NOVELTY - The valve for controlling flow of gas through a port, comprises a liquid source to provide a flowing liquid to the port, an injector (120) to generate a reactive jet for combustion of the flow of gas that passes through the port, and a wet scrubber to receive the flow of gas in upstream of the valve. The flowing liquid is subjected to forces such that a first combination of forces acting on the liquid causes the liquid to block the flow of gas through the port, and a second combination of forces acting on the liquid causes the liquid to allow the flow of gas through the port.    USE - The valve is useful in an apparatus for abating a gas stream comprising water-soluble species and other species, and for controlling a flow of a gas through a port and removing species from a gas stream (all claimed), where the abatement apparatus is useful in the fabrication of semiconductors, photovoltaic systems, flat panel displays, solar cells, communication devices, metals, ceramics and polymers.    ADVANTAGE - The valve exhibits high thermal conductivity thus efficiently removing heat from the walls of the reservoir, prevents the back-diffusion of reaction products from chamber toward gas inlet thus minimizing the clogging of inlet, and effectively reduces the deposition on and/or corrosion of upstream components.    DETAILED DESCRIPTION - The valve for controlling flow of gas through a port, comprises a liquid source to provide a flowing liquid to the port, an injector (120) to generate a reactive jet for combustion of the flow of gas that passes through the port, and a wet scrubber to receive the flow of gas in upstream of the valve. The flowing liquid is subjected to forces such that a first combination of forces acting on the liquid causes the liquid to block the flow of gas through the port, and a second combination of forces acting on the liquid causes the liquid to allow the flow of gas through the port. The forces include gravity, a momentum of the flowing liquid, a surface tension associated with the flowing liquid and a pressure exerted on the liquid by the gas. The injector includes a burner. INDEPENDENT CLAIMS are included for:    (1) an apparatus for abating a gas stream comprising water-soluble species and other species; and    (2) a method for removing species from a gas stream.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of operation of a reaction system.    Inlet (102)    Chamber (104)    Injector (120)    First reservoir (130)    Guide surface (150)    Second reservoir. (160)