WO2014022736A1 - Photobioréacteur pour capturer le phosphore - Google Patents

Photobioréacteur pour capturer le phosphore Download PDF

Info

Publication number
WO2014022736A1
WO2014022736A1 PCT/US2013/053342 US2013053342W WO2014022736A1 WO 2014022736 A1 WO2014022736 A1 WO 2014022736A1 US 2013053342 W US2013053342 W US 2013053342W WO 2014022736 A1 WO2014022736 A1 WO 2014022736A1
Authority
WO
WIPO (PCT)
Prior art keywords
photobioreactor
internal volume
light
phosphorus
beads
Prior art date
Application number
PCT/US2013/053342
Other languages
English (en)
Inventor
Micah P. McCREERY
Randy L. Jones
Stephanie A. Smith
Original Assignee
Battelle Memorial Institute
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 Battelle Memorial Institute filed Critical Battelle Memorial Institute
Publication of WO2014022736A1 publication Critical patent/WO2014022736A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M21/00—Bioreactors or fermenters specially adapted for specific uses
    • C12M21/02—Photobioreactors
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M25/00—Means for supporting, enclosing or fixing the microorganisms, e.g. immunocoatings
    • C12M25/14—Scaffolds; Matrices
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M25/00—Means for supporting, enclosing or fixing the microorganisms, e.g. immunocoatings
    • C12M25/16—Particles; Beads; Granular material; Encapsulation
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M29/00—Means for introduction, extraction or recirculation of materials, e.g. pumps
    • C12M29/06—Nozzles; Sprayers; Spargers; Diffusers
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
    • C12M31/00—Means for providing, directing, scattering or concentrating light
    • C12M31/08—Means for providing, directing, scattering or concentrating light by conducting or reflecting elements located inside the reactor or in its structure

