WO2013158795A1 - Récolte et déshydratation d'algues grâce à un procédé en deux étapes - Google Patents

Récolte et déshydratation d'algues grâce à un procédé en deux étapes Download PDF

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Publication number
WO2013158795A1
WO2013158795A1 PCT/US2013/037023 US2013037023W WO2013158795A1 WO 2013158795 A1 WO2013158795 A1 WO 2013158795A1 US 2013037023 W US2013037023 W US 2013037023W WO 2013158795 A1 WO2013158795 A1 WO 2013158795A1
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Prior art keywords
algae
growth medium
tank
stage
flotation tank
Prior art date
Application number
PCT/US2013/037023
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English (en)
Inventor
Nicholas Eckelberry
Jose Sanchez
Original Assignee
Originoil, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US13/753,484 external-priority patent/US20130192130A1/en
Application filed by Originoil, Inc. filed Critical Originoil, Inc.
Priority to MX2014012607A priority Critical patent/MX2014012607A/es
Priority to CN201380020617.3A priority patent/CN104768877A/zh
Priority to IN2073MUN2014 priority patent/IN2014MN02073A/en
Priority to JP2015507155A priority patent/JP2015515375A/ja
Priority to AU2013249299A priority patent/AU2013249299A1/en
Priority to EP13778445.0A priority patent/EP2838852A4/fr
Priority to KR1020147031760A priority patent/KR20140144742A/ko
Priority claimed from US13/865,097 external-priority patent/US20130228464A1/en
Publication of WO2013158795A1 publication Critical patent/WO2013158795A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/465—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electroflotation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/005—Combined electrochemical biological processes
    • 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
    • C02F3/32—Biological treatment of water, waste water, or sewage characterised by the animals or plants used, e.g. algae
    • C02F3/322—Biological treatment of water, waste water, or sewage characterised by the animals or plants used, e.g. algae use of algae
    • 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
    • C12M33/00—Means for introduction, transport, positioning, extraction, harvesting, peeling or sampling of biological material in or from the apparatus
    • 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
    • C12M47/00—Means for after-treatment of the produced biomass or of the fermentation or metabolic products, e.g. storage of biomass
    • C12M47/02—Separating microorganisms from the culture medium; Concentration of biomass

Definitions

  • Processes involved in achieving separation can vary, along with the desired end result.
  • the desired result is typically treated water that can be released into the environment.
  • the primary desired result may be the harvest of a usable biomass for energy production.
  • a metal ion or cation is added to improve flocculation by increasing conductivity of the matrix.
  • the following cations have lower electrode potential than H+ and are therefore considered suitable for use as electrolyte cations in these processes: Li+, Rb+, K+, Cs+, Ba2+, Sr2+, Ca2+, Na+ and Mg2+ (sodium and lithium are frequently used as they form inexpensive salts).
  • Other metals are used in conjunction with electro- flocculation to assist in precipitation of solids from the waste water, such as iron oxides and other oxidants. These metals are extremely effective at precipitating solids out of solution; however, they taint the product and the water itself with an inorganic chemical that then must be removed or otherwise processed in the tertiary waste treatment phase.
  • DAF Dissolved Air Flotation
  • microorganisms and intracellular products of microorganisms shows promise as a partial or full substitute for fossil oil derivatives or other chemicals used in manufacturing products such as pharmaceuticals, cosmetics, industrial products, biofuels, synthetic oils, animal feed, and fertilizers.
  • methods for harvesting the cells including steps of recovering and processing of intracellular products must be efficient and cost-effective in order to be competitive with the refining costs associated with fossil oil derivatives.
  • Current extraction methods used for harvesting microorganisms such as algae to ultimately yield products for use as fossil oil substitutes are laborious and yield low net energy gains, rendering them unviable for today's alternative energy demands.
