Abstract: Disclosed herein is a system for circulating fluid in an algae cultivation pond. The system includes an algae cultivation pond having an aspect ratio of length to width between 0.7:1 to 2:1, and the pond is at least 5 acres in overall size. An island has a first side and a second side and is positioned in the pond to create a first channel adjacent the first side of the island and a second channel adjacent the second side of the island. An energy input means is located in the first channel and moves fluid around the island through the first channel and through the second channel. The second channel is at least three times wider than the first channel, and a length of the island is at least six times larger than a width of the island.

Abstract: Disclosed herein is a pond for cultivating a non-vascular photosynthetic organism in a liquid medium, comprising a sump comprising an inflow slope with an angle of about 20 to about 70 degrees, and optionally an outflow slope of with an angle of about 5 to about 40 degrees. The novel sump design results in good overall carbonation efficiency and does not result in a large loss of biomass of a cultivated organism.

Abstract: A clarification system may comprise a channel having an inlet and an outlet, a length, bottom, and a height sufficient to contain a liquid having a depth. The clarification system may include one or more gas injectors disposed within the channel, configured to inject gas bubbles into a suspension flowing in the channel. In some embodiments, at least one gas injector injects gas bubbles having average or median size that does not exceed 100 microns in diameter. Some gas injectors inject bubbles having mean size below 50 microns. Some gas injectors inject gas via the precipitation of gas bubbles from a supersaturated liquid including a dissolved gas. Certain embodiments may be configured to form a quiet zone, typically near the top of the flowing suspension, in which turbulence may be minimized or substantially eliminated. Certain systems include a plurality of gas injectors disposed at different lengths along the channel.

Abstract: Systems and methods for reducing an amount of unwanted living organisms within an algae cultivation fluid are provided herein. According to some embodiments, methods may include subjecting the algae cultivation fluid to an amount of cavitation, the amount of cavitation being defined by a pressure differential between a downstream pressure and a vapor pressure, the pressure differential divided by half of a product of a fluid density multiplied by a square of a velocity of an apparatus throat.

Abstract: Systems, methods and media for generating fluid flow in an algae cultivation pond are disclosed. Circulation of fluid in the algae cultivation pond is initiated via at least one jet. The circulation of fluid generates a velocity of fluid flow of at least ten centimeters per second in the algae cultivation pond. A head is provided to the at least one jet that overcomes a head loss associated with the velocity of fluid flow of at least ten centimeters per second in the algae cultivation pond.

Abstract: Provided herein are exemplary algae cultivation ponds having the circulation of fluid optimized for such factors as decreased energy consumption, decreased predators/competitors, decreased or eliminated flow dead zones (i.e., stagnant regions), and increased algae biomass production, such as for the production of biofuels and other algae-based products.

Abstract: Systems, methods and media for carbonation of fluid in an algae cultivation pond via the use of backward-facing steps are disclosed. In a first aspect, a method for initiating carbonation of a fluid flow in an algae cultivation pond is disclosed. Fluid flow is initiated over a backward-facing step in the algae cultivation pond. A backflow region is generated in the fluid flow downstream of the backward-facing step. Carbon dioxide is provided to the backflow region.

Abstract: Provided herein are exemplary algae cultivation ponds having the circulation of fluid optimized for such factors as decreased energy consumption, decreased predators/competitors, decreased or eliminated flow deadzones (i.e. stagnant regions), and increased algae biomass production, such as for the production of biofuels and other algae-based products.

Abstract: Systems and methods for reducing an amount of unwanted living organisms within an algae cultivation fluid are provided herein. According to some embodiments, methods may include subjecting the algae cultivation fluid to an amount of cavitation, the amount of cavitation being defined by a pressure differential between a downstream pressure and a vapor pressure, the pressure differential divided by half of a product of a fluid density multiplied by a square of a velocity of an apparatus throat.

Abstract: Systems, methods and media for carbonation of fluid in an algae cultivation pond via the use of backward-facing steps are disclosed. In a first aspect, a method for initiating carbonation of a fluid flow in an algae cultivation pond is disclosed. Fluid flow is initiated over a backward-facing step in the algae cultivation pond. A backflow region is generated in the fluid flow downstream of the backward-facing step. Carbon dioxide is provided to the backflow region.

Abstract: A nozzle for generating fluid flow in an algae cultivation pond is disclosed. The nozzle includes a surface forming a smooth flow path from an inlet to an outlet. The surface corresponds to a monotonically decreasing function from the inlet to the outlet. A ratio of an inlet cross-sectional area to an outlet cross-sectional area is greater than sixteen.

Abstract: Systems, methods and media for carbonation of fluid in an algae cultivation pond via the use of jets are disclosed. Carbon dioxide is provided to a pressurized fluid. A jet of carbonated fluid is generated from the pressurized fluid and the carbon dioxide. Circulation of the fluid in the algae cultivation pond is initiated via the jet of carbonated fluid.

Abstract: A clarification system may comprise a channel having an inlet and an outlet, a length, bottom, and a height sufficient to contain a liquid having a depth. The clarification system may include one or more gas injectors disposed within the channel, configured to inject gas bubbles into a suspension flowing in the channel. In some embodiments, at least one gas injector injects gas bubbles having average or median size that does not exceed 100 microns in diameter. Some gas injectors inject bubbles having mean size below 50 microns. Some gas injectors inject gas via the precipitation of gas bubbles from a supersaturated liquid including a dissolved gas. Certain embodiments may be configured to form a quiet zone, typically near the top of the flowing suspension, in which turbulence may be minimized or substantially eliminated. Certain systems include a plurality of gas injectors disposed at different lengths along the channel.

Abstract: Systems, methods and media for generating fluid flow in an algae cultivation pond are disclosed. Circulation of fluid in the algae cultivation pond is initiated via at least one jet. The circulation of fluid generates a velocity of fluid flow of at least ten centimeters per second in the algae cultivation pond. A head is provided to the at least one jet that overcomes a head loss associated with the velocity of fluid flow of at least ten centimeters per second in the algae cultivation pond.