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Electrokinetic processes (Electrofiltration, Electrophoresis, Electroosmosis)

Electrofiltration/electrophoresis

  • the principle

Electrofiltration is a method of solid-liquid separation that combines filtration and the application of electric field across the filtration cell. The particle charge of many important wastes (mineral suspensions, waste waters) is negative, so the particles are attracted to the electrode called anode during the electrofiltration.

The particles deposition at the other electrode side (called cathode) will be arrested. As a result, the filtrate flow is constant during the electrofiltration at correctly chosen conditions, and it’s higher than that in classical filtration. When the filter chamber is filled by the cake (growing from anode side to cathode side) the process passes to the stage of the filter cake consolidation (electrodewatering).

Electrodewatering/Electro osmosis

  • the principle

The electrodewatering corresponds to the application of electric fields to the filter cake during the consolidation. Generally, colloidal particles have negative surface charge (drilling sludge, activated sludge), so the ions of electrical double layer are cations. Hence, application of the electrical field during the filter cake consolidation results in the electroosmotic flux of liquid towards the cathode, and in better cake dewatering.

  • benefits
    • reduce the classical treatment time
    • increase the dryness sludge after a treatment
    • decrease the use of chemical products
  • fields of application
    • solid-liquid separation (filter press, belt filter…)