Patent Publication Number: US-2021170424-A1

Title: System for collecting and harvesting algae for biofuel conversion

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 62/659,391 filed Apr. 18, 2018. The entire content of this application is hereby incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Algal-derived biofuels are one of the best alternatives for economically replacing liquid fossil fuels with a fungible renewable energy source. Algae can accumulate more than 50% of their biomass in oil and can be grown in saline water on land not suitable for agriculture. These characteristics mean algal biofuels do not compete for fresh water and arable land with conventional food crops. In addition, less land will be needed to produce the needed fuel than is required for other biofuel feed stocks. 
     One major problem with algal biofuels is that the algae most suited for biofuel production are small in size and difficult to harvest. Efficient harvest is crucial because algae cultures yield. at best a few grams of algae per liter of water. The algae must be separated from the water before they can be converted to fuel. At the laboratory scale, algae cultures can be harvested by centrifugation or filtration, but these methods are too energy- and capital-intensive for harvesting algae from the immense volumes of water needed for commercial scale production of algal biofuels. Chemical flocculation can be used at large scales, but requires treatment of the water after the algae are removed so the water can safely be reused or released into the environment. 
     Furthermore, nuisance algal blooms are a problem for private individuals, businesses and local governments alike. While algal blooms are unsightly for businesses, such as golf courses and housing developments, they pose a real health hazard when toxic algae are present. In the summer of 2014 about 500,000 residents in the city of Toledo, Ohio were cut off from their water supply due to a toxic algae bloom in Lake Erie. Residents could not drink or even bathe in public water due to the presence of toxins. During this crisis, the city of Toledo had no means of getting rid of the algae. The National Oceanic and Atmospheric Administration estimates that $82 million is lost in revenue per year for the United States due to harmful algal blooms. As another example, the city of Cleveland, Ohio spends $2 million per year when an algal bloom is present in Lake Erie. 
     There is a need for improved methods for collecting and harvesting algae for biofuel conversion. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a system including: an algae pool containing at least one algae organism; a magnetic particle storage unit adapted or configured to introduce at least one magnetic particle into the algae pool, wherein the at least one magnetic particle binds to the at least one algae organism to form at least one algae conjugate; and an algae harvester, including: at least one magnetic disc adapted or configured to attach, via a surface of the at least one magnetic disc, to the at least one algae conjugate when the at least one algae conjugate comes in contact with the at least one magnetic disc; and at least one scraper adapted or configured to: remove the at least one algae conjugate from the surface of the at least one magnetic disc; and transport the at least one algae conjugate from the algae harvester. This object of the invention can have a variety of embodiments. The system can further include a conjugate separator adapted or configured to: receive the at least one algae conjugate from the algae harvester; and separate the at least one algae conjugate into the at least one magnetic particle and the at least one algae organism. Separating the at least one algae conjugate can further include reducing a calcium concentration of a solution containing the at least one algae conjugate. 
     The system can further include a hydrodynamic shear, where separating the at least one algae conjugate can further include shearing, via the hydrodynamic shear, the at least one algae conjugate. Separating the at least algae conjugate can further include magnetically separating the at least one algae conjugate. The at least one magnetic particle can be transported back to the algae pool after being separated from the at least one algae organism. 
     The at least one magnetic disc can be further adapted or configured to rotate along a center axis of the at least one magnetic disc. The scraper can be further adapted or configured to remove the at least one algae conjugate from the surface of the at least one magnetic disc as the at least one magnetic disc rotates along the center axis. Transporting the at least one algae conjugate can further include transporting the at least one algae conjugate back to the algae pool. 
     The at least one magnetic disc can further include a plurality of magnetic tiles. In varying embodiments, each magnetic tile includes a north magnetic pole and a south magnetic pole, or the plurality of magnetic tiles further comprise a plurality of north magnetic poles and a plurality of south magnetic poles, or the plurality of magnetic tiles further comprise at least one Holbach array, or there is a combination thereof. The plurality of magnetic tiles can be configured to form an aggregate north pole and an aggregate south pole for the at least one magnetic disc. The plurality of magnetic tiles can be configured to form a closed magnetic circuit within the at least one magnetic disc. 
