A system and method is disclosed to remove cross talk terms from speech signals in a multi-party conference system using an estimator to first estimate the respective cross talk terms for each of the said plurality of users. Suction ports are formed on the inner side of the suction pipe. In this way, all the poles of one polarity are surrounded by the active layer, all the poles of opposite polarity being surrounded by the electrolyte. The solid particulate is discharged from the rotor opening through an outlet such that the solid particulate is at the second pressure, and the rotor is rotated such that at least one end of the rotor opening is aligned in flow communication with a pressure source that is at approximately the first pressure, and such that the opening is at the first pressure.