Definitions

  • the present disclosure relates to a photobioreactor in which microorganisms are maintained to produce desirable products.
  • the microorganisms are immobilized in an artificial or synthetic biofilm.
  • the photobioreactor can be used to capture phosphorus present in a phosphorus-containing liquid and remove it from the liquid.
  • AD anaerobic digester
  • AD releases a large portion of the phosphorus from the manure into an aqueous effluent, leaving behind a solid material that can be used for animal bedding or as a soil amendment.
  • sufficient agricultural land area is available to apply this phosphorus rich effluent at beneficial agronomical rates, thereby substituting for and reducing the need for petroleum based chemical fertilizer.
  • phosphorus must be extracted from the effluent as a concentrated product for transport to another location for beneficial land application.
  • Photobioreactors are described that are based on artificially immobilizing phosphate-accumulating microorganisms into an artificial or synthetic biofilm. Upon exposure to light and anaerobic conditions, such microorganisms can capture phosphorus and build other potentially valuable products.
  • a method of capturing phosphorus comprising: locating phosphate-accumulating microorganisms in an internal volume of a photobioreactor; and exposing the microorganisms to a phosphorus-containing fluid in the presence of light under anaerobic conditions to capture the phosphorus.
  • the light may be provided using light sources that emit only at wavelengths between 700 nm and 950 nm.
  • the light sources can be light emitting diodes.
  • the light may be provided by light sources that are located throughout the internal volume so that no location in the internal volume is greater than a threshold distance away from a light source.
  • the phosphate-accumulating microorganisms can be purple non-sulfur bacteria, such as Rhodopseudomonas palustris, Rhodobacter sphaeroides, Rhodobacter capsulatus, or Rhodospirillum rubrum.
  • the phosphorus may be captured in the form of phosphate granules.
  • the purple non-sulfur bacteria can also produce a polyhydroxyalkanoate.
  • the light may be provided by a light source located within a light pipe that extends from a first end of the internal volume towards a second end of the internal volume.
  • Radial fins may extend radially from a sidewall of the light pipe. Circumferential fins may extend from the radial fins.
  • the phosphate-accumulating microorganisms can be immobilized in a matrix.
  • the matrix may be alginate, and may be in the shape of beads.
  • the photobioreactor may be at an ambient temperature range of 27°C to 34°C. Nitrogen sparging of the internal volume may occur to maintain anaerobic conditions.
  • the internal volume may have a volume of from about 1 liter to about 10,000 liters, or a volume of 5,000 liters or greater.
  • the phosphorus-containing fluid may have a residence time in the photobioreactor of from about 1 minute to about 1 hour, or even longer. Solids may have a residence time in the photobioreactor of from about one day to about 10 days, or even longer.
  • the phosphate-accumulating microorganisms can be added as an inoculum to the internal volume of the photobioreactor, or are present in the internal volume of the photobioreactor in the form of natural biofilms, or are present in the wastewater stream fed to the internal volume of the photobioreactor.
  • a photobioreactor comprising: an outer casing, a first end wall, and a second end wall that define an internal volume; a fluid inlet, a fluid outlet, and a gas inlet connecting to the internal volume; and a plurality of light sources distributed so that no location in the internal volume is greater than a threshold distance away from a light source.
  • the threshold distance can be 2 cm.
  • the light sources emit only at wavelengths between 700 nm and 950 nm.
  • the light sources may be light emitting diodes.
  • the light sources can be fiber optic pads that transmit light from an external source.
  • the light sources are located within light pipes that extend from one end wall into the internal volume towards the other end wall.
  • Radial fins can extend radially from a sidewall of the light pipe.
  • Circumferential fins can extend from the radial fins.
  • the photobioreactor may further comprise synthetic biofilms within the internal volume.
  • the synthetic biofilms can be made of phosphate-accumulating microorganisms immobilized in a matrix.
  • the phosphate-accumulating microorganisms can be purple non-sulfur bacteria, such as Rhodopseudomonas palustris, Rhodobacter sphaeroides, Rhodobacter capsulatus, or Rhodospirillum rubrum.
  • the matrix may contain alginate.
  • the synthetic biofilms can be in the shape of beads.
  • the gas inlet and the fluid inlet may be located in the second end wall, and the fluid outlet may be located in the first end wall.
  • the gas inlet can be located at a lower end of the photobioreactor.
  • the outer casing may be opaque.
  • the photobioreactor may further comprise a mechanical agitator.
  • the photobioreactor may further comprise a floor above the second end wall.
  • the internal volume may be from about 1 liter to about 10,000 liters, or may be 5,000 liters or greater.
  • the photobioreactor may further comprise a mesh container for placement within the internal volume.
  • FIG. 1 is a diagram illustrating a synthetic biofilm in the shape of a bead or sphere.
  • FIG. 2 is a picture showing the synthetic biofilm in the form of spheres.