     The plurality of magnetic tiles can form a plurality of magnetic field lines, where the plurality of magnetic field lines are configured in a parallel line pattern or a grid pattern. In some cases, a spacing between each south magnetic pole or north magnetic pole, and an adjacent magnetic pole is between 0.06 inches and 4 inches. 
     The algae harvester can be located within or on a surface of the algae pool. The system can further include an axial flow pump configured or adapted to transport the at least one algae organism from the algae pool to the algae harvester. 
     Another object of the invention is to provide a method for harvesting algae, the method including: introducing at least one magnetic particle into an algae pool containing at least one algae organism; binding the at least one magnetic particle to the at least one algae organism to form at least one algae conjugate; attaching, via a surface of at least one magnetic disc of an algae harvester, to the at least one algae conjugate when the at least one algae conjugate comes in contact with the at least one magnetic disc; removing, via a scraper, the at least one algae conjugate from the surface of the at least one magnetic disc; and transporting the at least one algae conjugate from the algae harvester. 
     This object of the invention can have a variety of embodiments. The method can further include receiving, by a conjugate separator, the at least one algae conjugate from the algae harvester; and separating the at least one algae conjugate into the at least one magnetic particle and the at least one algae organism. Separating the at least one algae conjugate can further include reducing a calcium concentration of a solution containing the at least one algae conjugate. 
     Separating the at least one algae conjugate can further include shearing, via a hydrodynamic shear, the at least one algae conjugate. Separating the at least algae conjugate can further include magnetically separating the at least one algae conjugate. The at least one magnetic particle can be transported back to the algae pool after being separated from the at least one algae organism. 
     The method can further include rotating the at least one magnetic disc along a center axis of the at least one magnetic disc. The method can further include removing, via the scraper, the at least one algae conjugate from the surface of the at least one magnetic disc as the at least one magnetic disc rotates along the center axis. Transporting: the at least one algae conjugate can further include transporting the at least one algae conjugate back to the algae pool. 
     The at least one magnetic disc further can further include a plurality of magnetic tiles, where each magnetic tile includes a north magnetic pole and a south magnetic polo, or a plurality of north magnetic poles and a plurality of south magnetic poles, at least one Holbach array, or a combination thereof. The plurality of magnetic tiles can be configured to form an aggregate north pole and an aggregate south pole for the at least one magnetic disc. The plurality of magnetic tiles can be configured to form a closed magnetic circuit within the at least one magnetic disc. 
     The plurality of magnetic tiles can form a plurality of magnetic field lines, where the plurality of magnetic field lines are configured in a parallel line pattern or a grid pattern. In some cases, a spacing between each south magnetic pole or north magnetic pole, and an adjacent magnetic pole is between 0.06 inches and 4 inches. 
     The algae harvester can be located within or on a surface of the algae pooh The method can further include transporting, via an axial flow pump, the at least one algae organism from the algae pool to the algae harvester. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature and desired objects of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawing figures wherein like reference characters denote corresponding parts throughout the several views. 
         FIG. 1  depicts a system for harvesting and converting algae into biofuel, in accordance with embodiments of the claimed invention. 
         FIG. 2  depicts a system for separating algae/magnetic particle conjugates, in accordance with embodiments of the claimed invention. 
         FIG. 3  depicts a graph of algae recovery rates for a separator, in accordance with embodiments of the claimed invention. 
         FIGS. 4 and 5  depict a magnetic algae harvester, in accordance with embodiments of the claimed invention. 
         FIG. 6  depicts a flow profile for a magnetic algae harvester, in accordance with embodiments of the claimed invention. 
         FIGS. 7 and 8  depict magnetic assemblies for a magnetic algae harvester, in accordance with embodiments of the claimed invention. 
         FIG. 9  depicts a magnetic particle recovery results table, in accordance with embodiments of the claimed invention. 
         FIG. 10  depicts algal particle recovery results graphs, in accordance with embodiments of the claimed invention, 
         FIG. 11  depicts a workflow process for collecting and harvesting algae for biofuel conversion, in accordance with embodiments of the claimed invention. 
     
    
    
     DEFINITIONS 
     The instant invention is most clearly understood with reference to the following definitions. 
     As used herein, the singular form “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. 
     Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within  2  standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from context, all numerical values provided herein are modified by the term about. 
     As used in the specification and claims, the terms “comprises,” “comprising,” “containing,” “having,” and the like can have the meaning ascribed to them in U.S. patent law and can mean “includes,” “including,” and the like. 
