WO2022229193A1 - Micro-organismes immobilisés sur un support polymère pour éliminer l'azote de l'eau - Google Patents

Micro-organismes immobilisés sur un support polymère pour éliminer l'azote de l'eau Download PDF

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WO2022229193A1
WO2022229193A1 PCT/EP2022/061064 EP2022061064W WO2022229193A1 WO 2022229193 A1 WO2022229193 A1 WO 2022229193A1 EP 2022061064 W EP2022061064 W EP 2022061064W WO 2022229193 A1 WO2022229193 A1 WO 2022229193A1
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microorganisms
water
spp
immobilized
polymer support
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PCT/EP2022/061064
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Henriette Draborg
Reinhold Sebastian SOERENSEN
Alexander Findeisen
Cédric HOBEL
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Novozymes A/S
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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
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/30—Aerobic and anaerobic processes
    • C02F3/302—Nitrification and denitrification 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
    • C02F3/08—Aerobic processes using moving contact bodies
    • C02F3/085—Fluidized beds
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N11/00—Carrier-bound or immobilised enzymes; Carrier-bound or immobilised microbial cells; Preparation thereof
    • C12N11/02—Enzymes or microbial cells immobilised on or in an organic carrier
    • C12N11/04—Enzymes or microbial cells immobilised on or in an organic carrier entrapped within the carrier, e.g. gel or hollow fibres
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N11/00—Carrier-bound or immobilised enzymes; Carrier-bound or immobilised microbial cells; Preparation thereof
    • C12N11/02—Enzymes or microbial cells immobilised on or in an organic carrier
    • C12N11/08—Enzymes or microbial cells immobilised on or in an organic carrier the carrier being a synthetic polymer
    • C12N11/082—Enzymes or microbial cells immobilised on or in an organic carrier the carrier being a synthetic polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C12N11/084—Polymers containing vinyl alcohol units
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N11/00—Carrier-bound or immobilised enzymes; Carrier-bound or immobilised microbial cells; Preparation thereof
    • C12N11/02—Enzymes or microbial cells immobilised on or in an organic carrier
    • C12N11/10—Enzymes or microbial cells immobilised on or in an organic carrier the carrier being a carbohydrate
    • 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
    • C02F3/105—Characterized by the chemical composition
    • C02F3/108—Immobilising gels, polymers or the like
    • 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
    • C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
    • C02F3/341—Consortia of bacteria
    • 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 microorganisms immobilized on a polymer support for nitrogen removal from drinking water or wastewater.
  • the processes for nitrogen treatment in water are most commonly undertaken by biological treatment processes due to their relatively low cost and high level of efficacy.
  • the two most common processes are known as nitrification (oxidation of ammonium (NH 4 + ) to nitrite (NO 2 ) and then nitrate (NO 3 ) by a community of nitrifying microorganisms) and denitrification (reduction of nitrate and/or nitrite to elemental nitrogen (N 2 ) by a community of denitrifying microorganisms), thereby removing the nitrogen from the water.
  • nitrification oxidation of ammonium (NH 4 + ) to nitrite (NO 2 ) and then nitrate (NO 3 ) by a community of nitrifying microorganisms
  • denitrification reduction of nitrate and/or nitrite to elemental nitrogen (N 2 ) by a community of denitrifying microorganisms
  • Nitrification consumes oxygen and alkalinity. Denitrification is generally most efficient in an anoxic (no elemental oxygen present) environment and consumes COD (Chemical Oxygen Demand otherwise known as a carbon source) while producing alkalinity. As with all microbiological processes, both nitrification and dentification require an optimal pH condition and the presence of a range of micronutrients to support the growth and function of the microorganisms.
  • Nitrifying communities are generally dominated by ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB).
  • AOB ammonia oxidising bacteria
  • NOB nitrite oxidising bacteria
  • the nitrifying biomass is generally only 10-40% of the total biomass of microorganisms that are present in a water or wastewater treatment process.
  • denitrifying bacteria are only a small proportion of the total microbiological community present in a denitrification process. The proportion of actively nitrifying or denitrifying microorganisms can vary over time based on operational conditions.
  • ammonium In drinking water, the presence of ammonium (NH 4 + ) will lead to nitrification in the distribution network that can lead to aesthetic issues (taste and odour), corrosion, alkalinity consumption and decreased pH. The presence of ammonium can also increase chlorine demand, which then increases the presence of disinfection by-products and increases the potential for unwanted growth in distribution systems. In areas where drinking water sources are anoxic groundwater resources, the presence of nitrate (NO 3 ) can be an issue. Nitrate can impact how blood transports oxygen, especially in babies, leading to “blue baby syndrome”.
  • the presence of nitrogen in any form in treated effluent can be harmful to the environment the treated wastewater is being discharged to.
  • Ammonium is directly toxic to fish and other aquatic lifeforms, while excessive levels of nitrate and nitrite can lead to eutrophication in water courses, leading to fish die offs, odours and other environmental issues.
  • Modern drinking water and wastewater treatment plants have been designed to meet standards for nitrogen concentrations. However, as regulations are tightened, enhanced nitrogen removal processes are required to supplement the normal nitrogen removal processes already in place. These enhanced processes can involve the nitrification of ammonium to nitrate or the dentification of nitrate and nitrate to nitrogen, or a combination of both processes.
  • a range of treatment technologies can be applied, with the technology of choice based on the application, the level of treatment required and standards that are required to be met.
  • commonly applied technologies include, but are not limited to, ion exchange resins, reverse osmosis membranes and biological sand filters.
  • wastewater applications commonly applied technologies include, but are not limited to, activated sludge, integrated fixed film activated sludge (IFAS), moving bed bio-reactors (MBBR), membrane bio-reactors (MBR) and biological sand filters.
  • beads from polymeric and other materials.
  • these beads can have the characteristics required to enable the integration of selected and concentrated microorganisms.
  • the beads will need to allow for the passage of the required substrates from the water to the microorganisms, and also the passage of the reaction products from the microorganism back to the water.
  • These beads can be utilised in a treatment process designed by one skilled in the art, to achieve the treatment goals required.
  • the benefits of the application of immobilized microorganisms include, but are not limited to: an ability to maintain a microbiological community that is enhanced to achieve the treatment goals, an ability to limit or eliminate the production of excess biomass, protection of the microorganisms from extreme operational conditions including for example pH and temperature.
  • An aspect of the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hydrogel; wherein polymer hydrogel comprises a cross-linked polymeric material and water or aqueous medium; wherein the cross-linked polymeric material is a cross-linked polymer comprising polyvinyl alcohol, and alginate; wherein the microorganisms are selected from the group consisting of ammonium oxidizing microorganisms, nitrite oxidizing microorganisms, denitrifying microorganisms, combinations thereof and anammox bacteria.
  • a further aspect of the invention is directed to a method of treating wastewater comprising ammonia removal using a polymer support as defined herein.
  • a further aspect of the invention is directed to a method of treating wastewater comprising nitrate removal using a polymer support as defined herein.
  • a further aspect of the invention is directed to a method of treating wastewater using a polymer support as defined herein.
  • a further aspect of the invention is directed to a method of treating ground water, surface water, lake water or drinking water comprising ammonia removal using a polymer support as defined herein.
  • a further aspect of the invention is directed to a method of treating ground water, surface water, lake water or drinking water comprising nitrate removal using a polymer support as defined herein.
  • a further aspect of the invention is directed to a method of treating ground water, surface water, lake water or drinking water using a polymer support as defined herein.
  • a further aspect of the invention is directed to a method of immobilizing microorganisms in a polymer hydrogel wherein the microorganisms are selected from the group consisting of ammonium oxidizing microorganisms, nitrite oxidizing microorganisms, denitrifying microorganisms and combinations thereof, the method comprising the steps of:
  • I i. combining polyvinyl alcohol, optionally with a plasticizer, to provide solution A ii. combining solution A with an alginate to provide solution B iii. combining solution B with a solution of said microorganisms to provide solution C iv. adding solution C dropwise to a solution comprising a cross-linking agent to provide a polymer support of immobilized microorganisms; or i. combining an aqueous solution of polyvinyl alcohol with ii. a solution comprising an alginate, optionally with a plasticizer, to provide solution B iii. combining solution B with a solution of said microorganisms to provide solution C iv. adding solution C dropwise to a solution comprising a cross-linking agent to provide a polymer support of immobilized microorganisms.
  • Figure 1 shows a simplified version of the nitrogen cycle.
  • Organic nitrogen nitrogen fixated in living organisms
  • Ammonium is converted to nitrite and then nitrate in the nitrification process.
  • Nitrite and nitrate can then be converted to nitrogen gas in the denitrification process.
  • Nitrogen gas can then be fixated.
  • Annamox processes can use nitrite and ammonium directly to produce nitrogen gas, thereby simplifying the nitrification/denitrification process. That rate at which process in the cycle progresses is based on the concentration of the reactants, the presence of the required microbial organisms, the concentration of these required microbial organisms, temperature, pH and other factors well known to one skilled in the art.
