A method of operating a dual reverse osmosis/pressure retarded osmosis plant, including when electricity costs less than a first predetermined price, moderate salinity water is pumped into the first portion of a pressure vessel having first and second portions separated by a water permeable/salt impermeable osmotic membrane to yield desalinated permeate in the second portion and brine in the first portion. Further, when electricity costs greater than the first predetermined price, low salinity water is pumped into the second portion and brine is pumped into the first portion to yield pressurized moderate salinity water in the second portion which is run through an energy recovery device to generate electricity. The salinity of the low salinity water is lower than the salinity of the moderate salinity water, and the salinity of the moderate salinity water is lower than the salinity of the brine.

A method for filtering a dairy product is used in a filter system that includes at least one pump loop having a pump and a filter, with the pump being arranged to feed a feed product to the filter for filtering the feed product and outputting a permeate product and a retentate product. The method includes supplying the feed product to the pump at a feed pressure, during a first operational mode in which the feed pressure is below a first predefined threshold, controlling the pump to operate at a first power that is within a first percentage range of a maximum rated power of the pump, and during a second operational mode in which the feed pressure is above the first predefined threshold, controlling the pump to operate within a second percentage range of the maximum rated power which is higher than the first percentage range.

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.

The present disclosure provides a complete set of equipment for supplying drinking water in field. The complete set of equipment for supplying drinking water in field consists of several units carried by single person, making the water purification equipment easy to use and transport. The complete set of equipment includes a multistage filtration unit, a reverse osmosis unit, and a power control unit connected by a plug-in pipeline.

A water conditioning system of an electrodialysis reversal (EDR) water purifier includes a first source water inlet, a second source water inlet, an EDR film stack, a first conductive probe, a second conductive probe, a third conductive probe, a fourth conductive probe, a variable speed pump, a one-way valve, a clean water outlet, a waste water outlet, an electrode A, an electrode B, and a control system module. With the four conductive probes detecting conductivity of water flowing through four ports on two sides of the EDR film stack and by sending detected data to the control system module, the control system module adjusts voltages of the electrode A and electrode B accordingly to instantly increase or decrease removal efficiency of the EDR film stack. Thus, the conductivity of the discharged clean water and the quality of the clean water can be stabilized.

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.

A water treatment device using a hollow fiber membrane module is provided, including: a water container filled with raw water; a hollow fiber membrane module installed in the water container and provided with hollow fiber membranes therein to perform water treatment by a water pressure difference; and a raw water supplying part positioned on the water container, and configured to supply the raw water into the water container through the hollow fiber membrane module, in which the hollow fiber membrane module causes the raw water supplied from the raw water supplying part collide with the hollow fiber membrane to move the hollow fiber membrane, so that it is possible to minimize contamination of the hollow fiber membrane, minimize use of energy using electricity, and wash the hollow fiber membrane by a physical method.

A control method is provided for a filter system, which includes at least one filter element (2). The method includes continuously recording a total energy consumption (E.sub.G) during a filtration cycle (22) of the filter system. The total energy consumption (E.sub.G) includes at least of the energy consumption (E.sub.B) for a physical cleaning (24) and the energy consumption (E.sub.P) for the subsequent production cycle (23) up to a predefined, in particular current point in time. The method further includes computing a relative energy consumption (E.sub.rel) by way of division of the recorded total energy consumption (E.sub.G) by a net permeate volume (Q.sub.N) which has been produced during the filtration cycle (22) up to the predefined point in time and starting a physical cleaning (24) in dependence on the relative energy consumption or of a characteristic value derived from this.

A method for controlling a membrane distillation system includes determining whether there is a day time or a night time at a location of a solar collector system associated with the membrane distillation system; applying a first control mode during the day time to a flow velocity of a feed used by the membrane distillation system; and applying a second control mode, different from the first control scheme, during the night time, to the feed. The first control scheme is a model-free mode.

The present invention relates to a method for concentrating, with low energy, a solute-containing solution in a state of multiple-no osmotic pressure difference (M(multiple)−Δπ=0 RO), and, more specifically, to a method for concentrating, with low energy, an solute-containing solution intended to be concentrated, as a low pressure in a state of multiple-no osmotic pressure difference. The method for concentrating a solution containing a solute at a low pressure in a state of multiple-no osmotic pressure difference, of the present invention, consumes less energy, enables concentration to be performed until a saturated aqueous solution with a maximum solute concentration is obtained or the concentration of the solute becomes 100% even though an extraction solvent is not used, and does not require the use of an additional osmosis-inducing solution.