Abstract: In a gravity-type separator for floating and sinking matter operating without a free level, both the separated floating matter and the separator content must be withdrawn or removed. According to the invention, this is accomplished with a pump that on the suction side has connecting ducts to the vertical center of the separator housing and the sinking matter outlet, and on the pressure side has connecting ducts to the waste water inlet duct and the clean water outlet duct. The pressurized water duct for the floating matter removal is taken from the inlet duct.

Abstract: Water, especially waste water, from which organic compounds such as, in particular, halogenated hydrocarbons are to be separated by extraction using a lipophilic extraction agent is passed through an open-cell carrier of large internal contact surface area in which the extraction agent is deposited on the contact surface and/or floods the carrier over at least part of its height to form a continuous liquid layer.

Abstract: Filter apparatus embodying a filter bed back-washing unit comprising a raisable and lowerable suction bell, the side walls of which define division walls to compart the respective partial volume of the filter bed to be cleaned. The side walls of the suction bell are of a height at least equal to the height of the filter bed, and the suction bell is raisable and lowerable by a stroke length which corresponds at least approximately to this height.