Membrane treatment apparatus

A membrane treatment apparatus, comprising:

• a plurality of flat membrane elements which are immersed in a liquid to be treated, each flat membrane element having a first horizontal direction, a second horizontal direction and a height direction, the first horizontal direction being a thickness direction of the flat membrane element, each flat membrane element having respective membrane surfaces on opposite sides in the first horizontal direction, each membrane surface extending in the second horizontal direction and the height direction, wherein the plurality of flat membrane elements are disposed adjacent to each other in the first horizontal direction so that opposing membrane surfaces of adjacent flat membrane elements face each other in the first horizontal direction;
• a supporting member for holding at least one of the flat membrane elements provided at an end part of the at least one of the flat membrane elements on a first side in the second horizontal direction;
• and
• an aeration means provided below the plurality of flat membrane elements,
• wherein each flat membrane element extends from the first side in the second horizontal direction to a second side in the second horizontal direction, and a lower edge of each flat membrane element is formed
• to extend upward from the first side to the second side along the second horizontal direction, or
• to consist of a first portion which extends horizontally in the second horizontal direction from the first side toward the second side, and a second portion which extends upward from the first portion to the second side along the second horizontal direction.