The present invention relates to a method for operating a separation membrane in which a liquid-to-be-filtrated is subjected to filtration to obtain a filtrate, the method including: an accumulated amount calculation step of calculating an amount of constituent components of the liquid-to-be-filtrated accumulated on a surface and in pores of the separation membrane after setting an initial value; a chemical liquid cleaning effect calculation step of calculating a restoration degree of an accumulated amount of the constituent components or membrane filtration resistance in chemical liquid cleaning based on a result of accumulated amount calculation; and a chemical liquid cleaning condition determination step of determining a chemical liquid cleaning condition based on results obtained in the accumulated amount calculation step and the chemical liquid cleaning effect calculation step.

The present invention relates to a method for operating a separation membrane module including a separation membrane having a first face and a second face, a liquid-to-be-filtrated flow channel along which liquid to be filtrated which is to be fed to the first face flows, and a permeated-liquid flow channel along which permeated liquid obtained from the second face flows, the method including: a filtration step of obtaining permeated liquid containing components that become insoluble when coming into contact with acids by feeding liquid to be filtrated to the liquid-to-be-filtrated flow channel; a first water substitution step of substituting liquid in the permeated-liquid flow channel with water, after the filtration step; a first chemical cleaning step of performing backwashing by causing an acidic chemical solution to flow from the second face toward the first face of the separation membrane, after the first water substitution step; and a second water substitution step of substituting liquid in the permeated-liquid flow channel with water, after the first chemical cleaning step.

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 and a method for purifying a produced water using a nanomembrane formed from polymeric waste are provided. The method includes placing the nanomembrane into an aqueous solution, wherein a surface of the nanomembrane is functionalized with carboxyl groups. Carbon dioxide is injected into the aqueous solution, and bivalent alkaline earth cations are adsorbed on the surface of the nanomembrane in the presence of carbonate ions (CO.sub.3.sup.2) to form carbonate crystals on the surface of the nanomembrane.

The disclosure provides a novel flush method using a recovery flush technique that minimizes yield losses due to inadequate flushing and prevents or reduces dilution of a target protein during a recovery flush.

A filter device includes one or more filter membranes, and a filter housing enclosing the one or more filter membranes. Each of the filter membranes includes a base membrane made of a ceramic material, and a plurality of through holes. The base membrane is coated with a coating material.

This filtration treatment system is provided with a membrane filtration device as a prefiltration treatment device for removing insoluble components from the water to be treated containing organic substance, a reverse osmosis membrane treatment device for subjecting the prefiltration-treated water to reverse osmosis membrane treatment, and a chemical agent supply pipe for supplying a chemical agent into the membrane filtration device, wherein the chemical agent contains a sulfamic acid compound, and a bromine-based oxidizing agent or the reaction product of a bromine compound with a chlorine-based oxidizing agent, or, contains the reaction product of a sulfamic acid compound with a bromine-based oxidizing agent or with the reaction product of a bromine compound with a chlorine-based oxidizing agent.

In a method for operating a clarification membrane module the invention, either following steps is conducted after the position of the closed ends in the clarification membrane module is made above the position of the open ends therein: (a) closed-end high-position cleaning step A in which the outer side of the clarification membranes within the clarification membrane module is filled with liquid and air scrubbing is then performed by supplying a gas; (b) closed-end high-position cleaning step B in which air scrubbing is conducted by supplying a gas, while supplying liquid to the outer side of the clarification membranes within the clarification membrane module.

The present disclosure relates to biocide compositions, formulations and methods for using formulations. In particular the present disclosure relates to biocide compositions and their use in treating reverse osmosis membranes.

Disclosed herein are surfactant booster compositions for filtration membrane cleaning, multi-part detergents comprising the surfactant booster compositions, an enzyme composition, and alkalinity composition. Further disclosed are methods of cleaning filtration membranes with the aforementioned compositions and system. Beneficially, the surfactant booster compositions have low toxicity with high butterfat removal capacity. The compositions and methods are suitable for filtration membranes including microfiltration, ultrafiltration, nanofiltration, and reverse osmosis membranes.