Methods of algae harvesting utilizing a filtering substance and uses therefor

Abstract

Methods of harvesting algae, and using algae as a biofuel, livestock feed, or food supplement are provided. The methods comprise contacting liquid algae suspensions with a filtration media. Depending upon the filtration media, the resulting algae and filtration media admixture is then utilized as a biofuel, livestock feed, food supplements, or for the extraction of algae oil. Admixtures comprising a combustible filtration media, such as coal, are particularly preferred. The methods are suitable for use with any algae species. Compositions for use as a biofuel, livestock feed, or food supplement are also provided. These compositions comprise an admixture of algae and a filtration media.

I claim: 
     
         1 . A composition for use as a biofuel comprising an admixture of algae and a filtration media. 
     
     
         2 . The composition of  claim 1 , wherein said filtration media is selected from the group consisting of carbonaceous solids, fibrous plant materials, torrified biomass, fibrous animal waste, fibrous industrial waste products, fibrous recyclable waste products, paper products, and combinations thereof. 
     
     
         3 . The composition of  claim 1 , wherein said filtration media is selected from the group consisting of coal, petroleum coke, charcoal, torrified biomass, wood, grasses, straw, leaves, hulls, shells, bagasse, chaff, corn stover, distillers dried grains, sawdust, ground refuse, manure, paper, paperboard, pulp, seed cleanings, hay, ground corn, wheat, wheat middlings, soybean hulls, oat hulls, milo, rye, oats, soybeans, alfalfa, canola meal, safflower, safflower meal, corn gluten feed, hemp, jute, cotton, plastics, rocks, sand, gravel, minerals, ceramic, dirt, clay, metal, metal mesh or screens, sintered metal, pebbles, fly ash, aluminosilicates, glass, porous glasses, lime, limestone, ash, activated alumina, silica, zeolites, grains, chaff, flour, tires, rubber, fabric, gauze, fiberglass, aggregate, batting, soot, carbon, shale, activated carbon, filter membranes, magnets, diatomaceous earth, Kieselguhr, and combinations thereof. 
     
     
         4 . The composition of  claim 1 , wherein said admixture comprises from about 0.5% by weight algae to about 90% by weight algae, based upon the dried algae weight as a % of the total weight of the dried algae and filtration media admixture taken as 100% by weight. 
     
     
         5 . The composition of  claim 1 , wherein said admixture is dried. 
     
     
         6 . The composition of  claim 5 , wherein said admixture has a moisture content of less than about 15% by weight, based upon the total weight of the admixture taken as 100% by weight. 
     
     
         7 . A method of processing algae for biofuel comprising:
 (a) providing an admixture comprising algae and a filtration media;   (b) heating said admixture to produce a vapor.   
     
     
         8 . The method of  claim 7 , wherein said vapor comprises algae oil. 
     
     
         9 . The method of  claim 8 , further comprising:
 (c) collecting said algae oil.   
     
     
         10 . The method of  claim 7 , wherein said providing (a) comprises:
 providing an algae suspension comprising algae dispersed in a liquid medium; and   contacting said algae suspension with a filtration media, wherein said algae is collected by said filtration media to yield said algae and filtration media admixture.   
     
     
         11 . The method of  claim 10 , said admixture further comprising other organic material from said algae suspension. 
     
     
         12 . The method of  claim 10 , wherein said contacting comprises passing said algae suspension through a filtration bed comprising said filtration media. 
     
     
         13 . The method of  claim 12 , wherein said filtration media comprises a granular, particulate, or fibrous filtering substance, said algae being collected on said filtration media and in the interstitial spaces or voids between said filtration media granules, particles, or fibers. 
     
     
         14 . The method of  claim 7 , wherein said filtration media is selected from the group consisting of grains, plant materials, biomass, fermentation byproducts, chaff, flour, and mixtures thereof. 
     
     
         15 . The method of  claim 14 , wherein said biomass is selected from the group consisting of wood, grasses, straw, leaves, torrefied biomass, hulls, shells, bagasse, chaff, corn stover, distillers dried grains, sawdust, ground refuse, manure, paper, paperboard, pulp, seed cleanings, hay, ground corn, wheat, wheat middlings, soybean hulls, oat hulls, milo, rye, oats, soybeans, alfalfa, canola meal, safflower, safflower meal, corn gluten feed, and mixtures thereof. 
     
     
         16 . The method of  claim 7 , wherein said heating (b) comprises heating said admixture under vacuum.