 2023-02-27 2023-02-27 Sistema e metodo per rimuovere ossido nitroso.
PCT/US2024/015425 WO2024182111A1 (fr) 2023-02-27 2024-02-12 Système et procédé de piégeage d'oxyde nitreux

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KR (1) KR20250161532A (fr)
CN (1) CN120693306A (fr)
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IT (1) IT202300003423A1 (fr)
WO (1) WO2024182111A1 (fr)

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CN118993343B (zh) * 2024-09-26 2025-12-09 天津海之凰科技有限公司 一种mabr耦合mbr的污水处理及其使用方法

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US7300571B2 (en) * 2003-02-13 2007-11-27 Zenon Technology Partnership Supported biofilm apparatus
CN103827285A (zh) * 2011-08-15 2014-05-28 小利兰·斯坦福大学托管委员会 一氧化二氮的微生物生成：偶联有气相一氧化二氮化学反应且包括磷回收和亚硝酸盐还原成一氧化二氮
GB201906298D0 (en) * 2019-05-03 2019-06-19 Arborea Ltd Bioreactor device and methods
WO2021163184A1 (fr) * 2020-02-11 2021-08-19 Bl Technologies, Inc. Procédé et appareil de nitritation à l'aide d'un réacteur à biofilm aéré à membrane
CN112320933B (zh) * 2020-10-21 2023-04-07 西安建筑科技大学 一种将生活污水中氨氮转化为n2o的装置及方法
CN112320940B (zh) * 2020-10-21 2023-03-14 西安建筑科技大学 一种利用膜接触器富集产n2o反硝化菌的装置及方法
GB2606128A (en) 2021-03-03 2022-11-02 Oxymem Ltd Air flow control in a membrane aerated biofilm reactor

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IT202300003423A1 (it) 2024-08-27
CN120693306A (zh) 2025-09-23
KR20250161532A (ko) 2025-11-17
WO2024182111A1 (fr) 2024-09-06

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