  • Figure 2 illustrates a preferable example of the application of immobilized microorganisms for the nitrification and/or denitrification of wastewater in a tertiary treatment configuration.
  • the process in which the immobilized microorganisms are applied is after the secondary clarification of the treated wastewater.
  • the process can effectively polish the remaining ammonia and/or nitrate and nitrite from the effluent, thereby allowing the owner to discharge without breaching any nitrogen effluent quality requirements.
  • Figure 3 Example of the application of immobilized microorganisms for the nitrification and/or denitrification of a high-strength wastewater in a side-stream treatment configuration in order to reduce the loading on the following biological treatment process.
  • the application of the immobilized microorganisms in such a side-stream process in commercially attractive as it allows for a compact, intensive treatment of the side-stream wastewater for the removal of nitrogenous compounds such as ammonia, nitrate and nitrite. By removing these nitrogen compounds in a compact and efficient side-stream process, the operator of the following wastewater treatment plant will not need to remove the nitrogen compounds of interest in a less- efficient activated sludge process.
  • Figure 4 Example of the application of immobilized microorganisms directly in the biological treatment process to enhance and/or reinforce the nitrification and/or denitrification activity of the activated sludge in order to achieve higher nitrogen treatment rates and resist process shocks.
  • the owner of the wastewater treatment plant can potentially boost the rate of nitrification and/or denitrification achieved in the process, thereby saving on operating costs and more reliably meeting effluent quality requirements.
  • Figure 5 Example of the application of immobilized microorganisms for the nitrification of drinking water. This example is commercially relevant as it aims to utilize the already existing process steps in drinking water treatment to provide the conditions required for nitrification.
  • the compact immobilized nitrifying process would be able to reliably remove ammonia from the drinking water being processed, thereby reducing costs and customer complaints associated with the presence of ammonia in the drinking water distribution system.
  • FIG. 6 Example of the application of immobilized microorganisms for the denitrification of drinking water.
  • This example highlights the potential application of immobilized denitrifying microorganisms, thereby replacing the need for the application of ion exchange systems or reverse osmosis membranes.
  • the biological denitrification process will not produce brines or other by-products that require further treatment.
  • Ultrafiltration membranes and UV treatment of the water after denitrification by the immobilized microorganisms will ensure the safety of the drinking water supply despite the application of a biological treatment step.
  • Table 1 Description of the beads applied to reactors A1-A4. Sample 1 contained only polymeric beads that had no immobilized microorganisms, while samples 2-4 contained microorganisms. The fill volumes of the beads in the reactor were chosen to be in a range of commercially relevant values.
  • FIG. 7 Denitrification rates achieved in reactors A1 - A4.
  • the results indicate that all of the beads with immobilised denitrification microorganisms were able to denitrify at a higher rate than the beads without microorgansims.
  • the beads in A3 demonstrated a significantly higher denitrification rate that was over 200% greater than other beads with immobilised microorganisms.
  • the rate of denitrification achieved by A3 was found to be commercially relevant at a rate of over 5 mg- NCV -N/L.d.g-beads and was relatively stable over time.
  • the results demonstrate that denitrifying microorganisms immobilised in biobeads could be a practical and competitive manner to remove nitrate from drinking water.
  • Table 2 Description of the beads applied to reactors B5-B8.
  • Sample B5 contained only polymeric beads that had no immobilized microorganisms, while samples B6-B8 contained denitrifying microorganisms.
  • the fill volumes of the beads in the reactor were chosen to be in a range of commercially relevant values.
  • FIG. 8 Denitrification rates achieved in reactors B5 - B8. B5 ( ⁇ ), B6 (A), B7 ( ⁇ ) and B8 ( ⁇ ). The results indicate that only the beads in reactor B7 were able to achieve a denitrification rate that was greater than that achieved in reactor B5. It is clear that the presence of dissolved oxygen at significant levels inhibited the denitrification in reactor B7, and when the anoxic conditions were recovered, a very signiicant increase in denitrifaction rate of approxiamtely 500% was achieved in the final days of the trial. Although not stable, the denitrifaction rate achieved by reactor B7 is in the range of well known commercially viable processes for the denitrifation of wastewater in a tertiary stage configuration.
  • Table 3 Description of the beads applied to reactors C9-C12. Sample C9 contained only polymeric beads that had no immobilized microorganisms, while samples C10-C12 contained nitrifying microorganisms. The fill volumes of the beads in the reactor were chosen to be in a range of commercially relevant values.
  • An object of the invention includes the use of microorganisms immobilized within an inert polymer hydrogel support for nitrogen removal from wastewater or water for use as drinking water. Although some leakage of microorgansisms does occur during the process, the inert polymer hydrogel retains a substantial portion of the microorganisms during the nitrification and denitrification steps of nitrogen removal, while being adequately porous to allow the substrate to diffuse into the polymer hydrogel support and the products to diffuse out.
  • the efficacy of biological nitrogen removal processes is herein enhanced through the application of high concentrations of nitrifying/denitrifying organisms in a biological treatment process.
  • selected microorganisms are immobilized.
  • An aspect of the invention improving the efficacy of biological nitrogen removal processes comprises preparing structures or beads from polymeric and other materials, namely polymer hydrogels.
  • these beads comprise characteristics required to enable the integration of selected and concentrated microorganisms. These beads are utilised in a treatment process designed by one skilled in the art, to achieve the treatment goals required.
  • the benefits of the application of immobilization of microorganisms include, but are not limited to: an ability to maintain a microbiological community that is enhanced, and stable enough to achieve the treatment goals, an ability to limit or eliminate the production of excess biomass, protection of the microorganisms from extreme operational conditions including for example pH and temperature.
  • An interesting aspect of the invention is the replacement of chemical means to purify water by using microorganisms immobilized within an inert polymer hydrogel support, wherein the support comprises, at least in part, a biological polymer, given the support comprises the natural polysaccharide found in many forms of algae and seaweed, thus providing a biology-in-biology solution to nitrogen removal from water.
  • the term “community” is intended to mean a microbiological community originating from a single bacterial species or a consortium of multiple strains.
  • a community is a microbial community, composed of a pure strain or a mixed culture, that is enhanced.
  • the term mixed culture defines both defined (constructed by combining strains) or complex (an enriched community).
  • an aspect of the invention is directed to a polymer support and to its preparation. Accordingly, an aspect of the invention is directed to a method of immobilizing microorganisms in a polymer hydrogel wherein the microorganisms are selected from the group consisting of ammonium oxidizing microorganisms, nitrite oxidizing microorganisms, denitrifying microorganisms and combinations thereof, the method comprising the steps of:
  • the plasticizer may be selected from the group consisting of polyols, such as ethylene glycol, propylene glycol, glycerol and ethyleneglycol, mono- and dimethyl ether, tetrahydrofuran, sodium thiocyanate, ammonium thiocyanate, ethanol amine salts, such as triethanolamine acetate and triethanolamine hydrochloride, formamide, dimethylformamide and dimethylsulfoxide. Most preferably, the plasticizer is selected from the group consisting of ethylene glycol, propylene glycol or glycerol.
  • Salts of alginic acid, alginates, are combined in solution A.
  • the alginate may be in solid (powder), gel, gum, liquid or solution form.
  • Any salt of alginic acid is suitable, typically sodium alginate, calcium alginate and potassium alginate.
  • a suitable source of the alginate is seaweed, including brown seaweed (Phaeophyceae), red seaweed (Rhodophyceae), and green seaweed (Chlorophyceae).
  • a suitable source of alginate is the giant kelp Macrocystis pyrifera and Laminaria japonica, Ascophyllum nodosum, and various other types of Laminaria and the bacterial alginates, Pseudomonas and Azotobacter.
  • an aqueous solution of polyvinyl alcohol (PVA) containing 1-50 % w/w PVA, such as 5-25% w/w, such as 5-20%, such as 10% is obtained by dissolving PVA in deionized water.
  • PVA polyvinyl alcohol
  • the mixture is typically heated up under constant mixing until dissolution of the PVA
  • polymer solutions are suitably obtained by mixing the PVA solution with a solution of an alginate and optionally a plasticizer.
  • the combined solution is added to solution comprising microorganisms, wherein the microorganisms are selected from a mixed or pure culture of nitrite-oxidizing bacteria, a mixed or pure culture of ammonium oxidizing bacteria, a mixed or pure culture of ammonium oxidizing and nitrite-oxidizing bacteria, a mixed or pure culture of denitrifying bacteria and a mixed or pure culture of anammox bacteria.
  • the microorganisms may be a combination of ammonium oxidizing microorganisms and nitrite oxidizing microorganisms.
  • the microorganisms may be a combination of the ammonia oxidizing bacteria Nitro-somas spp. and the nitrite oxidizing microorganisms Nitrobacter spp.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and a Nitrobacter, and a combination of a Nitrosomonas europea and a Nitrobacter.
  • the microorganisms may be a combination of a Nitrosomonas and Nitrobacter Winogradsky.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi, and a combination of Nitrosomonas europea and Nitrobacter winogradskyi, preferably a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi.