     Unless specifically stated or obvious from context, the term “or,” as used herein, is understood to be inclusive, 
     Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 (as well as fractions thereof unless the context clearly dictates otherwise). 
     DETAILED DESCRIPTION OF THE INVENTION 
     A system for collecting and harvesting algae for biofuel conversion and associated methods are described herein. In some embodiments, the system includes a harvester for harvesting algae from an algae source. The algae are bound to magnetic particles that are introduced to the algae source. The particle/algae combination is pumped through a series of magnetic discs in the harvester. The magnetic discs attract the particle/algae combination through magnetic attraction, where the particle/algae combination “attach” to the surface of one of the magnetic discs. Furthermore, the magnetic discs rotate about an axis, where the surface of the magnetic disc is in contact with a scraper. The scraper serapes the surface of the magnetic disc, thereby removing the particle/algae combination from the magnetic disc. The particle/algae combination is then funneled to a collection point, where the combination is then transported to a separator. 
     The system described herein thus allows for a cost-efficient technique for generating biofuel. The magnetic particle collection reduces the strength of water pumps utilized for transporting algae throughout the system. Further, the system is not limited to the collection and harvesting of certain types of algae and can therefore be used in a variety of settings, including toxic algae removal. 
       FIG. 1  depicts a system  100  for collecting and harvesting algae for biofuel conversion, according to the claimed invention. The system  100  includes a feedstock pool  105 . The feedstock pool  105  can contain a strain of algae, or in some cases multiple strains of algae. 
     The feedstock pool  105  is housed by an algal pond  110 . The algal pond can, in some cases, be an unlined, above-ground structure. Additionally or alternatively, the algal pond  110  can be composed of earthen clay, which retains the feedstock pool  110 . Eliminating the lining requirement allows for a significant reduction in algal pond  110  construction costs. 
     In certain embodiments, algae can be grown by adding manure to the algal pond  110 . The nutrients in the manure stimulates the growth of a consortia of native algae species. Algal strains contemplated for collecting, harvesting or concentration herein can include, but are not limited to,  Phaeodactulum tricornutum, Chloreclla protothecoides, Nannochloropsis salina, Nannochloropsis  sp.  Tetraselmis succica, Tetraselmis chuii, Botrycoccus braunii, Chlorella  sp.,  Chlorella ellipsoidea, Chlorella emersonii, Chlorella minutissima, Chlorella salina, Chlorella protothecoides, Chlorella pyrenoidosa, Chlorella sorokiniana, Chlorella vulgaris, Chroomonas salina, Cyclotella cryptica, Cyclotella  sp.,  Dunaliella salina, Dunaliella hardawil, Dunaliella tertiolecta, Euglena gracilis, Gymnodinium nelsoni, Haematococcus pluvialis, Isochrysis galbana, Monoraphidium minutum, Monoraphidium  sp.,  Neochloris oleoabundans, Nitzschia laevis, Onoraphidium sp., Pavlova lutheri, Phaeodactylum tricotnutum, Porphyridium cruentum, Scenedesmus obliquuus, Scenedesmus quadricaula Scenedesmus  sp.,  Stichococcus bacillaris, Spirulina platensis, Thalassiosirs  sp. or combinations thereof. 
     The algae are harvested with magnetic particles. Magnetic harvesting particles are introduced to the feedstock pool  105  through a continuous harvester  115 . In some cases, the magnetic particles can be stored in a magnetic panicle storage unit  120 , which then introduces the magnetic particles into the harvester  115 . For example, in one embodiment the magnetic particles are injected from a concentrated feed into the flow to obtain a final concentration of 1 g/L. In other embodiments the concentration of the particles can vary between 0.25 g/L-15 g/L. Binding of the algae to the magnetic particles is rapid (e.g., occurs in less than half a second). The magnetic panicles bind to the algae inside the harvester  115 , and the particle-algae conjugates are removed from the algal pond  110  magnetically. Binding of the algae to the panicles is due to electrostatic attraction. The magnetic particles are positively charged and algae are negatively charged. These oppositely charged particles bind to form particle-algae conjugates. 
     The concentrated conjugates are transferred to a conjugate separator  125  where the magnetic particles are separated from the algae. In some cases the conjugate separator is external to the feedstock pool  105  (e.g., on shore). In some embodiments, the separated magnetic particles are reintroduced into the feedstock pool  105  to lower operating costs. 
