A NEW MODEL FOR THE ANALYSIS OF CONSTANT-CURRENT ELECTRO-OSMOTIC DEWATERING OF PRECONSOLIDATED SLUDGE

摘要

A constant-current electro-osmotic dewatering is analyzed by use of the combined Terzaghi-Voigt model for considering creep deformation of the material. The basic differential equation based on the model is solved analytically by assuming that both an electro-osmotic pressure gradient E_(pg) and a modified consolidation coefficient C_e of the material are constant. The progress of electro-osmotic dewatering can be represented by an average consolidation ratio U_c as in mechanical expression. Both C_e and E_(pg) increase with an electric current density i. A larger C_e leads to a higher dewatering rate; a larger E_(pg) results in a higher solid compressive pressure distribution in the material. It is found that the amount of creep deformation depends upon the dewatering rate; the faster the dewatering rate, the larger the creep deformation, i.e., the creep deformation is more remarkable when a higher current density is applied to the material.