  • the microorganisms may be wherein the ammonia oxidizing bacteria are selected from Nitrosomonas spp., Nitrosococcus spp., Nitrosospira spp., Nitrosolobus spp., and Nitrosovibrio spp, and wherein the nitrite oxidizing bacteria are selected from Nitrobacter spp., Nitrococcus spp., Nitrospira spp., and Nitrospina spp.
  • the microorganisms may be a culture comprising Paracoccus pantotrophus (formerly Paracoccus denitrificans and Thiosphaera pantotropha). In a suitable embodiment, the microorganism is Microvirgular aerodenitrificans.
  • the microorganisms are selected from the group consisting of Pseudomonas spp.; Paracoccus spp., Castellaniella spp., and Janthinobacterium spp.)
  • a cross-linking solution typically comprises a borate, more typically a combination of a tetraborate and a lactate, such as a combination of boric acid and calcium lactate or sodium tetraborate and calcium lactate.
  • the pH is typically adjusted using an acid or base, so as to maintain the pH at from pH 7 to pH 8, such as approximately 7.3 to 7.8, such as pH 7.5.
  • the plasticizer may be removed from the aqueous gel of by washing the hydrogel with water, prior to the crosslinking the polyvinyl alcohol with the borate.
  • the method of immobilizing microorganisms in a polymer hydrogel of the invention may further comprise the step of curing the beads of step iv, typically step v. curing beads using heat, chemical additives or electron beams.
  • the method of immobilizing microorganisms in a polymer hydrogel of the invention may further comprise the step of washing said cured beads, namely step vi. washing the cured beads.
  • the cross-linking step is controlled in so as to obtain a solid structure of high mechanical stability.
  • parameters, including pH, time of curing, stirring speed, are controlled so as to obtain a desired mechanical stability.
  • the mechanical stability is obtained by simultaneous cross-linking of PVA and alginate.
  • polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hydrogel; wherein polymer hydrogel comprises cross-linked polymeric material and water or aqueous medium; wherein the cross-linked polymeric material is a cross-linked polymer comprising polyvinyl alcohol, alginate and optionally a plasticizer; wherein the microorganisms are selected from the group consisting of ammonium oxidizing microorganisms, nitrite oxidizing microorganisms, denitrifying microorganisms, combinations thereof and anammox bacteria.
  • the polymer support is a hydrophilic polymer.
  • the polymer hydrogel comprises at least 60 wt% cross-linked polymeric material and water or aqueous medium.
  • polymer hydrogel comprises from 60 to 99 wt% cross-linked polymeric material and 1 to 40 wt% water or aqueous medium, such as from 60 to 98 wt% cross-linked polymeric material and 2 to 40 wt% water or aqueous medium, such as from 65 to 95 wt% cross-linked polymeric material and 5 to 35 wt% water or aqueous medium, such as from 65 to 90 wt% cross-linked polymeric material and 10 to 35 wt% water or aqueous medium, such as from 65 to 85 wt% cross-linked polymeric material and 15 to 35 wt% water or aqueous medium, such as from 65 to 80 wt% cross-linked polymeric material and 20 to 35 wt% water or aqueous medium, or such as from 65 to 75 wt%
  • the immobilized microorganisms are substantially immobilized within of the polymer hydrogel.
  • the inert polymer hydrogel retains the microorganism without leakage into the treatment basins during the water treatment method of the invention, while being adequately porous to allow the substrate to diffuse into the polymer hydrogel support and the products to diffuse out.
  • Entrapment in gel matrices provides an advantage of the method in that it serves to physically protect immobilized cells.
  • Cell attachment to an organic or inorganic substratum may be obtained by creating chemical (covalent) bonds between cells and the support using cross- linking agents, such as glutaraldehyde or carbodiimide.
  • the spontaneous adsorption of microbial cells to the polymer carrier also gives natural IC systems in which cells are attached to their support by weak (non-covalent), generally non-specific interactions such as electrostatic interactions.
  • the hydrogel of the invention is advantageously resistant to dissolution in water and reusable.
  • the polymer hydrogel comprises a cross-linked polymeric material wherein the cross- linked polymer comprises polyvinyl alcohol, alginate and optionally a plasticizer.
  • the plasticizer may be selected from the group consisting of polyols, such as ethylene glycol, propylene glycol, glycerol and ethyleneglycol, mono- and dimethyl ether, tetrahydrofuran, sodium thiocyanate, ammonium thiocyanate, ethanol amine salts, such as triethanolamine acetate and triethanolamine hydrochloride, formamide, dimethylformamide and dimethylsulfoxide. Most preferably, the plasticizer is selected from the group consisting of ethylene glycol, propylene glycol or glycerol.
  • the cross-linked polymer comprises polyvinyl alcohol, alginate and polyethylene glycol.
  • the cross-linked polymer comprises polyvinyl alcohol, alginate and glycerol.
  • the polymer material comprises polyvinyl alcohol wherein the polyvinyl alcohol is a blend of polyvinyl alcohol of different molecular weights (MW), such as a blend of 2, 3, 4 or 5 PVA types, each with a MW from approximately 75.000 to approximately 225.000, such as a MW of approximately 95.000 to approximately 205.000, such as a PVA blend comprising a PVA selected from the group consisting of a PVA with a MW of approximately 125.000, PVA with a MW of approximately 145.000, and PVA with a MW of approximately 195.000.
  • MW molecular weights
  • the polymeric carrier is chemically substantially uniform in that the surface, body and core of the carrier is made of the same chemical components.
  • some physio-chemical properties on the surface may differ with the physio-chemical properties within the core and throughout the hydrogel. Accordingly, there may be different degrees of crosslinking at the surface.
  • these differences do not constitute a shell or coating or fibrous network on the surface.
  • a high cell density of immobilized microorganisms within the polymer support is used to improve the product yield and the volumetric productivity of the bioreactors.
  • the population of microorganisms in the support is suitably at a concentration of at least about 25 grams, such as at least 30 grams, such as at least 40 grams, such as at least 50 grams, such as at least 60 grams, such as at least 70 grams, such as at least 80 grams per liter based upon the volume defined by the exterior of the solid structure when fully hydrated.
  • the microorganisms are selected from a mixed or pure culture of nitrite-oxidizing bacteria, a mixed or pure culture of ammonium oxidizing bacteria, a mixed or pure culture of ammonium oxidizing and nitrite-oxidizing bacteria, a mixed or pure culture of denitrifying bacteria and a mixed or pure culture of anammox bacteria.
  • the microorganisms are a combination of ammonium oxidizing microorganisms and nitrite oxidizing microorganisms.
  • the microorganisms are a combination of the ammonia oxidizing bacteria Nitrosomas spp. and the nitrite oxidizing microorganisms Nitrobacter spp.
  • the microorganisms are the microorganisms.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hydrogel.
  • the microorganisms immobilized within the polymer hydrogel may be selected from the group consisting of ammonia oxidizing bacteria, nitrite oxidising bacteria, heterotrophic bacteria and anaerobic ammonium-oxidizing bacteria.
  • the microorganisms immobilized within the polymer hydrogel may be se lected from the group consisting of Nitrosomonas spp., Nitrobacter spp., Nitrosococcus spp., Nitrosospira spp., Nitrosolobus spp., and Nitrosovibrio spp., Nitrotoga spp., Nitrospira spp.
  • the microorgan isms immobilized within the polymer hydrogel may be selected from the group con- sis- tingof Nitrosomonas spp., Nitrobacter spp, Nitrospira spp.
  • Nitrosococcus spp. Nitrosospira spp., Nitrosoio bus spp., and Nitrosovibrio spp., Pseudomonas spp., Paracoccus spp., Castellaniella spp., Hyph omicrobium spp., Ochrobactrum spp., and Janthinobacterium spp.
  • the microorganisms immobilized within the polymer hydrogel may be selected from the group consisting of Nitrosomonas spp., Nitrobacter spp., Nitrospira spp., Nitrosococcus spp., Para coccus spp., and Pseudomonas spp.
  • the microorganisms immobilized within the polymer hydrogel may be selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus denitrificans, Castellaniella defragrans, Pseudomonas proteolytica, Pseudomonas alcaliphila, Pseudomonas chlororaphis, Pseudomonas monteilii, Pseudomonas Uni, Pseudomonas alkylphenolica, Pseudomonas nitroreducens, Pseudomonas stutzeri, Ochrobactrum anthropic, Ochrobactrum intermedium, Aeromonas media, Aeromonas veronii, Aeromonas jandaei, Aeromonas hydrophila, Cellulomonas chitinilytica, Cellulomonas cellasea, Cellulomonas hominis,
  • Candidatus Kuenenia Candidatus Brocadia, Candidatus Anammoxoglobus,
  • the microorganisms immobilized within the polymer hydrogel may be selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus denitrificans, Castellaniella defragrans, Pseudomonas proteolytica, Pseudomonas alcaliphila, Pseudomonas chlororaphis, Pseudomonas monteilii, Pseudomonas Uni, Pseudomonas alkylphenolica, Pseudomonas nitroreducens, Ochrobactrum anthropic, Ochrobactrum intermedium, Aeromonas veronii, Cellulomonas chitinilytica, Cellulomonas cellasea, Cellulomonas hominis, Flavimobis soli, Achromobacter denitrificans, Pelosinus fermentans, Acidovorax soli, Hy
  • the microorganisms immobilized within the polymer hydrogel may be selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus denitrificans, Castellaniella defragrans, Pseudomonas Uni, Pseudomonas proteolytic, Pseudomonas alkylphenolica, Nitrosomonas eutropha, Nitrosomonas europaea, and Nitrobacter Winogradsky.
