Fluid bed expansion and fluidisation

A method of treating a liquid by passing said liquid through a fluidised bed of particulate material in which a biofilm as a reactant moiety is carried on 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;

• 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.

A method as claimed in Claimed 42, wherein the glassy coke has a particle size of 0.7 to 1.0 mm.

A method of treating a liquid by passing said liquid through a fluidised bed of particulate material in which a biofilm as a reactant moiety is carried on carrier particles constituting the fluidised bed within a bioreactor having a base, fluidising the bed by the upwards passage of said liquid therethrough, removing carrier particles having an excess of biofilm on their surface from an upper part of the fluidised bed, and recycling and injecting the same into the bed at said base of the bioreactor.

A method as claimed in claimed 81, wherein the glassy coke has a particle size of 0.7 to 1.0 mm.