  • the spheres are made from microorganisms and alginate.
  • FIG. 3 is a cross-sectional view of an exemplary embodiment of a photobioreactor of the present disclosure. This embodiment includes multiple light pipes.
  • FIG. 4 is a cross-sectional view of another exemplary embodiment of a photobioreactor of the present disclosure. This embodiment has a single light pipe with multiple fiber optic pads.
  • FIG. 5 is a cross-sectional view of another exemplary embodiment of a different photobioreactor, where a fiber optic pad is used as the light source.
  • FIG. 6 is a cross-sectional view of the embodiment of FIG. 5, but with the encapsulated bacteria beads placed in the internal volume.
  • FIG. 7 is another embodiment of a light pipe having radial fins.
  • FIG. 8 is a top view of the light pipe of FIG. 7.
  • FIG. 9 is another embodiment of a light pipe having radial fins and circumferential fins.
  • FIG. 10 is a top view of the light pipe of FIG. 9.
  • FIG. 11 is a picture illustrating the lighting profile of an LED strip contained in a light pipe.
  • FIG. 12 is a graph of a test tube experiment showing the phosphate concentration in the wastewater vs. the time.
  • FIG. 13 is a picture of a bench-scale photobioreactor used in the examples. DETAILED DESCRIPTION
  • approximating language may be applied to modify any quantitative representation that may vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about” and “substantially,” may not be limited to the precise value specified, in some cases. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value.
  • the modifier "about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4" also discloses the range "from 2 to 4.”
  • inlet and outlet are relative to a direction of flow, and should not be construed as requiring a particular orientation or location of the structure.
  • upper and lower are relative to each other in location, i.e. an upper component is located at a higher elevation than a lower component.
  • the present disclosure relates to methods and devices that can be used to capture phosphorus.
  • phosphate-accumulating microorganisms are located in the internal volume of a photobioreactor. These PAOs can capture phosphorus present in a phosphorus-containing fluid when exposed to the fluid in the presence of light and under anaerobic conditions.
  • the photobioreactor itself is formed from an outer casing, a first end wall, and a second end wall. Appropriate inlets/outlets for fluid and gas are present in the end walls.
  • a plurality of light sources is distributed within the internal volume so that no location is greater than a given threshold distance away from a light source.
  • the phosphate-accumulating microorganisms may be placed in the photobioreactor as artificial or synthetic biofilms of a given shape.
  • the microorganisms are immobilized in a matrix, which can then be shaped as appropriate (e.g. beads). This both improves handling of the components and increases phosphorus capture.
  • biofilm refers to an aggregate of microorganisms that are embedded within a self-produced matrix of an extracellular polymeric substance. This extracellular polymeric substance generally contains extracellular DNA, proteins, and polysaccharides.
  • the photobioreactor uses artificial biofilms composed of microorganisms immobilized in a matrix.
  • artificial and synthetic are used interchangeably to indicate that the matrix in which the microorganisms are embedded or immobilized is made of a material that is not naturally produced by the microorganisms.
  • the microorganisms in the synthetic biofilms used with the photobioreactor are purple non-sulfur (PNS) bacteria.
  • bacteria are metabolically versatile organisms that grow on a variety of carbon substrates (e.g. CO, CO 2 , hydrocarbons) under aerobic or anaerobic conditions. They are typically pigmented with bacteriochlorophyll a or b, together with other carotenoids, and may have colors ranging between purple, red, brown, and orange. During photosynthesis, hydrogen is typically used as the reducing agent.
  • carbon substrates e.g. CO, CO 2 , hydrocarbons
  • bacteriochlorophyll a or b bacteriochlorophyll a or b, together with other carotenoids, and may have colors ranging between purple, red, brown, and orange.
  • hydrogen is typically used as the reducing agent.
  • the microorganisms in the synthetic biofilms used with the photobioreactor are phosphate-accumulating microorganisms (PAOs). They incorporate phosphorus into their biomass during growth, just like all bacteria, but also sequester large amounts of phosphorus into polyphosphate storage granules. Polyphosphate accumulates in the cells of PAOs when the organism is not limited for energy.
  • PNS photoheterotrophic microorganisms can accumulate polyphosphate granules under anaerobic conditions in the presence of light (i.e. photoheterotrophic growth).
  • suitable bacteria include Rhodopseudomonas palustris, Rhodobacter sphaeroides, Rhodobacter capsulatus, and Rhodospirillum rubrum. It should be noted that some PNS bacteria can also produce and sequester polyhydroxyalkanoate (PHA) plastics when exposed to excess amounts of sugar substrate. This can also be a valuable byproduct.
  • PHA polyhydroxyalkanoate
  • the microorganisms are immobilized in a matrix (i.e. encapsulated) to form the synthetic biofilm.
  • the matrix is made of a material that is both gas-permeable and water-permeable.
  • the matrix can be described as a gel.
  • An exemplary material suitable for the matrix is alginate, which is also known as algin or alginic acid (CAS# 9005-32-7), is commercially available, and can absorb a large quantity of water.
