Solid bowl screw centrifuge with mixing blades or paddles arranged on the screw shaft

A method, comprising:

• providing a solid bowl screw centrifuge, which comprises
• a housing;
• a rotor rotatably mounted in the housing;
• a rotatable drum having a rotational axis, wherein the rotatable drum has a cylindrical section having a length L1 and a conical section having the length L2;
• at least one first feed configured to supply a suspension to be processed into the rotatable drum;
• at least one liquid drain arranged in the cylindrical section of the rotatable drum;
• at least one solid discharge arranged in the conical section of the rotatable drum;
• a screw having windings and a screw shaft, wherein the screw is rotatable relative to the rotatable drum at a differential speed and is arranged in the rotatable drum, wherein the rotatable drum and the screw jointly form the rotor;
• a second feed configured to supply an additive to a solid phase inside the rotatable drum, wherein the second feed is arranged coaxially to the rotational axis, and wherein the second feed protrudes into an interior of the screw shaft opposite to the at least one first feed;
• a line radially extending from the second feed in a direction of a casing of the rotatable drum, wherein the line is configured to deflect the additive, and wherein the line has an orifice opening located in a region between the screw shaft and the casing of the rotatable drum;
• and
• mixing blades or mixing paddles, in addition to the windings of the screw, are arranged along a wall of the screw shaft;
• supplying a liquid, gaseous, or solid additive via the second feed to the conical section of the rotatable drum;
• mixing the solid phase in the conical section of the rotatable drum with the liquid, gaseous, or solid additive;
• and
• using the conical section of the rotatable drum, at least in regions, as a mixing zone, in which mixing of the solid phase with the supplied additive occurs.