A method and system of providing ultrapure water for semiconductor fabrication operations is provided. The water is treated by utilizing a free radical scavenging system. The free radical scavenging system can utilize actinic radiation with a free radical precursor compound, such as ammonium persulfate. The ultrapure water may be further treated by utilizing ion exchange media and degasification apparatus. A control system can be utilized to regulate a continuously variable intensity of the actinic radiation.

The present invention relates to a method for treating an aqueous liquid effluent containing calcium and carbonate ions and containing precipitation-inhibiting products, said process comprising the following successive steps: a) providing an aqueous liquid effluent supersaturated with CaCO.sub.3 and containing precipitation-inhibiting products; b) having the effluent obtained in step a) pass into a reactor with high solid content with a solid content maintained between 20 and 800 g/l and integrated solid-liquid separation, at a pH comprised between 8 and 9.2 allowing in a single step precipitation in situ of the aragonite polymorph of calcium carbonate and removal of the precipitation-inhibiting products; c) recovering an aqueous liquid supernatant containing a suspended solids content of less than or equal to 0.1% by mass of the solid content in the reactor, advantageously a suspended solids content of less than 50 mg/l, the precipitation-inhibiting products being phosphonates.

A method for treating wastewater having one or more of suspended solids, dissolved solids, biological oxygen demand includes solids filtration followed by a bi-polar/bi-directional flow through ionic module fitted with anionically/cationically charged plates followed by a sub-sonic resonance module followed by another bi-polar/bi-directional flow through ionic module followed by a ultra-sonic resonance module followed by one or more anion/cation collection membrane modules. Recycle is provided in each step, wherein each step may be repeated, and wherein one or more of the steps can be bypassed.

A method for starting up a hot ultrapure water production system that produces hot ultrapure water by heating ultrapure water to a supply water temperature, for supplied to a point of use, the method involving: alternately passing heated water and cooled water through a hot ultrapure water pipe through which the hot ultrapure water flows, the heated water being obtained by heating the ultrapure water to a temperature higher than room temperature and the cooled water being obtained by cooling the ultrapure water to a temperature lower than the temperature of the heated water in a range of from room temperature to the supply water temperature.

An electrochemical system has a first reservoir receiving a feed stream. The feed stream includes a solvent and a solute different than the salt. A second reservoir receives a brine stream with a higher salt concentration higher than the feed stream. Electrodes contact a loop of redox- active electrolyte material causing reversible redox reactions. The reactions cause the loop to accept a first ion from the salt in the first reservoir and drive a second ion into the brine stream in the second reservoir. Three ionic exchange membranes of alternating type define the first and second reservoirs. A concentrate stream is output from the first reservoir, the concentrate stream having a second solute concentration greater than the first solute concentration.

A solar-powered distillation process converts saline water into potable water and useful solid residues. A solid material is heated by solar energy, and the solid material is brought into direct contact with saline water. Some of the water becomes steam and vapor, which can be condensed to produce potable water. The water-soluble salts within the saline water are precipitated separately, and collected for commercial use. Scale formed on the solid material can be removed, and the solid material reheated by solar energy, and the reheated solid material can again be used to heat incoming saline water in a continuous process.

In general, the present invention is directed to systems and methods of providing improved ballasted clarification systems for the treatment of water or wastewater. In accordance with some embodiments, a method may include introducing an influent including the water or wastewater and a coagulant; agitating or mixing the influent causing flocs to develop; introducing polymer and ballast wherein the ballast has an aspect ratio of less than 1.15; agitating or mixing the influent causing the ballast to move through the influent and penetrate the flocs; agitation or mixing the flocs to cause larger flocs to form through collision of smaller flocs among the flocs; providing the influent into a clarifying tank having a bottom and a top, wherein the ballast particles in flocs cause the flocs to settle to the bottom of the clarifier; and outputting an effluent from the top of the clarifying tank.

A system and method of filtering waters contaminated by pollutants, in particular for removing heavy metals from said contaminated waters, said system comprising a duct for the transit of said contaminated waters, said system further comprising a tank of activated carbon powders in communication with said duct for the transit of said contaminated waters by introduction means adapted to introduce said activated carbon powders into said duct.

A method for treating a fluid, notably liquid, in particular water, containing pollutants, is performed by passing a downward stream of fluid through a bed of activated carbon in the form of grains in a treatment station. The method includes a partial renewal of activated carbon including at least one injection of activated carbon and at least one extraction of activated carbon. An installation suitable for implementation of the fluid treatment method is also disclosed.

Systems and methods for water treatment involving use of a magnetic ballast material to facilitate settling operations are provided. Magnetic ballast material is recovered downstream of clarification with a magnetic drum for reuse. At least one in-line magnetic recovery device augments the recovery of magnetic ballast material.