摘要 |
<p>This anaerobic digestion method is a method to biologically treat precipitated sludge obtained by a precipitating operation to sewage or wastewater, sludge containing livestock waste sludge, or organic wastewater containing suspended solids of 5000 mg/L or more as a treatment object, by a fixed bed (20) using organism-attaching carriers (22) formed of spherical porous bodies. In addition, a part of the treatment object which has been supplied to the fixed bed (20) is extracted from an upper layer of the fixed bed (20). The extracted treatment object is supplied to a fixed layer (28) composed of the organism-attaching carriers (22), the fixed layer (28) constituting a lower layer of the fixed bed (20). The treatment object is circulated in the fixed bed (20) so as to uniformly disperse the treatment object therein without making the organism-attaching carriers (22) flow and without blocking the fixed layer (28), by using the organism-attaching carriers (22) formed of spherical porous bodies whose average spherical diameter is greater than or equal to 4.0 mm.</p> |