Abstract: Methods for treating phosphogypsum-containing water are disclosed. The water may be treated so as to promote precipitation of one or more target constituents and to facilitate downstream membrane treatment. A coagulant may be added to promote phosphate recovery. Ammonia may optionally be removed. Related systems are also disclosed.

Abstract: A monovalent selective ion exchange membrane is disclosed. The membrane includes a polymeric microporous substrate, a cross-linked ion-transferring polymeric layer on a surface of the substrate, and a charged functionalizing layer covalently bound to the ion-transferring layer. A method of producing a monovalent selective cation exchange membrane is also disclosed. The method may include chemically adsorbing a styrene intermediate layer to a cross-linked ion-transferring polymeric layer on a surface of a polymeric microporous substrate, chlorosulfonating the styrene intermediate layer to attach a sulfonyl chloride group layer, aminating the sulfonyl group layer to attach an amine group layer, and functionalizing the amine group layer with a charged compound layer to produce the cation exchange membrane.

Abstract: Techniques and systems for neutralizing discharge waters from ballast and/or cooling water biocidal treatment and disinfection systems are provided.

Abstract: Methods for processing pretreated phosphogypsum wastewater are disclosed. Precipitation of select constituents may be promoted to control a hardness level of the pretreated wastewater. Ammonia may then be removed from the process stream via reverse osmosis. A membrane contactor and/or polishing unit(s) may optionally be used. Related systems are also disclosed.

Abstract: An electrochlorination system includes an electrolyzer fluidically connectable between a source of feed fluid and a product fluid outlet, and a sub-system configured to one of increase a pH of the feed fluid, or increase a ratio of monovalent to divalent ions in the feed fluid, upstream of the electrolyzer.