A membrane separation pretreatment apparatus including a membrane separation unit and a first underwater plasma discharge unit disposed in front of the membrane separation unit is provided. The membrane separation pretreatment apparatus includes a membrane separation unit configured to remove particulate matter contained in raw water, and a first underwater plasma discharge unit disposed in front of the membrane separation unit and configured to cause a portion of the raw water to be introduced into the membrane separation unit to perform underwater plasma discharging.

A pulsed voltage is repeatedly applied between a first electrode and a second electrode to which a gas is supplied, a plasma is generated between the first electrode and the second electrode, and an active species is produced in the plasma. The energy necessary for plasma generation is set to a value greater than or equal to 1.8 W/cm.sup.3 and less than or equal to 8.5 W/cm.sup.3.

To provide a sterilizing liquid and a method of producing the same that have no restrictions on application methods and usage and can be widely used for sterilization, a sterilizing liquid including water containing reactive oxygen species and a nanoparticle catalyst in a stationary state is produced by causing cavitation in water having a conductivity of 2000 μS/cm or less and COD of 2000 ppm or less while causing the water to flow by a stirrer 2, and causing generation of plasma by a plasma generation mechanism 3 in which a pulse voltage is applied across electrodes 31 in the water including air bubbles mainly containing water vapor generated by the cavitation.

A dewatering apparatus for cellulosic materials includes a chamber for an aqueous solution of a cellulosic material, an inner electrode in the chamber, an outer electrode in the chamber about the inner electrode, and a power supply connected to the inner electrode and the outer electrode applying a voltage potential across the electrodes to remove water associated with the aqueous solution and to dewater the cellulosic materials.

A water treatment system includes a water inlet that intakes water to be treated, a high voltage (HV) electrode having a porous metal surface area in a range of between 0.1 cm.sup.2 and 5 cm.sup.2 in fluid communication with the water, such that the water flows through the porous metal surface area of the HV electrode, a ground electrode disposed across a gap from the HV electrode, in fluid communication with the water, a high voltage power supply electrically connected to the HV electrode for generating spark plasma or pulsed electric fields having a rise time equal to or less than 60 nanoseconds (ns) and an amplitude greater than or equal to 30 kV/cm across the gap, thereby producing treated water, and a water outlet that discharges the treated water.

The present invention describes a PEF (pulsed electric field) chamber 1 intended for treating a flow with electric field pulses, said PEF chamber comprising a PEF treatment tube 2 and opposite electrode units 3, 4, wherein said opposite electrode units 3, 4 each has one flow receiving end 5a, 5b and one flow exit end 6a, 6b, wherein the PEF treatment tube 2 comprises exit flow portions 7a, 7b arranged subsequent to the flow exit ends 6a, 6b of the electrode units 3, 4 in the intended flow direction, and thus functioning as an extension of the opposite electrode units 3, 4 in the intended flow direction, wherein the exit flow portions 7a, 7b of the PEF treatment tube 2 are arranged to provide a geometrical narrowing 20 subsequent to the flow exit ends 6a, 6b.

An algae treatment device of the present invention is installed in a ship or a barge and selectively destroys only the air-sacs of algae by discharging high-voltage micro pulses into waters of interest in which green tide or red tide has occurred. Thus, the algae treatment device can efficiently solve green tide or red tide by treating algae using a minimal amount of chemicals, or none at all.

Disclosed is a water treatment device such as a water purifier. In particular, a water treatment device capable of producing sterilizing water is disclosed. The device includes a sterilizing water producing module for electrolyzing raw water to produce sterilizing water, wherein the sterilizing water producing module includes a plurality of first electrodes and a plurality of second electrodes arranged alternately with each other and spaced from each other, wherein the first and second electrodes have opposite polarities to each other, wherein a polarity of each of the first electrode and the second electrode is switchable to between a positive potential and a negative potential, such that the sterilizing water producing module operates such that a positive potential operation and a negative potential operation are alternately repeated, wherein a magnitude of voltage or current applied to the sterilizing water producing module under the negative potential operation is smaller than a magnitude of voltage or current applied to the module under the positive potential operation.

This publication relates to a method and a system for producing freshwater through a reverse osmosis process in a submerged membrane system requiring a differential pressure over the membrane system. The differential pressure is provided by introducing gas bubbles in the riser device (2) downstream the outlet (7) for fresh water in the riser device (2). The system comprises at least one submerged, reverse osmosis unit (1), with an inlet (4) for water and an outlet (7) for fresh water, a riser device (2) extending from the outlet (7) of the submerged membrane system to at, above or below sea level and a system for providing a low pressure side for the reverse osmosis process.

The invention relates to a method for activation of concrete mixing water. The method includes preliminary action on the mixing water in continuous flow by pulsed high-voltage electrohydraulic discharges with supply DC voltage from 500 V to 5000 at a pulse frequency from 2 Hz to 10,000 Hz and a current from 0.1 A to 10 A on electrodes of copper and/or iron and/or titanium. Then the water is treated in a mechanical and/or ultrasonic cavitator in the developed cavitation mode and at a water pressure from 0.8 atm to 6 atm without addition of plasticizers and/or surface-active agents.