AU2009213072A1

AU2009213072A1 - An Algae Cultivation Device

Info

Publication number: AU2009213072A1
Application number: AU2009213072A
Authority: AU
Inventors: Michael Aldwell
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-09-18
Filing date: 2009-09-11
Publication date: 2010-04-01

Description

AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION STANDARD PATENT AN ALGAE CULTIVATION DEVICE The following statement is a ful description of this invention including the best method of performing it known to me: AN ALGAE CULTIVATION DEVICE TECHNICAL FIELD 5 The present invention generally relates to an algae cultivation device. BACKGROUND The reference to any prior art in this specification is not, and should not be 10 taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge. Algae are industrially farmed and can be used for the production of bioplastics, dyes and colorants, feedstock, pharmaceuticals, pollution control 15 and fuel. Traditionally, algae have been cultivated in open-ponds which are open to the elements and therefore can be vulnerable to contamination by other microorganisms. In these open-pond systems, control over environmental factors such as water temperature and lighting conditions is somewhat limited and can be suboptimal for promoting algae growth. 20 It is an object of the present invention to provide an alternative means for cultivating algae. SUMMARY OF THE INVENTION 25 According to one aspect of the present invention, there is provided an algae cultivation device for laying on a body of water, the device including one or more retainers for retaining one or more vessels cultivating algae. 30 Each retainer may include vessel collars for receiving the vessels. Each retainer may further include float collars for receiving floats. The float collars may be interleaved between the vessel collars. Each vessel may be tubular and include upper and lower parts, the lower part being thicker and more durable than the upper part.

2 Each retainer may be elongate and terminate in fastening means at their ends to facilitate fastening of algae cultivation devices together. Each fastening means may include one or more loops. 5 According to another aspect of the present invention, there is provided an algae cultivation device for laying on a body of water, the device including: a sheet; and one or more retainers for fastening to the sheet and for retaining one or 10 more vessels cultivating algae. The sheet may be a floatable backing sheet defining internal air pockets or air bubbles. The sheet may by multilayered, and include a first layer which is black or another like dark color to absorb light and a second layer which is 15 white or another like light color to reflect light and heat. Each retainer may include either a sleeve or another sheet fastened to the backing sheet at spaced apart locations. Each retainer may be white or another like light color to reflect light and heat. Each retainer may be 20 translucent to allow between 40% to 60% light penetration. The sheet and retainer may include plastics material and be ultrasonically welded together. Each retainer may retain one or more vessels. The algae cultivation device may further include the vessels. Each vessel may 25 include a tube and have a pair of inlets at one end and a single outlet at the other end. The tube may be frosted or translucent. In use, carbon dioxide can be supplied through a first one of the inlets and cultured water can be supplied though a second one of the inlets. Advantageously, the carbon dioxide can be supplied to the first inlet from an industrial process to thereby reduce carbon 30 dioxide emissions (which are linked to global warming) and aid in photosynthesis to promote algae growth. The algae cultivation device may further include a carbon dioxide manifold for supplying carbon dioxide from a carbon dioxide supply to the first inlet of each 3 vessel. The algae cultivation device may further include a cultured water manifold for supplying water carrying an algae culture to the second inlet of each vessel. The algae cultivation device may further include a holding tank for receiving fluid from the outlet of each vessel. 5 The algae cultivation device may further include a plurality of floats for fastening to the sheet. According to another aspect of the present invention, there is provided an 10 algae cultivation device including: a backing sheet for laying on a body of water; retainers for fastening to the backing sheet and for retaining algae transport vessels; and the algae transport vessels for being retained by the retainers, and for 15 transporting and cultivating algae. In one embodiment, the backing sheet is a floatable sheet and each retainer is defined by another sheet fastened to the backing sheet at spaced apart locations. Each vessel may be tubular so that the algae can be transported 20 without being exposed to airborne contaminants and frost. Advantageously, the sheet may be opaque and form a cover to impede evaporation from the body of water and sunlight penetration into the body of water. The weight of the occupied vessels may also impede wind from lifting the backing sheet from the body of water. 25 BRIEF DESCRIPTION OF THE DRAWINGS Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient 30 information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows: 4 Figure 1 is an upper perspective view of an algae cultivation device in accordance with an embodiment of the present invention; Figure 2 is a schematic view of an algae cultivation system including the algae 5 cultivation device of Figure 1; Figure 3 is an upper perspective view of a algae cultivation device in accordance with another embodiment of the present invention; 10 Figure 4a is a sectioned view of a tubular transport vessel in accordance with another embodiment of the present invention; Figure 4b is an upper perspective view of an algae cultivation device in accordance with another embodiment of the present invention, the device 15 bearing the transport vessel of Figure 4a; and Figure 4c is an upper perspective view of a holder of the algae cultivation device of Figure 4b. 20 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS According to an embodiment of the present invention, there is provided an industrial algae cultivation device 2 as shown in Figure 1. The cultivation device 2 includes a floatable backing sheet 4 for laying on a body of water 6. 25 A pair of retainers 8a,8b is fastened to the backing sheet 4 and retain respective algae transport vessels 10a, 10b. The retainers 8a,8b are formed by a single sheet of translucent UV treated plastics material which is intermittently fastened to the backing sheet 4 at spaced apart locations. The algae transport vessels 10 are retained within the retainers 8 and are tubular 30 to transport algae being cultivated therein. The backing sheet 4 is opaque and acts as a cover to impede evaporation from the body of water 6. In addition, the weight of the occupied vessels 10 impedes wind from lifting the backing sheet 4 from the body of water 6. A detailed description of the algae cultivation device 2 is provided below.