  • the plasma membrane is composed of a double layer (bi-layer) of lipids, an oily or waxy substance found in all cells. Most of the lipids in the bilayer can be more precisely described as phospholipids, that is, lipids that feature a phosphate group at one end of each molecule.
  • glycoproteins Within the phospholipid bilayer of the plasma membrane, many diverse, useful proteins are embedded while other types of mineral proteins simply adhere to the surfaces of the bilayer. Some of these proteins, primarily those that are at least partially exposed on the external side of the membrane, have carbohydrates attached and therefore are referred to as glycoproteins.
  • the positioning of the proteins along the internal plasma membrane is related in part to the organization of the filaments that comprise the cytoskeleton, which helps anchor them in place. This arrangement of proteins also involves the hydrophobic and hydrophilic regions of the cell.
  • Intracellular extraction methods can vary greatly depending on the type of organism involved, their desired internal component(s), and their purity levels. However, once the cell has been fractured, these useful components are released and typically suspended within a liquid medium which is used to house a living microorganism biomass, making harvesting these useful substances difficult or energy-intensive. In most current methods of harvesting intracellular products from algae, a dewatering process has to be implemented in order to separate and harvest useful components from a liquid medium or from biomass waste (cellular mass and debris). Current processes are inefficient due to required time frames for liquid evaporation or energy inputs required for drying out a liquid medium or chemical inputs needed for a substance separation. Additionally, such processes are commonly limited to batch processing and are difficult to adapt for continuous processing systems.
  • the present invention is generally directed to an apparatus for harvesting algae using a two-stage approach.
  • the two-stage approach includes a flocculation stage and a dewatering stage.
  • the flocculation stage is implemented within a first-stage flocculation tank in which algae suspended within a growth medium is flocculated.
  • the flocculated algae is then fed to a second-stage flotation tank in which electrodes are used to produce hydrogen and oxygen bubbles which attach to the flocculated algae causing the flocculated algae to float to the surface.
  • the mat of floating algae can then be skimmed off the surface of the growth medium.
  • the present invention is implemented as an apparatus for harvesting algae using a two-stage process.
  • the apparatus includes a flocculation tank in which the first stage of the two-stage process occurs.
  • the flocculation tank comprises a reactor tube for creating an electric field within a growth medium containing suspended algae, the electric field causing the algae to flocculate.
  • the apparatus also includes a flotation tank in which the second stage of the two stage process occurs.
  • the flotation tank comprises a tank containing a plurality of electrodes which cause the formation of gas bubbles which attach to the flocculated algae and lift the flocculated algae to the surface of the growth medium.
  • the flotation tank is connected to the flocculation tank to allow the flocculated algae to flow from the flocculation tank into the flotation tank.
  • the present invention is implemented as a method for harvesting algae using a two-stage process.
  • a growth medium containing suspended algae is supplied into a flocculation tank.
  • the flocculation tank comprises a reactor tube for creating an electric field within the growth medium, the electric field causing the algae to flocculate.
  • the growth medium containing flocculated algae is transferred into a flotation tank.
  • the flotation tank comprises a tank containing a plurality of electrodes which cause the formation of gas bubbles which attach to the flocculated algae and lift the flocculated algae to the surface of the growth medium.
  • the floating algae are then removed from the surface of the growth medium.
  • the present invention is implemented as an apparatus for removing ammonia from a fluid.
  • the apparatus comprises a reactor tube for creating an electric field within a fluid containing ammonia.
  • the reactor tube includes a cathode and an anode, the anode comprising a titanium ruthenium alloy.
  • the anode causes the creation of free chlorine within the fluid leading to the oxidation of the ammonia into nitrite and nitrate.
  • the apparatus also includes a flotation tank connected to the reactor tube.
  • the flotation tank comprises a tank containing a plurality of electrodes which cause the formation of gas bubbles.
