The present disclosure is directed to filtering technologies that combine elements of continuous and batch NF/RO based on the constraints of the end-user facility to achieve a target balance between, for instance, recovery and power consumption, and to reduce long term operating cost of a plant. A method for extending batch operation into a second induction period with antiscalant injection is also disclosed herein, with the second induction period allowing for yet higher water recovery.

The present invention includes: a first sealing portion which has a first entry/exit selectively opened or closed by a first opening/closing valve and a second entry/exit selectively opened or closed by a second opening/closing valve and is configured to seal one end of a housing; a second sealing portion which has a third entry/exit selectively opened or closed by a third opening/closing valve and a fourth entry/exit selectively opened or closed by a fourth opening/closing valve, and is configured to seal the other end of the housing; and a controller which is configured to control the supply of raw water through any one of the first entry/exit and the second entry/exit or control the supply of raw water through any one of the third entry/exit and the fourth entry/exit.

A reverse osmosis desalination system has a combined displacement pump and displacement pressure recovery motor that propagate feed water with a structurally fixed recovery rate and structurally stabilized volume flow through continuously alternating discharging and recirculation intervals. Thereby enabled is an instantaneous discharge of the entire feed water concentrate and unmixed replacement with low salinity source water that intermittingly and effectively flushes the reverse osmosis membranes. This in turn provides for high recirculation peak salinity and recovery rate that are simple and reliably controlled without impairing membrane longevity.

Apparatus and processes for controlling a reverse osmosis system for water desalination to reduce energy consumption. The system has a controller configured to receive information from the sensor array and determine a fouling parameter for each reverse-osmosis stage based on one or more of: an A-Value, a B-value and a normalized differential pressure. The controller is then configured to control the flow through each of the reverse-osmosis assemblies based on the determined fouling parameters to meet a predetermined criterion for total permeate production for the reverse-osmosis system.

Provided is an apparatus for controlling a seawater desalination plant. The apparatus includes: a dissolved air flotation device configured to provide treated water obtained by treating seawater according to a dissolved air flotation (DAF); an ultrafiltration device including a plurality of ultrafiltration units each having an ultrafiltration membrane, and configured to perform an ultrafiltration (UF) process of filtering impurities remaining in the treated water using the ultrafiltration membranes of the plurality of ultrafiltration units; a reverse osmosis device; an information collection unit; and a state treatment unit.

The present invention provides a fresh water generator operating method and a determination program that are employed in a method for cleaning a separation membrane module following membrane filtration, and that, while various cleaning steps such as reverse pressure cleaning, air cleaning, chemical solution cleaning are taking place after completion of the membrane filtration, determines cleaning troubles by calculating a temporal change in resistance increase rate on the basis of an increase in membrane differential pressure.

The present disclosure is directed to filtering technologies that combine elements of continuous and batch NF/RO based on the constraints of the end-user facility to achieve a target balance between, for instance, recovery and power consumption, and to reduce long term operating cost of a plant. A method for extending batch operation into a second induction period with antiscalant injection is also disclosed herein, with the second induction period allowing for yet higher water recovery.

There is described the processing seawater in a subsea facility on the seabed in various methods and apparatus. In various examples, the facility is coupled to at least one well, is configured to provide the well with water to be injected into at least one formation of the well, and comprises filter elements arranged in housings, the filter elements being configured for ultrafiltration or microfiltration. In such examples, treated seawater in at least one of the housings is filtered using at least one filter element, producing thereby filtered water, and at least one filter element in at least one other of the filter housings is cleaned by backwashing performed using at least some of the produced filtered water.

A deposit monitoring device includes a non-permeated water line discharging non-permeated water where dissolved components and dispersed components are concentrated from water to be treated from a separation membrane device for obtaining permeated water by concentrating the dissolved components and dispersed components from water to be treated by a separation membrane; a first deposit detecting unit using part of the non-permeated water branched off as a detection liquid, and having a first separation membrane for detection in which the detection liquid is separated into permeated water for detection and non-permeated water for detection; a deposition condition altering device altering deposition conditions for deposits in the first separation membranes for detection; and first flow rate measuring devices for separated liquid detection that measure the flow rates of one or both of the permeated water for detection and the non-permeated water for detection separated by the first separation membrane for detection.

The present invention relates to a method of operating a membrane filtration unit including plural hollow fiber membrane modules connected to each other in parallel, the method including: a filtration step; a collection step; and a recovery step, in which a relation of n.sub.1≥n.sub.2>n.sub.3 is satisfied, where n.sub.1 is the number of the hollow fiber membrane modules simultaneously used in executing the filtration step, n.sub.2 is the number of the hollow fiber membrane modules simultaneously used in executing the collection step, and n.sub.3 is the number of the hollow fiber membrane modules simultaneously used in executing the recovery step.