A method and system of removing environmental contaminants from water comprising adding a fatty chemical to form a mixture with the water in which the fatty chemical and the environmental contaminants complex to form molecular complexes. The mixture is then filtered to remove the molecular complexes from the water.

Systems and methods including a pretreatment component for pretreating a produced water obtained from a subterranean formation operation to remove at least a portion of dispersed hydrocarbons and hydrogen sulfide therein, thereby producing a high salinity produced water; a desalination component for desalinating of the high salinity produced water to remove at least one or more salts therein, thereby producing a desalinated water and a saturated saline water; and a mineral recovery component for treating the saturated saline water to recover mineral salts therein, thereby producing the recovered mineral salts.

A liquid purification system includes a system raw liquid feed unit and a filtration unit, which includes a liquid concentration device having an internal partition dividing a variable volume collection cavity for raw liquid coming from an initial stage of liquid filtration and for mixing therein concentrate and a raw liquid displacement cavity. The cavity is connected to a secondary line that supplies raw liquid to the cavity to displace concentrate from the collection cavity and to recycle raw liquid from the displacement cavity through the secondary line under pressure exerted by concentrate and raw liquid in the collection cavity. A filtration unit provides long-term contact between raw liquid and concentrate in the variable-volume collection cavity to provide smooth increase in the concentration of liquid supplied to a liquid purification device.