Abstract:
A photobioreactor system may include a one or more fluidly connectable tubes for growing or producing microorganisms or biomass such as microalgae. The system may include either a single tube loop or an array of tubes. A first fluid may be held in the tube or tubes, and an inlet port may be provided for introducing a second fluid into the tube or tubes. The tube or tubes may be arranged vertically so that the second fluid rises through the tube or tubes. An outlet port may be provided at the top of the tube or tubes to remove the second fluid. The second fluid may be recirculated through the system via inlet and outlet lines as well as a pump and a replaceable reservoir for holding the second fluid. Where there is an array of tubes, a single inlet and outlet line may be sued for each tube.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application is a Continuation of application Ser. No. 14/081,488, filed Nov. 15, 2013 which claims the benefit of U.S. Provisional Application No. 61/771,002 filed Feb. 28, 2013 and U.S. Provisional Application No. 61/867,880 filed Aug. 20, 2013, the disclosures of which are each hereby incorporated herein by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to the field of photobioreactors for growing or producing microorganisms or biomass such as microalgae. 
       BACKGROUND 
       [0003]    As the atmospheric prevalence of carbon dioxide (CO 2 ) has increased over the previous decades, both governments and private entities have increasingly focused on new technologies for reducing and sequestering CO 2  and other anthropogenic emissions. This is especially true in the field of power or electricity generation where power plants operate through the combustion of fossil fuels, such as coal or natural gas, and emit significant amounts of CO 2  along with other greenhouse gases (GHG). Microorganisms such as microalgae and cyanobacteria (also known as blue-green algae) are well known to consume CO 2  as a part of their growth process. Thus, one area of CO 2  emission reduction research and technological advancement has been in the development of photobioreactors. A photobioreactor (PBR) may refer to a device or system that supports biological activity or growth and can rely on the use of a light source. Photobioreactors may be used to grow and cultivate microorganisms such as algae or cyanobacteria. Aiding in the microorganisms&#39; growth process, a photobioreactor may be utilized for removal of CO 2  and GHG emissions from a power plant or other GHG emitting structure by capturing the emitted CO 2  or GHG and introducing it into the photobioreactor. The introduced CO 2  or GHG may thus assist the growth of the microorganisms, and the microorganisms&#39; consumption of the flue gas thus operates to remove the GHG from the system, effectively filtering the gaseous emissions. Photobioreactors may also be similarly utilized in a variety of pollution control or treatment systems by relying on the microorganisms grown in the photobioreactor to capture or remove harmful particles, such as fertilizers from runoffs or effluent discharge in farms or chemicals in sewage. In addition to acting as a treatment system, photobioreactors offer the ability to effectively grow and harvest algae, which has many known beneficial uses. Various types of algae are known to be useful as a biofuel, fertilizer, or nutritional source, to name a few current uses for algae. 
         [0004]    Presently known photobioreactors tend to be extremely complicated systems consisting of elaborate tube structures with a flow control mechanism for circulating water within the tube structures. In one example of a known photobioreactor, Burbidge et al. reportedly disclose a photobioreactor comprising an upstanding core structure; a plurality of substantially transparent tubes supportable by the core structure; flow means; and withdrawal means, where the plurality of transparent tubes are helically wound in parallel (U.S. Pub. Application No. 2003/0228684). In U.S. Pub. Application No. 2011/0159581, Another example of a known photobioreactor is reported by Zhang et al. to disclose an airlift circulation micro-algae photoautotrophic-heterotrophic coupling photo bioreactor for wastewater treatments carbon emission mitigation. Furthermore, non-patent literature including “Closed Photobioreactor Assessments to Grow, Intensively, Light Dependent Microorganisms: A Twenty-Year Italian Outdoor Investigation,” published in 2008 by the Open Biotechnology Journal, generally discusses the state of photobioreactor technology. Each of these references is incorporated herein, by reference, in its entirety. 
         [0005]    These and other complex design features increase the cost to produce, install, and operate these known photobioreactors, while not necessarily improving their efficiency or production output. Additionally, due to the size and complication of the system, presently known photobioreactors are usually embodied in large, gaudy structures which have marginal utility beyond the structure&#39;s primary purpose as a photobioreactor. Moreover, large structures generally lack transportability. Accordingly, new photobioreactor systems and structures are desired to improve upon one or more of these deficiencies and expand photobioreactors&#39; uses. The invention is directed to these and other important ends. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later. 