  • Figure 1A illustrates a two-stage algae harvesting apparatus having a first stage flocculation tank and a second stage flotation tank;
  • Figure IB illustrates side views of various possible configurations of electrodes within the second stage flotation tank
  • Figure 1C illustrates a side view of the first stage flocculation tank
  • Figure 2A illustrates the first stage flocculation tank when filled with a growth medium containing suspended algae
  • Figure 2B illustrates the first stage flocculation tank when the algae is flocculated in a batch mode
  • Figure 2C illustrates the first stage flocculation tank when the algae is flocculated in a continuous flow mode
  • Figures 3A-3D illustrate the process, performed within the second stage flotation tank, of dewatering the flocculated algae using hydrogen bubbles to float the flocculated algae to the surface;
  • Figure 4 illustrates an actual implementation of a two- stage algae harvesting apparatus in accordance with one or more embodiments of the present invention.
  • the present invention is generally directed to an apparatus for harvesting algae using a two-stage approach.
  • the two-stage approach includes a flocculation stage and a dewatering stage.
  • the flocculation stage is implemented within a first-stage flocculation tank in which algae suspended within a growth medium is flocculated.
  • the flocculated algae is then fed to a second-stage flotation tank in which electrodes are used to produce hydrogen and oxygen bubbles which attach to the flocculated algae causing the flocculated algae to float to the surface.
  • the mat of floating algae can then be skimmed off the surface of the growth medium.
  • the algae harvested in this manner are free of harmful substances that are often required in other algae harvesting methods. Additionally, because harmful substances are not used in the two-stage process, the nutrient-rich growth medium can be reused in subsequent algae harvesting.
  • the apparatus of the present invention can be configured in various sizes. However, in many embodiments, the apparatus can be sized so that it is relatively portable to allow its use in virtually any location. In this way, many entities can employ the apparatus to produce an algae biomass without requiring a large area of land and/or large amounts of electricity as is often required in other harvesting approaches.
  • Figure 1A illustrates an example configuration of an apparatus 100 that harvests algae using the two-stage approach.
  • Apparatus 100 includes two primary components: a first stage flocculation tank 101, and a second stage flotation tank 102.
  • a growth medium containing suspended algae is input into first stage flocculation tank 101.
  • This growth medium can be obtained in virtually any manner.
  • a dedicated unit for growing algae within water can be connected to first stage flocculation tank 101, or a growth medium otherwise obtained can be directly supplied to first stage flocculation tank 101.
  • the suspended algae is flocculated (i.e. caused to form clumps) within first stage flocculation tank 101. This flocculation can be caused using an electric current produced by electrodes as will be further described below.
  • the growth medium containing the flocculated algae is fed into second stage flotation tank 102.
  • Second stage flotation tank 102 produces gas (e.g. hydrogen and oxygen) bubbles which rise through the growth medium. While rising, the bubbles attach to the flocculated algae and lift the flocculated algae to the surface. This process results in a mat of algae forming at the surface of the growth medium. Finally, the algae can be collected using conveyors 115 and 116 as will be further described below.
  • gas e.g. hydrogen and oxygen
  • Figure 4 illustrates an actual implementation of an apparatus in accordance with one or more embodiments of the present invention.
  • flocculation tank 101 includes two primary components: a cathode 105 formed by an outer cylinder (e.g. an enclosed pipe or tube), and an anode 106 formed by an inner cylinder (e.g. a pipe or other enclosed cylindrical shape) that is contained within the outer cylinder. Accordingly, the growth medium flows between cathode 105 and anode 106 as shown by the arrows in Figure 1A.
  • Other shapes other than cylinders can also be used as long as a fluid pathway is formed between the two components.
  • multiple inner cylinders can be used for anode 106.
  • the surfaces of cathode 105 and anode 106 which are in contact with the growth medium can include grooves (e.g. rifling) which may decrease the occurrence of build-up on the surfaces.
  • FIG. 1C illustrates a cross-sectional side view of flocculation tank 101.
