Landfill leachate has also been effectively treated by the
rotating biological contactor (RBC) process. The RBC is a
biological process consisting of a large disk with radial and
concentric passages slowly rotating in a concrete tank. During
the rotation, about 40 percent of the media surface area is in
the wastewater. The rotation and subsequent exposure to
oxygen allows organisms to multiply and form a thin layer
of biomass. This large, active population causes the biological
degradation of organic pollutants. Excess biomass shears off at