A system for modifying pH in an aqueous environment comprises an aqueous salt solution feed stream having a first pH and an electrochemical device positioned proximate an aqueous restoration area. The electrochemical device is configured to receive the feed stream and convert the feed stream to an acid stream and a base stream having respective predetermined pH values. A first effluent stream comprises the base stream, wherein the first effluent stream has a second pH that is higher than the first pH. The first effluent stream is delivered proximate the aqueous restoration area. A second effluent stream comprises the acid stream, wherein the second effluent stream has a third pH that is lower than the second pH.

A system and method for controlling the accelerated remediation of the water of an aquatic facility using at least one sanitizer sensor, a pH sensor, a temperature sensor and a chlorine dioxide sensor all interfaced with a programmable controller that is programmed to implement an accelerated remediation cycle and configured to calculate a Ct value of the water chemical feed system. The programmable controller activates a chemical feed system to supply an acid, an oxidizer and a chlorite ion donor to a conduit to form chlorine dioxide that is supplied to the water until a desire Ct value is reached.

This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.

Provided are a water treatment method and a water treatment device wherein in a biological treatment of ammonium nitrogen-containing water to be treated, the water to be treated can be treated stably at a high treatment speed even when the nitrogen concentration of the water to be treated is high. This water treatment device biologically treats ammonium nitrogen-containing water to be treated. The water treatment device (water treatment method) is provided with: a nitrification device (nitrification step) for oxidizing ammonium nitrogen to nitrite or nitrate nitrogen using nitrifying bacteria including autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria contained in microbial activated sludge; and a nitrification rate control means which maintains a molybdenum compound in the nitrification device in such a manner as to control the molybdenum concentration of the water to be treated to 0.025 mg Mo/gN or more, and controls the nitrification rate for the sludge to 0.11 [kgN/(kgVSS.Math.day)].

A method of treating a sulphate-bearing stream which includes the steps of hydrolysing aluminium sulphate to produce a chemically-reactive aluminium trihydroxide and sulphuric acid, adding lime to immobilize the sulphuric acid as gypsum and using the aluminium trihydroxide to remove sulphate from the sulphate-bearing stream without interference of sulphate derived from the aluminium sulphate used as an aluminium source in the hydrolysis step.

A water-processing electrochemical reactor that comprises a cylindrical inner anode (73), an outer tubular cathode (74), an intermediate chamber between the anode (73) and the cathode (74) and being crossed by the water, an outer shell (77) surrounding the cathode (74), a water inlet (71) and a water outlet (78), and a gas inlet (80) and gas outlet (79) connected to the outer shell (77) and to the gas chamber. The cathode surrounds the inner anode (73) and is porous to gas. A gas chamber is defined between the cathode (74) and the outer shell (77). The gas chamber contains a gas comprising oxygen and is at an overpressure that forces the gas through the porous cathode (74).

The present invention relates to a process and plant for treating feed water containing nitrate. The process includes, sorbing nitrate from the feed water onto an ion exchange resin to form a loaded resin and produce a treated water stream depleted in nitrate, regenerating the loaded resin so that the resin can be reused and produce a brine stream high in nitrate; and converting nitrate in the brine stream into molecular nitrogen gas with the assistance of a bioactive agent.

Methods of treating a waste stream containing perfluoroalkyl substances (PFAS) are disclosed. The methods include directing the waste stream to a dilution compartment of an electrochemical separation device, directing a treatment stream to a concentration compartment of the electrochemical separation device, and applying a voltage across the electrodes to produce a dilute stream substantially free of the PFAS and a concentrate stream. At least one of the waste stream and the treatment stream comprises a water miscible organic solvent. Methods of concentrating PFAS from a wastewater are also disclosed. PFAS concentration systems are also disclosed. The systems include a column comprising an ion exchange resin and an electrochemical separation device having a dilution compartment fluidly connected to an outlet of the column. Methods of facilitating treatment of a waste stream containing PFAS are also disclosed.

Disclosed are wastewater treatment systems and methods for semiconductor fabrication process. The method comprises performing first concentration on wastewater discharged from a semiconductor process chamber, and performing second concentration on concentrated wastewater or at least a portion of the wastewater concentrated by the first concentration. The step of performing the first concentration includes performing in a first electrodialysis apparatus an ion exchange between the wastewater and first treatment water. The step of performing the second concentration includes allowing the concentrated wastewater to circulate in a second electrodialysis apparatus, allowing second treatment water to circulate in the second electrodialysis apparatus, providing a power to an anode and a cathode of the second electrodialysis apparatus to perform an ion exchange between the second treatment water and the concentrated wastewater, and joining a portion of the concentrated wastewater to the second treatment water.

A management device for a water treatment facility includes: a transmembrane pressure difference prediction unit configured to predict a general trend in a transmembrane pressure difference in a water treatment system based on an operation information, the operation information being related to the water treatment system including a membrane separation device installed therein; a chemical solution cleaning planning unit configured to devise such a chemical solution cleaning plan that chemical solution cleaning is performed before a period when a value of the transmembrane pressure difference predicted reaches a specified value; and a chemical solution order placement information generation unit configured to generate chemical solution order placement information based on the and the cleaning chemical solution stock information.