Trickling filter media for biological filters

Abstract

A generally hollow packing element of relatively high surface area having a plurality of open end tubes situated radially within and connected to one another. At least two of the tubes have walls with or without openings therein extending around and inclined relative to each other and at an angle to a central axis of the body. A plurality of ribs are angularly spaced around the axis and include ribs extending between the walls, ribs projecting from and beyond an end of an outer tube and ribs extending from the central axis which divide the body into a plurality of sectors and chambers. Whether stacked or randomly dumped into a vessel the majority of the surface area of the body is inclined and neither parallel nor normal to the axis of the element or the vessel. Hence, liquid treated in a biological trickling filter vessel packed with the elements must undergo a horizontal displacement which tends to correct any initial maldistribution thereof, increase the length of the path of liquid flow and contact time between the liquid and biomass and reduce the velocity of the liquid allowing biomass to become more easily established. Also a continuous slower flow of liquid is maintained across the inclined surface which eliminates stagnation, loss of efficiency, and exerts a scouring action tending to wash away dead biomass to keep activity high and limits the growth of biomass which might tend to plug the openings in the elements.