  • Other exemplary materials suitable for the matrix include sol-gel silica, carrageenan, latex, polyvinyl alcohol, polystyrene sulfonate, and mixtures of these materials (including with alginate).
  • Sol-gel silica refers to using silica in a sol-gel procedure to obtain a three-dimensional network containing both a liquid phase and a solid phase.
  • exemplary silicates include tetraethyl orthosilicate (TEOS).
  • TEOS tetraethyl orthosilicate
  • the microorganisms can be contained within the network.
  • Carrageenan refers to polysaccharides which can gel, and which can be obtained from seaweed. Other materials, which are both gas-permeable and water-permeable, may also be used to immobilize the microorganisms.
  • the synthetic biofilm aids in retaining structural integrity and bacterial viability.
  • the cell density, cell placement, and consistency of the synthetic biofilm can also be controlled.
  • the synthetic biofilm can be formed quickly, without the need for a long incubation period while waiting for a natural biofilm to be created.
  • the microorganisms are immobilized in the biofilm instead of living in the growth medium that typically circulates within the bioreactor vessel.
  • the synthetic biofilm can also be shaped into any desired configuration or shape.
  • the synthetic biofilms used in the photobioreactor are in the shape of spheres.
  • One advantage to using such synthetic biofilms is that they provide an easy way to collect the desired products. Such products may accumulate within the spheres, and can be collected by removal of the spheres from the photobioreactor.
  • FIG. 1 is a diagram illustrating an artificial biofilm in the form of a sphere. This diagram is not drawn to scale.
  • the sphere 100 is made up of a matrix 110 in which microorganisms 120 are immobilized. It is contemplated that the microorganisms can be either homogeneously dispersed throughout the volume of the sphere, or can be concentrated in the center of the sphere.
  • the sphere may have a diameter 130 of from about 0.1 millimeters (mm) to about 20 mm, including in specific embodiments a diameter of from about 1 .5 mm to about 2.5 mm.
  • FIG. 2 is a picture of a test tube containing purple non-sulfur (PNS) bacteria encapsulated into spheres containing 2% alginate. This value refers to the final percentage of alginate (w/v) in the sphere that is mixed with the bacteria.
  • the spheres are made dropwise and fall into a 100 mM CaC ⁇ solution that solidifies the drops.
  • the artificial biofilms used in the photobioreactor are PNS bacteria encapsulated in an alginate matrix and shaped as spheres.
  • the synthetic biofilms / bacteria-encapsulated beads are used in a photobioreactor that exposes the microorganisms to appropriate conditions which encourage them to capture phosphorus.
  • the photobioreactor can used to remove phosphorus from waste water and retain it for use in other applications, for example as plant fertilizer.
  • the use of microorganisms encapsulated in a matrix significantly simplifies the process of inoculating, retaining, and harvesting the microorganisms with their captured phosphorus.
  • the artificial biofilms are also generally denser than the fluid and thus settle quickly, facilitating their removal.
  • encapsulation increases the amount of phosphorus that can be removed and retained.
  • FIG. 3 is a cross-sectional view of an exemplary embodiment of a photobioreactor 300 of the present disclosure.
  • the photobioreactor includes an outer casing 310, a first end wall 320, and a second end wall 330.
  • An internal volume 340 is present within the photobioreactor, in which the beads containing the phosphate- accumulating microorganisms (PAOs) are located.
  • the internal volume will vary in size depending on its application.
  • a bench scale photobioreactor may be as small as from about 1 liter to about 1 .5 liters.
  • commercial photobioreactors may have an internal volume of 5,000 liters or greater, or 10,000 liters or greater.
  • a plurality of light sources are located within the internal volume, and are distributed so that no location in the internal volume is greater than a threshold distance away from a light source.
  • the photobioreactor may be considered as having a lower end 302 and an upper end 304.
  • the first end wall and the second end wall can be described as being disc-shaped.
  • the outer casing is formed from an outer wall 312 and has a radial lip 314 at each end.
  • the outer wall 312 may be of any shape, and here is cylindrical.
  • the outer casing 310 is joined to the first end wall 320 and the second end wall 330 at each radial lip 314. It is contemplated that the outer casing is opaque, or in other words that light does not need to penetrate the outer casing to illuminate the internal volume. This allows a wider range of materials to be used for constructing the outer casing. However, if desired, the outer casing may be design to allow for the penetration of certain wavelengths of light to enter the internal volume.
  • the inner surface 316 of the outer casing is reflective.
  • a gas inlet 342, a fluid inlet 344, and a fluid outlet 346 are also present connecting to the internal volume 340.
  • Inert gas usually nitrogen
  • the gas can also be used to mix the beads within the internal volume with the fluid.
  • the incoming fluid is rich in phosphorus, and the dwell time in the photobioreactor is controlled to permit the PAOs to capture the phosphorus.
  • the exiting fluid has a greatly reduced concentration of phosphorus compared to the incoming fluid.