         [0007]    In one embodiment of the disclosure, a photobioreactor system may include a first reactor tube having opposed upper and lower ends, an upper end tube having opposed first and second ends, with the first end of the upper end tube fluidly connectable to the upper end of the first reactor tube, a lower end tube having opposed first and second ends, with the first end of the lower end tube fluidly connectable to the lower end of the first reactor tube, and a second reactor tube having opposed upper and lower ends, with the upper end of the second reactor tube fluidly connectable to the second end of the upper end tube thereby fluidly connecting the upper end of the first reactor tube with the upper end of the second reactor tube through the upper end tube, with the lower end of the second reactor tube fluidly connectable to the lower end of the second reactor tube thereby fluidly connecting the lower end of the first reactor tube with the lower end of the second reactor tube, the fluidly connected first reactor tube, second reactor tube, lower end tube, and upper end tube defined as a photobioreactor loop in an installed position. The system may also include an inlet port provided proximate to the lower end tube for introducing a second fluid into the photobioreactor loop, an inlet line fluidly connectable with the inlet port and fluidly communicable with a second fluid source in order to fluidly connect the inlet port with the second fluid source, a pump fluidly communicable with the inlet line in order to move the second fluid from the second fluid source to the inlet port through the introduction line, and an outlet port provided proximate to the upper end tube for removing the second fluid from the photobioreactor loop. The upper end of the first reactor tube may be elevated above the lower end of the first reactor tube when the photobioreactor is in an installed position, and the upper end of the second reactor tube is elevated above the lower end of the second reactor tube when the photobioreactor is in the installed position. The system may also include an outlet line for fluidly connecting the outlet port with the second fluid source thereby establishing a closed system for circulating the second fluid between the second fluid source and the photobioreactor. The second fluid source may be a reservoir for holding the second fluid, and the reservoir may be interchangeable with a replacement reservoir. The first and second reactor tubes may each bend independently substantially elongate, and the upper and lower end tubes may be independently U-bends. The system may include a first fluid filling at least a portion of the photobioreactor loop, the first fluid having a greater density than the second fluid. The system may include at least one valve fluidly connected to the inlet port for regulating introduction of the second fluid into the photobioreactor loop. The system may include a split valve associated with the outlet port and an additive line fluidly connectable with the outlet port, with the spilt valve operable to control the fluid communication of the additive line and the exit line with the outlet port. The system may include a draining port provided proximate to the lower end for removing the first fluid from the photobioreactor loop, the draining port spaced at a distance from the inlet port. The system may include a plurality of baffles provided within the first reactor tube. The system may include a heat source provided within the photobioreactor loop in order to thermally urge fluid flow. The system may include a filter provided in fluid communication with the outlet port in order to prevent solid or semi-solid material from passing through the exit port. The first reactor tube may include a first side wall and a second side wall substantially enclosing the first side wall, the first and second side walls may also have different material properties for facilitating a photosynthetic process within the first reactor tube. 
         [0008]    In another embodiment of the disclosure, a photobioreactor system may include a plurality of first reactor tubes each having opposed upper and lower ends, a plurality of upper end tubes, each upper end tube having opposed ends, one end of each upper end tube independently fluidly connectable to the upper end of one of the first reactor tubes, a plurality of lower end tubes, each lower end tube independently having opposed ends, one end of each lower end tube independently fluidly connectable to the lower end of one of the first reactor tubes, and a plurality of second reactor tubes, each second reactor tube having opposed upper and lower ends, the upper end of each second reactor tube independently fluidly connectable with one end of one of the upper end tubes in order to establish fluid communication between each second reactor tube and an adjacent first reactor tube at the upper ends, the lower end of each second reactor tube independently fluidly connectable with one end of one of the lower end tubes in order to establish fluid communication between each second reactor tube and an adjacent first reactor tube at the first and second reactor tubes&#39; lower ends, creating a plurality of upper end tubes, lower end tubes, first reactor tubes, and second reactor tubes collectively defining a reactor tube array. The system may also include an inlet port provided proximate to the lower end of at least one first reactor tube for introducing a second fluid into at least a portion of the reactor tube array, an inlet line fluidly connectable with the inlet port and fluidly communicable with a second fluid source in order to fluidly connect the inlet port with the second fluid source, a pump fluidly communicable with the inlet line in order to move the second fluid from the second fluid source to the inlet port through the inlet line, and an outlet port provided proximate to the upper end of the at least one first reactor tube or the upper end of the adjacent second reactor tube for removing the second fluid from the at least a portion of the reactor tube array. Each upper end of the plurality of first reactor tubes may be independently elevated above its opposed lower end when the photobioreactor is in an installed position, and each upper end of the plurality of second reactor tubes may be independently elevated above its opposed lower end when the photobioreactor is in an installed position. The reactor tube array may be at least partially enclosed by a structure. The structure may be a wall of a building and the reactor tube array and be substantially concealed from a view taken from outside the building. The system may further include an outlet line for fluidly connecting the outlet port with the second fluid source thereby establishing a closed system for circulating the second fluid between the second fluid source and the reactor tube array. The second fluid source may be a reservoir for holding the second fluid, and the reservoir may be interchangeable with a replacement reservoir. 