  • a space exists between cathode 105 and anode 106 through which the growth medium flows. In some embodiments, this space can be between .5 mm and 200 mm wide.
  • a voltage is applied to each of cathode 105 and anode 106 to cause an electric current to pass through the growth medium. This electric current causes the suspended algae in the growth medium to flocculate (i.e. to clump together).
  • the cells are exposed to both a magnetic field, causing a cellular alignment, and to an electrical field which induces cellular current absorption. These effects can cause the cells to flocculate.
  • FIGS 2A-2C illustrate how this flocculation can occur.
  • a source 210 of growth medium containing suspended algae is connected to flocculation tank 101.
  • growth medium could be supplied manually to flocculation tank 101.
  • the shading in Figure 2A indicates that the algae are initially suspended in the growth medium.
  • FIG. 2B illustrates the case where the growth medium is treated in a batch mode.
  • flocculation tank 101 is initially filled with growth medium containing suspended algae.
  • the growth medium is then subject to the electrical fields generated by cathode 105 and anode 106 until the desired level of flocculation has occurred.
  • the flocculated algae can be between 1 and 4 mm in size.
  • the growth medium with the flocculated algae is transferred to second stage flotation tank 102.
  • Figure 2B illustrates that the growth medium within flocculation tank 101 contains clumps of algae which are ready to be transferred to flotation tank 102.
  • FIG. 2C in contrast, illustrates the case where the growth medium is treated in a continuous flow mode.
  • the algae can be flocculated in the same manner as in the batch mode (e.g. by applying an electric current to the growth medium).
  • the growth medium can be continuously flowed into flocculation tank at an appropriate rate so that, by the time the growth medium reaches the opposite end of the flocculation tank, the algae has been sufficiently flocculated.
  • the growth medium at the left end having a similar degree of flocculation as the growth medium in source 210 and the degree of flocculation increasing towards the right end.
  • flocculation tank 101 can be configured with controls for automatically determining the appropriate settings to ensure that the algae is sufficiently flocculated before exiting flocculation tanks 101. For example, in batch mode, flocculation tank 101 can automatically determine an appropriate duration of time to treat the growth medium or appropriate voltage levels to apply to cathode 105 and anode 106. Similarly, in continuous flow mode, flocculation tank 101 can automatically determine an appropriate flow rate and appropriate voltage levels to apply to cathode 105 and anode 106.
  • the flow rate through flocculation tank 101 can be 0.1 ml/second per ml of volume. In other embodiments, however, the flow rate is at least 0.5 ml/second per ml of volume or at least 1.0 ml/second per ml of volume. In still other embodiments, the flow rate through the volume is at least 1.5 ml/second per ml of volume. In yet other embodiments, the flow rate through the volume exceeds 1.5 ml/second per ml of volume. In at least one additional embodiment, the flow rate can be controlled by controlling the pressure using a pump or other suitable fluid flow mechanical devices.
  • the supplied voltage can be pulsed on and off repeatedly to cause extension and relaxation of the algae cells.
  • voltages can be higher and peak amperage lower while average amperage remains relatively low.
  • this condition or controlled circumstance reduces the energy requirements for operating the apparatus and reduces wear on the anode and cathode pair or pairs.
  • the frequency of the pulses is at least about 500 Hz, 1 kHz, 2 kHz, or 30 kHz. In other embodiments, the frequency is less than 200 kHz, 80 kHz, 50 kHz, 30 kHz, 5 kHz, or 2 kHz. Ranges for the pulse frequency can be any combination of the foregoing maximum and minimum frequencies according to various embodiments.
  • an electrical pulse is repeated in frequency to create an electromagnetic field and electrical energy transfer between the electrodes.
  • an electromagnetic field is produced resulting in the elongation of the algae cells due to their polarity according to certain embodiments.
  • the suspended algae absorb electrical input which causes internal cellular components and their liquid mass to swell in size.
