Abstract: The invention relates to a reverse-osmosis water desalination plant comprising: a reverse-osmosis membrane unit (TP); at least one high-pressure pump (HP); a pressure-exchange-type energy collector (SRE) capable of transferring pressure from the concentrate leaving the membrane unit to a portion of the water to be treated; sensors for various operating parameters, in particular pressure, flow rate, temperature and salinity level, said sensors being provided at suitable locations; and control loops so that the various adjustable elements are maintained at a setpoint value. The plant also includes a secondary control system (D) comprising calculation means (26) programmed to determine, on the basis of the operating conditions of the plant supplied by the sensors, a combination of setpoint values for the flow rate of the high-pressure pump, the mixing ratio of the energy collector and the conversion ratio, which combination minimizes the energy consumption of the high-pressure pump.

Abstract: The invention relates to a method for managing the plugging of membrane modules and of filtration membranes, in particular for nanofiltration, ultrafiltration or reverse osmosis for desalinating water, which comprises carrying out consecutive rinsing operations for controlling clogging, in particular biological clogging: evaluating the thickness of the biofilm; starting a rinsing operation at the latest when the evaluated thickness of the biofilm exceeds a first predetermined setpoint value for the biofilm thickness and stopping the rinsing operation not before the biofilm thickness has become lower than a second predetermined setpoint value lower than the first one for the biofilm thickness.

Abstract: Method for disinfecting a filtration works (F) for the pretreatment of salt water, particularly seawater, upstream of a water desalination unit (1) using a reverse osmosis membrane, whereby an operation of disinfecting the filtration works is carried out periodically by adding a bactericidal agent to the water that is to be pretreated, the filtration works being periodically subjected to a declogging operation; the operation of disinfecting the filtration works (F) is carried out during a declogging operation, and the liquid used for the declogging is formed of an aqueous declogging solution the salt content of which differs from the content of the water being pretreated; the bactericidal agent is added (14) to the declogging solution upstream of its injection into the filtration works (F).

Abstract: The invention relates to a reverse-osmosis water desalination plant comprising: a reverse-osmosis membrane unit (TP); at least one high-pressure pump (HP); a pressure-exchange-type energy collector (SRE) capable of transferring pressure from the concentrate leaving the membrane unit to a portion of the water to be treated; sensors for various operating parameters, in particular pressure, flow rate, temperature and salinity level, said sensors being provided at suitable locations; and control loops so that the various adjustable elements are maintained at a setpoint value. The plant also includes a secondary control system (D) comprising calculation means (26) programmed to determine, on the basis of the operating conditions of the plant supplied by the sensors, a combination of setpoint values for the flow rate of the high-pressure pump, the mixing ratio of the energy collector and the conversion ratio, which combination minimizes the energy consumption of the high-pressure pump.

Abstract: The invention concerns a water clarifying device comprising a flotation zone (c), a membrane-based filtering zone (e) and extracting means (d), the flotation zone (c) and the membrane-based filtering zone (e) having a common partition wall (P), the common partition wall (P) including in its lower part an opening (o) directly allowing through flotated water towards the filtering zone (e), thereby feeding the membranes with flotated water from down upwards both in filtering phase and in backwashing phase.

Abstract: The invention relates to an effluent treatment installation which can be used to improve the filtration capacity of membranes and to reduce water losses without increasing the floor area thereof. For said purpose, the invention comprises a pulsed sludge blanket settling tank (1) containing membrane filtration modules (10) which are submerged in or above the sludge blanket, and the system (11) for extracting the treated effluents is connected upstream of said filtration modules (10). The invention also relates to a method for clarification by means of coagulation/flocculation/decantation and for filtration using said installation.

Abstract: The invention relates to a method of cleaning membrane filters comprising hollow fibres and an inner skin. The inventive method comprises the following steps consisting in: emptying the concentrate compartment in order to release the liquid to be filtered contained therein and the suspended matter, and, subsequently, performing a backwashing step involving the passage of liquid from the permeate compartment into the concentrate compartment through membranes in order to detach and release impurities deposited thereon, while circulating a gas in the concentrate. According to the invention, backwashing liquid and/or gas pulses are produced by control means (5, 5a; 7, 7a) during at least one backwashing phase.

Abstract: Process for removing nitrogenous compounds, in particular nitrates, and for remineralizing water with a low mineral content, characterized in that the removal of the nitrogenous compounds and at least partial remineralization of the untreated water are carried out simultaneously by biological treatment, in the same reactor. The denitrified and remineralized water is then subjected to coagulation, flocculation and clarification treatments.