A method for preparation of FCC slurry oil retentate for downstream processing while simultaneously cleaning catalyst fine retentate from filter elements or separation media of a filter assembly of an FCC slurry oil filtration system includes front-washing the filter or separation media with a low boiling point solvent, and then backwashing the filter elements with the same solvent. The front wash and backwash is conducted at a temperature of below 350 F. and at a pressure of about 25-75 psig.

A method for preparation of FCC slurry oil retentate for downstream processing while simultaneously cleaning catalyst fine retentate from filter elements or separation media of a filter assembly of an FCC slurry oil filtration system includes front-washing the filter or separation media with a low boiling point solvent, and then backwashing the filter elements with the same solvent. The front wash and backwash is conducted at a temperature of below 350 F. and at a pressure of about 25-75 psig.

A membrane filtration apparatus 110 including a membrane 113 that is made from an acid-resistant material, has pores having a pore size capable of capturing microorganisms, and has a surface that has a negative charge in a neutral to alkaline range.

A membrane filtration apparatus 110 including a membrane 113 that is made from an acid-resistant material, has pores having a pore size capable of capturing microorganisms, and has a surface that has a negative charge in a neutral to alkaline range.

A decentralized water treatment unit is for purifying untreated water to purified water for human consumption. The unit includes i) a filtration module, having at least one filtration membrane configured to, during a filtration cycle, purify the untreated water; and ii) a cleaning module, having an electrolytic cell configured to, during a generation cycle, generate a cleaning solution of predetermined composition from a chloride starting solution. The cleaning module is further configured to, during a cleaning cycle, pump the cleaning solution through the filtration module to clean the at least one filtration membrane.

A decentralized water treatment unit is for purifying untreated water to purified water for human consumption. The unit includes i) a filtration module, having at least one filtration membrane configured to, during a filtration cycle, purify the untreated water; and ii) a cleaning module, having an electrolytic cell configured to, during a generation cycle, generate a cleaning solution of predetermined composition from a chloride starting solution. The cleaning module is further configured to, during a cleaning cycle, pump the cleaning solution through the filtration module to clean the at least one filtration membrane.

Provided are a method for preserving a composite semipermeable membrane which is less likely to cause a decrease in the water permeability of the composite semipermeable membrane even in a high-temperature environment, a preservation solution used for the method, and a spiral membrane element including the preservation solution. A method for preserving a composite semipermeable membrane that allows monovalent ions to selectively permeate therethrough, the method includes using an aqueous solution containing an inorganic salt and/or an organic salt composed only of monovalent cations and monovalent anions as a preservation solution to be brought into contact with the composite semipermeable membrane.

Provided are a method for preserving a composite semipermeable membrane which is less likely to cause a decrease in the water permeability of the composite semipermeable membrane even in a high-temperature environment, a preservation solution used for the method, and a spiral membrane element including the preservation solution. A method for preserving a composite semipermeable membrane that allows monovalent ions to selectively permeate therethrough, the method includes using an aqueous solution containing an inorganic salt and/or an organic salt composed only of monovalent cations and monovalent anions as a preservation solution to be brought into contact with the composite semipermeable membrane.

The present invention relates to a method for filtering a microbial culture solution using a membrane module, said method comprising four stages including (a) cross-flow filtration of the microbial culture solution, (b) rinsing with water, (c) washing with a chemical solution and (d) rinsing with water, wherein: the filtrate passing through the membrane module in the cross-flow filtration has a total sugar concentration of 1,000-100,000 mg/1 inclusive and a protein concentration of 50-1,000 mg/l inclusive; the aforesaid stage (c) comprises step (c-1) for washing with a chemical solution containing a hypochlorite and a nonionic surfactant; and the aforesaid stages (a) to (d) are repeated in this order.

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.