Methods and systems directed to recovery of lithium (e.g., lithium salts) from liquid streams are provided. In some embodiments, methods relate to obtaining lithium (e.g., as a solid lithium salt) by removing at least a portion of liquid from a feed stream to form a concentrated stream with respect to solubilized lithium cations. Liquid removal may include transporting at least a portion of the feed stream to an osmotic unit and/or a humidifier. Some methods include removing impurities (e.g., non-lithium cations) from the concentrated stream (e.g., via precipitation and/or crystallization). In some embodiments, solutions containing solubilized lithium cations and anions are electrochemically-treated such that first solubilized anions are replaced with second, different anions. In some embodiments, solid lithium salt containing at least a portion of the lithium cations and the second anions is obtained (e.g., via precipitation and/or crystallization following concentration of the electrochemically-treated solution in a humidifier).

Methods, systems, and apparatus, relate to a method for carbon capture from sea water. A first source of sea water into a reverse osmosis chamber. Reverse osmosis is performed on the sea water to produce fresh water and brine. The brine is provided to an electrolyzer. A current is passed through the brine and fresh water, thereby producing a hydroxide solution in a cathode chamber of the electrolyzer. The hydroxide solution is collected and placed into a contacting chamber and new sea water introduced. Precipitates are produced comprising at least calcium carbonate and magnesium carbonate.

According to one embodiment, there is provided a carbon dioxide fixation system includes an electrolytic cell and a settling tank. An electrolytic cell electrolyzes seawater to generate sodium hydroxide (NaOH). A settling tank mixes the sodium hydroxide generated in the electrolytic cell, concentrated seawater, and carbon dioxide (CO.sub.2) to precipitate magnesium carbonate in which the carbon dioxide is fixed to magnesium (Mg) contained in the concentrated seawater.

A composition for treating swimming pool water comprises sodium bisulphate and aluminium sulphate. The aluminium sulphate in the composition minimizes the precipitation of sodium bisulphate at temperatures lower than about 5 degrees Celsius for a time period to maintain a concentrated form of acid to control the pH level of the water. In some embodiments, the composition includes 30 to 40% sodium bisulphate (NaHSO4) wt/wt %, 0.2% to 5% aluminium sulphate Al2(SO4)3 wt/wt %, 0.1% to 1% copper sulphate/chelating agent wt/wt %, 0.01% to 0.02% sodium hydroxide, and balance water.

The present invention relates to a method for recovering N, K, and P from liquid waste stream, preferably from a stream of urine, or from a stream comprising excreta (e.g. faeces, manure, digestate, fertilizer), or from (concentrated) wastewater, for example, municipal (e.g. sewage, septic) and/or industrial wastewater (e.g. food and feed industry, agriculture, mining, etc.); more preferably from urine, such as human or animal urine; most preferably from human urine.

There is provided a method for controlling bio-slimes in a clean circulating water system through a physical-chemical-superconducting high gradient magnetic separation coupling process. An inorganic composite flocculant is added to circulating water to gather Zoogloea in the circulating water with micro-nano particles in hydrosol through demulsification to form alum floc. The resulting water passes through a superconducting high gradient magnetic separation system. A magnetic field strength of the superconducting high gradient magnetic separation system and flow rate of the circulating water are controlled to generate strong magnetic flocculation to allow floc to grow, such that the Zoogloea in the circulating water wraps the micro-nano particles to separate the Zoogloea from water.

A water remediation system and accompanying method includes remediation by reducing the concentration of nutrients in the water and dosing the water with metal ions. It has been found that through a combination of reducing nutrients present in the water and treating with metal ions, the requirement to treat with high chemical dosages is removed.

A method of extracting lithium from a lithium-containing solution according to an exemplary embodiment of the present invention includes: obtaining a lithium chloride solution from the lithium-containing solution; and crystallizing and removing sodium chloride in the obtained lithium chloride solution.

A method of extracting lithium from a lithium-containing solution according to an exemplary embodiment of the present invention includes: obtaining a lithium chloride solution from the lithium-containing solution; and crystallizing and removing sodium chloride in the obtained lithium chloride solution.

Disclosed is a system for producing magnesium hydroxide including: a generation unit; and a recovery unit connected to the generation unit, wherein the generation unit has a reaction tank in which a calcium hydroxide slurry is added to water to be treated containing magnesium ions to crystallize magnesium hydroxide and to obtain a reaction slurry containing particles of magnesium hydroxide, and a sedimentation tank in which the reaction slurry is reserved to sediment the particles and to separate the reaction slurry into a separation slurry containing the particles at a high concentration and a separation liquid containing the particles at a low concentration, and wherein, in the recovery unit, an alkaline aqueous solution is added to the separation liquid to crystallize magnesium hydroxide and to obtain the reaction slurry and then the reaction slurry is reserved to sediment the particles and to recover the sedimented particles.