Biological filter structures

摘要

A cartridge for holding compost in a biofilter is substantially uniform in cross section perpendicular to the axis of the cartridge and has a sidewall formed with openings that are small enough to substantially retain the compost in the cartridge yet large enough to allow filaments of bacteria present in the compost to project through the openings. The cartridge is of cross-sectional form such that multiple cartridges can be placed side-by-side in an array with passages between each cartridge and adjacent cartridges.