Manhole shaft for primary treatment of sewage from chemical industry, has spacer and filter mat arranged on inner side of shaft, and filter mat including sorption substance for metal sorption so that filter mat acts as sorption filter mat

摘要

The shaft (1) has a spacer (2) and a filter mat arranged on an inner side (11) of the shaft. Sewage initially flows through the mat, the spacer and out from the shaft. The mat includes a sorption substance e.g. absorbing substance, for sorption of metal e.g. copper, so that the mat acts as a sorption filter mat (5). A mat layer is arranged between the spacer and the sorption filter mat. A main filter mat (4) is provided adjacent to the sorption filter mat. A fine filter mat (3) is provided adjacent to the main filter mat and includes a pore width smaller than the main filter mat.