     Algae separation is achieved through a three-step process. First calcium concentration in the particle-algae conjugate solution is reduced. Next, a hydrodynamic shear is applied to the solution to physically separate the algae from the particles. Finally, the particles are separated from the algae with a magnetic separator. An example embodiment of this separation system is shown in  FIG. 2 . In this embodiment the particle-algae conjugates are stored in a tank  205  which is stirred by a motor  210 . Control of the flow to a pump  220  is mediated by a control valve  215 . Pressure of the flow immediately subsequent to the pump is monitored by a pressure gauge  225  before the flow passes through filters  230 . Pressure of the flow after the filters is monitored by a pressure gauge  235 . The difference between pressure gauges  225  and  235  allows for a determination of whether a filter begins to clog. 
     The flow then passes into a column  240  which is filled with cation exchange resin. Upon exiting the column, pressure of the flow is measured by a pressure gauge  245  before passing though the shearing apparatus  250 . The shearing apparatus  250  can be but is not limited to a small-diameter orifice, an inline mixing fixture, or a vibrating fixture. Flow to the magnetic particle separator  260  is controlled by a control valve  255 , inside the magnetic separator  260  the particles are magnetically removed from the flow, yielding a constant stream of concentrated algae. The magnetic particle separator  260  can be of various designs with either ferrite magnets, rare earth magnets or other similar magnets. 
     The resin in the column  240  is continuously depleted as it removes calcium from the particle-algae conjugates. As the resin becomes depleted the column  240  removes loss and less calcium from the flow. To regenerate the column  240 , the flow control valve  215  is closed and a flow control valve  270  is opened to allow sodium chloride brine from a brine tank  265  to be introduced into the column  240 . The control valve  255  is also closed and a control valve  275  is opened so the flow goes to waste  280 . Brine is pumped by the pump  220  through the column  240  to regenerate the column  240 . Next, the control valve  270  is closed and a control valve  290  is opened to allow rinse water  285  to be pumped through the column  240 . After this cycle is completed the system can continue processing particle algae conjugates by closing control valves  275  and  290  and opening control valves  215  and  255 . 
     The lifetime of the resin has been tested with over 1,000 bed volumes and showed no signs of fouling. Testing data  300  are shown in  FIG. 3 . These data  300  depict the percent of algae recovered from the particles after the system is operational. The data  300  demonstrate that the system quickly stabilizes to a recovery rate of about 80%. 
       FIG. 4  depicts an algae harvester  400  in accordance with embodiments of the claimed invention. In some cases, algae harvester  400  can be an example of harvester  115  as described with reference to  FIG. 1 . 
     Algae water is pumped from the environment, such as algal pond  110  of  FIG. 1 , by pump  405 . 
     Magnetic particles are injected into the flow and bind to the algae, forming particle-algae conjugates. The particle-algae conjugates are then introduced into the algae harvester via plenum  410  into separation channels  460 . The conjugates flow into the plenum  410  that separates the flow so that the conjugates are introduced evenly across the inflow of the separation chambers  460 . The separation chambers  460  are contained within a shell  455  that is supported by a frame  425 . Even introduction of the conjugate feedstock fluid ensures that each magnetic separator  420  receives the same flow rate. 
     The particle-algae conjugates flow past magnetic separators  420  that remove the conjugates from the water magnetically. 
     Conjugate separation is achieved using magnetic discs (e.g., separator  420 ). These discs are composed of one or more magnets. In some embodiments, each separator  420  can be composed of multiple magnets. In some of these embodiments, the magnets can be glued together with flexible epoxy. In some cases, magnets that are used to form a separator  420  include, but are not limited to, ferrite grades C1-C8 and their international equivalents. 
     The magnetic separators  420  can include different magnetic pole orientations. In one embodiment, each separator disc includes a dipole orientation where each disc separator  420  has a single north pole and south pole. Other embodiments include multipole arrays where each separation disc includes arrays of multiple north poles and south poles on each side of the disc. These fields can be arranged in either parallel lines or in a grid pattern with a spacing between each pole (e.g., between 0.06″-4″). In another embodiment, the discs include Halbach arrays. These arrays are similar to multipole magnets in that each face of the separator  420  has multiple poles. However, in a Halbach array, the magnetic field generate an internal circuit within the magnetic material. Thus, instead of the magnetic field traveling straight through two parallel surfaces of the magnet, the magnetic field completes a circuit in a parabola traveling from one adjacent pole to the other. 
