A membrane filter (1, 17, 42) for submerged operation for filtering a liquid, the membrane filter comprising: membrane units (2, 18, 57) and a gas distribution system (3, 19, 43) for distributing a gas to the membrane units and flushing the membrane units, wherein each of the membrane units (2, 18, 57) includes a respective gas inlet opening (16, 32, 59) and at least one membrane element (4, 20, 55), and wherein each of the membrane elements (4, 20, 55) has the following features: - membranes for filtering a liquid permeate from the liquid, - a permeate collection cavity connected to permeate sides of the membranes, and a permeate outlet configured to drain the permeate from the permeate collection cavity, and wherein the gas distribution system (3, 19, 43) includes exactly one gas outlet (14, 29, 48) for each membrane unit (2, 18, 57), the exactly one gas outlet (14, 29, 48) configured to exhaust the gas from the gas distribution system (3, 19, 43) into the respective gas inlet opening (16, 32, 59) of the membrane unit (2, 18, 57), characterized in that the gas distribution system (3, 19, 43) includes the following features: - a downward open tub (12, 27, 41) including a base (13, 31, 60) arranged at a top of the tub and forming a boundary for the gas, and - a gas inlet (11, 26) configured let the gas into the tub (12, 27, 41), wherein the gas outlets (14, 29, 48) are configured downward open in a lateral wall (15, 30) of the tub (12, 27, 41), and the membrane units (2, 18, 57) respectively include a downward open gas collection cavity below the at least one membrane element (4, 20, 55), and the membrane units (2, 18, 57) respectively include a geyser element (21, 58) below the at least one membrane element (4, 20, 55), the geyser element (21, 58) including an outlet device configured for a pulsating outlet of the gas in an upward direction from the gas collection cavity, wherein the geyser element (21, 58) includes the gas inlet opening (16, 32, 59) at a bottom of the geyser element (21, 58). membrane units (2, 18, 57) and a gas distribution system (3, 19, 43) for distributing a gas to the membrane units and flushing the membrane units, wherein each of the membrane units (2, 18, 57) includes a respective gas inlet opening (16, 32, 59) and at least one membrane element (4, 20, 55), and wherein each of the membrane elements (4, 20, 55) has the following features: - membranes for filtering a liquid permeate from the liquid, - a permeate collection cavity connected to permeate sides of the membranes, and - membranes for filtering a liquid permeate from the liquid, - a permeate collection cavity connected to permeate sides of the membranes, and a permeate outlet configured to drain the permeate from the permeate collection cavity, and wherein the gas distribution system (3, 19, 43) includes exactly one gas outlet (14, 29, 48) for each membrane unit (2, 18, 57), the exactly one gas outlet (14, 29, 48) configured to exhaust the gas from the gas distribution system (3, 19, 43) into the respective gas inlet opening (16, 32, 59) of the membrane unit (2, 18, 57), characterized in that the gas distribution system (3, 19, 43) includes the following features: - a downward open tub (12, 27, 41) including a base (13, 31, 60) arranged at a top of the tub and forming a boundary for the gas, and - a gas inlet (11, 26) configured let the gas into the tub (12, 27, 41), - a downward open tub (12, 27, 41) including a base (13, 31, 60) arranged at a top of the tub and forming a boundary for the gas, and - a gas inlet (11, 26) configured let the gas into the tub (12, 27, 41), wherein the gas outlets (14, 29, 48) are configured downward open in a lateral wall (15, 30) of the tub (12, 27, 41), and the membrane units (2, 18, 57) respectively include a downward open gas collection cavity below the at least one membrane element (4, 20, 55), and the membrane units (2, 18, 57) respectively include a geyser element (21, 58) below the at least one membrane element (4, 20, 55), the geyser element (21, 58) including an outlet device configured for a pulsating outlet of the gas in an upward direction from the gas collection cavity, wherein the geyser element (21, 58) includes the gas inlet opening (16, 32, 59) at a bottom of the geyser element (21, 58).