  • the gas inlet 342 is usually present at the lower end 302 of the photobioreactor so that gas can passively rise through the beads and fluid in the internal volume.
  • the gas inlet 342 is in the second end wall 330.
  • the gas inlet may be on the central axis 305 of the photobioreactor.
  • the fluid inlet 344 and fluid outlet 346 are generally located at opposite ends of the photobioreactor, and on opposite sides of the photobioreactor as well.
  • the fluid inlet 344 is in the second end wall 330 and the fluid outlet 346 is in the first end wall 320. This configuration generally ensures that fluid exiting the internal volume 340 has achieved the desired residence time needed for phosphorus capture to occur. Filters may be placed upstream of the gas inlet and fluid inlet to remove solid particles and prevent blockage within the photobioreactor.
  • a plurality of light sources is present in the internal volume of the photobioreactor to provide internal illumination.
  • Many conventional systems are illuminated with broad-spectrum light, such as incandescent or fluorescent bulbs or sunlight.
  • Broad-spectrum light includes many wavelengths which are usually not used by the microorganisms, and also generates excess heat. This wasted energy increases operating costs for the system.
  • the photobioreactors of the present disclosure use light sources that produce only the wavelengths of light that are needed for the microorganism of choice, significantly decreasing input energy costs.
  • the light sources emit only at wavelengths between 700 nm and 950 nm. In this regard, bacteriochlorophyll pigments of purple non-sulfur bacteria are excited around 850 nm.
  • the light sources emits only light at wavelengths between 700 nm and 950 nm and in a width of 100 nm (for example from 800 nm to 900 nm) or a width of 50 nm.
  • the light sources can generally be any type of illumination.
  • the light sources are light emitting diodes (LEDs).
  • the light sources are fiber optic pads.
  • a fiber optic pad contains individual plastic fibers that transmit light from an external source. The fibers are woven into a mat that produces a pad which is lighted over the entirety of either one side of the pad or both sides of the pad. The fiber optic pad channels light from the external source into the internal volume of the photobioreactor.
  • the light sources are placed within light pipes 350.
  • the light pipes extend from the first end wall 320 into the internal volume towards the second end wall 330.
  • the light pipe itself is formed from a sidewall 356 that surrounds a pipe volume 358 and is capped at its distal end. This construction encases the light sources so that they do not contact the bacteria-containing beads, any fluids, or any gases in the internal volume.
  • the artificial biofilms/beads are present in the interstitial spacing between the outer casing and the light pipes.
  • the sidewall and cap may be made of a transparent material, or may be used to filter the light so that only wavelengths between 700 nm and 950 nm reach the internal volume.
  • the light sources can be distributed throughout the internal volume such that no location in the internal volume is greater than a threshold distance away from a light source.
  • a threshold distance away from a light source In this regard, testing has shown that even in pure water, light at the wavelengths of interest (700-950 nm) only penetrates a distance of 1 .5 cm. Penetration depth decreases rapidly as a function of turbidity, and it is likely that the phosphorus- containing waste water will be turbid.
  • the light sources are thus distributed so that the provided light penetrates substantially the entire internal volume. For example, in embodiments, no location in the internal volume is greater than 1 meter, or 10 cm, or 5 cm, or 2 cm, or 1 .5 cm, or 1 cm away from a light source.
  • a floor 332 is present above the second end wall.
  • the floor is constructed to permit the fluid and gas to flow through the floor, but prevent the artificial biofilms/beads from entering the inlets.
  • the floor may be a mesh.
  • a mesh container (not shown) may be placed within the internal volume.
  • the synthetic biofilms/beads can be loaded into the mesh container and then placed into the photobioreactor. Again, the beads are denser than water and so should remain at the bottom of the reactor, i.e. in the mesh container. This would enable more convenient removal of the beads from the internal volume, without the need to also empty the photobioreactor of any fluid.
  • an end wall can be removed to permit access to the internal volume and the mesh container.
  • the mesh container would be shaped as appropriate to avoid the light pipes.
  • the internal volume may range from about 1 liter to about 10,000 liters, or higher as desired.
  • the artificial biofilms/bead themselves may take up a volume of from about 40% to about 80% of the internal volume of the photobioreactor.
  • the artificial biofilms/beads may be moved while they are present in the internal volume. For example, it may be beneficial to move the beads past the light sources so that they can be more evenly irradiated, as well as to encourage better mixing with the phosphorus-containing fluid. This agitation can be accomplished, for example, by bubbling the gas through the internal volume and the fluid.
  • a mechanical agitator (not shown) can be used to move the beads.
