Revolving algal biofilm photobioreactor systems and methods

Abstract

An algal growth system can include a vertical reactor that can include a flexible sheet material, where the flexible sheet material can be configured to facilitate the growth and attachment of algae. The vertical reactor can include a shaft, where the shaft can be associated with and can supports the flexible sheet material and a drive motor, where the drive motor can be coupled with the shaft such that the flexible sheet material can be selectively actuated. The algal growth system can include a raceway pond, where the vertical reactor can be positioned at least partially within the raceway pond, where the raceway pond can include a fluid reservoir, where the flexible sheet material can be configured to pass through the fluid reservoir during operation of the algal growth system, a contacting liquid, where the contacting liquid can be retained within the fluid reservoir and can includes nutrients that facilitate the growth of the algae, and a liquid phase and a gaseous phase, where the liquid phase can include rotating the flexible sheet material through the contacting liquid retained in the fluid reservoir and the gaseous phase can include rotating the flexible sheet material through gaseous carbon dioxide.

We claim: 
     
         1 . An algal growth system comprising:
 (a) a vertical reactor comprising;
 (i) a flexible sheet material, the flexible sheet material being configured to facilitate the growth and attachment of algae; 
 (ii) a shaft, wherein the shaft is associated with and supports the flexible sheet material; and 
 (iii) a drive motor, the drive motor being coupled with the shaft such that the flexible sheet material is selectively actuated; 
   (b) a raceway pond, the vertical reactor being positioned at least partially within the raceway pond, the raceway pond comprising;
 (i) a fluid reservoir, wherein the flexible sheet material is configured to pass through the fluid reservoir during operation of the algal growth system; and 
 (ii) a contacting liquid, wherein the contacting liquid is retained within the fluid reservoir and includes nutrients that facilitate the growth of the algae; and 
   (c) a liquid phase and a gaseous phase, wherein the liquid phase comprises rotating the flexible sheet material through the contacting liquid retained in the fluid reservoir and the gaseous phase comprises rotating the flexible sheet material through gaseous carbon dioxide.   
     
     
         2 . The algal growth system of  claim 1 , further comprising a harvesting mechanism. 
     
     
         3 . The algal growth system of  claim 1 , wherein the harvesting mechanism is a squeegee. 
     
     
         4 . The algal growth system of  claim 1 , wherein the flexible sheet material is selected from the group consisting of cheesecloth, fiberglass, porous PTFE coated fiberglass, chamois, vermiculite, microfiber, synthetic chamois, burlap, cotton duct, velvet, vinyl laminated nylon, polyester, wool, acrylic, lanolin, woolen, cashmere, leather, silk, lyocell, hemp fabric, polyurethane, olefin fiber, polylactide, and carbon fiber. 
     
     
         5 . The algal growth system of  claim 1 , wherein the algae is selected from the group consisting of  Nannochloropsis, Scenedesmus, Haematococcus, Botryococcus, Spirulina, Dunaliella, Arthrospira, Porphyridium, Phaeodactylum, Nitzschia, Crypthecodinium  and  Schizochytrium.    
     
     
         6 . The algal growth system of  claim 1 , further comprising an enclosed greenhouse. 
     
     
         7 . The algal growth system of  claim 6 , wherein the enclosed greenhouse has a higher carbon dioxide concentration than the atmosphere. 
     
     
         8 . The algal growth system of  claim 1 , wherein the drive motor is configured to rotate the flexible sheet material on a predetermined schedule. 
     
     
         9 . The algal growth system of  claim 1 , wherein the flexible sheet material is a biofilm. 
     
     
         10 . The algal growth system of  claim 1 , wherein the flexible sheet material is configured to grow and retain the algae until the algae is physically removed. 
     
     
         11 . The algal growth system of  claim 1 , wherein the algal growth system is configured for industrial use. 
     
     
         12 . A method of growing algae comprising the steps of:
 providing an algal growth system comprising;
 (a) a vertical reactor comprising;
 (i) a flexible sheet material, the flexible sheet material being configured to facilitate the growth and attachment of algae; 
 (ii) a shaft, wherein the shaft is associated with and supports the flexible sheet material; and 
 (iii) a drive motor, the drive motor being coupled with the shaft such that the flexible sheet material is selectively actuated; and 
 
 (b) a raceway pond, the vertical reactor being positioned at least partially within the raceway pond, the raceway pond comprising;
 (i) a fluid reservoir, wherein the flexible sheet material is configured to pass through the fluid reservoir during operation of the algal growth system; and 
 (ii) a contacting liquid, wherein the contacting liquid is retained within the fluid reservoir and includes nutrients that facilitate the growth of the algae; 
 
   rotating the flexible sheet material of the algal growth system through a liquid phase such that the flexible sheet material passes through the contacting liquid retained in the fluid reservoir;   rotating the flexible sheet material of the algal growth system through a gaseous phase such that the flexible sheet material passes through gaseous carbon dioxide; and   harvesting the algae from the flexible sheet material.   
     
     
         13 . The method of growing algae of  claim 12 , wherein the algal growth system further comprises an enclosed greenhouse. 
     
     
         14 . The method of growing algae of  claim 12 , wherein the algae is selected from the group consisting of  Nannochloropsis, Scenedesmus, Haematococcus, Botryococcus, Spirulina, Dunaliella, Arthrospira, Porphyridium, Phaeodactylum, Nitzschia, Crypthecodinium  and  Schizochytrium.    
     
     
         15 . The method of growing algae of  claim 12 , wherein the flexible sheet material is selected from the group consisting of cheesecloth, fiberglass, porous PTFE coated fiberglass, chamois, vermiculite, microfiber, synthetic chamois, burlap, cotton duct, velvet, vinyl laminated nylon, polyester, wool, acrylic, lanolin, woolen, cashmere, leather, silk, lyocell, hemp fabric, polyurethane, olefin fiber, polylactide, and carbon fiber. 
     
     
         16 . The method of growing algae of  claim 12 , wherein the algal growth system is configured for industrial use. 
     
     
         17 . The method of growing algae of  claim 12 , further comprising the step of rotating the algal growth system according to a predetermined schedule.