  • the microorganisms immobilized within the polymer hydrogel are selected from the group consisting of Pseudomonas lini, Paracoccus pantotrophus, Paracoccus pandtodrophus, Castellaniella defragans, Pseudomonas proteolytica, Paracoccus versutus, Paracoccus denitrificans, Nitrosomonas eutropha, Nitrosomonas europaea, and Nitrobacter Winogradsky,
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi, and a combination of Nitrosomonas europaea and Nitrobacter winogradskyi, preferably a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi.
  • the microorganisms are selected from the group consisting of Pseudomonas lini, Paracoccus pantotrophus, Paracoccus versutus and combinations thereof.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution; wherein the immobilized microorgansims comprise Pseudomonas linil.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution; wherein the immobilized microorgansims comprise Paracoccus pantotrophus.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution; wherein the immobilized microorgansims comprise Castellaniella defragans.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution; wherein the immobilized microorgansims comprise Pseudomonas proteolytica.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution, wherein the immobilized microorgansims comprise Paracoccus versutus.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution; wherein the immobilized microorgansims comprise Paracoccus denitrificans.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution, wherein the immobilized microorgansims comprise Nitrosomonas eutropha.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hy drogel; and water or an aqueous solution wherein the immobilized microorgansims comprise Nitrosomonas europaea.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hydrogel; and water or an aqueous solution wherein the immobilized microorgansims compris Nitrobacter Winogradsky.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and a Nitrobacter, and a combination of a Nitrosomonas europaea and a Nitrobacter.
  • the microorganisms are a combination of a Nitrosomonas and Nitrobacter Winogradsky.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi, and a combination of Nitrosomonas europaea and Nitrobacter winogradskyi, preferably a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi.
  • the immobilized microorganisms comprise ammonia oxidizing bacteria selected from Nitrosomonas spp., Nitrosococcus spp., Nitrosospira spp., Nitrosolobus spp., and Nitrosovibrio spp, and comprise nitrite oxidizing bacteria selected from Nitrobacter spp., Nitrococcus spp., Nitrospira spp., and Nitrospina spp.
  • the microorganisms may be selected from the group consisting of ammonia oxidizing bacteria.
  • Ammonia oxidizing bacteria AOB
  • AOB Ammonia oxidizing bacteria
  • WWTPs wastewater treatment plants
  • NCV nitrite
  • the oxidation of NH3 is a two-step process in which NH 3 is oxidized, via the ammonia monooxygenase (AMO) enzyme, to hydroxylamine (NH 2 OH), which is further oxidized to NO 2 , via the hydroxylamine oxidoreductase (HAO) enzyme.
  • ammonia-oxidizing bacteria may be selected from Nitrosomonas and Nitrosococcus.
  • the microorganisms may be selected from the group consisting of heterotrophic bacteria.
  • Heterotrophic bacteria may be selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus denitrificans, Castellaniella defragrans, Pseudomonas proteolytica, Pseudomonas alcaliphila, Pseudomonas chlororaphis, Pseudomonas monteilii, Pseudomonas Uni, Pseudomonas alkylphenolica, Pseudomonas nitroreducens, Pseudomonas stutzeri, Ochrobactrum anthropic, Ochrobactrum intermedium, Aeromonas media, Aeromonas veronii, Aeromonas jandaei, Aeromonas hydrophila, Cellulomonas chitinilytica, Cellulomonas cellasea,
  • Candidatus Jettenia, and Candidatus Scalindua Heterotrophic bacteria may be typically selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus denitrificans, Castellaniella defragrans, Pseudomonas proteolytica, Pseudomonas alcaliphila, Pseudomonas chlororaphis,
  • Pseudomonas monteilii Pseudomonas Uni, Pseudomonas alkylphenolica, Pseudomonas nitroreducens, Ochrobactrum anthropic, Ochrobactrum intermedium, Aeromonas veronii, Cellulomonas chitinilytica, Cellulomonas cellasea, Cellulomonas hominis, Flavimobis soli, Achromobacter denitrificans, Pelosinus fermentans, Acidovorax soli, Hyphomicrobium denitrificans, and Microvirgula aerodenitrificans.
  • Heterotrophic bacteria may be preferably selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus denitrificans, Castellaniella defragrans, Pseudomonas Uni, Pseudomonas proteolytic, and Pseudomonas alkylphenolica
  • the denitrification process typically requires a carbon source.
  • the microorganism is a denitrifier and denitrification is accompanied by the addition of a carbon source.
  • Suitable embodiments of this aspect of the invention comprise a carbon source selected from the group consisting of methanol, ethanol, acetate, acetic acid, glycerol, glycol, molasses, corn syrup, sucrose solutions, commercially available carbon sources, fermented organic wastes, industrial wastewaters.
  • a more preferable embodiment consisting of methanol, ethanol, acetate, acetic acid, glycerol, commercially available carbon sources.
  • the carbon source is selected from the group consisting of methanol, glycerol or commercially available carbon sources.
  • the microorganism may be selected from a methylotrophic bacteria, which use methanol as a carbon source, selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus denitrificans, Castellaniella defragrans, Pseudomonas proteolytica, Pseudomonas alcaliphila, Pseudomonas chlororaphis, Pseudomonas monteilii, Pseudomonas Uni, Pseudomonas alkylphenolica, Pseudomonas nitroreducens, Pseudomonas stutzeri, Ochrobactrum anthropic, Ochrobactrum intermedium, Aeromonas media, Aeromonas veronii, Aeromonas jandaei, Aeromonas hy- drophila, Cellulomonas media, Aeromonas veronii, Aeromona
  • the mi croorganism is a methylotrophic bacteria
  • methanol is used as a carbon source, and is selected from the group consisting of Paracoccus pantotrophus, Paracoccus versutus, Paracoccus deni- trificans, Hyphomicrobium denitrificans, Pseudomonas Uni, Pseudomonas chlororaphis, Pseudomonas alcaliphila and Pseudomonas alkylphenolica such as Pseudomonas Uni, Paracoccus pantotrophus and Paracoccus versutus.
  • microorganisms of the invention are microorganisms having a feature selected from the group consisting of a robust performance, activity at low temperatures, activity with low levels of additional carbon, selectivity for specific carbon sources.
  • the invention is directed to a polymer support of immobilized microorganisms wherein the polymer support comprises said microorganisms immobilized within a polymer hydrogel; and water or an aqueous solution, wherein has at least 80% its maximum activity at below 20°C
  • the polymer support of immobilized microorganisms within the water treatment vessel is typically at a concentration from 5 to 100 kg/m 3 , more typically from 10 to 75 kg/m 3 , such as 10 to 50 kg/m 3 .
  • the polymer support of immobilized microorganisms is spherical, oval, elliptical bead shaped, oblong, cylindrical, or capsule-like in shape.
  • the polymer support of immobilized microorganisms the polymeric support is spherical or bead-shaped having a diameter of 1 to 10 mm, typically 2 to 8 mm, such as 3 to 7 mm or 3 to 6 mm.
  • the presence of nitrogen in any form in treated effluent can be harmful to the environment the treated wastewater is being discharged to.
  • Ammonium is directly toxic to fish and other aquatic lifeforms, while excessive levels of nitrate and nitrite can lead to eutrophication in water courses, leading to fish die offs, odours and other environmental issues.
  • wastewater includes industrial wastewater, municipal wastewater, run-off from landfills, drainage of agricultural land, drainage from fish farms/aqua culture.
  • the shortcomings of existing nitrogen treatment processes include but are not limited to: required cleaning cycles in biological filters reducing operational time, the relatively low concentration of active microorganisms in biological filters, cost of operation and the production of a brine by ion exchange membranes that then requires further treatment.
  • the goal of wastewater treatment plants according to the invention is to treat the incoming wastewater to a standard where it can then be responsibly discharged to the environment.
  • An important aspect of modern wastewater treatment is the removal of nutrients that can cause damage to the environment the treated wastewater is discharged to, including nitrogen.
  • immobilized microorganisms for nitrogen treatment the requirements will depend on the design of the site. These applications of immobilized microorganisms are suitably tertiary treatment, side-stream treatment and integrated immobilized microbe activated sludge (IIMAS) processes.
  • IIMAS integrated immobilized microbe activated sludge
  • Figure 2 illustrates a preferable application of the immobilized microorganisms of the invention, namely for tertiary nitrification and/or denitrification treatment in a wastewater treatment process.