5 The backing sheet 4 is multilayered with each layer formed from plastics material, and defines internal air pockets or air bubbles to facilitate floatation on the water 6. The sheet 4 includes a lower layer which is black or another 5 like dark color to absorb light. The sheet 4 further includes an upper layer which is white or another like light color to reflect light and heat. In addition, each retainer 8 is white or another like light color to reflect light and heat. Each retainer 8 is formed from plastics material and is translucent to allow between 40% to 60%, and preferably 50% light penetration there-through to 10 the vessels 10. The plastic sheet 4 and retainers 8 are ultrasonically welded together in a manner so that the vessels 10 can be loosely inserted into the retainers 8. In this way, the retainers 8 are not stretched under tension in use which could otherwise contribute to rupturing of the retainers 8 (e.g. if contacted by a sharp object). 15 The cultivation device 2 further includes a plurality of floats 12 which are fastened to the backing sheet 4 in rows, with each retainer 8 being located between a pair of adjacent rows of floats 12. 20 Each vessel 10 includes a polyethylene tube having a pair of valve inlets at one end (not shown) and a single valve outlet at the other end (not shown). The tube is frosted or translucent to provide suitable lighting for promoting the growth of the transported algae. In use, carbon dioxide is supplied through a first one of the inlets and cultured water is supplied though a second one of 25 the inlets. The provision of carbon dioxide pressurizes the vessels 10, which facilitates migration of the cultured water toward the outlet with the algae culture growing as the water is slowly transported. The gaseous carbon dioxide in the vessels 10 assists with the buoyancy of the cultivation device 2 so that the algae remains close to the surface of the body of water 6 at a 30 desirable depth, and is subject to desirable light exposure and temperature. The controlled transportation of the algae within the vessels 10 also facilitates even and optimal light exposure to the contained algae.

