Liquid-solid circulating fluidized bed waste water treatment system for simultaneous carbon, nitrogen and phosphorus removal

A twin liquid-solid fluidized bed system, comprising:

• solid particles having effective immobilized bacteria coated thereon,
• a first fluidized bed having a first and second end, said first fluidized bed being a riser fluidized bed including an inlet at said second end for introducing a first fluidizing fluid into said first fluidized bed;
• a second fluidized bed being a downer fluidized bed having a first end and a second end;
• first connecting conduit connecting said second end of said first fluidized bed to said first end of said second fluidized bed, said first connecting means including means to feed said solid particles into said second fluidized bed;
• second connecting conduit connecting said second end of said second fluidized bed to said first end of said first fluidized bed;
• and
• means to feed said solid particles having effective immobilized bacteria coated thereon into said second fluidized bed through said first connecting conduit and to feed said solid particles into said first fluidized bed through said second connecting conduit, wherein said solid particles and said second fluidizing fluid flow in counter flow relationship in said second fluidized bed and wherein said solid particles and said first fluidizing fluid flow co-currently in said first fluidizing column.