The disclosure pertains to sanitizing the permeate flow path of a reverse osmosis system. A method of sanitizing a filtration system is disclosed that can include injecting a biocide into a permeate compartment of an operating reverse osmosis system. The method can also include maintaining pressure in a concentrate compartment of the reverse osmosis system simultaneously while injecting the biocide.

By having a coating layer, this composite semipermeable membrane has fouling resistance easily maintainable before and after contact with acid, and enables stable operation over a long period of time. This composite semipermeable membrane comprises a porous support layer, a separation function layer arranged on the porous support layer, and a coating layer arranged on the separation function layer, wherein the separation function layer contains a crosslinked aromatic polyamide which is a polycondensate of polyfunctional aromatic amines and polyfunctional aromatic acid chloride, and the coating layer contains an aliphatic polymer having the structure (I) in the description.

Methods for producing a food product that involve use of a cross-flow filtration module are disclosed. The cross-flow filtration module may be used to recycle wastewater effluent and/or to recover antioxidant compounds from the wastewater effluent. In some embodiments, the cross-flow filtration module includes a stainless steel or nickel alloy substrate.

This method, for regenerating a member used in a device that treats seawater, involves a cleaning step for removing deposits from the member. In the cleaning step, a first chemical solution containing an acid other than hydroxydicarboxylic acid and a second chemical solution containing hydrogen peroxide, a heavy metal compound and hydroxydicarboxylic acid are used.

Provided are a filter device and a washing method therefor. The filter device comprises a membrane housing (1); a spacer (2) having an ion transmittance and separating the membrane housing (1) into a first chamber (11) and a second chamber (12); a membrane element (6) disposed in the first chamber (11); a first electrode (4) disposed in the first chamber (11); and a second electrode (5) disposed in the second chamber (12). The method comprises respectively connecting a positive electrode and a negative electrode to the first electrode (4) and the second electrode (5), such that the first electrode (4) and the second electrode (5), water in the first chamber (11) and water in the second chamber (12) form an electrolytic cell, thus generating acidic water or alkaline water in the first chamber (11). The acidic water and/or the alkaline water are/is used for washing the member element.

A composition for cleaning membranes used in food processing comprising an amine oxide and an alkyl sulfate, the composition maintaining good cleaning performance whilst leaving a low residue of surfactant on the membrane that is cleaned using the composition. A method of use of the composition is also presented.

Provided is a method for cleaning a filtration membrane provided in a membrane filtration device that is immersed in a liquid to be treated and performs solid-liquid separation on the liquid to be treated. When a transmembrane pressure difference exceeds a first predetermined pressure difference P1, a first cleaning step W1 for cleaning a filtration membrane is performed using a first chemical solution; when the transmembrane pressure difference immediately after performing the first cleaning step W1 exceeds a second predetermined pressure difference P2 that is lower than the first predetermined pressure difference, a second cleaning step W2 for cleaning the filtration membrane is performed using a second chemical solution having a concentration higher than the first chemical solution; and when the second cleaning step W2 is performed, the concentration of the second chemical solution and/or the cleaning time is changed according to the temperature of the liquid to be treated.

A method of producing a sugar liquid includes a step of filtering a saccharified liquid derived from cellulose-containing biomass, through a nanofiltration membrane and/or reverse osmosis membrane; and a two-step washing step of washing the nanofiltration membrane and/or reverse osmosis membrane after the filtration, with an acid washing liquid and then with an alkali washing liquid; is provided. The method of producing a sugar liquid in which a cellulose-derived sugar liquid is processed through a nanofiltration membrane and/or reverse osmosis membrane is/are effectively washed in a contaminated separation membrane(s).

A system for descaling apparatus is described. The system provides for: a water inlet feedstream; a reverse osmosis system in fluid communication with the water inlet feedstream, in which the reverse osmosis system produces a water permeate output feedstream; and a pressurised carbon dioxide feedstream. The pressurised carbon dioxide feedstream and water permeate output feedstream are arranged in use to combine to produce a pressurised carbonic acid input feedstream.

Provided is a method for operating an RO-membrane treatment system that includes an energy recovery device that recovers energy from the concentrate of an RO-membrane device and the RO-membrane treatment system that reduce the occurrence of biofouling in not only the RO-membrane device but also the energy recovery device in order to increase the energy efficiency of the entire system and operate the RO-membrane treatment system with consistency. The method includes adding at least one slime-control agent selected from a combined-chlorine slime-control agent and a stabilized-bromine slime-control agent to water that is to be treated with the reverse-osmosis-membrane device such that a residual halogen concentration in the concentrate that is to be introduced into the energy recovery device is 0.1 to 10000 mg/L as total chlorine.