Dissolving gas in a liquid

摘要

A sparingly soluble gas, typically oxygen, is dissolved in a liquid, typically, waste water by an apparatus comprising a main vessel, a reservoir 10 above the main vessel 2, a lift pump 6 for transferring liquid from the main vessel 2 to the reservoir 10, a siphon 12 for transferring liquid from the reservoir 10 back to the main vessel 2, a pump 32 for extracting gas from liquid being siphoned, and a pipe 28 for introducing the gas into the liquid as it flows down leg 16 of the siphon 12. Preferably, the pipe 28, terminates in a constricted region 20 of the leg 16, the constricted region creating turbulent flow. The constricted region 20 is immediately above chambers 22 and 24 which in operation, reduce the velocity of the liquid and provide a prolonged residence time for bubbles of gas in the liquid.