Abstract: Embodiments of a water treatment unit are disclosed. An embodiment of a water treatment unit according to the present disclosure comprises a generally vertical riser having a lower end and an upper end, at least one inlet adjacent the lower end, and at least one outlet adjacent the upper end, a substantially spherical housing surrounding the riser, the housing comprising at least one opening in a lower portion of the housing, the housing enclosing a chamber, a motor coupled to the housing, a shaft coupled to the motor, the shaft extending downward from the motor within the riser, the shaft being in general axial alignment with the riser, at least one propeller coupled to the shaft, and a biomedia material within the chamber.

Abstract: A water treatment unit includes a mixing chamber surrounding the upper end of a riser containing an impeller. Water can be moved from a body of water up through the riser, and out through laterally directed openings into the chamber adjacent to an air inlet. The water moving out the laterally directed openings of the stand pipe, mixes with air drawn in through the air inlet to oxygenate the water, and the oxygenated water exits the chamber into the body of water through one or more water outlets in the lower portion of the chamber due to the head developed by the inflow of water into the chamber. The outward flow of water from the chamber can cause a toroidal or other desired flow of water within the body of water surrounding the water treatment apparatus.

Abstract: A recirculated marine aquaculture system and process for growing crustaceans or other fish within a body of water. Water from the body of water is treated by stripping carbon dioxide and biological byproducts and by oxygenating the water. A water treatment unit may be provided to treat the water and provide movement to the body water. The water treatment unit can be configured to provide cavitation to the water, which aids in the removal of carbon dioxide and biological byproducts. Water may also be cycled through a deflocculation tank to reduce the floc of bacteria within the body of water to acceptable levels for optimal growth of crustaceans or other fish within a body of water. Using the system and the deflocculation tank has the advantage of significantly reducing the water exchange rates and even the water effluent, while maintaining acceptable water quality for growing crustaceans or other fish.