         [0009]    An additional embodiment of a photobioreactor system may include a plurality of first reactor tubes, each first reactor tube substantially elongate with opposed upper and lower ends, a plurality of upper end tubes, each upper end tube substantially dimensioned in a U-bend and having opposed ends, one end of each upper end tube fluidly connectable to the upper end of one of the first reactor tubes, a plurality of lower end tubes, each lower end tube substantially dimensioned in a U-bend and having opposed ends, one end of each lower end tube fluidly connectable to the lower end of one of the first reactor tubes, and a plurality of second reactor tubes, each second reactor tube substantially elongate with opposed upper and lower ends, the upper end of each second reactor tube fluidly connectable with one end of one of the upper end tubes in order to establish fluid communication between each second reactor tube and an adjacent first reactor tube at the upper ends, the lower end of each second reactor tube fluidly connectable with one end of one of the lower end tubes in order to establish fluid communication between each second reactor tube an adjacent first reactor tube at the lower ends, the plurality of interconnected upper end tubes, lower end tubes, first reactor tubes, and second reactor tubes may be collectively defined as a reactor tube array. The system may further include a first fluid containable within at least a portion of the reactor tube array, a plurality of inlet ports, each inlet port provided proximate to one of the lower end tubes in order to introduce a second fluid into the reactor tube array, at least one inlet line fluidly connectable to one or more inlet ports and fluidly communicable with a second fluid source in order to fluidly connect the one or more inlet ports with the second fluid source, a plurality of outlet ports, each outlet port provided proximate to one of the upper end tubes in order to remove the second fluid from the reactor tube array, at least one exit line fluidly connectable to one or more exit ports and fluidly communicable with the second fluid source in order to fluidly connect the one or more exit ports with the second fluid source thereby establishing a closed system between the reactor tube array and the second fluid source, and at least one pump fluidly communicable at a point in the closed system in order to generate a flow path of the second fluid between the second fluid source and the reactor tube array through the at least one introduction line and the at least one exit line. Each upper end of the plurality of first reactor tubes may be elevated above the opposed lower end when the photobioreactor is in an installed position, and each upper end of the plurality of second reactor tubes is elevated above the opposed lower end when the photobioreactor is in an installed position. The first fluid may have a greater density than the second fluid. The reactor tube array may be substantially enclosed within a structure. A single outlet line may be connectable with every outlet port and the second fluid source, and a single introduction line may be connectable with every inlet port and the second fluid source. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]      FIG. 1  illustrates a side view of an embodiment of a photobioreactor system in accordance with the disclosure; 
           [0011]      FIG. 2  illustrates a side cross-section view of an embodiment of a photobioreactor tube in accordance with the disclosure in order to show possible components on the inside of the photobioreactor tube; 
           [0012]      FIG. 3  illustrates a side cross-section view of an embodiment of a photobioreactor tube in accordance with the disclosure in order to show possible components on the inside of the photobioreactor tube; 
           [0013]      FIG. 4  illustrates a side perspective view of an embodiment of multiple interconnected photobioreactor tubes as an array. 
           [0014]      FIG. 5  illustrates a side perspective view of an embodiment of multiple interconnected photobioreactor tubes as an array and embedded in an embodiment of a structure in accordance with the disclosure; 
           [0015]      FIG. 6  illustrates a top perspective view of an embodiment of a photobioreactor tube interlocking array in accordance with the disclosure; 
           [0016]      FIG. 7  illustrates a top perspective view of an embodiment of a photobioreactor tube array with supports to facilitate the embodiment of the array to be embedded in a structure in accordance with the disclosure; and 
           [0017]      FIG. 8  illustrates a side view of an embodiment of a photobioreactor system having a plurality of photobioreactor tubes in accordance with the disclosure; 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The following detailed description and the appended drawings describe and illustrate exemplary embodiments of the invention solely for the purpose of enabling one of ordinary skill in the relevant art to make and use the invention. As such, the detailed description and illustration of these embodiments are purely exemplary in nature and are in no way intended to limit the scope of the invention, or its protection, in any manner. It should also be understood that the drawings are not to scale and in certain instances details have been omitted, which are not necessary for an understanding of the present invention, such as details of fabrication and assembly. 
