Abstract: Provided is an effluent treatment method based on a membrane separation activated sludge method, the effluent treatment method being characterized in that activated sludge collected from a membrane separation activated sludge tank is observed by an optical means, image processing is performed, and effluent treatment conditions are controlled in accordance with the results thereof.

Abstract: Provided is an effluent treatment method based on a membrane separation activated sludge method, the effluent treatment method being characterized in that activated sludge collected from a membrane separation activated sludge tank is observed by an optical means, image processing is performed, and effluent treatment conditions are controlled in accordance with the results thereof.

Abstract: In a waste water treatment method using membrane separation-activated sludge, when, during filtration while supplying air using an immersion-type membrane separation unit loaded with multiple flexible membranes, the filtration differential pressure of the membranes at a set filtration flow rate exceeds a specified value P2 with respect to the filtration differential pressure P1 of the initial period of operation, membrane filtration is continued with air supply stopped until the filtration differential pressure P3 becomes P3?P1+20 [kPa]. Then with the filtration flux or filtration pressure being smaller or negative compared to when filtering while supplying air, air is supplied and after the filtration differential pressure P4 during filtration reaches P4?P1+5 [kPa], filtration is returned to filtration while supplying air.

Abstract: In a waste water treatment method using membrane separation-activated sludge, when, during filtration while supplying air using an immersion-type membrane separation unit loaded with multiple flexible membranes, the filtration differential pressure of the membranes at a set filtration flow rate exceeds a specified value P2 with respect to the filtration differential pressure P1 of the initial period of operation, membrane filtration is continued with air supply stopped until the filtration differential pressure P3 becomes P3?P1+20 [kPa]. Then with the filtration flux or filtration pressure being smaller or negative compared to when filtering while supplying air, air is supplied and after the filtration differential pressure P4 during filtration reaches P4?P1+5 [kPa], filtration is returned to filtration while supplying air.

Abstract: A separation membrane module has an element unit. The element unit includes: a shaft; a plurality of separation membrane elements each including a separation membrane pair having two separation membranes disposed so that permeate-side surfaces of the separation membranes face each other and a water collecting flow path provided between the separation membranes, and a sealed portion that seals the separation membranes at peripheral edge portions of the separation membranes; a suspension portion that suspends the separation membrane elements on the shaft; and a water collection nozzle provides communication between the water collection flow path and an outside of the separation membrane elements.

Abstract: A separation membrane element including a pair of separation membranes containing two separation membranes arranged so that the filtrate-side surfaces thereof are disposed in mutually opposed relation, and a plurality of resin members bonded to both of the mutually opposed filtrate-side surfaces, a peripheral edge of the pair of separation membranes being sealed.

Abstract: The present invention relates to a cleaning method for a submerged membrane element used in a membrane bioreactor treatment in which organic wastewater containing 1 mg/L or more of manganese is subjected a biological treatment in a bioreactor treatment tank and then subjected to solid-liquid separation by a membrane filtration device provided in the bioreactor treatment tank, in which after a first liquid containing an oxidizing agent is injected from a secondary side of the submerged membrane element to a primary side thereof and maintained for a certain period of time, the first liquid containing an oxidizing agent is suction-discharged from the secondary side to the outside of the system, and then a second liquid containing an acid is injected from the secondary side of the submerged membrane element to the primary side thereof and maintained for a certain period of time, followed by conducting suction filtration operation.

Abstract: A method for operating a reverse osmosis membrane filtration plant having a raw water intake unit, a pre-treatment unit, and a reverse osmosis membrane filtration unit having a reverse osmosis membrane module in this order, the method including: disposing a biofilm formation base material under conditions that reverse osmosis membrane supply water and/or reverse osmosis membrane non-permeated water in the reverse osmosis membrane filtration unit are/is flowed at a linear speed equal to a non-permeated water linear speed in the reverse osmosis membrane module of the reverse osmosis membrane filtration unit; evaluating a biofilm amount on the biofilm formation base material at a frequency of from once a day to once in six months; and controlling the method for operating a reverse osmosis membrane filtration plant based on results of the evaluation.