  • the raw wastewater passes through primary clarification where large solids, fats and grit are removed from the wastewater.
  • chemical precipitants may be added at this stage to remove soluble phosphorus from the wastewater.
  • the primary treated water is then passed to the biological treatment process.
  • activated sludge may be utilised to encourage the removal of nutrients, including but not limited to, nitrogen, phosphorus and biochemical oxygen demand (BOD).
  • ammonium is nitrified to nitrate
  • ammonium and nitrite and nitrate is removed completely in a combined nitrification/denitrification process.
  • the microbial biomass can be in the form of activated sludge or a fixed biofilm on a carrier or bearing material.
  • the mixed liquor (wastewater and biomass) is then typically passed to the secondary clarifier.
  • the biomass solids settle under gravity and are separated from the treated water.
  • a membrane is used to separate the biomass from the treated wastewater.
  • a proportion of the biomass produced in the biological wastewater treatment process is then returned to the biological treatment process, with the remainder removed from the process as a by-product.
  • the effluent from the secondary clarifier does not entirely meet the requirement for environmental discharge. Therefore, a tertiary nitrogen treatment process is typically required.
  • This process would, according to the invention, use immobilized microorganisms in a nitrification and/or denitrification process to produce an effluent that meets the required standards.
  • treatment may be applied in the required concentration.
  • This can include, but is not limited to, phosphorus, trace elements, pH adjusting chemicals, alkalinity, BOD.
  • the process suitably aims to provide the conditions required for sustainable high rate microbial treatment, with the requirements specific for nitrification or dentification known to one skilled in the art. The exact requirements will depend on the immobilization, the specific microbial community applied and the effluent standards that are required.
  • the immobilized microbial nitrification and/or denitrification process may be utilised to treat a high strength side-stream of wastewater before it is blended into the primary treated wastewater.
  • side-stream wastewaters can be, but not limited to, the liquid fraction from anaerobic digestate dewatering processes, industrial wastewater effluents and septic tanks.
  • An embodiment of this treatment process is illustrated in Figure 3.
  • the high strength wastewater if it meets certain quality standards including, but not limited to, total suspended solids (TSS) concentration, BOD concentration, pH, temperature, may be treated according to the invention for the nitrification and/or denitrification of the side-stream wastewater.
  • TSS total suspended solids
  • the application of a compact, high rate biological process such as the immobilized microorganisms advantageously reduces the ammonium, nitrate or nitrite loading that is applied to the biological treatment process. This can ensure the process is not overloaded and can continue to meet its obligations with regards to effluent quality.
  • the advantages of the application of an immobilized microorganism process on side-stream wastewater treatment include, but not are not limited to, a resistance to operational conditions such as pH, temperature and detrimental components in the wastewater and the process does not produce solids that could create issues for the following biological treatment process.
  • the application of a side-stream immobilized treatment process does not absolutely remove the requirement for a tertiary immobilized microorganism process as outlined earlier.
  • the immobilized microorganisms may be applied directly in the biological treatment process.
  • This application is similar to an Integrated Fixed-film Activated Sludge (I FAS) system.
  • immobilized microorganisms are used to boost the amount of microorganisms with a specific activity required by the process, for example by integrating immobilized nitrifying microorganisms to specifically boost the nitrification activity in the process.
  • These immobilized microorganisms also have the advantage of being able to be easily retained in the activated sludge process through physical separation techniques that would be well known to one skilled in the art. This process could be considered as being an Integrated Immobilized Microorganism Activated Sludge (IIMAS) process.
  • IIMAS Integrated Immobilized Microorganism Activated Sludge
  • an example of an IIMAS process is illustrated.
  • the immobilized microorganisms are applied directly into the former biological treatment process. This process is most preferably an activated sludge process.
  • the immobilized microorganisms supplement the activity of the biological treatment process through the supplementation of the already existing biomass with high activity microorganisms for nitrification and/or denitrification.
  • the advantages of an IEMAS type application include, but are not limited to, an increased resistance of the process to operational shocks including pH, temperature and the concentration of components in the wastewater.
  • the immobilized microorganisms would add nitrification and/or denitrification activity to the activated sludge process without increasing the production of biomass, thereby saving on operational costs.
  • the application of an IIMAS type system has the potential to increase volumetric treatment capacity of the biological treatment process, thereby allowing the biological treatment process to treat more wastewater without increasing the volume of the treatment basins.
  • the immobilized microorganisms should preferably be retained in the biological treatment process through the application of screens, filters, or more preferably with hydrocyclones. This will ensure that the immobilized microorganisms remain in the process, thereby maintaining a high rate of activity and lowering the risk of the immobilized microorganisms leaving the biological treatment process and causing a pollution risk themselves.
  • the application of an IIMAS type treatment process does not absolutely remove the requirement for a tertiary immobilized microorganism process as outlined earlier.
  • the two-step process of nitrogen bio-elimination from wastewater generally consists of nitrification under strict aerobic conditions followed by denitrification under anoxic conditions.
  • Ammonia primarily present in wastewaters are being oxidized to nitrite and eventually nitrate with the help of obligate aerobic autotrophs known as ammonia-oxidizing bacteria (AOB) such as Nitrosomonas, Nitrosococcus.
  • AOB ammonia-oxidizing bacteria
  • NOB nitrite-oxidizing bacteria
  • the polymer support of immobilized microorganisms may be such that the ammonia oxidizing bacteria are selected from Nitrosomonas spp., Nitrosococcus spp., Nitrosospira spp., Nitrosolobus spp., and Nitrosovibrio spp, and wherein the nitrite oxidizing bacteria are selected from Nitrobacter spp., Nitrococcus spp., Nitrospira spp., and Nitrospina spp.
  • the microorganisms are a combination of the ammonia oxidizing bacteria Nitrosomas spp. and the nitrite oxidizing microorganisms are Nitrobacter spp.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and a Nitrobacter, and a combination of a Nitrosomonas europea and a Nitrobacter.
  • the microorganisms are a combination of a Nitrosomonas and Nitrobacter Winogradsky, such as wherein the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi, and a combination of Nitrosomonas europea and Nitrobacter winogradskyi, preferably a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi.
  • Denitrification occurs under anoxic/anaerobic conditions, Denitrification is the sequential process involving the dissimilatory reduction of one or both the ionic nitrogen oxides, nitrate (NO 3 ) and nitrite (N0 2 ⁇ ) to gaseous nitrogen oxides, nitric oxide (NO), nitrous oxide (N 2 0) and finally reduce to the ultimate product, dinitrogen (N 2 ) thus removing biologically available nitrogen and returning it to the atmosphere.
  • N 2 O production is to select the right organisms for the denitrification process.
  • Denitrifiers with their facultative anaerobic traits perform denitrifying activities under the presence of oxygen driving an increase in N 2 O as a denitrification intermediate.
  • Many heterotrophic nitrifiers along with the oxidation of NH 3 can simultaneously perform aerobic denitrification. N 2 O is then generated. Accordingly, the judicious selection of denitrifiers is an important aspect of the present invention.
  • polymer hydrogels comprising Paracoccus are a preferred embodiment in the denitrification of wastewater.
  • Paracoccus pantotrophus grows aerobically with a large variety of carbon sources and with molecular hydrogen or thiosulfate as an energy source, and nitrate serves as electron acceptor under anaerobic conditions.
  • the denitrification properties of Paracoccus denitrificans render it a preferred microorganism.
  • Paracoccus denitrificans reduces nitrite to nitrogen gas while either Nitrosomonas eutropha or Nitrosomonas europaea oxidizes ammonia to nitrite, thus fuelling the former metabolism.
  • one embodiment comprises the combined use of Paracoccus denitrificans and either Nitrosomonas eutropha or Nitrosomonas europaea.
  • denitrification is accompanied by the addition of a carbon source.
  • Suitable embodiments of this aspect of the invention comprise a carbon source selected from the group consisting of methanol, ethanol, acetate, acetic acid, glycerol, glycol, molasses, corn syrup, sucrose solutions, commercially available carbon sources, fermented organic wastes, industrial wastewaters.
  • a carbon source selected from the group consisting of methanol, ethanol, acetate, acetic acid, glycerol, glycol, molasses, corn syrup, sucrose solutions, commercially available carbon sources, fermented organic wastes, industrial wastewaters.
  • methanol, ethanol, acetate, acetic acid, glycerol commercially available carbon sources.
  • methanol, glycerol or commercially available carbon sources are preferable embodiment consisting of methanol, glycerol or commercially available carbon sources.
  • nitrate In drinking water, the presence of ammonium (NH 4 + ) will lead to nitrification in the distribution network that can lead to aesthetic issues (taste and odour), corrosion, alkalinity consumption and decreased pH. This uncontrolled nitrification can also lead to incomplete nitrification, resulting in the production of nitrite (NCV), a toxic intermediate. The presence of ammonium can also increase chlorine demand, which then increases the presence of disinfection by- products and increases the potential for unwanted growth in distribution systems. In areas where drinking water sources are anoxic groundwater resources, the presence of nitrate (NO 3 ) can be an issue. Nitrate can impact how blood transports oxygen, especially in babies, leading to “blue baby syndrome’’.