6 A circulatory algae cultivation system 20 including the algae cultivation device 2 is shown in Figure 2 in which solution flows in an anti-clockwise direction. The closed-loop system 20 includes the algae cultivation device 2in which incident sunlight can be used to facilitate the growth of algae contained 5 therein. Cultured water 26 containing algae is distributed to the second inlets of the vessels 10 via a water manifold 24. Similarly, carbon dioxide 28 is distributed to the first inlets of the vessels 10 via a carbon dioxide manifold 30. The manifolds 24, 30 regulate fluid pressure to the vessels 10. The carbon dioxide can be supplied directly or indirectly to the first inlets from an industrial 10 process (e.g. power plant) to thereby reduce carbon dioxide emissions from the process (which are linked to global warming) and aid in photosynthesis to promote algae growth in the vessels 10. The algae cultivation system 20 further includes a holding tank 32 for 15 receiving fluid 34 carrying algae from the outlet of each vessel 10. A water storage dam can 36 be used to supply water to the holding tank 32 and nutrients 38 to promote further algae growth can also be added to the holding tank 32, if required. Oxygen 40 is produced as a by-product of the photosynthesis and can be forced from the holding tank 32 and into the 20 atmosphere by introducing carbon dioxide into the base of the holding tank 32. Cultured water 26 is pumped from the holding tank 32 to the water manifold 24 by pump 22 which also facilitates transport of the algae along the vessels 10. 25 The algae cultivation system 20 further includes a separation tank 42 for receiving an algae/water mixture 43 from the holding tank 32, when the algae in the holding tank 32 is ready for harvesting, and separating the algae 44 from the reconditioned water 46 which is fed back into the holding tank 32. The separated algae 44 can then be processed as required. 30 According to another embodiment of the present invention, there is provided another algae cultivation device 2 as shown in Figure 3. Like reference numerals refer to like features previously explained in relation to Figure 1. Each retainer 8 is sized so that it can concurrently retain a pair of vessels 10.

7 A plurality of eyelets 46 is located around the periphery of the backing sheet 4 to facilitate fastening of the cultivation device 2 to another cultivation device or an anchor at the edge of the body of water 6. The backing sheet 4 further defines weep holes 11 through which any excess (rain) water on the backing 5 sheet 4 can pass. A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention. 10 For example, the cultivation device 2 of the preferred embodiments included a pair of retention retainers 8a, 8b formed by a single sheet of plastics material which is intermittently welded to the backing sheet 4 at spaced apart locations. In alternative embodiments, the device 2 may include many more 15 retainers 8 in the form of respective sleeves or other like retainers for retaining vessels 10. . In one embodiment, the edges of each backing sheet 4 may include fastening means to facilitate fastening of a plurality of cultivation devices 2 together. In 20 this manner, a number of cultivation devices or modules can be readily fastened together to suit the particular expanse of the body of water 6. The present embodiment provides an improved means for economically growing and harvesting large scale algae biomass. 25 According to another embodiment of the present invention, there is provided a floatable algae cultivation device 48 as shown in Figure 4b. The cultivation device 48 includes floatable pipes 50a, 50b, 50c, and algae transport vessels 10a, 1Ob for laying on a body of water 6. Three vessel holders (or harnesses) 51a, 51b, 51c are positioned at spaced apart locations and retain the 30 respective algae transport vessels 10a, 1Ob and the floatable pipes 50a, 50b, 50c in even and regular positions. The algae transport vessels 10 can be retained within the holders 51 and can be tubular to transport algae being cultivated therein. The floatable pipes 50 can be retained within the holders 51. The pipes 50 are made from plastic material, and are tubular to hold air 8 and to aid with floatation of the device 48. The algae cultivation device 48 acts as a cover to impede evaporation from the body of water 6. In addition, the weight of the occupied vessels 10 impedes wind from lifting the algae cultivation device 48 from the body of water 6. 5 The skilled person will appreciate that the floatable pipes 50, the vessels 10 and the holders 51 can be configured in many different ways to form an algae cultivation device 48 having suitable dimensions. The algae cultivation device 48 may form a single module, and a plurality of these modules can be 10 cascaded together to form a modular algae cultivation device. In one embodiment, the algae cultivation device 48 can be placed on dry land instead of floated on the body of water 6. In this embodiment, the algae cultivation device would not require floatable pipes 50, and the holders 51 15 could be pegged to the ground with pegs or stirrups to hold the device 48 in place. Each vessel 10 includes a welded and formed PVC (or other like plastic material) tube having a pair of valve inlets at one end (not shown) and a single 20 valve outlet at the other end (not shown). Turning to Figure 4a, each algae transport vessel 10 can be made from two types of PVC materials, namely including a top part 52 of the tubular vessel 10 and a bottom part 53 of the tubular vessel 10. 25 The top part 52 is white in color, is UV and stain resistant, and is translucent to allow between 40% to 60% (and preferably 50%) light penetration there through to provide suitable lighting for promoting the growth of the transported algae. In contrast, the bottom part 53 is made of a heavier and possibly laminated PVC (or other like plastic material). The bottom part 53 is white on 30 the top surface facing the transported algae, and UV and stain resistant and opaque on its underside to block light penetration there-through and to stop the growth of algae underneath the cultivation device. The thicker and possibly laminated PVC nature of the bottom part 53 strengthens the underside of the tubular vessel 10 which is particularly advantageous when 9 the tubular vessel 10 is placed on a hard ground surface rather than on the body of water 6. The holders 51a, 51b, 51c can include collars 58, 60 made from PVC (or other 5 like plastic material) material. Turning to Figure 4c, each holder 51 includes a plurality of larger tubular collars 58 for each receiving a vessel 10, and a plurality of smaller tubular collars 60 interleaved between the larger collars 58 and for receiving the floatable pipes 50. Although the collars 58, 60 alternate in the present embodiment, in other embodiments holders 51 could include 10 two or more smaller collars 60 for every larger collar 58, or visa versa. In yet another embodiment, each holder 51 may include only larger collars 58 and no smaller collars 60 at all. As shown in Figure 4c, the free ends of each holder 51 terminate in fastening 15 loops or folds 54 and 55. Each fold 54, 54 is made and cut in such a way so as to allow separate holders 51 to be joined together. In particular, the single cut fold 54 can be placed between the double cut fold 55 allowing a pin or other fixing device to be affixed through the folds 54, 55 to thereby join and secure the holders 51 together. The holders 51 can be slid and placed at 20 intervals along the vessels 10 and pipes 50 to effectively secure the tubes 10 and pipes 50 together. In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be 25 understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

