(a) A submerged biological contactor (SBC) must be air driven and does not require a cover. An SBC is any biological contactor where more than 60% of the surface is below the water level at design flow.(b) An SBC system requires the same pretreatment as a rotating biological contactor system and must meet the criteria in §217.185 of this title (relating to Rotating Biological Contactors), except as described in paragraphs (1) and (2) of this subsection.(1) Each SBC unit must include two air headers - one to provide rotation of the unit, and one to provide dissolved oxygen for biological activity.(2) Submerged bearings must be sealed to prevent intrusion of wastewater.(c) If an SBC has any moving parts that require lubrication, an SBC must have lubrication access above the water level.