ACCURACY AND COST SAVINGS FROM AUTOMATIC OPTIMIZATION OF DEWATERING

Improvements in sensor and automation technology in recent years have made it possible to design a system to control the key variable parameters in and around the dewatering process. By continuously analyzing feed conditions and output from the process, an automated optimization system can make necessary proactive adjustments to the internal settings of the dewatering equipment, the polymer dosage and the feed. The result is continuous process optimization, 24 hours a day, 7 days a week, with drastically reduced operator involvement.In late 2005, Alfa Laval tested automatic optimization at the City of San Diego Metro Biosolids Center (MBC). The optimization system provided “real-time” measurement of suspended solids content of the incoming sludge, suspended solids content in the centrate, polymer dosing rate and differential speed and conveyor torque of the decanter. These parameters are used in combination with the operational cost structure, factoring in MBC's costs of polymer, disposal, and power. The system's algorithms automatically vary the polymer dose, the differential speed of the decanter and the feed rate of sludge to ensure the optimal operation and minimize the overall cost of operation.