A water purification apparatus and method for optimizing efficiency of the water purification apparatus comprising a fluid circuit including a Reverse Osmosis, RO, unit (3), providing a permeate flow, and an electrically controlled deionization unit (4) downstream the RO unit (3) receiving at least part of the permeate flow. The method comprises obtaining (S1) a value indicative of power consumption by the electrically controlled deionization unit and determining (S2) whether the obtained value indicative of the power consumption meets at least one criterion. The method further comprises controlling recirculation of reject water produced by the water purification apparatus, based on a result of the determining (S2), in order to optimize efficiency of the water purification apparatus.

A drainless reverse osmosis (RO) water purification system provides relatively pure water for on-demand dispensing, while recycling brine to a domestic hot water system. The drainless purification system includes a pre-filter catalyst cartridge for removing chlorine-based contaminants from a tap water supply upstream from an RO membrane. The catalyst is regularly refreshed by a high through-flow of water to a conventional cold water dispense faucet, thereby significantly prolonging the service life of the RO membrane. The RO membrane is incorporated into a multi-cartridge unit adapted for facilitated slide-out removal and replacement as needed. A control valve recycles brine from the RO membrane to the hot water system during pure water production, and recirculates tap water through the RO membrane when a pure water reservoir is substantially filled. The multi-cartridge unit may further include an air filtration system for providing a flow of filtered air.

A method for operating a diffusiophoretic water filter includes removing a membrane in a diffusiophoretic water filter; and replacing the membrane with a new membrane.

A water purification apparatus and method for optimizing efficiency of the water purification apparatus comprising a fluid circuit including a Reverse Osmosis, RO, unit (3), providing a permeate flow, and an electrically controlled deionization unit (4) downstream the RO unit (3) receiving at least part of the permeate flow. The method comprises obtaining (S1) a value indicative of power consumption by the electrically controlled deionization unit and determining (S2) whether the obtained value indicative of the power consumption meets at least one criterion. The method further comprises controlling recirculation of reject water produced by the water purification apparatus, based on a result of the determining (S2), in order to optimize efficiency of the water purification apparatus.

A hollow-fiber membrane module of the invention includes: a cylindrical case having a first end and a second end in a height direction thereof; a hollow-fiber membrane bundle being housed in the cylindrical case and having a plurality of hollow-fiber membranes each closed at an end part on the first end side and opened at an end part on the second end side; a first binding part binding the end parts on the first end side of the hollow-fiber membranes; a first flow channel guiding fluid to pass through the first binding part from the first end side to the second end side of the first binding part; and a channel material directing, at a terminal on the second end side of the first flow channel, a flow of at least a part of the fluid flowing out from the terminal on the second end side of the first flow channel toward a direction intersecting the height direction of the cylindrical case.

A drainless reverse osmosis (RO) water purification system provides relatively pure water for on-demand dispensing, while recycling brine to a domestic hot water system. The drainless purification system includes a pre-filter catalyst cartridge for removing chlorine-based contaminants from a tap water supply upstream from an RO membrane. The catalyst is regularly refreshed by a high through-flow of water to a conventional cold water dispense faucet, thereby significantly prolonging the service life of the RO membrane. The RO membrane is incorporated into a multi-cartridge unit adapted for facilitated slide-out removal and replacement as needed. A control valve recycles brine from the RO membrane to the hot water system during pure water production, and recirculates tap water through the RO membrane when a pure water reservoir is substantially filled. The multi-cartridge unit may further include an air filtration system for providing a flow of filtered air.

A drainless reverse osmosis (RO) water purification system provides relatively pure water for on-demand dispensing, while recycling brine to a domestic hot water system. The drainless purification system includes a pre-filter catalyst cartridge for removing chlorine-based contaminants from a tap water supply upstream from an RO membrane. The catalyst is regularly refreshed by a high through-flow of water to a conventional cold water dispense faucet, thereby significantly prolonging the service life of the RO membrane. The RO membrane is incorporated into a multi-cartridge unit adapted for facilitated slide-out removal and replacement as needed. A control valve recycles brine from the RO membrane to the hot water system during pure water production, and recirculates tap water through the RO membrane when a pure water reservoir is substantially filled. The multi-cartridge unit may further include an air filtration system for providing a flow of filtered air.

The present invention provides a submerged type membrane separation device and a membrane separation method which allow long-term stable filtration. In the submerged type membrane separation device including a membrane module having membrane units stacked on top of each other in stages, in each of which flat sheet membrane element each having a separation membrane are arranged, the membrane module is constructed of various membrane units differing in sludge-filtration resistance or pure-water permeation resistance, whereby it becomes possible to extend a device operation period of time lapsing before transmembrane plugging occurs, or equivalently, the necessity to clean membranes arises. Further, it also becomes possible to design to synchronize timings with which a plurality of membrane units require cleaning.