An immersed membranes uses aeration (air bubbles rising past the membranes) as a means to scour the membrane surface and keep it clean from solids, or foulants, allowing for continuous and effective operation. In a module of flat sheet membranes, fine bubble aeration is used to create and maintain space between the membrane sheets. The bubbles inhibit the sheets from touching and clogging together, thus reducing their surface area and their productivity. The aeration may be used for scouring, to supply oxygen to biomass and as a spacer to maintain the working surface area of immersed flat sheet membranes. The face-to-face spacing between the membrane sheets may be 4 mm or less. The bubbles may be less than twice the face-to-face spacing between the membrane sheets.

A gravity type water-purifying device is provided. A gravity type water-purifying device according to an embodiment of the present invention comprises: a filtered water generating part comprising a filler module for filtering out foreign materials contained in raw water by using gravity, a housing which stores a predetermined amount of the raw water and has a filtering space formed therein in which the filter module is disposed, and an outlet formed through the housing to allow the filtered water generated through the filter module to be discharged to the outside; and a filtered water storing part which has a filtered water storing space formed therein in order to store a predetermined amount of filtered water generated by the filtered water generating part, is detachably connected to the filtered water generating part by unit of a connection pipe so as to be separable from the filtered water generating part and be movable by itself, and is provided with an opening/closing unit for discharging filtered water stored in the filtered water storing space to the outside.

Stack assembly comprising a hollow external housing having a central axis, the external housing extending from a first end to a second end and enclosing a housing space, and a membrane stack comprising a plurality of membranes, wherein the membrane slack is positionable inside the external housing and a number of side plates extending substantially parallel to the central axis, wherein each side plate of the number of side plates is associated with a side of the membrane stack and extending along the associated side and a number of sealing connectors that extend substantially parallel to the central axis and adjacent with an inner surface of the external housing, wherein each sealing connector of the number of sealing connectors is configured to connect two side plates to each other, wherein the sealing connectors and the side plates cooperate to form an enclosing structure, and wherein, in use of the stack assembly, the enclosing structure encloses the membrane stack. The invention also relates to a method for assembling a stack assembly and a method for generating energy or performing an electrodialysis process.

The outer edge of a filtration membrane is thermally welded to a filter plate by a first thermal welding part. The first thermal welding part includes an outer boundary line disposed inside an outer edge of the filter plate and an inner boundary line disposed inside the outer boundary line. The outer boundary line has a plurality of first projected portions and first recessed portions that are alternately formed. The first projected portion projects toward the outer edge of the filter plate, and the first recessed portion is formed between the first projected portions and retracts in an inward direction A opposite to the outer edge of the filter plate.

A device including a housing having a first side, a second side opposed to the first side, and a wall disposed between the first side and the second side. The wall forms at least a partially enclosed space inside the housing. The device also includes a membrane mounted to the wall inside the housing. The device also includes a drop pipe disposed inside the housing and through or around the membrane, the drop pipe having a proximal end and a distal end, the distal end being closer to the second side than the proximal end. The device also includes a diffuser connected to the distal end of the drop pipe.

A method of operating an immersed membrane filtration system includes a step of providing a liquid flow, for example a recirculation flow, past the surface of the membranes to clean, or help clean, the membrane surface. Since immersed outside-in membranes are effectively filtering out clean water from the effluent, they are also dewatering the effluent. To avoid solids concentration, most immersed membrane systems require that a certain amount of effluent liquid is recirculated back to an area upstream of the membranes. This is called a recirculation flow in general and is, for example, associated with the flow of return activated sludge (RAS) in a membrane bioreactor (MBR). In systems and methods described herein, we control a recirculating flow to have enough energy to scour the surface of the membranes, thus combining its use of providing liquid to the membranes and scouring their surfaces.

A membrane treatment apparatus (1) comprising: a plurality of flat membrane elements (2) which are immersed in a liquid to be treated, disposed side by side in the first direction so that membrane surfaces face each other; a supporting member (8) for holding the flat membrane element (2) provided at an end part of the flat membrane element on a first side in the second direction; and an aeration means (10) provided below the flat membrane element (2); wherein a lower edge of the flat membrane element (2) is formed to extend upward from the first side to a second side in the second direction, or to extend upward and horizontally from the first side to the second side in the second direction.