         [0019]    With reference to  FIGS. 1-3 , an embodiment of a photobioreactor system  100  is provided for growing organisms such as algae, cyanobacteria, artemia, rotifers, or other single or multi-celled microorganisms. Photobioreactor system  100  may include a single photobioreactor tube  110  having a rising or up portion  112  and a falling or down portion  114 . Embodiments of system  100  having one more tubes  110 , such as the embodiment illustrated in  FIG. 8  as well as embodiments including an array of interconnected tubes  110  as illustrated for example in the embodiments of  FIGS. 4-7 , are also described herein. Fluidly connecting rising portion  112  with falling portion  114  are first or upper end portion  116  and second or lower end portion  118 . In  FIG. 1 , end portions  116 ,  118  are U bends respectively connecting the top and bottom ends of rising portion  112  with falling portion  114  to an enclosed system. It should be appreciated that tube  110  may be constructed with alternative orientations or dimensions in addition to the illustrated embodiment of  FIG. 1  where rising and falling portions  112 ,  114  are substantially elongate tubes or tube sections and end portions  116 ,  118  are U bends. For instance, rising portion  112  and/or falling portion  114  may coil or bend at one or more angles, and rising portion  112  may or may not be similarly sized or dimensioned as falling portion  114 . Additionally, end portions  116 ,  118  may be sized and dimensioned to have an orientation other than the U bend illustrated in  FIG. 1  so long as first end portion  116  and second end portion  118  fluidly connect rising portion  112  and falling portion  114  thereby establishing a single photobioreactor tube  110  in order to function as described in accordance with an embodiment of the disclosure. Tube  110  may be manufactured with each portion  112 ,  114 ,  116 ,  118  as a single integral piece or, alternatively, portions  112 ,  114 ,  116 ,  118  may be separate pieces which may be connected together by known or to be developed means thereby assembling tube  110 . In another embodiment, portions  112  and  116  may be dimensioned and shaped into an “L” or “J” that can be inverted, rotated and connected to simulate portions  114  and  118 . An array of tubes  110 , such as the embodiments of tube arrays  110  described herein and illustrated in  FIGS. 4-7 , may be quickly and cost efficiently produced through manufacturing methods such as but not limited to injection molding or three-dimensional printing, for instance or piecemealed. Tube  110  includes tube walls from which fluid  300  may be contained within, as described herein and illustrated in the embodiments illustrated in  FIGS. 2 and 3 . In some embodiments, all or a portion of tube  110  features a double wall design having an inner diameter wall for containing fluid  300  and an outer diameter wall surrounding the inner wall. A double wall design may add increased structural strength to tube  110  as well as permit tube  110  to be constructed from two separate materials, thereby permitting a variety of designs for controlling photosynthetic reactions as well as temperature regulation of the environment and material within tube  110 . For instance, an outer wall of tube  110  may be constructed from a uniform material while an inner wall of tube  110  may be constructed from a first material at or proximate to first portion  112  and a second material at or proximate to second portion  114 , with first and second materials having different thermal, luminous, electrical and/ or photosynthetic properties. 
         [0020]    Connected to lower end portion  118  is at least one gas introduction port  120  which may introduce a gas  200  into rising portion  112 , as illustrated for instance in  FIGS. 2 and 3 . A valve  130  may be further provided so as to control the rate of gas  200  introduction. Valve  130  may operate through any known or to be developed mechanical or electrical means, including manual and automatic actuation as well as local and remote actuation, for instance as part of a controllable electrical system for operating photobioreactor system  100 . In one embodiment, valve  130  may be a one-way valve permitting introduction of gas  200  in accordance with the disclosure and preventing backflow of gas  200  that may occur as a result of gravity. Various positions of introduction port  120  on lower end portion  118  are contemplated within the disclosure so long as gas  200  is introduced into rising portion  112  and not falling portion  114 . Accordingly, in some embodiments introduction port  120  is positioned below or substantially below rising portion  112  so that gas  200  may naturally rise up and through rising portion  112  upon introduction into tube  110 . Some embodiments may include a gas directing element (not illustrated), such as a miniature tube or a lower baffle in end portion  118 , to facilitate alternative placements of gas introduction port  120  so that gas  200  may be introduced into rising portion  112  even though port  120  may not be provided at a position where gas  200  would naturally rise through rising portion  112  but for the utilization of a gas directing element. As one or more introduction ports  120  are contemplated within the disclosure, additional injection ports may be provided at intervals, for instance, along the rising portion  112  to facilitate consumption of different nutrients at different intervals. Alternatively, in an embodiment containing an array ( FIGS. 4-7 ), injection of different gases at different individual interconnected rising portions  112  of a given array. 