  • an Archimedean screw (a helical surface surrounding a shaft) could be located within the internal volume. If present, the mechanical agitator should be located so as not to contact the light sources.
  • a pressure valve which may be present to release any excess gas from the internal volume (for example, if the nitrogen sparging introduces excess gas).
  • FIG. 3 illustrates the use of multiple light pipes
  • the light pipe simply having a larger diameter such that the distance between the sidewall of the light pipe and the sidewall of the outer casing is relatively small.
  • the sidewall of the outer casing could be made of a material that permits light to penetrate into the internal volume.
  • FIG. 4 illustrates one such embodiment having a single light pipe 350 containing the plurality of light sources.
  • the outer wall of the outer casing is removed.
  • This embodiment depicts both LEDs 360 and fiber optic pads 370 being used to provide light.
  • the light pipe in this embodiment extends completely between the first end wall and the second end wall, so that the artificial biofilms/beads would be located in an annular space.
  • FIG. 5 is a cross-sectional view of a different embodiment of the photobioreactor. Compared to FIG. 3, this figure illustrates a version where a fiber optic pad 370 is used as the light source. A port 372 is present in the first end wall 320 to permit a cord 374 to travel from the external source (not shown) to the pad. Also, the nitrogen sparger is depicted as traveling throughout the internal volume, rather than simply below the floor as in FIG. 3.
  • FIG. 6 is a cross-sectional view of the embodiment of FIG. 5, but with the encapsulated bacteria beads 380 placed in the internal volume 340.
  • the photobioreactors described herein can also be used to distribute light to naturally occurring biofilms.
  • the internal volume includes additional surfaces on which bacteria can adhere and develop as a natural biofilm.
  • FIG. 7 and FIG. 8 show one such embodiment.
  • FIG. 7 is a perspective view
  • FIG. 8 is a plan view.
  • radial fins 392 extend radially from the sidewall 356 of the light pipe 350.
  • the outer casing 310 is also shown.
  • FIG. 9 and FIG. 10 show another such embodiment.
  • FIG. 9 is a perspective view
  • FIG. 10 is a plan view.
  • radial fins are present as in FIG. 7.
  • Circumferential fins 394 also extend from the radial fins 392.
  • These radial fins and circumferential fins provide additional surface area upon which bacteria can adhere and form biofilms. This construction permits the fins to be removed from the internal volume so that the bacteria, phosphate granules, and possibly the bioplastics can be harvested.
  • FIG. 11 is a picture illustrating the lighting profile of an LED strip contained in a light pipe.
  • the power at any given point in the internal volume may be the sum of the contributions from multiple LEDs.
  • the side view (left) shows the overlapping light fields of multiple LEDs at the distance where the light absorbance is at the extinction coefficient of 1/e.
  • the absorbance contour lines in the top cross-sectional view (right) are provided for one LED per light pipe, though illustrated from four different light pipes.
  • the actual power at any given point in the internal volume may be the sum of the overlapping contributions from multiple LEDs. At 2-3 cm from the light pipe, only 1 % of the original power emitted by an LED remains due to the light absorbance of the liquid medium. This is seen on the right side.
  • the power is 16.8 mW.
  • the power is 1 .6 mW, or 10% of the original power.
  • the power is 0.016 mW, or one-thousandth the original power.
  • the bacteria-containing beads are placed in the internal volume of the photobioreactor, and phosphorus-containing fluid (e.g. waste water) fills the remainder of the volume.
  • phosphorus-containing fluid e.g. waste water
  • the light sources are activated to provide energy so that the bacteria perform their desired function under photosynthetic conditions.
  • the waste water provides the necessary nutrients to the bacteria.
  • Nitrogen gas is sparged into the internal volume to obtain and maintain anaerobic conditions within the photobioreactor.
  • the ambient temperature within the photobioreactor i.e. in the internal volume) is from 27°C to 34°C.
  • the fluid should have a hydraulic residence time in the photobioreactor of from about 1 minute to about 1 hour, but can also be longer than 1 hour.
  • the solids in the wastewater (not the PAOs) in the photobioreactor may have a residence time in the photobioreactor of from about 1 day to about 10 days, but can also be longer than 10 days.
  • the residence time for each phase (liquid, solid) is determined by the requirements of the system.
  • the process steps are envisioned as follows. First, the organisms will be grown in the photobioreactor to the stationary phase of growth, using sunlight or artificial illumination for energy and deriving nutrients from the wastewater. With continuous illumination for an estimated two days, the organisms will accumulate both polyphosphates and possibly bioplastics like polyhydroxyalkanoates (PHA). After this time it is expected that the organisms, which will have sequestered a great deal of phosphorus while also producing PHA granules, may begin to slough from the photobioreactor because they have reached maximum biofilm densities possible. Illumination will be discontinued, and the majority of the organisms will be removed from the bioreactor so that the biomass can be collected.
  • PHA polyhydroxyalkanoates
