Abstract: The high-speed centrifugation heretofore required for harvesting micro algae and cyanobacteria cultured for biofuels and other co-products is a major cost constraint. Mixing algae/cyanobacteria at high-density culture with far less alkali than previously assumed is sufficient to flocculate the cells. The amount of flocculant required is a function of the logarithm of cell density, and is not a linear function of cell density as had been thought. The least expensive alkali treatments are with slaked limestone or dolomite (calcium hydroxide and magnesium hydroxides). Further water can be removed from the floc by sedimentation, low speed centrifugation, dissolved air flotation or filtration, prior to further processing to separate oil from valuable co-products.

Abstract: An apparatus for propagating benthic marine invertebrates in water. The apparatus comprises (a) a culture cell, (b) a sedimentation chamber in fluid connection with the culture cell, and (c) a pump in fluid connection with the culture cell and with the sedimentation chamber capable of pumping water from the sedimentation chamber to the culture cell. Also disclosed is a method for propagating benthic marine invertebrates comprising culturing the invertebrates in a water environment in the apparatus.