         [0021]    Provided within tube  110  is a fluid  300 , which in one embodiment comprises water. Other fluids  300  or mixtures of fluids suitable for the growth or cultivation of algae or other microorganisms are contemplated within the disclosure. Fluids  300  can be supplied from any source, including but not limited to waste streams or intermittently placed within a system to stepwise alter liquid composition for further processing. In some embodiments, gas  200  is comprised of carbon dioxide, or any GHG or gaseous emission, which may be harvested for instance from fossil fuel emissions such as those from a gas or coal power plant. Atmospheric air is another contemplated gas  200 . It is further contemplated that gas  200  may be a liquid having a lighter density than fluid  300  so that this lighter liquid  200  may rise through rising portion  112  in accordance with the disclosure. An introduced gas or liquid  200  may have its density further reduced by passing proximately by one or more heater elements, as described herein. It should be understood and appreciated by those of ordinary skill in the art that tube  110  should have at least a partial vertical orientation so that gas  200  rises through rising portion  112  of tube  110 . In one embodiment, tube  110  may have a vertical or substantially vertical orientation. Frames or structures for maintaining tube  110 &#39;s orientation are further described herein. 
         [0022]    As shown in the illustrated embodiments of  FIGS. 2 and 3 , tube  110  may be only partially filled with fluid  300  so as to leave a head space or gap  122  in upper portion  116 . In the illustrated embodiment, a sufficient quantity of fluid  300  is provided in tube  110  so that there is a space or gap between fluid  300  in rising portion  112  and fluid in falling portion  114 . As a result of introduction and rising of gas  200 , bubbles may be regularly introduced at the surface of fluid  300  on the side of upper portion  116  near rising portion  112 . Additionally, as described in greater detail herein with regard to the growth and formation of microorganisms, a flow of fluid  300  occurs through rising portion  112 . As a result of bubbles from gas  200  and fluid  300 &#39;s flow, quantities of fluid  300  may be introduced into the head space or gap  122  and enter into falling portion  114  of tube  110 . Certain embodiments of the disclosure contemplate tube  110  entirely or nearly entirely filled with fluid  300 . Some embodiments contemplate partially filing tube  110  with fluid  300  thereby creating a head space or gap  122 , thereby reducing, mitigating, and/or substantially eliminating backflow, swirling or other similar fluid phenomena which may destruct fluid  300  flow as described herein. Fluid  300  flow may also be regulated or adjustable by other known or to be developed devices for regulating fluid flow placed in or proximate to tube  110 . 
         [0023]    In order to temporarily contain gas  200 , or optionally to separate gas and liquid from line  142 , a reservoir or tank  140  may be included in system  100 . An introduction line or hose  142  may be provided between tank  140  and introduction port  120 , and valve  130  may regulate the flow of gas  200  introduction. Gas  200  may be removed from gap  122  in upper end portion  116  through one or more exit ports  124 . Exit port  124  may be connected to tank  140  through an exit line or hose  144 . In embodiments where tube  110  is filled or nearly filled with fluid  300 , thereby eliminating gap  122 , one or more exit ports  124  may be provided to remove fluid  300  from tube  110  in order to facilitate circulation of fluid  300  within system  100 . A screen  128  may also be provided in or proximate to exit port  124  in order to block biomaterial, introduced nutrients, or other particles from exiting tube  110 . Similarly, screen  128  may be placed at any port  120 ,  124 ,  126  in order to prevent or substantially block material from leaving tube  110  or system  100 . One or more ports  120 ,  124  may be controlled by a split or dual line valve  132  in order to facilitate multiple lines or hoses communicating with the controlled port  120 ,  124 . Dual source valve  132  may be a “Y” valve or a multi-port valve. In the illustrated embodiment, exit port  124  positioned over falling portion  114  includes a dual valve  132 , with an exit line  144  as well as an additive line  146  connected to, and in fluid communication with, exit port  124 . Dual valve  132  may, thus, operate to switch the function of port  124 . In one operation mode, dual valve  132  may operate to permit gas  200  to escape from exit port  124  through exit line  144 . In a second operation mode, dual valve  132  may operate to place additive line  146  in fluid communication with tube  110  in order to permit introduction of nutrients or other additives into tube  110  as may be desired. Alternately a dual valve  132  can be positioned at introduction port  120  an additional introduction line (not illustrated) may be utilized for supplemental gas or low density fluid addition into tube  110 , which may include a variety of gases for any number of uses including environmental control or optimization of growth. Any additive may be introduced proximately over falling portion  114  so that they may enter circulation, in accordance with the fluid flow and gas  200  introduction described herein, throughout the entirety of the microorganisms growing in tube  110 , particularly at the lower end of rising portion  112 . Providing a dual valve  132  and additive line  146  to be in communication with exit port  124  proximately over rising portion  112  is also contemplated within the disclosure. Some or all of the valves  130 ,  132  described herein may be pressure or release valves having in order facilitate pressurization and safety in system  100  by purging to but not limited to the environment, reservoir  140 , or another reservoir (not illustrated). 