  • Biological sand filters are the most commonly used process to treat drinking water with low to medium concentrations of ammonium, nitrate or nitrite. In cases with extreme concentrations, ion exchange resins and reverse osmosis membranes are most commonly used. The operation of these processes will not be discussed further here, but there is a general need for improved methods as sources of ammonium or nitrite contamination of drinking water are plentiful in industrialized and pre-industrialized countries.
  • the goal of drinking water treatment is to produce safe and reliable water for human and industrial consumption. Depending on the source of the water, this may require the removal or reduction in concentration of ammonium or nitrite/nitrate before it can be considered safe for consumption.
  • the process steps for drinking water treatment are well known. Once water is extracted from the source, a primary treatment may be applied to remove large particles or other contaminants including, but not limited to organic matter, iron, manganese. This is generally not required when the source is groundwater.
  • the process should be different depending on whether the process needs to nitrify (oxidise ammonium) or denitrify (remove nitrite/nitrate).
  • Figure 5 illustrates a commercially relevant example of a process where immobilized microorganisms are applied in a nitrification process.
  • the water could pass through an aeration ladder. This will introduce oxygen to the water.
  • the water could pass to an immobilized biological nitrification process.
  • what is required for successful nitrification should be applied in the required concentration. This can include, but is not limited to, phosphorus, trace elements, alkalinity, pH adjusting chemicals, dissolved oxygen.
  • the process should aim to provide the conditions required for sustainable high rate microbial nitrification. The exact requirements will depend on the immobilization and the specific microbial community applied.
  • the effluent from the nitrification step should have an ammonium concentration that is from 0.0 to 1.0 mg/L, more preferably from 0.0 to 0.5 mg/L and most preferably from 0.0 to 0.1 mg/L.
  • Figure 6 illustrates the most preferable embodiment of a process where immobilized microorganisms are applied in a denitrification process.
  • the water would pass directly to an immobilized biological dentification process.
  • the water could pass through a short de-oxygenation stage to lower the dissolved oxygen concentration in the water to between 0.0 - 0.3 mg/L, most preferably to 0.0 - 0.1 mg/L.
  • what is required for successful denitrification should be applied in the required concentration. This can include, but is not limited to, phosphorus, trace elements, pH adjusting chemicals, carbon source.
  • the process should aim to provide the conditions required for sustainable high rate microbial denitrification.
  • the effluent from the denitrification step should have a NO x (NCV + NCV) concentration that is between 0.0 - 5.0 mg/L, more preferably between 0.0 - 2.0 mg/L and most preferably between 0.0 - 1.0 mg/L.
  • NO x NCV + NCV
  • the water can then be oxygenated to the required level in the aeration ladder, followed by other treatment to ensure the quality requirements for the water met, including filtration to remove solids and disinfection to ensure the safe delivery of the drinking water.
  • the microorganism is selected from the group consisting of Pseudomonas spp.; Paracoccus spp., Castellaniella spp., Janthinobacterium spp.).
  • the two-step process of nitrogen bio-elimination from drinking water generally consists of nitrification under strict aerobic conditions followed by denitrification under anoxic conditions.
  • Ammonia primarily present in wastewaters are being oxidized to nitrite and eventually nitrate with the help of obligate aerobic autotrophs known as ammonia-oxidizing bacteria (AOB) such as Nitrosomonas, Nitrosococcus.
  • AOB ammonia-oxidizing bacteria
  • NOB nitrite-oxidizing bacteria
  • the polymer support of immobilized microorganisms may be such that the ammonia oxidizing bacteria are selected from Nitrosomonas spp., Nitrosococcus spp., Nitrosospira spp., Nitrosolobus spp., and Nitrosovibrio spp, and wherein the nitrite oxidizing bacteria are selected from Nitrobacter spp., Nitrococcus spp., Nitrospira spp., and Nitrospina spp.
  • the microorganisms are a combination of the ammonia oxidizing bacteria Nitrosomas spp. and the nitrite oxidizing microorganisms are Nitrobacter spp.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and a Nitrobacter, and a combination of a Nitrosomonas europea and a Nitrobacter.
  • the microorganisms are a combination of a Nitrosomonas and Nitrobacter Winogradsky, such as wherein the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi, and a combination of Nitrosomonas europea and Nitrobacter winogradskyi, preferably a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi.
  • Denitrification occurs under anoxic/anaerobic conditions, Denitrification is the sequential process involving the dissimilatory reduction of one or both the ionic nitrogen oxides, nitrate (NO 3 ) and nitrite (NO 2 ) to gaseous nitrogen oxides, nitric oxide (NO), nitrous oxide (N 2 0) and finally reduce to the ultimate product, dinitrogen (N 2 ) thus removing biologically available nitrogen and returning it to the atmosphere. Both nitrate and nitrite are fully converted to atmospheric nitrogen. However, insufficient carbon sources, low dissolved oxygen (DO) concentrations and operational fluctuations or environmental conditions lead to improper denitrification and N 2 O accumulation and emissions. One pathway to reduce N 2 O production is to select the right organisms for the denitrification process.
  • DO dissolved oxygen
  • Denitrifiers with their facultative anaerobic traits perform denitrifying activities under the presence of oxygen driving an increase in N 2 O as a denitrification intermediate.
  • Many heterotrophic nitrifiers along with the oxidation of NH 3 can simultaneously perform aerobic denitrification. N 2 O is then generated. Accordingly, the judicious selection of denitrifiers is an important aspect of the present invention.
  • Suitable embodiment of microorganism for this aspect of the invention may be selected from the group consisting of Pseudomonas spp; Paracoccus spp, Janthinobacterium, Microvirgula aerodenitrificans and Castellaniella defragrans
  • the oxidation of the ammonium to nitrogen gas may be achieved in wastewater treatment processes using the polymer carrier of the invention.
  • the two step conversion comprise the autotrophic organisms, Nitrosomonas and Nitrobacter, and many different heterotrophs.
  • the former obtain energy from the oxidation of ammonia, obtain carbon from CO 2 , and use oxygen as the electron acceptor. They are termed autotrophic because of their carbon source and termed aerobes because of their aerobic environment.
  • the heterotrophic organisms are responsible for denitrification or the reduction of nitrate, NO 3 , to nitrogen gas, N 2 . They use carbon from complex organic compounds, prefer low to zero dissolved oxygen, and use nitrate as the electron acceptor.
  • simultaneous nitrification-denitrification may be achieved by immobilizing both autotrophic bacteria and heterotrophic bacteria in one polymer hydrogel support or by immobilizing an autotroph in one polymer support and a heterotroph in a second polymer hydrogel support, with strict control of dissolved oxygen.
  • An embodiment of the method of the invention for nitrification involves developing an oxygen gradient by adding oxygen in one location in the basin. Near the O 2 injection point, a high DO concentration is maintained allowing for nitrification and oxidation of other organic compounds. Oxygen is the electron acceptor and is depleted. The DO level in localized environments decreases with increasing distance from the injection point. In these low DO locations, the heterotrophic bacteria complete the nitrogen removal.
  • Another embodiment comprises establishing an oxygen gradient within the polymer beads that immobilize the microorganisms. The DO concentration remains high in the outside rings of the beads where nitrification occurs but low in the inner rings of the beads where denitrification occurs.
  • a single denitrifying strain such as a Paracoccus, in the bead creates an oxygen gradient with an aerobic and anoxic environment allowing for both nitrification and denitrification
  • the outer portion of the polymer support has access to oxygen, thus allowing for an aerobic process, and the oxygen of aerobic medium/environment is consumed prior to the medium/environment enters the interior portion of the polymer support wherein an anoxic process is performed.
  • simultaneous nitrification and denitrification has slower ammonia and nitrate utilization rates as compared to separate basin designs because only a fraction of the total biomass is participating in either the nitrification or the denitrification steps.
  • Another embodiment comprises autotrophic denitrifying bacteria in the process termed the Anammox process.
  • the microorganism is selected from the group consisting of Microvirgular aerodenitrificans, Paracoccus pantotrophus, Castellaniella defragrans and Pseudomonas lini.
  • the combined solution is added to solution comprising microorganisms, wherein the microorganisms are selected from a mixed or pure culture of nitrite-oxidizing bacteria, a mixed or pure culture of ammonium oxidizing bacteria, a mixed or pure culture of ammonium oxidizing and nitrite-oxidizing bacteria, and a mixed or pure culture of anammox bacteria.
  • the microorganisms may be a combination of ammonium oxidizing microorganisms and nitrite oxidizing microorganisms.
  • the microorganisms may be a combination of the ammonia oxidizing bacteria Nitrosomas spp. and the nitrite oxidizing microorganisms Nitrobacter spp.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and a Nitrobacter, and a combination of a Nitrosomonas europea and a Nitrobacter.
