| 摘要 |
<p>A square filler is used as a contact medium for aerobic or anaerobic contact treatment of sewage. The square filler is made of synthetic resin net sheet or net tube of which a plurality of net layers are formed, and melt-bonding is applied to at least one spot (13) on each layer for fixing all layers together. An apparatus for manufacturing square fillers flattens the net sheet or net tube for forming net layers with the application of pressure, intermittently feeds the flattened net sheet or net tube in the longitudinal axial direction and heats the net sheet or net tube for softening during transfer. The heated net sheet or net tube is locally pressed with projections for melt-bonding so that net layers are locally melt-bonded to each other, and square fillers having net layers fixed by solidification thereof are obtained by cutting. <IMAGE></p> |