         [0024]    Valves  130 ,  132  may be individual or a manifold, remote, or part of each respective port  120 ,  124 ,  126  valve  130 ,  132  is connected to or associated with, and may be manufactured with or separately from their respective port  120 ,  124 ,  126  and from tube  110 . A filter  128  may be further provided in or proximate to one or more ports  120 ,  124 ,  126  as well as in or proximate to one or more valves  130 ,  132 . Filter  128  may effectively eliminate or reduce unintentional removal of biomass or nutrients from tube  110  or unintentional introduction of material mixed with gas  200  which should not be introduced into tube  110   
         [0025]    By connecting lines  142 ,  144  to reservoir  140 , a closed system may be established for moving gas  200  between reservoir  140  and tube  110 . A pump  150  may be provided in fluid communication with the closed system in order to move gas  200  throughout the system. In one embodiment, pump  150  may include a variable speed motor in order to vary the volume of gas  200  flowing through photobioreactor system  100 . By controlling the speed or force of which gas  200  is introduced, optimal algal growth conditions may be maintained, for instance by assuring fluid  300  flow is sufficiently strong to circulate nutrients while maintaining the flow as laminar which may be preferable to a turbulent flow. System  100  may be able to introduce captured gaseous emissions, including for example, CO 2 , by collecting the emissions in reservoir  140  and introducing reservoir  140  into system  100 . Gaseous plant emissions can also be directly connected to port  120  overriding or as opposed to the collection of gas  200  in  140 , and pump  150  may be utilized to circulate plant emissions or, in another embodiment, to take plant emissions introduced in addition to or in place of gas  200  and to begin a recirculation process leading plant emissions to reservoir  140 . When the available nutrients has been effectively converted by the microorganisms, reservoir  140  may be replaced or switched with another reservoir containing collected emission gases. In another embodiment of system  100 , reservoir  140  is replaced by open atmospheric air thereby creating an open system  100 . Pump  150  may then be utilized to introduce air as gas  200  into system  100 . Introduction line  142  or other lines connected to port  120  may deliver emissions from or proximate to an emission source, such as the coal stacks of a power plant. A line or tube may be placed at or proximate to the bottom of reservoir  140 , such as where introduction line  142  is provided in the illustrated embodiment. Thus, fluid  300  which may have been pumped from tube  110  through exit line  144  may be reintroduced into tube  110  through introduction line  142 . Alternatively, a separate drain line (not illustrated) may be connected to reservoir  140  so as to drain introduced fluid  300  from reservoir  140 . Alternatively in the case that an array is long enough to allow for enough residence and processing time the exit line may pass through a filter/screen  128  into another PBR array containing another type of microorganism for a stepwise processing of fluid/gas. Multiple pumps  150  and multiple tanks  140  per system  100  are also contemplated within the disclosure. 
         [0026]    A heating element or thermal regulatory device  160  may be further provided in tube  110  in order to encourage fluid flow as well as to potentially affect the environment within tube  110  so as to facilitate growth conditions for the microorganisms inside tube  110 . For instance, thermal source  160  may be placed at the lower end of rising portion  112  so as to increase flow of fluid  300  upwards through rising portion  112  through the introduction of heat and decrease in density of fluid  300  around element  160  facilitating vertical motion. Thermal source  160  may also be used to control both by increasing or decreasing the temperature of fluid  300  and/or tube  110  so as to promote or encourage optimal growth conditions. 
