Abstract: A method for operating a membrane separation device includes (a) setting a flow amount M(t) of permeated water and extracting the permeated water from the membrane separation device by the set flow amount M(t), and (b) temporarily stopping the extracting the permeated water, when a water level of a first water tank in which the membrane separation device is immersed, a water level of a second water tank in communication with the first tank, or a water level of a third water tank receiving overflowing water from the first water tank becomes lower than a predetermined halt water level. M(t), which is the flow amount of the permeated water during a time period t, satisfies a equation M(t)=KQ(t?1), where K is a gain (K>1), and Q(t?1) is an amount of inflow of the water-to-be-treated during a time period t?1 immediately prior to the time period t.

Abstract: 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.

Abstract: A sheet filter membrane is arranged on a surface of a filter plate of a thermoplastic resin, and a plurality of projections provided in a hot plate is pressed against the filter plate above a periphery of the filter membrane with different timing for each of the projections to abut on the filter membrane. A plurality of recessed bonding portions with different depths are thus formed in the filter plate, and the filter membrane is bonded to the filter plate by heat welding in each of the recessed bonding portions. Sealing is therefore provided between the filter membrane and the filter plate along the periphery of the filter membrane.

Abstract: A low-cost membrane cartridge and a low-cost method for producing a membrane cartridge, in which fatigue durability can be increased with a simple structure, are provided by focusing on a bonding position of the filtration membrane onto the filtration plate. The membrane cartridge includes a filtration membrane disposed on both faces of a filtration plate made of a thermoplastic resin, such that a joining portion provided at the periphery of the filtration membrane is joined to the filtration plate. At least an inner edge portion of the joining portion has a downward inclination with respect to the surface of the filtration plate inside of the inner edge portion at an angle in a range of 10 to 45 degrees toward an outer peripheral edge of the filtration membrane. The joining portion is pressed and welded using a heating plate or an ultrasonic horn having such an inclined surface.

Abstract: A method for operating a membrane separation device includes (a) setting a flow amount M(t) of permeated water and extracting the permeated water from the membrane separation device by the set flow amount M(t), and (b) temporarily stopping the extracting the permeated water, when a water level of a first water tank in which the membrane separation device is immersed, a water level of a second water tank in communication with the first tank, or a water level of a third water tank receiving overflowing water from the first water tank becomes lower than a predetermined halt water level. M(t), which is the flow amount of the permeated water during a time period t, satisfies a equation M(t)=KQ(t?1), where K is a gain (K>1), and Q(t?1) is an amount of inflow of the water-to-be-treated during a time period t?1 immediately prior to the time period t.

Abstract: A submerged membrane separator includes: a plurality of membrane cartridges arranged at predetermined spaces; a flow generating device for generating flows in one direction along the membrane surfaces of the membrane cartridges; and wall members on both sides of a channel of the flow in the one direction formed between the membrane cartridges adjacent to each other. The membrane cartridges can be attached and detached from another direction substantially orthogonal to the flows in the one direction and substantially orthogonal to the arrangement direction of the membrane cartridges.

Abstract: A sheet filter membrane is arranged on a surface of a filter plate of a thermoplastic resin, and a plurality of projections provided in a hot plate is pressed against the filter plate above a periphery of the filter membrane with different timing for each of the projections to abut on the filter membrane. A plurality of recessed bonding portions with different depths are thus formed in the filter plate, and the filter membrane is bonded to the filter plate by heat welding in each of the recessed bonding portions. Sealing is therefore provided between the filter membrane and the filter plate along the periphery of the filter membrane.

Abstract: A low-cost membrane cartridge and a low-cost method for producing a membrane cartridge, in which fatigue durability can be increased with a simple structure, are provided by focusing on a bonding position of the filtration membrane onto the filtration plate. The membrane cartridge includes a filtration membrane disposed on both faces of a filtration plate made of a thermoplastic resin, such that a joining portion provided at the periphery of the filtration membrane is joined to the filtration plate. At least an inner edge portion of the joining portion has a downward inclination with respect to the surface of the filtration plate inside of the inner edge portion at an angle in a range of 10 to 45 degrees toward an outer peripheral edge of the filtration membrane. The joining portion is pressed and welded using a heating plate or an ultrasonic horn having such an inclined surface.

Abstract: A submerged membrane separator 31 includes: a casing 33 opened at the top; a plurality of flat membrane cartridges 34 arrayed at intervals in the casing 33; and an air diffuser 36 provided below the membrane cartridges 34. The membrane cartridges 34 are movably held in the up-down direction in the casing 33 while having a space ? in the up-down direction. Lifting suppressing members 63a and 63b for restricting a lifting amount of the membrane cartridges 34 during filtration operation to be smaller than the space ? in the up-down direction are provided in the casing 33.