Claims

1. An algae cultivation device for laying on a body of water, the device including one or more retainers for retaining one or more vessels cultivating algae.

2. An algae cultivation device as claimed in claim 1, further including the vessels which are algae transport vessels for transporting and cultivating algae.

3. An algae cultivation device as claimed in claim 2, wherein each vessel is tubular and includes upper and lower parts, the upper part being translucent and the lower part being opaque.

4. An algae cultivation device as claimed in claim 3, wherein the upper part allows between 40% to 60% light penetration there-through

5. An algae cultivation device as claimed in claim 3, wherein the lower part is thicker and more durable than the upper part.

6. An algae cultivation device as claimed in any one of the preceding claims, wherein each retainer includes vessel collars for receiving respective vessels.

7. An algae cultivation device as claimed in claim 6, wherein each retainer further includes float collars for receiving respective floats, the float collars being interleaved between the vessel collars.

8. An algae cultivation device as claimed in any one of the preceding claims, wherein each retainer is elongate and terminates in fastening means at either end to facilitate fastening of algae cultivation devices together.

9. An algae cultivation device as claimed in claim 8, wherein each fastening means includes one or more loops. 11

10. An algae cultivation device as claimed in claim 1, further including a backing sheet for laying on a body of water and to which the retainers can be fastened.

11. An algae cultivation device as claimed in claim 10, wherein the backing sheet is a floatable sheet and each retainer is defined by another sheet fastened to the backing sheet at spaced apart locations.

12. An algae cultivation device as claimed in claim 10, wherein the backing sheet either defines internal air pockets or has floats attached thereto.

13. An algae cultivation device as claimed in any one of claims 10 to 12, wherein the backing sheet is opaque and forms a cover to impede evaporation from the body of water and sunlight penetration into the body of water.

14. An algae cultivation device as claimed in any one of claims 10 to 13, wherein the backing sheet is multilayered, and includes a first layer which is black or another like dark color to absorb light and a second layer which is white or another like light color to reflect light and heat.

15. An algae cultivation device as claimed in claim 10, wherein each retainer includes a sleeve.

16. An algae cultivation device as claimed in any one of claims 10 to 15, wherein each retainer is white or another like light color to reflect light and heat.

17. An algae cultivation device as claimed in claim 16, wherein each retainer is translucent to allow between 40% to 60% light penetration. 12

18. An algae cultivation device as claimed in any one of claims 10 to 17, wherein the backing sheet and the retainers include plastics material and can be ultrasonically welded together.

19. An algae cultivation device substantially as herein described with reference to Figure 4.

20. An algae cultivation device substantially as herein described with reference to Figure 1. Dated this 111h day of September 2008 MICHAEL ALDWELL by my attorneys Cullens Patent and Trade Mark Attorneys