         [0027]    Tube  110  may further include additional internal structure for encouraging or promoting the mixing of fluid  300  during its fluid flow, thereby circulating or mixing introduced nutrients. In one embodiment, one or more baffles  170  may be included in at least a portion of tube  110 , for instance in rising portion  112  as provided in the illustrated embodiment. Ridges along tube  110  walls may also be provided, which may for instance be sized and dimensioned to be circular, helical or spiral within tube  110 . 
         [0028]    In order to encourage and facilitate microorganism growth, a light source  172  may be provided so as to direct or emit light towards system  100  and, more particularly, tube  110 . Light is a necessary component of the photosynthetic process. In some embodiments, natural sunlight may be utilized to grow the microorganisms. Light source  172 , however, may be incorporated to emit light at a specific spectrum or a specific light wavelength in order to facilitate microorganism growth which may be more responsive to wavelengths other than those naturally provided in sunlight. Additionally, light source  172  permits microorganism growth at night. So that the microorganisms may receive light, tube  110  may be constructed from material having photosynthetic properties. In some embodiments, this may be a clear or translucent material, such as plastic or glass, but in some embodiments a non-translucent photosynthetic material, such as photosynthetic metals like aluminum, may be utilized. Combination of translucent and opaque materials is also considered to regulate the light/dark cycles, or the specific wavelengths of light that penetrate the tubes. Light source  172  may be any known or to be developed light emitting device including, for instance, lasers, light emitting diodes, bulbs, or a fiber optic network with an on/ off cycle that is indeterminate and variable. 
         [0029]    As described herein, system  100  thus operates as a recirculating microorganism cultivation apparatus for growing a biomass, such as microalgae, which in some embodiments may grow as algal bloom  600  along the walls of tube  110 , as illustrated for instance in  FIG. 2 . In order to determine when microorganism growth has peaked and/or is ready for harvesting, a sensor  180  may be provided as part of system  100 . Any number of sensor(s)  180  may be utilized for monitoring the quantity or quality of one or more substances within system  100  such as biomass concentration, chlorophyll concentration, dissolved nutrients and dissolved gases  200 . Sensors(s)  180  may thus assist an operator of system  100  to determine when algae should be harvested or reservoir  140  should be removed or changed. There are a variety of positions which one or more sensors  180  may be utilized. Sensor(s)  180  may be provided in or proximate to reservoir  140  as well as in, on or proximate to tube  110 . Sensor(s)  180  may also, for instance, be provided for within or in proximity to any of the one or more valves  130 ,  132  or ports  120 ,  124 ,  126  included in an embodiment of system  100 . In one embodiment, sensor(s)  180 , valves  130 ,  132 , and/or ports  120 ,  124 ,  126  may be connectable to an electrical control system, which may include a processor (not illustrated) and a display (not illustrated) for controlling at least one valve  130 ,  132  or port  120 ,  124 ,  126  in addition to pump  150  and light source  170 . A control system may also include memory, data logging and transmission means (not illustrated) for recording sensor(s)  180  readings as well as control history of the system  100 . Control system may automatically control system  100  in response to sensor(s)  180  readings and may operate to activate or deactivate pump  150 , valve  130 ,  132  or port  120 ,  124 ,  126  as is appropriate based on sensor(s)  180  readings. Control system may also be manually controlled through a user and the processor may alert the user of changes in sensor(s) readings so that the user may act accordingly in operation of system  100 . 
         [0030]    When it is time to harvest the microorganisms, fluid  300  may be removed through a draining port  126  and a draining tube or line  148  provided on or proximate to lower end region  118 . Removal of fluid  300  may be through gravitational force or, in one embodiment, pump  150  may be utilized to pressurize tube  110  in order to force water out of tube  110 , for instance by reversing the operating direction of pump  150  and forcing gas  200  through exit port  124  positioned at the upper end  116  of tube  110 . A screen or filter  128  may be provided in or proximate to either port  124  or an associated valve  130  in order to trap microorganisms which may unintentionally flow into port  124  with draining fluid  300 . Once fluid  300  is drained, a second or draining fluid may be introduced into tube  100  for forcibly removing the microorganisms. This draining fluid, which may be water in certain embodiments, may be introduced for instance through feeding line  146  and may be sufficiently pressurized to force microorganisms, such as algal bloom  600 , from the walls of tube  110 . The draining fluid and removed microorganisms may then flow into draining port  126  and through drain line  148  thereby collecting the grown microorganisms. Cultivation can be on a batch basis or on a continuous basis depending on the application of system  100 . Also any number of subsequent microorganism processing steps to retrieve the produced materials is considered to be within the ambit of this disclosure. 
