Improved Centrifuge Sludge Dewatering by Automatic Backdrive Torque Control

An investigation of different automatic torque control systems for performance optimization of solid bowl centrifuges was conducted at the Stickney Water Reclamation Plant of the Metropolitan Water Reclamation District of Greater Chicago (District). Two automatic hydraulic backdrives and a direct current automatic torque controlled backdrive were tested on centrifuges used for dewatering digested sludge conditioned with a polymer and a combination of polymer and ferric chloride. The centrifuge unit of an advanced design coupled with the direct current automatic torque controlled backdrive produced a cake having a solids content of 30% and a solids capture of 97%. The regular production unit produced a cake having a solids content of 15% and a solids capture of 85%.