Amount of diffuser discs at the base of an SBR basin?

How can I calculate the amount of ceramic diffuser discs needed for aeration at the base of the Sequencing Batch Reactor (SBR) basin? What is the oxygen transfer of a single diffuser disk? I want to make a grid of diffusers at the base. The parameters are: Flow rate: 4000 m3/day Tank depth: 6 m Oxygen required: 3920 kg/day Aeration time: 14 hours/day Oxygen transfer efficiency: 36% Average OTE: 15% Average oxygen transfer rate: 3.7 kg/hr