Gas purification, especially for desulfurizing and deodorizing waste gases, comprises passing a gas sequentially through beds of biologically active filter material having acidic and neutral pH values

摘要

Gas purification, comprising passing a gas through a vessel (2) containing an upstream bed (6) of biologically active filter material having an acidic pH and a downstream bed (7) of biologically active filter material having a neutral pH, is new. An Independent claim is also included for apparatus for carrying out the novel process, in which the downstream bed is provided with a liquid supply (14) and the upstream bed is provided with a liquid circulation system comprising devices (20) for controlling the pH.