  • the microorganisms may be a combination of a Nitrosomonas and Nitrobacter Winogradsky.
  • the microorganisms are selected from the group consisting of a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi, and a combination of Nitrosomonas europea and Nitrobacter winogradskyi, preferably a combination of Nitrosomonas eutropha and Nitrobacter winogradskyi.
  • the microorganisms may be wherein the ammonia oxidizing bacteria are selected from Nitrosomonas spp., Nitrosococcus spp., Nitrosospira spp., Nitrosolobus spp., and Nitrosovibrio spp, and wherein the nitrite oxidizing bacteria are selected from Nitrobacter spp., Nitrococcus spp., Nitrospira spp., and Nitrospina spp.
  • a denitrifying bacteria partially nitrifies the ammonia, that is to say from ammonia to nitrite.
  • the nitrite is then leaked out of the polymer support. This process is used in combination with the annamox process, that is depended on a supply of nitrite.
  • the AOB may belong to the species Nitrosomonas eutropha and/or it may have a 16S rDNA sequence which is less than 2% dissimilar from (more than 98% identical to) SEQ ID NO: 1 disclosed in W02006044499A2, particularly less than 1% dissimilar (more than 99% identical).
  • the AOB has a 16S rDNA sequence which is SEQ ID NO: 1 disclosed in W02006044499A2 or is the Nitrosomonas eutropha strain contained in ATCC PTA-6232.
  • the NOB may belong to Nitrobacter winogradskyi and/or it may have a 16S rDNA sequence which is less than 10% dissimilar from (more than 90% identical to) SEQ ID NO: 2 disclosed in W02006044499A2, particularly less than 6% or less than 3% dissimilar (more than 94% or more than 97% identical).
  • the NOB has a 16S rDNA sequence which is SEQ ID NO: 2 or is the Nitrobacter winogradskyi strain contained in ATCC PTA-6232.
  • a given sequence may be aligned with SEQ ID NO: 1 or 2 and the dissimilarity or identity may be calculated using the BLAST program (Basic Local Alignment Search Tool, available at www.ebi.ac.uk/blast/index.html where the expectation value is set at 10, the penalty for nucleotide mismatch is -3, the reward for match is +1 , the gap opening penalty is -5 and the gap extension penalty is -2.
  • a sequence alignment may be produced using the CLUSTALW program from the PHYLIP Phylogenetic Inference Package (Felsenstein, J. 1989. PHYLIP - Phylogeny Inference Package (Version 3.2). Cladistics 5: 164-166).
  • the Accurate Method using the IUB/BESTFIT weight matrix may be used with a gap penalty of -15 and an extension penalty of -6.66.
  • the resulting alignment may be used to determine % dissimilarity (and % identity) using the DNADIST program from PHYLIP according to the Jukes-Cantor model.
  • the AOB or NOB may be combined with other bacteria, e.g., Bacillus such as a combination of the commercial product Prawn Bac PB-628 (product of Novozymes Biologicals), together with Enterobacter or Pseudomonas.
  • Bacillus such as a combination of the commercial product Prawn Bac PB-628 (product of Novozymes Biologicals), together with Enterobacter or Pseudomonas.
  • the nitrifying consortium may be formulated as a liquid, a lyophilized powder, or a biofilm, e.g., on bran or corn gluten.
  • ammonia oxidizing bacterium will typically be inoculated to an ammonia oxidation rate of about 50-5000 mg NH3-N/L/hr (typically around 800), and the nitrite oxidizing bacterium will typically be inoculated to a nitrite oxidizing rate of about 10-2000 mg N0 2 ⁇ -N/L/hr (typically around 275).
  • Anammox is the oxidation of ammonium with nitrite as the electron acceptor and dinitrogen gas as the product.
  • Another embodiment comprises autotrophic denitrifying bacteria in the process termed the Anammox process.
  • the process is mediated by obligately anaerobic chemolithoautotrophic bacteria that form a monophyletic cluster inside the Planctomycetales, one of the major divisions of the bacteria.
  • the anammox bacteria may be sleeted from the group consisting of C. Brocadia anammoxidans, Candidatus Kuenenia stuttgartiensis, Candidatus Scalindua wagneri, and Candidatus Scalindua brodae.
  • SNdN has slower ammonia and nitrate utilization rates as compared to separate basin designs because only a fraction of the total biomass is participating in either the nitrification or the denitrification steps.
  • Mowiol® is a commercially available water soluble hydrocolloid based on poly (vinyl alcohol).
  • Prawnbac® NNC is Nitrosomonas eutropha and Nitrobacter winogradskyi, commercially available and produced by Novozymes.
  • PVA polyvinyl alcohol
  • Solution 1A was used as such, whereas solution 1B was further diluted at a 70/30 ratio with de ionized water. 20 g of each solution were used subsequently.
  • a cross-linking solution containing 3 % w/w sodium tetraborate decahydrate (Sigma) and 3 % w/w calcium L-lactate (Sigma) was prepared in tap water. pH in the cross-linking solution was adjusted to 7.5 with drops of 7 M acetic acid.
  • Beads were then obtained by introducing each diluted solution of polymers, drop-wise by means of pipette, into the cross-linking solution of tetraborate/calcium lactate under constant stirring. 100 ml of cross-liking solution was used for each of the 20 g of polymers. The beads were left for reacting 1 h at room temperature. After completion of the reaction time, beads were collected on a sieve, rinsed quickly in tap water and washed for 20 min in 100 ml cold tap water under constant stirring. A second cross-linking solution was prepared by mixing 5 % w/w boric acid (Sigma) with 3 % w/w calcium L-lactate. Only 100 ml were prepared to produce beads using the solution of polymer A. The cross-linking process was identical to the one described here above.
  • PVA polyvinyl alcohol
  • 10 % w/w PVA Three aqueous solutions of polyvinyl alcohol (PVA) containing 10 % w/w PVA were obtained by dissolving either 10 g Mowiol® 20-98 (Sigma), 10 g Mowiol® 28-99 or 10 g Mowio® 56-98 into a total of 88.5 g de-ionized water and 1.5g glycerol. The mixtures were heated up to 90 °C under constant mixing and kept at this temperature until full dissolution of the PVA.
  • a fourth PVA solution was prepared by mixing 9 g Mowio® 10-98 and 3 g Mowio® 2899 into 78 g de ionized water, following the protocol described here above.
  • a cross-linking solution containing 5 % w/w boric acid (Sigma) and 2 % w/w calcium chloride anhydrate (Sigma) was prepared in tap water.
  • Beads were then obtained by introducing each diluted solution of polymers, drop-wise by means of pipette, into the cross-linking solution of boric acid/calcium chloride under constant stirring. 100 ml of cross-liking solution were used for each of the 20 g of polymers. The beads were left for reacting 3 h at room temperature. After completion of the reaction time, beads were collected on a sieve, rinsed quickly in tap water and washed for 20 min in 100 ml cold tap water under constant stirring.
  • PVA polyvinyl alcohol
  • aqueous solution of polyvinyl alcohol (PVA) containing 10 % w/w PVA was obtained by dissolving 100 g Mowio® 20-98 (Sigma) into a total of 885 g tap water and 15 g glycerol. The mixture was heated up to 90 °C under constant mixing and kept at this temperature until full dissolution of the PVA. After cooling, 990 g of the solution were mixed to 10 g of sodium alginate (Sigma). Four mixtures of polymers were prepared accordingly, three of each included microorganisms: 3A. 420 g of PVA/glycerol/alginate were added to 180 g of Prawnbac® NNC 1500 (Novozymes)
  • the P. pantotrophus cells had first been grown in a total of 600 ml medium following guidelines from ATCC®, prior to centrifugation and resuspension into M9 medium.
  • a cross-linking solution containing 5% w/w boric acid (Sigma) and 2 % w/w calcium chloride, dihydrate (Sigma) was prepared in tap water.
  • Beads were then obtained by introducing each mixture, drop-wise by means of pipette, into the cross-linking solution of boric acid/calcium chloride under constant stirring. Pipetting of the solution was operated by a peristaltic pump; the flow rate of the pump was adjusted so that 300 g of mixture would be introduced to the cross-linking solution within 15 min. Approximately 1 L of cross-linking solution was used for ca. 300 g of polymers/microorganisms mixture. The beads were left for reacting 1 h at room temperature. After completion of the reaction time, beads were collected on a sieve, rinsed quickly in tap water and cured for 120 min in 10% w/w sodium sulfate under constant stirring.
  • PVA polyvinyl alcohol
  • aqueous solution of polyvinyl alcohol (PVA) containing 10 % w/w PVA was obtained by dissolving 100 g Mowiol® 20-98 (Sigma) into a total of 885 g tap water and 15 g glycerol. The mixture was heated up to 90 °C under constant mixing and kept at this temperature until full dissolution of the PVA. After cooling, 990 g of the solution were mixed to 10 g of sodium alginate (Sigma).
  • the P. pantotrophus cells had first been grown following guidelines offered by bacterial strain suppliers, e.g. DSMZ or ATCC, and then centrifuged and resuspended.
