BIOFILTER Russian patent published in 2000 - IPC

FIELD: sewage treatment systems. SUBSTANCE: biofilter has housing filled with filter medium and casing surrounding the housing with circular groove in its lower portion; this groove is communicated with risers provided with branches on which widening heads are fitted; thy are provided with curvilinear helical guides. Heads are directed towards each other at angle of 135 dwg in horizontal plane; inner and outer surfaces of circular groove and risers are provided with fins; partition mounted between top of housing and wall of casing at angle of 45 deg is provided with ports and diffusers with inner curvilinear helical guides. Hot waste gases entering the circular groove are distributed over entire perimeter of housing and passing through risers and branches get twisted encountering and forming cyclone and gas flows around housing both over perimeter and in height intensively transferring heat to filter medium. EFFECT: enhanced efficiency of usage of hot waste gases for preheating sewage to be treated. 3 dwg