An exhaust gas cleaning system comprises a first sub system including a scrubber unit comprising a scrubber arranged to wash the exhaust gas with a scrubber fluid, and a centrifugal separator arranged in communication with the scrubber unit for receiving the scrubber fluid after washing and separate it into a first and a second fraction, which second fraction is more polluted than the first fraction. The exhaust gas cleaning system further comprises a second sub system including a membrane filter arranged in communication with the centrifugal separator for receiving the first fraction output from the centrifugal separator and separating it into a third and a fourth fraction, which fourth fraction is more polluted than the third fraction. A method for cleaning exhaust gas onboard a ship involves cleaning an exhaust gas onboard a ship.

The present invention provides a new method for fixing carbon dioxide. A method for fixing carbon dioxide, includes: a contact step of bringing a mixed liquid containing at least one of sodium hydroxide or potassium hydroxide and further containing at least one of a chloride of a Group 2 element or a chloride of a divalent metal element into contact with a gas containing carbon dioxide; and an electrolysis step of electrolyzing the mixed liquid after the contact to prepare a mixed liquid after the electrolysis. In the contact step, the mixed liquid after the electrolysis is reused as the mixed liquid.

Methods, systems, and techniques for desalinating monovalent anion species from wastewater. A system includes an electrodialysis stack that performs the desalination. The stack has a cathode, an anode, and at least one electrodialysis cell. The at least one electrodialysis cell includes a product chamber, a metal cation concentrating chamber adjacent to a cathodic side of the product chamber, and a transfer solution chamber adjacent to an anodic side of the product chamber. The product chamber and the metal cation concentrating chamber are each bounded by and share a cation exchange membrane, the product chamber and the transfer solution chamber are each bounded by and share a monovalent anion exchange membrane, and the transfer solution chamber is bounded on an anodic side by one of an anion exchange membrane and a monovalent anion exchange membrane. The wastewater may be generated by a flue gas desulfurization process.

Systems and methods of performing temperature swing solvent extraction (TSSE) descaling of produced water and desalination of high-salinity brines, e.g., those having a total dissolved solids (TDS) greater than about 250,000 ppm are capable of producing descaled water products including less than about 5% weight percent TDS. The brine/produced water feedstreams and combined with a solvent having temperature-dependent water solubility at a temperature T.sub.L. Water is extracted from the feedstream into the solvent to form a water-in-solvent extract component and a raffinate component, from which a solid phase can be precipitated as more water is portioned in the solvent and basicity increases. Heating of the water-in-solvent extract component reduces the solubility of the water therein, producing a biphasic mixture of dewatered solvent and descaled water that can be separated. Because these systems and methods do not require a phase change of water, these products are achieved with significantly higher energy efficiencies when compared to evaporation-based thermal methods.

An ash management trench system is provided for harvesting byproducts from sluice water, such as a discharge from a power plant. The system comprises a first section comprising at least one flow control structure. The at least one flow structure is typically configured to capture a predetermined byproduct. The system further comprises a second section comprising a stilling basin. The second section is coupled to the first section by a connection structure.

In a water treatment system, in particular for cooling towers, comprising a fluid basin and a circulation circuit designed to draw a fluid from the fluid basin and subsequently return it again, the circulation circuit comprising an ozone supply device for introducing ozone into the fluid, it is provided that the ozone supply device comprises a swirl chamber reactor and an ozone generator, which is connected to a filter system having an inlet opening for ambient air such that ambient air cleaned by the filter system, in particular substantially pure oxygen, can be fed to the ozone generator for ozone generation.

A treatment apparatus for treating wastewater produced by purification of an energy gas and containing at least an ammonium ion includes a decompression facility for reducing a pressure of the wastewater, an alkaline agent addition facility for adding an alkaline agent to the wastewater whose pressure has been reduced, and an ammonia stripping facility for stripping ammonia in the wastewater to which the alkaline agent has been added.

Activated iron media and methods for generating and using the activated iron media. The method involves aqueous suspension comprising a zero-valent iron, ferrous iron, and an iron oxide to provide a settled solid and re-suspending the settled solid to provide an aqueous suspension containing an activated iron media.

Methods and systems for reducing the concentration of selenium species in water, particularly water containing recalcitrant selenium species. In the methods and systems, water containing one or more selenium species is treated with permanganate to provide permanganate-treated water, which is then contacted with a zero-valent iron treatment system comprising (a) a reactive solid comprising zero-valent iron and one or more iron oxide minerals in contact therewith and (b) ferrous iron.

A method for removing or preventing a microbial growth, biofilm, biomass and/or mineral deposit on a hard surface inside an SO.sub.2 scrubber is disclosed. In particular, biocide compositions may be dosed in pulse or continuously for the reduction and prevention of biofilms on the hard surfaces inside an SO.sub.2 scrubber. A biocide composition disclosed here uses one or more non-oxidizing biocides, especially a mixture of one or more quaternary ammonium compounds and one or more other biocides.