Abstract: Disclosed is a membrane cartridge used in a submerged membrane separator. A peripheral portion of a filtration membrane is joined to the surface of a filtration plate. A portion higher than the surface of the filtration plate corresponding to the peripheral edge of the filtration membrane is formed on the surface of the filtration plate further on the outer side than the peripheral edge of the filtration membrane.

Abstract: A channel groove pattern 38 allowing the passage of a permeated liquid having passed through a filtration membrane 37 is provided on one filtration plate surface of a filtration plate 36, and a permeated liquid outlet nozzle 39 is provided on the filtration plate 36. The channel groove pattern 38 includes multiple channel grooves 38a, and a header groove 44 for averaging suction pressures is formed on the filtration plate 36. An area where the channel groove pattern 38 is formed is divided into upper and lower water collection areas 46 and 47 by the header groove 44. The permeated liquid outlet nozzle 39 and the header groove 44 communicate with each other through the channel grooves 38a of the water collection area 46, and the channel cross-sectional area of the header groove 44 is larger than that of the channel groove 38a.

Abstract: A filtration membrane and multiple channel groove patterns 38 and 39 are provided on a filtration plate 36, and permeated liquid outlet nozzles 41 and 42 for collecting and taking out a permeated liquid in the channel groove patterns 38 and 39 are provided at the circumferential edge of the filtration plate 36, wherein the channel groove patterns 38 and 39 include linear through-channel grooves 38a and 39a that are inclined in parallel and communication grooves 38b and 39b connecting the through-channel grooves 38a and 39a, the through-channel grooves 38a and 39a are arranged from one end to the other end so as to gradually approach the closest permeated liquid outlet nozzles 41 and 42, and the permeated liquid flows to the permeated liquid outlet nozzles 41 and 42 through the through-channel grooves 38a and 39a.

Abstract: A channel groove pattern 38 allowing the passage of a permeated liquid having passed through a filtration membrane 37 is provided on one filtration plate surface of a filtration plate 36, and a permeated liquid outlet nozzle 39 is provided on the filtration plate 36. The channel groove pattern 38 includes multiple channel grooves 38a, and a header groove 44 for averaging suction pressures is formed on the filtration plate 36. An area where the channel groove pattern 38 is formed is divided into upper and lower water collection areas 46 and 47 by the header groove 44. The permeated liquid outlet nozzle 39 and the header groove 44 communicate with each other through the channel grooves 38a of the water collection area 46, and the channel cross-sectional area of the header groove 44 is larger than that of the channel groove 38a.

Abstract: A submerged membrane separator includes: a plurality of membrane cartridges arranged at predetermined spaces; a flow generating device for generating flows in one direction along the membrane surfaces of the membrane cartridges; and wall members on both sides of a channel of the flow in the one direction formed between the membrane cartridges adjacent to each other. The membrane cartridges can be attached and detached from another direction substantially orthogonal to the flows in the one direction and substantially orthogonal to the arrangement direction of the membrane cartridges.

Abstract: Disclosed is a membrane cartridge used in a submerged membrane separator. A peripheral portion of a filtration membrane is joined to the surface of a filtration plate. A portion higher than the surface of the filtration plate corresponding to the peripheral edge of the filtration membrane is formed on the surface of the filtration plate further on the outer side than the peripheral edge of the filtration membrane.

Abstract: A submerged membrane separator 31 includes: a casing 33 opened at the top; a plurality of flat membrane cartridges 34 arrayed at intervals in the casing 33; and an air diffuser 36 provided below the membrane cartridges 34. The membrane cartridges 34 are movably held in the up-down direction in the casing 33 while having a space ? in the up-down direction. Lifting suppressing members 63a and 63b for restricting a lifting amount of the membrane cartridges 34 during filtration operation to be smaller than the space ? in the up-down direction are provided in the casing 33.

Abstract: A scroll member has a scroll wall having an axial end having a transverse surface on which a groove 20 is cut along the spiral direction of the scroll wall, to which groove a seal member contacting a facing scroll member is received. The scroll wall has a radially inner portion having a width larger than the width of the remaining part of the scroll wall. At the radially inner portion, the groove is also widened. When molding the scroll member, a recess deeper than the depth of the groove to be machined is created. The groove is obtained by machining the scroll member as molded by a milling tool. The widened portion of the groove is formed by moving a milling tool along a closed trajectory, so that the recess is left un-machined.

Abstract: A herbicidal composition comprising metsulfuron methyl and at least one compound selected from the group consisting of pyrazosulfuron ethyl and halosulfuron methyl as active ingredients, and a method for controlling weeds comprising using the composition.