Dual parallel lateral with internal air distribution pipe

A dual parallel underdrain lateral for use in a filtration system having a filtration media includes a primary conduit extending along the underdrain lateral, which has a plurality of metering orifices for providing gas and liquid thereby; a secondary conduit, where the secondary conduit has a plurality of dispersion apertures in an upper side thereof to deliver the gas and liquid from the secondary conduit to the filtration media; and at least one gas conduit extending along the underdrain lateral, where the at least one gas conduit is connected to a gas source and is configured to provide the gas from the gas source directly to the primary conduit, or the secondary conduit, or any combination thereof.