Filter Press for Electrodewatering of Waterworks Sludge
Titel:
Filter Press for Electrodewatering of Waterworks Sludge
Auteur:
Lee, Jung Eun Lee, Jae Keun Choi, Hee Kyu
Verschenen in:
Drying technology
Paginering:
Jaargang 25 (2007) nr. 10 pagina's 1649-1657
Jaar:
2007-10
Inhoud:
An electrodewatering filter press was designed and its performance was evaluated for basic operating parameters such as the electric field strength, time of electric field application, and changes in pressure. Dewatering efficiency improves with the increase of the electric field strength, application time, and pressure. Considering the operating costs due to energy consumption and electrode erosion, the optimal conditions were found to be: 70 V/cm of electric field strength, 30 min of application time, and 588 kPa of pressure. The rate of electrodewatering doubled compared with that of mechanical dewatering (MDW) while the water content of the dewatered cake decreased by 25%. When an electric field is applied to the cake, clogging of the filter cloth becomes minimized due to electrophoretic mobility. The discharge of water from the cake porous matrix is facilitated owing to electroosmosis and the thermal effect due to joule heating. As a result, the dewatering capacity of electrodewatering improves compared with the mechanical dewatering. The energy consumption of electrodewatering was about 370-450 kWh/t (dry solid), which accounts for only one tenth of the existing sludge treatment costs.