  • This biomass can be processed for recovery of the PHA in a separate process. Meanwhile, within the bioreactor, enough organisms will have been retained to "reseed" the reactor, meaning that the organisms will enter into a second cycle of illumination and photo heterotrophic growth, followed by collection of PHA-containing biomass that results.
  • the biomass also contains phosphorus, and could be used for fertilizer.
  • the photobioreactors of the present disclosure may be applied for phosphorus reduction in wastewater treatment plants, streams, or lakes.
  • Other potential applications include retrofitting existing conventional bioreactors or anaerobic digesters with the lighting systems described herein to enhance light distribution or increase the activity/productivity of phototrophic organisms.
  • the photobioreactor could be strategically placed to receive effluents from an anaerobic digester. Such effluents are often rich in phosphorus but less so in other products that might be inhibitory to phosphorus accumulation.
  • the photobioreactor could be a final nutrient removal step that would help to prevent the discharge of phosphorus-rich treatment effluents into lakes, rivers, or streams.
  • the photobioreactor can be used as a polishing step at the end of the wastewater treatment process, when the wastewater contains for example only 1 to 2 ppm of phosphorus. The photobioreactor can reduce the concentration of phosphorus even further.
  • FIG. 12 is a graph showing the phosphate concentration in the wastewater vs. the time.
  • the PBR had a working volume of approximately 1 .25 liters. LED strips were inserted into clear polyvinyl chloride tubes and then into the PBR. The PVC tubes had small hoses to blow compressed air through the tubes to address the heat production from the LED strips. This was necessary because the LED strips had resistors that produced heat that increased the temperature of the PBR above the target range of 27°C to 34°C when compressed air was not blown. LED lights were selected to consume the least amount of energy required for PAO activation. It was found that the LED lights had a spectral power density nearly 4 times greater than the fluorescent lights. In addition, LED lights were expected to last 2-3 times longer than fluorescent lights. Accordingly, the use of LED lights could reduce the PBR operating cost by over 50% compared to fluorescent lights. Nitrogen sparging of the PBR was employed to help to maintain anaerobic conditions.
  • the PBR was operated with the fluid flow either flowing upwards or downwards (i.e. the fluid inlet was either at the bottom or the top of the PBR).
  • the PBR was also operated with different recycle flow rates.
  • Dairy Farm 1 manages about 1 ,000 head. It operates a partial-cover lagoon digester. Solids and liquids from the digester are used for bedding and fertilizer, respectively. Biogas is combusted. Samples were collected from the primary and tertiary lagoons for treatment in the PBR.
  • Dairy Farm 2 manages about 2,100 head. It operates a mixed plug flow anaerobic digester (AD) reactor and generates about 600 kW of electricity that is sold to the local utility. Solids from the reactor are used as fertilizer. Samples were collected from the AD reactor for treatment in the PBR.
  • AD mixed plug flow anaerobic digester
  • Test tube experiments were initially completed with samples of wastewater from Farm 1 primary lagoon to determine phosphorus removal. During these experiments, phosphorus removal of about 75% was achieved.
  • PBR with alginate beads achieved 90% phosphorus removal in four days and maintained that level through the end of the experiment at six days.
  • Saline beads no encapsulated PAO
  • Nitrate concentrations were analyzed during these secondary treated wastewater experiments to determine if denitrifying bacteria were active in the PBR anaerobic conditions.
  • alginate beads encapsulated PAO
  • 90% NO3 " removal was achieved, with nitrate level reduced from 29.63 mg/L to less than 1 mg/L.
  • saline beads no encapsulated PAO
  • nitrate levels reduced from 32 mg/L to 2.56 mg/L in 7 days.
  • a second set of experiments with secondary clarified wastewater operating with upward flow showed similar results with greater than 90% nitrate removal for both alginate and saline beads.
  • Preliminary system design parameters are summarized below: anaerobic conditions; internal LED lights; temperature of ⁇ 30°C; 500 mL R. palustris beads; Total quantity of 2.5 L circulating wastewater; recycle flow rate (slow gravity fed) -0.03 L/min (40 minute reactor residence time); and recycle flow rate (upward flow) ⁇ 126mL/min (9.5-minute reactor residence time).
  • PBR conditions were identified that provided effective phosphorus removal from municipal and livestock wastewater streams. PAOs in these wastewater streams appear to be selected and grow under anaerobic and lighted conditions. Simultaneous phosphorus removal and denitrification was observed treating secondary clarified municipal wastewater.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Bioinformatics & Cheminformatics (AREA)
  • Wood Science & Technology (AREA)
  • Zoology (AREA)
  • Biotechnology (AREA)
  • Genetics & Genomics (AREA)
  • General Engineering & Computer Science (AREA)
  • Biochemistry (AREA)
  • Biomedical Technology (AREA)
  • General Health & Medical Sciences (AREA)
  • Sustainable Development (AREA)
  • Microbiology (AREA)
  • Immunology (AREA)
  • Molecular Biology (AREA)
  • Biological Treatment Of Waste Water (AREA)
  • Micro-Organisms Or Cultivation Processes Thereof (AREA)
  • Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)

