Apparatus for venting excess gas bubbles from a bubble contactor

A liquid treatment apparatus for removing potentially combustible contaminants from a liquid, said liquid treatment apparatus comprising

• a fluid bed reactor including means for removing, under aerobic conditions, potentially combustible contaminants from a liquid,
• a conduit connected to said reactor for delivering the liquid to the reactor,
• means for dissolving oxygen in the liquid, said means for dissolving oxygen including a bubble contactor disposed in said conduit, said bubble contactor defining a chamber having a lower chamber section and an intermediate chamber section diverging downwardly to said lower chamber section, said intermediate chamber section including a bubble contact zone having a lower level, and
• means for preventing undissolved gas from exiting the bubble contactor, said means for preventing undissolved gas from exiting the bubble contactor including a float-operated valve positioned above said lower chamber section, said float-operated valve including an upper portion communicating with said intermediate chamber section, said upper portion of said float-operated valve communicating with said intermediate chamber section at a level below the lower level of said bubble contact zone, a lower portion communicating with said lower chamber section, and means including the float of said float-operated valve for sensing undissolved gas in said lower chamber section, said float being operable to open said float-operated valve when undissolved gas is present in said lower chamber section.