  • an internal pressure is applied against the transmembrane, however this internal swelling is to be considered as only momentary according to certain embodiments as it is relieved during an off frequency phase of the pulsed electrical input.
  • rapid repeating of the on and off electrical frequency rearranges components and creates and/or increases the polar regions in the algae cells.
  • continuous frequency inputs further produce internal pressures caused by expanded internal component swelling which eventually creates the magnetic/electrostatic attraction causing coagulation/flocculation of the treated cells.
  • apparatus 100 can be used to lyse, flocculate, and dewater algae cells.
  • the growth medium is transferred to flotation tank 102.
  • An electrical field can be applied to the growth medium within flotation tank 102 using electrodes. The electric field increases interface potential between solvent and solute and creates micron-sized bubbles of hydrogen and oxygen gas which lift the flocculated algae to the surface.
  • the algae form a mat at the surface allowing for easy removal of the algae.
  • the mat of algae includes a substantial amount of hydrogen and oxygen gas.
  • the algae can be used with this gas present, or further downstream processes can be performed to recover the gas. For example, the gas can be recovered and used to power apparatus 100 thereby minimizing the energy requirements for using apparatus 100.
  • flotation tank 102 includes a cathode plate 111 and a series of stacked anode 112 and cathode 113 rods.
  • Figure IB illustrates side views of other configurations of electrodes that can be used within flotation tank 102. For example, at the top left corner of Figure IB, the configuration depicted in Figure 1A is shown. In some embodiments, a plate can be used in place of the rods.
  • a single cathode and a single anode two cathodes and a single anode, a single cathode and two anodes, two cathodes and two anodes, or other combinations include one or more cathodes and one or more anodes.
  • some embodiments provide a two-by-three electrode arrangement, with two vertical columns of three electrodes.
  • the top and bottom rows of electrodes can be cathodes and the middle row can include two anodes.
  • Various other such anode-cathode configurations can be used in embodiments of flotation tank 102.
  • combinations of between 1 and 20 anodes and between 1 and 20 cathodes can be used depending primarily on the size of flotation tank 102.
  • Flotation tank 102 also includes conveyor 115 (having rakes 115a and 115b) and conveyor 116 which are used to remove the algae cells from flotation tank 102 and into collector 114 as will be further described below.
  • conveyor 115 having rakes 115a and 115b
  • conveyor 116 which are used to remove the algae cells from flotation tank 102 and into collector 114 as will be further described below.
  • Other means for removing the algae from the surface of the growth medium can also be used as in known in the art.
  • Figures 3A-3D illustrate flotation tank 102 to provide an example of how the flocculated algae can be floated to the surface.
  • Figure 3A illustrates the state of flotation tank 102 when a growth medium containing flocculated algae is passed into flotation tank 102.
  • prior approaches for separating algae from the growth medium are difficult, expensive, and oftentimes harmful to the algae making them unsuitable to recover algae that is intended for certain purposes.
  • the present invention provides a simple and safe process for recovering the algae cells. This process includes applying an electric field to the growth medium using electrodes 111, 112, and, in some cases, 113.
  • Figure 3C illustrates the state of flotation tank 102 after the flocculated algae cells have floated to the surface.
  • Figure 3C also illustrates that the remaining growth medium underneath the floating clumps is substantially clear to indicate that this process is highly effective at separating the algae from the growth medium.
  • the growth medium which is nutrient dense, can then be reused.
  • Figure 3D illustrates an example of how the floating algae cells can be removed. As shown, this removal can be performed using rakes 115a, 115b which are rotated over the surface of the growth medium to rake the algae cells towards conveyor 116. Conveyor 116 is rotated to transfer the raked algae cells into collector 114 where it can be retrieved for further processing. Accordingly, this process yields a highly dewatered biomass that can be easily transported and used.
  • Figures 3A-3D generally represent the process as being performed in batches (i.e. the entire growth medium is fully flocculated before any new algae cells are added). However, in some embodiments, this process can be performed on a continuous basis such as by periodically adding new growth media containing flocculated algae.
