This standard specifies a method for the determination of the capillary suction time of sludge and sludge suspensions. The capillary suction time (CST) is a fast and simple way to evaluate the sludge dewaterability by filtration. This method gives no information on the obtainable solids content in a dewatering process. The measurement of CST should also make possible the evaluation, although only qualitatively, of other sludge characteristics, including dewaterability by centrifugation.#,,#