Abstract: In accordance with at least one aspect of this disclosure, a system for dissolving gases into a liquid without side-stream pumping includes a pressure vessel defining a liquid inlet and a liquid outlet, a gas inlet device disposed within an internal chamber of the pressure vessel, a gas source in selective fluid communication with the gas inlet device and the internal chamber of the pressure vessel through a gas control valve and configured to provide a gas pressure, a liquid inlet pipe in selective fluid communication with the liquid inlet of the pressure vessel through a liquid inlet valve, and an outlet pipe in selective fluid communication with the liquid outlet through a liquid outlet valve for discharging the liquid from the internal chamber of the pressure vessel. The gas pressure both facilitates the dissolving of the gas in the liquid and forces the liquid out of the pressure vessel when the liquid is exposed to the gas pressure.

Abstract: Disclosed are systems and methods for dissolving gases into a fluid that is passing through a force-main and gravity sewer system. The system includes a dissolution tank having a pressure vessel for containing a liquid and for providing a regulated gas head space above the liquid, an inlet that permits passage of wastewater into the gas head space, and an outlet that permits passage of treated wastewater out of the pressure vessel. The system also includes a gas source in communication with the pressure vessel; a pump for supplying wastewater from a force-main or sewer system sump into the pressure vessel under conditions effective to dissolve oxygen gas in the wastewater; and a discharge device in communication with the outlet of the dissolution tank assembly for discharging treated wastewater.

Abstract: Disclosed is a system and method for treating wastewater. The system includes a bioreactor which defines a basin for receiving wastewater to be treated; a membrane module in fluid communication with the bioreactor; and a dissolution tank. The tank includes a pressure vessel that contains a portion of the wastewater to be treated and provides a regulated, pressurized gas head space above the wastewater. The tank also includes at least one liquid spray nozzle that permits passage of the wastewater into the gas head space of the pressure vessel and an outlet for discharging the wastewater having a desired gas concentration from the pressure vessel. The system also includes a pumping mechanism for supplying the wastewater to the spray nozzle of the tank such that fluid droplets are formed in the gas head space and the gas contained within the pressurized head space is dissolved into the wastewater.

Abstract: An apparatus and method for maximizing the dissolved concentration of ozone in a liquid. The apparatus includes a dissolution tank having a pressure vessel configured to contain a treated fluid and at least one gas in a head space above the treated fluid, an inlet configured to permit passage of an untreated fluid into the head space, and an outlet configured to permit passage of the treated fluid out of the vessel; a gas supply system configured to transport the at least one gas to the head space; a fluid supply system configured to provide the untreated fluid to the tank; a bleed-off system for removing gas from the head space so as to maximize the dissolved concentration of the ozone gas in the liquid; and a discharge device configured to pass the treated fluid from the tank into the target liquid.