  • Gas bubble formation can be facilitated by strategically placing the electrodes in proximity to one another.
  • the cathode(s) and anode(s) are spaced between about 0.1 inches and about 36 inches apart, between about 0.2 inches and about 24 inches apart, about 0.5 inches and about 12 inches apart, about 0.5 inches and about 6 inches apart, about 3 to about 8 inches apart, about 1 inch to about 3 inches apart, or variations and combinations of these ranges or values within these ranges.
  • the ratio of separation may vary depending on the conductivity of the growth medium and/or the power levels applied to the electrodes. For example, the more saline or conductive the growth medium, the smaller the gap is required for hydrogen and/or oxygen production.
  • the placement of two or more cathodes near a single anode can increase turbulence about the anode, creating a heightened mixing effect that can assist in aggregating and lifting the algae cells.
  • An operating voltage of between about 1 and about 30 volts, about 1 and about 24 volts, about 2 to about 18 volts, about 2 to about 12 volts, or combinations and intermediate ranges within these ranges can be applied.
  • a voltage of about 4 volts, 6 volts, 8 volts, 10 volts, 12 volts, 14 volts, 16 volts, 18 volts, 20 volts, 22 volts, 24 volts, 26 volts, 28 volts, 30 volts, and/or combinations of these voltages or ranges encompassing these voltages can be applied.
  • the amperage may vary and generally be between about 1 A to about 20 A, about 2 A to about 15 A, or combinations or intermediate ranges within these ranges.
  • the actual current may reasonably vary depending on the density of the growth medium and its relative conductivity.
  • duty cycle refers to the relative lengths of the on and off portions of each power cycle, and can be expressed, for example, as a ratio of the duration of the on portion of the cycle to the total time for the cycle, or as a ratio of the duration of the on portion of the cycle to the off portion of the cycle, or by stating the on and off durations, or by stating wither the on or off duration and the total cycle duration. Unless otherwise stated or is clear from the context, duty cycle will be stated herein as the ration of on duration to off duration for a cycle.
  • the duty cycle can be about 1:1, about 1:1.1, about 1:1.2, about 1:1.3, about 1:1.4, about 1:1.5, about 1: 1.6, about 1:1.7, about 1:1.8, about 1:1.9, about 1:2, about 1:2.5, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9, or about 1:10. Additionally, the duration of the duty cycle can be varied based upon the flow rate, volume, and/or characteristics of the growth medium.
  • the electrodes can be made of a metal, composite, or other material known to impart conductivity, such as, but not limited to silver, copper, gold, aluminum, zinc, nickel, brass, bronze, iron, lead, platinum group metals, steel, stainless steel, carbon allotropes, and/or combinations thereof.
  • conductive carbon allotropes can include graphite, graphene, synthetic graphite, carbon fiber (iron reinforced), nano-carbon structures, and other form of deposited carbon on silicon substrates.
  • the anode and/or the cathode can serve as a sacrificial electrode which is used in the flocculation and/or bubble generation processes.
  • electrodes can include consumable conductive metals, such as iron or aluminum.
  • the electrodes e.g. cathodes 105, 111, 113 and anodes 106, 112
  • a catalyst-coated metal such as iridium oxide coated titanium.
  • Such metals can enhance the efficiency of the process. For example, by using iridium oxide coated titanium on the anode, the creation of gas bubbles can be facilitated.
  • one or more of the electrodes in flotation tank 102 can include numerous perforations or surface textures which allow the growth medium to pass through it. Such perforations and texturing provide an increase in the number of edges on the electrodes, which may facilitate bubble formation.
  • the one or more anodes may be formed as a mesh, grid, or other porous structure.
