Patent ID: 7708886

Claim:
A method of treating a liquid by passing said liquid through a fluidised bed of glassy coke carrier particles in which a biomass is immobilized as a biofilm grown on the surface of the carrier particles constituting the fluidised bed, whereby said bed is fluidised by the passage of said liquid therethrough, and wherein the liquid is caused or allowed to pass through a particulate distributor layer prior to passage through the fluidised bed, the carrier particles and the distributor layer being contained together in a single enclosure and there being no barrier between the carrier particles and the distributor layer; wherein the density of the particles of the distributor layer, and the flow rate of the liquid are selected such that the distributor layer is agitated by the liquid but not fluidised, and turbulence in the liquid is reduced or eliminated before acting on the fluidised bed, and wherein the density of the particles of the distributor layer is greater than that of the carrier particles.