         [0031]    With reference now to  FIGS. 4-8 , system  100  may comprise a plurality of tubes  110  arranged in an array. As illustrated in  FIGS. 4 and 5 , tube  110  array may feature a series of tubes  110  aligned or substantially aligned into a row or rows. This alignment may accordingly permit tube  110  array to be provided within a structure  500 , such as the wall of a building. The remainder of system  100 , such as reservoir  140  and pump  150 , may also be provided within structure  500  or, alternatively, may be provided at remote location from structure  500  connected to tube  110  array through lines  142 ,  144 , as individually routed lines, or a single designed conduit. As shown in  FIG. 6 , tubes  110  may also be placed in a cross-hatch or intersecting arrangement, where some tubes  110  are angled out of phase with respect to other tubes  110  creating an interlocking pattern where the spaces between one set of portions  112  and  114  coincide with the continuities of another set of portions  112  and  114 . 
         [0032]      FIG. 7  illustrates one arrangement of lines  142 / 144  connected to ports  120 / 124  for an array of tubes  110 . Here, lines  142 / 144  may connect to ports  120 / 124  for multiple tubes  110 . Lines  142 / 144  may then be in communication with a single pump  150  thereby creating a closed system for the entire array. Valves  130  may then be utilized to maintain a constant pressure in each tube  110  of the array thereby accommodating for pressure drops between each tube  110 . This arrangement lowers manufacturing costs by reducing material required in addition to facilitating the arrangement of tube  110  array so that it may compactly fit within structure  500 . 
         [0033]    Certain embodiments of system  100  including an array of tubes  110 , such as those illustrated in  FIGS. 4-7 , may include tubes  110  a plurality of rising portions  112  connected to an adjacent falling portion  114 , as well as one or more falling portions  114  connected to an adjacent rising portion  112 . In these embodiments, a single fluidly connected tube  110  contains a plurality of rising portions  112  and falling portions  114  interconnected by end portions  116 ,  118 . An upper end portion  116  may fluidly connect a first rising portion  112  with a first portion, and a lower end portion may fluidly connect first rising portion  112  with a second lower end portion  114 . This is in contrast to other embodiments, such as the embodiment illustrated in  FIG. 8 , where an array of tubes  110  may include tubes  110  having only one rising portion  112  and one falling portion  114  mutually connected by end portions  116 ,  118 . It should be understood and appreciated that system  100  may comprise an array of both types of tubes  110 , that is a first tube type having multiple rising and falling portions  112 ,  114  interconnected, such as the embodiments illustrated in  FIGS. 4-7 , and a second tube type having one rising and one falling portion  112 ,  114 , such as the embodiment illustrated in  FIG. 8 . 
         [0034]      FIG. 8  shows one embodiment of system  100  where a single reservoir  140  and pump  150  may be utilized for an array of tubes  110 . Lines  142 / 144  may commonly lead from respective tubes  110  into a common reservoir  140  which is associated with a pump  150 . In this way, gas  200  may be cycled through multiple tubes  110  thereby increasing the efficiency of system  100  and reduction of CO 2  emissions contained in gas  200 . It should be understood and appreciate that a single reservoir  140  and pump  150  may be utilized in tube  110  arrays having multiple rising and falling portions, such as those embodiments illustrated in  FIGS. 4-7 . 
         [0035]    In one embodiment of system  100 , an array of tubes  110  may be assembled inside an enclosed mobile vehicle, such as a trailer or any transportable container. The system  100  may then be easily transported to any nutrient or emission source, with connections to ports  120 ,  124 ,  126  made at exterior walls of the mobile vehicle for integration to an existing structure providing the required gas and liquid. In some embodiments, all ports  120 ,  124 ,  126  and pumps  150  and additional components of system  100  can be included in the enclosed transport container providing immediate, remote and/or self-sufficient implementation. 
         [0036]    The components described herein may be manufactured or produced through any known or to be developed methods of manufacturing including, but not limited to, forging, injection molding, CNC, laser cutting, or three dimensional printing etc. 
         [0037]    The descriptions set forth above are meant to be illustrative and not limiting. Various modifications of the invention, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the concepts described herein. The disclosures of each patent, patent application and publication cited or described in this document are hereby incorporated herein by reference, in their entireties. 
         [0038]    The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein. The invention illustratively disclosed herein suitably may also be practiced in the absence of any element which is not specifically disclosed herein and that does not materially affect the basic and novel characteristics of the claimed invention.