  • the mesh may include relatively large openings that are larger than a typical clump of algae or sludge particulates in the growth medium. This configuration can advantageously allow for faster flow rates since it allows for greater interfacial contact between the growth medium and the hydrogen generated by the anode. This configuration may be advantageous when a faster flow through is desired or when conductivity of the growth medium is low.
  • growth medium may be introduced into flotation tank 102 at the center of the anode. In this way, the growth medium will flow out one or more holes in the anode and be exposed to gas bubbles.
  • flotation tank 102 has shown flotation tank 102 as a separate elevated tank, it is also possible to form the flotation tank as a trench (e.g. in the ground). Using a trench can allow for the processing of greater amounts of growth medium.
  • the efficiency of flocculating and/or floating the algae can be increased by adding a protic solvent to the growth medium.
  • the growth medium may be injected with a dilute solution of a protic solvent such as formic acid, n-butanol, isopropanol, n-propanol, ethanol, methanol, and acetic acid, such as of approximately 0.05% by volume.
  • a protic solvent such as formic acid, n-butanol, isopropanol, n-propanol, ethanol, methanol, and acetic acid, such as of approximately 0.05% by volume.
  • This solution may be mixed into the growth medium at various times.
  • it is beneficial to add the protic solvent as the electric field of the flocculation process is generated, or just before the batch process occurs.
  • the above-described apparatus can also be used to remove ammonia from wastewater or other fluids such as in aquaculture environments.
  • the one or more anodes of flocculation tank 101 can be made of a titanium ruthenium alloy.
  • a titanium ruthenium alloy By using a titanium ruthenium alloy, free chlorine is produced in the growth medium when the voltage is applied to the cathode and anode. The free chlorine allows the ammonia to be oxidized eventually resulting in conversion of the ammonia into nitrate, nitrite, and some nitrogen gas.
  • a current density of between 30-50 mA/cm 2 of the anode is generally preferred to maximize the oxidation of the ammonia into nitrate and nitrite.
  • other current densities can also be used, and the ideal density will depend on various characteristics such as the temperature of the wastewater.
  • flotation tank 102 can still be used to remove other undesirable matter from the wastewater such as organic compounds.

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  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

La présente invention concerne de façon générale un appareil de récolte d'algues utilisant une approche en deux étapes. L'approche en deux étapes comprend une étape de floculation et une étape de déshydratation. L'étape de floculation est mise en œuvre dans un réservoir de floculation de première étape dans lequel les algues en suspension dans un milieu de culture sont floculées. Les algues floculées sont ensuite envoyées dans un réservoir de flottation de deuxième étape dans lequel des électrodes sont utilisées pour produire des bulles d'hydrogène et d'oxygène qui s'attachent aux algues floculées, ce qui les fait flotter à la surface. Le tapis d'algues flottantes peut ensuite être écrémé de la surface du milieu de culture.
PCT/US2013/037023 2012-04-17 2013-04-17 Récolte et déshydratation d'algues grâce à un procédé en deux étapes WO2013158795A1 (fr)

Priority Applications (7)

Application Number Priority Date Filing Date Title
MX2014012607A MX2014012607A (es) 2012-04-17 2013-04-17 Cosecha y deshidratacion de algas utilizando un proceso de dos etapas.
