TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The gas is air, oxygen, ozone, hydrogen, nitrogen, nitrous oxide, or carbon dioxide. The liquid comprises water.    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Component: The region external the chamber has a lower pressure than internal the chamber, so that the saturation concentration for the dissolved gas in liquid exiting the chamber is exceeded and microbubbles (28) of gas are formed at or near the chamber orifices. The pressurized pumping mechanism is provided by a high pressure liquid pump, a line source in a residential or industrial setting, or fixed volume vessels capable of forcing liquid into the saturation tank upon pressurization of the fixed vessel with a high pressure gas that enters the vessel and displaces the liquid through an outlet in the vessel. The ratio of liquid volume to head space gas volume in the saturation tank is maintained with an open-loop or closed-loop control system. The number, size, and placement of orifices in said chamber are predefined to permit the rate of liquid flow rate out of the chamber to balance the rate of liquid flow into the saturation tank, thus maintaining a constant desired pressure internal the saturation tank under constant flow conditions. The chamber is provided internal a liquid entrainment mechanism so that the liquid containing dissolved gas exiting the chamber mixes with lower pressure ambient liquid. The gas saturation threshold for the liquid is thermally controlled. The spray nozzle is adjustable to optimize the liquid droplet size and control the rate of gas saturation in the liquid. The source of gas comprises mechanism for separating oxygen from ambient air. It includes an ozone generator provided internal the saturation tank. A control system is included for controlling operation of the apparatus. A feedback loop permits recovery and recycling of the gas to the saturation tank. The gas is dissolved to enhance microbe growth and respiration rate in waste water treatment, fermentation processes, food synthesis and manufacturing, or solid waste treatment; promote physical flotation of matter suspended in the liquid; quench anaerobic biological activity in the liquid; produce nanobubbles (10-100 nm diameter); foam a polymer; create a biorefuge for attracting or sustaining fish populations; sterilize a body of water; facilitate surface freezing while aerating/oxygenating during cold weather; to control odor, antibiotic residuals, and/or bacterial loads in sewage transport conduits; improve the quality of water entering, transducing, or exiting a dam; improving aerobic digestion efficiency and/or odor control in a wastewater treatment pond (lagoon); respond to a pollutant spill into an environmental water body; isolate and/or treat a plume of pollution; disinfect and reduce organic carbon in drinking water; control aerobic and anaerobic conditions in biological processes associated with pharmaceuticals and biotechnology; deliver hydrogen or other gases to create and control aerobic and anaerobic conditions in biological processes associated with in situ waste treatment in groundwater; deliver hydrogen or other gases to create and control aerobic and anaerobic conditions in biological processes associated with in situ waste treatment in surface waters; deliver a high concentration of dissolved oxygen to enhance biological oxidation of organic carbon and nitrogen removal within wastewater treatment facilities; oxidize sediment in situ for enhanced bioremediation of contaminants sorbed to and associated with river, lake, and estuarine sediments; enhance oxygen treatment of refractory pollutants such as antibiotic residuals, endocrine disruptors, pesticides, and similar chemicals; enhance ozone treatment of refractory pollutants, e.g. antibiotic residuals, endocrine disruptors, pesticides, and similar chemicals; inject supersaturated stream (6) of oxygen, ozone, hydrogen or other gases for direct treatment or enhancing treatment of groundwater to remove pollutants; increase the rate of biological oxygen demand removal because of improved treatment rate from smaller bubble size; and increase the thickness of the aerobic layer in sediment for increase storage capacity of phosphorus or other water pollutants.Preferred Property: The microbubbles have an average diameter less than 150 microns. The orifices have a diameter of 1-15 mm.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The gas is air, oxygen, ozone, hydrogen, nitrogen, nitrous oxide, or carbon dioxide. The liquid comprises water.