     The now concentrated conjugates are removed from the magnetic separators  420  by rotating past fixed scrapers  435 , The separators  420  are rotated via a driveshaft  440 . The driveshaft  440  is turned by an electric motor  450  through a turndown gearbox  445 . As the separators  420  are rotated, a surface of a separator  420  comes into contact with, or in close proximity to, a surface of a scraper  435 . If a conjugate is present on the surface of the separator  420  as the separator is rotated, the conjugate is scraped from the surface of the separator  420 . In some cases, the conjugate is transferred over to the surface of the scraper  435 , additionally or alternatively, the conjugate can be transported to a funnel for further collection. 
     Scrapers  435  can be composed of flexible plastic. Additionally or alternatively, the scraper  435  can be compressed into a “U” shape between two adjacent magnetic separators  420 . In one embodiment, the scraper  435  is a flexible piece of thin plastic (e.g., 0.016″-0.125″ thick). In some cases, the scraper material is composed of ultra-high molecular weight polyethylene. However, other thermoset and thermoplastic materials can also be used. 
     The magnetic particles are scraped from the separation magnets either continuously or intermittently. If scraping occurs intermittently, the scrapers  435  can be operated at predetermined time periods. For example, in some embodiments scraping occurs between 10-600 seconds. In some cases, the collected conjugates can have a concentration of between 10-400 g/L depending on scraping frequency, feed concentration, and length of the scraping time. 
     The conjugates from multiple separators  420  are collected at a common point  415  in the harvester  400 . The conjugates are then either be processed to remove the algae from the magnetic particles or reinjected back into the algal source (e.g., algal pond  110 ) to harvest more algae. 
     The collected conjugates are either moved on for processing and recovery of the algae from the particles or are reinjected into the system (e.g., reintroduced to the algal source). Reinjection increases mass loading onto the particles. If the particles are reinjected, the particles are introduced into a flow of fresh feedstock (e.g., fresh flow through the harvester). In some cases, this process can be continually be repeated for a predetermined number of cycles. Increasing particle cycling improves algal loading on the particles, but also successively reduces algae harvesting rates. In some embodiments, 3-5 cycles are optimal. Alternatively, in some embodiments as many as 15 cycles are used. 
     If the conjugates are moved on for processing, the algae may be separated from the magnetic particles (e.g., in conjugate separator  125  of FIG,  1 ) and transferred over to a HTL reactor, such as HTL reactor  130  as described with reference to  FIG. 1 . 
       FIG. 5  depicts a side perspective of an algal harvester  500 . The algal harvester  500  can be an example of algal harvester  115  or algal harvester  400  with reference to FIGS,  1  and  4 , respectively. FIG,  5  provides another view of the pump  505 , which can be an example of pump or pump  405 , with reference to  FIGS. 1 and 4 , respectively. 
       FIG. 6  depicts a flow profile  600  for algae through a harvester, according to embodiments of the claimed invention. In some examples, the flow profile  600  depicts a side profile of a magnetic separator, such as separator  420  as discussed with reference to  FIG. 4 . 
     The arrows shown in the flow profile  600  illustrate the direction of fluid flow throng harvester. Flow profile  600  includes a first section  605 , a second section  610 , and a third section  615 . The first section  605  is an introduction section for the harvester. The first section  605  expands the fluid streamlines so they are evenly introduced into the separator. 
     The second section  610  is a separation area where the separator is located. In the second section  610 , magnetic particle/algae conjugates are collected by the magnetic separator. The magnetic particle/algae conjugates can be examples of magnetic particle/algae conjugates discussed in more detail with reference to  FIGS. 1-5 . 
     The third section  615  includes an outflow area. The third section  615  regulates the material depth that the sections  605 - 615  experience. The flow exits the machine at port  430  as shown in  FIG. 4 . In some embodiments, the width of the flow profile can vary between 0.0625″-3″, depending on the composition and design of the separators, as well as the desired flow rate. In some cases, higher flow rates can require wider flow profile widths. 
