Biochemical filter for the purification of exhaust air from refuse treatment and composting plants

摘要

The invention relates to a biochemical filter for the purification of the exhaust air from refuse treatment, refuse composting and animal carcase utilization plants. It is known that the exhaust air of these plants is associated with considerable odour pollution for the surroundings. It has already been proposed to use earth filters or biological filters in order to make the exhaust air volume removed by suction odour-free by means of bacterial cultures. However, the expense for this is comparatively high. Moreover, there is a difficulty in that such plants operate differently in individual months, since the refuse arising differs considerably in composition in the summer months from that in the winter months. In order to eliminate these difficulties, according to the invention it is proposed that a two-stage filter is used, the first filter stage of which comprises a strongly alkaline iron(II)/iron(III) hydroxide layer, preferably bog iron ore, and the following second layer comprises an acidic packing layer, such as peat impregnated with iron(II)/iron(III) sulphate. The exhausted filter compositions, such as bog iron ore and peat, can be added in neutralized form at about 1% to the composting compositions. IMAGE