The invention relates to a specific process and apparatus for separation of gas mixtures with reduced maintenance costs.

A metal surface treatment liquid recycling system includes a treatment liquid collecting tank, a pre-treatment device, a nanofiltration device and a vacuum distillation device, all of which are connected sequentially. The nanofiltration device includes a feed tank, a first-stage nanofiltration membrane unit, and a second-stage nanofiltration membrane unit. Treatment wastewater in the treatment liquid collecting tank is fed into the pre-treatment device to filter out suspended solids and then enter the feed tank. The wastewater in the feed tank is filtered by the first-stage nanofiltration membrane unit and transformed to a first-stage concentrated waste liquid and first-stage infiltration fluids. The first-stage infiltration fluids are fed into and re-filtered by the second-stage nanofiltration membrane unit and transformed to a second-stage concentrated waste liquid and second-stage infiltration fluids. The second-stage infiltration fluids are evaporated and concentrated by the vacuum distillation device for generation of distilled water and high-concentration acid concentrated fluids.

A system and method for increasing the efficiency of a multi-pass nanofiltration system associated with water desalination and mineral extraction. A saline source water is preferably subjected to a first treatment by passage through a first nanofiltration unit, followed by a second treatment by passage through a second nanofiltration unit. At least a portion of the second nanofiltration unit's reject stream is recirculated to the inlet of the first nanofiltration unit, thereby increasing the production of permeate from the first nanofiltration unit, as well as increasing the purity of monovalent ions in the first nanofiltration unit permeate. Further nanofiltration units with one or more recirculated reject streams may be connected in series and/or in parallel with the first and second nanofiltration units.

An object of the present invention is to provide a desalination apparatus in which a high pressure pump can be operated at a high efficient operation point even when temperature, salt concentration or the like of water to be treated vary. The desalination apparatus includes a high pressure pump which is provided in a first flow path and supplies raw water to a first module at high pressure to apply reverse osmotic pressure to a first module and a second module, a third flow path for supplying second concentrated water after separation in the second module to upstream of the high pressure pump in the first flow path, and a fourth flow path for supplying a portion of the first concentrated water after separation in the first module to upstream of the high pressure pump in the first flow path.

Systems and processes for purifying and concentrating a liquid feed stream are disclosed. In the systems, the concentrated liquid output from the high pressure side of a reverse osmosis stage is used as the draw solution in the low pressure side of the reverse osmosis stage in a configuration called osmotically assisted reverse osmosis. This reduces the osmotic pressure differential across the membrane, permitting high solute concentrations to be obtained, hastening the purification of the liquid. Reduced system pressures are also obtained by arranging multiple osmotically assisted reverse osmosis stages in a cross-current arrangement. Overall system energy consumption is reduced compared to conventional thermal processes for high concentration streams.

An apparatus for an extracorporeal treatment of blood has a supply line, a waste line, and an ultrafilter inserted in the supply line. An air inlet line is connected to a first chamber of the ultrafilter. A pressure sensor is configured for detecting pressure in the waste line or a second chamber of the ultrafilter. A controller is configured to perform an integrity test procedure for detecting when an ultrafilter membrane of the ultrafilter has multiple or single fiber breaks. A method of testing the ultrafilter is also disclosed.

This specification describes membrane based filtration and softening systems and methods. A system has a microfiltration or ultrafiltration (MF/UF) membrane unit upstream of a nanofiltration or reverse osmosis (NF/RO) membrane unit, optionally with no intermediate tank. In some cases, the system and method may be used with feed water provided at municipal line pressure to the membranes. NF/RO permeate is collected in a tank and then pumped to a header. Treated water may be drawn from the header for use or recycled to the system, for example to backwash or flush one or both of the membrane units. In a combined process, NF/RO permeate flushes the feed side of the NF/RO unit and then backwashes the MF/UF unit. In another process, the MF/UF unit and NF/RO unit are filled with NF/RO permeate before being placed in a standby mode.

A reverse osmosis treatment device includes: a first pressure vessel for treating an untreated water to produce a primarily treated water and a first permeated water; a second pressure vessel for treating the primarily treated water to produce a secondarily treated water and a second permeated water; a first cleaning solution tank for storing a first cleaning solution for cleaning the first pressure vessel; and a second cleaning solution tank for storing a second cleaning solution for cleaning the second pressure vessel. Each of the first pressure vessel and the second pressure vessel has therein a reverse osmosis membrane element having a reverse osmosis membrane. The first cleaning solution tank is connected to the first concentrate outlet pipe of the first pressure vessel, and the second cleaning solution tank is connected to the inlet pipe for the primarily treated water of the second pressure vessel.

The present invention relates to a method of controlling a fresh-water production apparatus for treating a raw water in stages by N-stage (N is a natural number of 2 or larger) water treatment methods, the method including: a filtration-characteristic prediction step; a filtration-characteristic deviation assessment step; a filtration-characteristic deviation assessment step; a cyclic prediction calculation step; a control condition recording step; a cyclic prediction calculation step; and a control condition recording step, in which the fresh-water production apparatus is controlled on the basis of the control condition recording step for the (n−1)-th stage water treatment method and the control condition recording step for the n-th stage water treatment method.

The present application provides a water treatment method, a water treatment device, and a slime inhibitor for membranes that are capable of, in water treatment using a separation membrane and a reverse osmosis membrane in the subsequent stage, inhibiting the generation of a slime both in the separation membrane and in the reverse osmosis membrane by a simple method. The water treatment method includes adding an iodine-based oxidizer to water to be treated, subjecting the water to be treated obtained during the adding of the iodine-based oxidizer to filtration with the separation membrane, and causing filtrated water obtained during the filtration to be separated with the reverse osmosis membrane into permeated water and concentrated water.