  • a cross-linking solution containing 5% w/w boric acid (Sigma) and 2 % w/w calcium chloride, dihydrate (Sigma) was prepared in tap water.
  • Beads were then obtained by introducing each mixture, drop-wise by means of pipette, into the cross-linking solution of boric acid/calcium chloride under constant stirring. Pipetting of the solution was operated by a peristaltic pump; the flow rate of the pump was adjusted so that 300 g of mixture would be introduced to the cross-linking solution within 15 min. Approximately 1 L of cross-linking solution was used for ca. 300 g of polymers/microorganisms mixture. The beads were left for reacting 1 h at room temperature. After completion of the reaction time, beads were collected on a sieve, rinsed quickly in tap water and cured for 120 min in 10% w/w sodium sulfate under constant stirring.
  • the aim of this example was to test the nutrient removal capacity (removal of nitrate and ammonia) of water treatment materials (biobeads) using the flow through reactor type used for moving bed biofilm reactor (MBBR) design tests.
  • the reactors were divided in 3 groups with different conditions. Three sets of four reactors, total 12 reactors, were established in the laboratory. The first group of four reactors (A1-A4) were tested denitrifying conditions in tap water at 15 °C. The second group of four reactors (B5-B8) were tested denitrifying conditions in wastewater effluent at 15 °C. The third group of four reactors (C9-C12) were tested nitrifying conditions in wastewater effluent at 10 °C.
  • Example 2 Denitrification performance of biobeads in drinking water
  • reactors for nitrate removal (A1-A4) from drinking water
  • the biological treatment system was established with four reactors (A1, A2, A3, A4) of 1 L each in parallel at 15 °C.
  • Each reactor contained different types of biobeads (Table 1).
  • the reactors were fed using two feed bottles; first feed bottle contained tap water spiked with 75 mg/L nitrate as an electron acceptor and phosphate for microbial growth and the second feed bottle contained acetic acid (later changed to glycerol) as carbon source (electron donor) to maintain denitrifying conditions.
  • Biobeads in the reactor were stirred by mechanical stirrers and later changed to magnetic stirrers due to the high oxygen input from the atmosphere.
  • the reactors were covered by floating lids made from parafilm covered styrofoam to minimize the headspace.
  • Table 1 Description of the beads applied to reactors A1-A4. Sample A1 contained only polymeric beads that had no immobilized microorganisms, while samples A2-A4 contained denitrifying microorganisms. The fill volumes of the beads in the reactor were chosen to be in a range of commercially relevant values.
  • Influent and effluent concentration of nitrate, nitrite and phosphate from the reactors were measured every working day. pH and oxygen concentration were controlled in the optimal range except the very first days of the operation. pH was maintained between 7 and 8 whilst the oxygen concentration was maintained less than 0.1 mg O2/L for all the reactors. After a period of acclimatization, the carbon source was changed from acetate to glycerol and the loading rate of nitrate to the reactors increased from 126 mg- NO 3 -N/L.d to 421 mg- NO 3 -N /L.d as most residual nitrate had been removed in the system. The activity of the reactors was assessed based on the denitrification rate achieved, which is calculated using Equation 1.
  • reactors B5-B9 for nitrate removal from nitrate spiked secondary treated wastewater
  • the second group of the four reactors were setup to test the removal of nitrate from secondary wastewater effluent via a biological denitrification process.
  • the biological treatment system was established with four reactors (B5, B6, B7, B8) of 1 L each in parallel at 15 °C.
  • Each reactor contained different types of biobeads (Table 2).
  • the reactors were fed using two feed bottles; first feed bottle contained wastewater effluent spiked with nitrate as electron acceptor and phosphate for microbial growth and the second feed bottle contained acetic acid (later changed to glycerol) as carbon source (electron donor) to maintain denitrifying conditions.
  • Biobeads in the reactors were stirred by magnetic stirrers and the reactors were covered with parafilm and styrofoam to minimize the available headspace and therefore oxygen transfer.
  • Table 2 Description of the beads applied to reactors B5-B8. Sample B5 contained only polymeric beads that had no immobilized microorganisms, while samples B6-B8 contained denitrifying microorganisms. The fill volumes of the beads in the reactor were chosen to be in a range of commercially relevant values.
  • Influent and effluent concentration of nitrate, nitrite and phosphate from the reactors were measured every working day. pH and oxygen concentration were controlled in the optimal range except the very first days of the operation. pH was maintained between 7 and 8 whilst the oxygen concentration was maintained less than 0.1 mg CVL for B5, B6 and B8. Oxygen in reactor B7 was above significantly above 1 mg/L which is not optimal for denitrification process. After an initial period of acclimatization, it was found that the microorganisms were removing all of the nitrate in the system (except in B7 which was inhibited by dissolved oxygen).
  • the volumetric loading rate was increased from 25 mg-NCh-N/L.d to 355 mg-N0 3 -N/L.d. During this period, the carbon source supplied was also changed from acetate to glycerol. After another period of acclimatization, and recovery of anoxic conditions in B7, a period of stable operation was achieved.
  • the rate of denitrification achieved by the biobeads in each reactor was calculated using Equation 1, and the results are presented in Figure 8, wherein the denitrification rates achieved in reactors B5 - B8. B5 ( ⁇ ), B6 (A), B7 ( ⁇ ) and B8 ( ⁇ ) are shown.
  • Example 4 Nitrification performance of biobeads in wastewater
  • the third group of four reactors were setup to test the removal of ammonium from secondary wastewater effluent via a biological nitrification process.
  • the biological treatment system was established with four reactors (C9, C10, C11, C12) of 1 L each in parallel at 10 °C.
  • Each reactor contained different types of biobeads (Table 3).
  • Reactors were fed with secondary wastewater effluent spiked with ammonium as an electron donor and phosphate for microbial growth. Reactors were aerated from the bottom to mix the biobeads and supply oxygen as the electron acceptor to maintain nitrifying conditions.
  • Table 3 Description of the beads applied to reactors C9-C12. Sample C9 contained only polymeric beads that had no immobilized microorganisms, while samples C10-C12 contained nitrifying microorganisms. The fill volumes of the beads in the reactor were chosen to be in a range of commercially relevant values.
  • reactor C12 was able to achieve a nitrification rate that was significantly greater than that achieved in reactor C9 that had no immobilized microorganisms.
  • Reactor C12 was able to maintain a nitrification rate that was approximately 3-5 times greater than the other reactors in the trial.
  • the performance of the biobeads in reactor C12 is relatively stable and was even able to maintain a high level of nitrification when the temperature was decreased to 5 °C in a single day.
  • the results achieved in reactor C12 indicate that the biobeads can achieve a commercial relevant rate of nitrification when treating secondary treated wastewater effluent.

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Abstract

Un support polymère à base de PVA pour des bactéries immobilisées sélectionnées permet une élimination de l'ammoniac, une élimination de l'azote, une dénitrification et une nitrification efficaces des eaux usées et de l'eau potable.
PCT/EP2022/061064 2021-04-26 2022-04-26 Micro-organismes immobilisés sur un support polymère pour éliminer l'azote de l'eau WO2022229193A1 (fr)

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Citations (6)

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Publication number Priority date Publication date Assignee Title
WO2006044499A2 (fr) 2004-10-14 2006-04-27 Novozymes Biologicals, Inc Groupement de bacteries nitrifiantes
CN103241835A (zh) * 2013-05-30 2013-08-14 南开大学 一种高效稳定的短程硝化-厌氧氨氧化生物脱氮方法
CN105000921A (zh) * 2015-05-13 2015-10-28 黑龙江八一农垦大学 一种固定化除氨菌系的改性沸石
CN108217936A (zh) * 2018-02-26 2018-06-29 扬州市职业大学 一种亚硝化-厌氧氨氧化固定化与养殖废水处理工艺
CN108330123A (zh) * 2017-01-20 2018-07-27 南京理工大学 一种脱氮包埋固定化颗粒的制备方法
CN112011476A (zh) * 2020-07-24 2020-12-01 河北科技大学 一种包埋脱氮硫杆菌的高强度固定化微球的制备方法

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WO2006044499A2 (fr) 2004-10-14 2006-04-27 Novozymes Biologicals, Inc Groupement de bacteries nitrifiantes
CN103241835A (zh) * 2013-05-30 2013-08-14 南开大学 一种高效稳定的短程硝化-厌氧氨氧化生物脱氮方法
CN105000921A (zh) * 2015-05-13 2015-10-28 黑龙江八一农垦大学 一种固定化除氨菌系的改性沸石
CN108330123A (zh) * 2017-01-20 2018-07-27 南京理工大学 一种脱氮包埋固定化颗粒的制备方法
CN108217936A (zh) * 2018-02-26 2018-06-29 扬州市职业大学 一种亚硝化-厌氧氨氧化固定化与养殖废水处理工艺
CN112011476A (zh) * 2020-07-24 2020-12-01 河北科技大学 一种包埋脱氮硫杆菌的高强度固定化微球的制备方法

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