CN201380020617.3A CN104768877A (zh) 2012-04-17 2013-04-17 使用两阶段过程来采收且脱水藻类
IN2073MUN2014 IN2014MN02073A (fr) 2012-04-17 2013-04-17
JP2015507155A JP2015515375A (ja) 2012-04-17 2013-04-17 ２段階プロセスを使用した藻類の収穫および脱水
AU2013249299A AU2013249299A1 (en) 2012-04-17 2013-04-17 Harvesting and dewatering algae using a two-stage process
EP13778445.0A EP2838852A4 (fr) 2012-04-17 2013-04-17 Récolte et déshydratation d'algues grâce à un procédé en deux étapes
KR1020147031760A KR20140144742A (ko) 2012-04-17 2013-04-17 2 단계 방법을 사용한 조류의 수확 및 탈수법

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
US201261625463P 2012-04-17 2012-04-17
US61/625,463 2012-04-17
US201261649083P 2012-05-18 2012-05-18
US61/649,083 2012-05-18
US13/753,484 2013-01-29
US13/753,484 US20130192130A1 (en) 2012-01-30 2013-01-29 Systems and methods for harvesting and dewatering algae
US13/865,097 2013-04-17
US13/865,097 US20130228464A1 (en) 2012-01-30 2013-04-17 Harvesting and Dewatering Algae Using a Two-Stage Process

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JP (1) JP2015515375A (fr)
KR (1) KR20140144742A (fr)
CN (1) CN104768877A (fr)
AU (1) AU2013249299A1 (fr)
IN (1) IN2014MN02073A (fr)
MX (1) MX2014012607A (fr)
WO (1) WO2013158795A1 (fr)

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US8668827B2 (en) 2012-07-12 2014-03-11 Heliae Development, Llc Rectangular channel electro-acoustic aggregation device
US8673154B2 (en) 2012-07-12 2014-03-18 Heliae Development, Llc Tunable electrical field for aggregating microorganisms
US8702991B2 (en) 2012-07-12 2014-04-22 Heliae Development, Llc Electrical microorganism aggregation methods
US8709258B2 (en) 2012-07-12 2014-04-29 Heliae Development, Llc Patterned electrical pulse microorganism aggregation
US8709250B2 (en) 2012-07-12 2014-04-29 Heliae Development, Llc Tubular electro-acoustic aggregation device
US8772004B2 (en) 2009-06-25 2014-07-08 Old Dominion University Research Foundation System and method for high-voltage pulse assisted aggregation of algae
WO2015196241A1 (fr) * 2014-06-24 2015-12-30 Muradel Pty Ltd Procédés et systèmes de séparation de particules d'un milieu liquide
US10053379B1 (en) 2017-02-16 2018-08-21 Proterrgo Inc. Device for wastewater purification
CN113521867A (zh) * 2021-07-27 2021-10-22 南京科赫科技有限公司 一种催化裂化油浆连续净化装置及工艺

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8772004B2 (en) 2009-06-25 2014-07-08 Old Dominion University Research Foundation System and method for high-voltage pulse assisted aggregation of algae
US8668827B2 (en) 2012-07-12 2014-03-11 Heliae Development, Llc Rectangular channel electro-acoustic aggregation device
US8673154B2 (en) 2012-07-12 2014-03-18 Heliae Development, Llc Tunable electrical field for aggregating microorganisms
US8702991B2 (en) 2012-07-12 2014-04-22 Heliae Development, Llc Electrical microorganism aggregation methods
US8709258B2 (en) 2012-07-12 2014-04-29 Heliae Development, Llc Patterned electrical pulse microorganism aggregation
US8709250B2 (en) 2012-07-12 2014-04-29 Heliae Development, Llc Tubular electro-acoustic aggregation device
WO2015196241A1 (fr) * 2014-06-24 2015-12-30 Muradel Pty Ltd Procédés et systèmes de séparation de particules d'un milieu liquide
US10053379B1 (en) 2017-02-16 2018-08-21 Proterrgo Inc. Device for wastewater purification
WO2018148823A1 (fr) * 2017-02-16 2018-08-23 Proterrgo Inc. Dispositif de purification d'eaux usées
CN113521867A (zh) * 2021-07-27 2021-10-22 南京科赫科技有限公司 一种催化裂化油浆连续净化装置及工艺

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IN2014MN02073A (fr) 2015-09-04
MX2014012607A (es) 2015-03-20
KR20140144742A (ko) 2014-12-19
JP2015515375A (ja) 2015-05-28
CN104768877A (zh) 2015-07-08
AU2013249299A1 (en) 2014-11-06

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