       FIG. 7  depicts a magnetic disc  700  in accordance with embodiments of the claimed invention. Magnetic disc  700  can be an example of a separator  420  as described with reference to  FIG. 4 , and can be a component of a harvester, such as harvesters  130  and  400  as described with reference to  FIGS. 1 and 4 , respectively. 
     Magnetic disc  700  includes multiple magnetic tiles, such as magnetic tiles  705 . Each magnetic tile  705  is a dipole magnet, and each magnetic tile  705  includes a north pole and a south pole. The magnetic tiles  705  can be configured in various way so as to organize the multiple north/south poles into separate designs as discussed above with reference to  FIG. 4  (e.g., Halbach arrays, single north/south pole configuration, etc.). 
     The center of magnetic disc  700  includes a strain relief component  710 . The strain relief component  710  mitigates straining on the magnetic tiles  705 , which mitigates the possibility of material failure (e.g., breaking, cracking, etc.) The strain relief component  710  can be composed of plastic, but may alternatively be composed of other material suitable for relieving strain on the magnetic disc  700 . 
     The strain relief component  710  interfaces with a drive shaft, such as drive shaft  440  as discussed with reference to  FIG. 4 . In some cases, the drive shaft is a keyed stainless steel drive shaft. The magnetic disc  700  is rotated about its center via the drive shaft. The magnetic disc  700  is rotated past a scraper, such as scraper  435  as discussed with further reference to  FIG. 4 . 
       FIG. 8  depicts a magnetic disc  800  in accordance with embodiments of the claimed invention. Magnetic disc  800  can be an example of magnetic disc  700  as described with reference to  FIG. 7 . Magnetic disc  800  can be an example of a separator  420  as described with reference to  FIG. 4 , and can be a component of a harvester, such as harvesters  130  and  400  as described with reference to  FIGS. 1 and 4 , respectively. 
     Magnetic disc is in some cases be a different view of magnetic disc  700  of  FIG. 7 . The magnetic disc  800  includes magnetic tiles  805 , which can be examples of magnetic tiles  705  of  FIG. 7 , and also includes a strain relief component  810 , which can be an example of strain relief. 
       FIG. 9  depicts particle recovery results table  900  in accordance with embodiments of the claimed invention. 
     The results table  900  provide testing data from a harvester taken every minute for a 5 minute span. The data show separation rates at different channel widths and at different flow rates. Both algal monocultures and multi-species polycultures have been harvested using this technology. 
       FIG. 10  depicts algal particle recovery results graphs  1000  in accordance with embodiments of the claimed invention. 
       FIG. 11  depicts a process workflow  1100  for harvesting bio fuel in accordance with embodiments of the claimed invention. The process workflow can be implemented by a harvesting system, such as system  100  as described with reference to  FIG. 1 . 
     At Step  1105 , a set of magnetic particles are introduced into an algae pool containing at least one algae organism. In some cases, Step  1105  is performed by a harvester, such as harvesters  115  or  400 , which are described in detail with reference to  FIGS. 1 and 4 , respectively. 
     At Step  1110 , at least one magnetic particle is bound to the at least one algae organism to form at least one algae conjugate. In some cases, Step  1110  is performed by a harvester, such as harvesters  115  or  400 , which are described in detail with reference to  FIGS. 1 and 4 , respectively. 
     At Step  1115 , the at least one algae conjugate is attached to a surface of at least one magnetic disc of an algae harvester, when the at least one algae conjugate comes in contact with the at least one magnetic disc. Additionally or alternatively, Step  1115  is performed by a harvester, such as harvesters  115  or  400 , which are described in detail with reference to  FIGS. 1 and 4 , respectively. 
     At Step  1120 , the at least one algae conjugate is removed, via a scraper, from the surface of the at least one magnetic disc. In some cases, Step  1120  is performed by a harvester, such as harvesters  115  or  400 , which are described in detail with reference to  FIGS. 1 and 4 , respectively. 
     At Step  1125 , the at least one algae conjugate is transported from the algae harvester. In some cases, Step  1125  performed by a harvester, such as harvesters  115  or  400 , which are described in detail with reference to  FIGS. 1 and 4 , respectively. 
     Equivalents 
     Although preferred embodiments of the invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims. 
     INCORPORATION BY REFERENCE 
     The entire contents of all patents, published patent applications, and other references cited herein are hereby expressly incorporated herein in their entireties by reference.