Method of and apparatus for reducing iron fouling in groundwater treatment system

Disclosed herein is a treatment facility comprising a fluid bed reactor (13) including a reactor tank (15) containing a bed of particles which function as a carrier for growth of biological material, the reactor tank having an inlet and an outlet, the reactor further including structure for conducting liquid to be treated, from the reactor tank inlet, upwardly through the bed of particles at a rate conducive to fluidization of the bed of particles; an equalization surge tank (31) for housing liquid to be treated in the fluid bed reactor, the equalization surge tank having an inlet, and an outlet; conduit structure for supplying liquid from the outlet of the equalization surge tank to the inlet of the fluid bed reactor; and structure for supplying an oxidant into the equalization surge tank, in such a manner that stripping of volatile constituents is avoided, for oxidizing iron in the liquid in the equalization surge tank.