Abstract

Cette invention concerne un photobioréacteur et des procédés permettant de capturer le phosphore contenu dans un fluide. Des biofilms artificiels sont fabriqués avec des micro-organismes accumulateurs de phosphate qui sont immobilisés ou inclus dans une matrice, et peuvent se présenter sous forme de billes. Ces biofilms sont situés dans un volume interne du photobioréacteur. Des sources de lumière sont réparties dans le volume interne de façon à ce qu'aucune zone du volume interne ne se trouve à une distance d'éclairage supérieure à la distance seuil. Le liquide et le gaz sont introduits dans le volume interne et les biofilms artificiels capturent le phosphore présent dans le liquide. Le photobioréacteur peut aussi utiliser des biofilms naturels.
PCT/US2013/053342 2012-08-03 2013-08-02 Photobioréacteur pour capturer le phosphore WO2014022736A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201261679375P 2012-08-03 2012-08-03
US61/679,375 2012-08-03

Publications (1)

Publication Number Publication Date
WO2014022736A1 true WO2014022736A1 (fr) 2014-02-06

Family

ID=50028549

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2013/053342 WO2014022736A1 (fr) 2012-08-03 2013-08-02 Photobioréacteur pour capturer le phosphore

Country Status (1)

Country Link
WO (1) WO2014022736A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3546562A1 (fr) 2018-03-27 2019-10-02 FCC Aqualia, S.A. Photobioréacteur anaérobie et procédé de culture de biomasse
US11214767B2 (en) 2020-05-22 2022-01-04 Brightwave Partners, LLC Internally illuminated bioreactor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6416993B1 (en) * 1998-12-11 2002-07-09 Biotechna Environmental International, Ltd. Method for treating a waste stream using photosynthetic microorganisms
US20090047722A1 (en) * 2005-12-09 2009-02-19 Bionavitas, Inc. Systems, devices, and methods for biomass production
US20100151558A1 (en) * 2006-09-13 2010-06-17 Petroalgae, Llc Tubular Microbial Growth System
WO2012000057A1 (fr) * 2010-07-01 2012-01-05 Mbd Energy Limited Procédé et appareil destinés à faire croître des organismes photosynthétiques

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6416993B1 (en) * 1998-12-11 2002-07-09 Biotechna Environmental International, Ltd. Method for treating a waste stream using photosynthetic microorganisms
US20090047722A1 (en) * 2005-12-09 2009-02-19 Bionavitas, Inc. Systems, devices, and methods for biomass production
US20100151558A1 (en) * 2006-09-13 2010-06-17 Petroalgae, Llc Tubular Microbial Growth System
WO2012000057A1 (fr) * 2010-07-01 2012-01-05 Mbd Energy Limited Procédé et appareil destinés à faire croître des organismes photosynthétiques

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3546562A1 (fr) 2018-03-27 2019-10-02 FCC Aqualia, S.A. Photobioréacteur anaérobie et procédé de culture de biomasse
WO2019185734A1 (fr) 2018-03-27 2019-10-03 Fcc Aqualia S.A. Photobioréacteur anaérobie et procédé de culture de biomasse
US11214767B2 (en) 2020-05-22 2022-01-04 Brightwave Partners, LLC Internally illuminated bioreactor

Similar Documents

Publication Publication Date Title
Cuellar-Bermudez et al. Nutrients utilization and contaminants removal. A review of two approaches of algae and cyanobacteria in wastewater
Tao et al. Enhanced biomass/biofuel production and nutrient removal in an algal biofilm airlift photobioreactor
Lee et al. Nitrogen removal from wastewaters by microalgae without consuming organic carbon sources
Sathinathan et al. Photobioreactor design and parameters essential for algal cultivation using industrial wastewater: A review
Leong et al. Pollution prevention and waste phycoremediation by algal-based wastewater treatment technologies: The applications of high-rate algal ponds (HRAPs) and algal turf scrubber (ATS)
Tan et al. Nutrients recycling and biomass production from Chlorella pyrenoidosa culture using anaerobic food processing wastewater in a pilot-scale tubular photobioreactor
US20120214198A1 (en) Algaculture method
WO2014022689A1 (fr) Système photobioréacteur pour éliminer l'azote et le phosphore
US10179895B2 (en) Device for fuel and chemical production from biomass-sequestered carbon dioxide and method therefor
CN104004645B (zh) 一种有机废水水解酸化耦合微藻培养的两相系统与方法
Solmaz et al. Optimization of membrane photobioreactor; the effect of hydraulic retention time on biomass production and nutrient removal by mixed microalgae culture
KR101409035B1 (ko) 인공 광원 및 플루 가스를 이용한 미세조류 배양조 및 이를 이용한 하폐수 처리공정 시스템
CN103789195A (zh) 一种实现原位固液分离的膜微藻光生物反应器及其培养方法
CN103910434A (zh) 用于处理沼液超标氮磷的膜式光生物反应器及其处理方法
WO2008010737A1 (fr) Photobioréacteur pour une culture de microorganismes photosynthétiques
CN101914430A (zh) 一种微藻养殖装置及方法
CN105621789A (zh) 一种基于微藻培养的沼液处理装置及方法
Zhang et al. Ammonia-nitrogen and orthophosphate removal by immobilized Chlorella sp. isolated from municipal wastewater for potential use in tertiary treatment
CN110407404A (zh) 一种将农业废水中营养物转化为粗蛋白原料的生产方法和系统
CN109456885A (zh) 一种自清洁流化床光生物反应器
Ghaffar et al. A review on the sustainable procurement of microalgal biomass from wastewaters for the production of biofuels
Dange et al. Trends in photobioreactor technology for microalgal biomass production along with wastewater treatment: Bottlenecks and breakthroughs
WO2014022736A1 (fr) Photobioréacteur pour capturer le phosphore
CN105712491A (zh) 脱氮装置
Li et al. Fabrication of immobilized algal-bacterial beads and its application in synthetic mariculture tail water treatment

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13825390

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13825390

Country of ref document: EP

Kind code of ref document: A1