Earth filter for noxious waste gas - has layer of expanded calcium aluminium silicate around perforated gas pipe, covered with soil

摘要

Earth filter for the absorption of smelly and dangerous waste gases consists of a layer of expanded Ca/Al/SiO2 (I) around and over a perforated gas pipe, covered with a layer of soil, pref. also contg. under 30% (I) compsn. (expanded perlite). (I) and the soil are sepd. by a layer (of perforated film or highly porous mat). The gas passes through a wet or dry filter before the earth filter. The earth filter is connected to a tank contg. liquid, which is circulated by pumping and pref. contains fertiliser for plants (lupins, etc.) grown in the soil. The filter is more effective than usual and the soil can be used later for the aforestation of tips.