A process and apparatus for enhanced boron removal from water. The process includes the steps of reacting potassium carbonate or ammonium carbonate with calcium borate in a stream of feed water to form a stream having calcium carbonate and potassium borate salt or ammonium borate salt. The stream having calcium carbonate and potassium borate or ammonium borate is introduced to an ion exchange vessel containing resin having methylglucamine in salt form with potassium carbonate or sodium carbonate to form borate and potassium sulfate or sodium sulfate. The resin in the ion exchange vessel is periodically regenerated.

Many processes generate wastewater streams rich in sulfate and chloride. These salt components are traditionally not recovered and are discharged to the environment. The invention recovers pure water for recycle/reuse and simultaneously generates valuable pure salts of NaCl and Na2SO.sub.4 for beneficial reuse, eliminating the waste stream. Process consists of the sequential crystallization of salt products with an intermediate purification step in which a chemical reactant is added to elevate levels of purity. The process is configured to simultaneously achieve zero liquid discharge.

As pellets grow from seed/sand in a fluidized bed pellent reactor, the weight of the reactor is measured and the density of the contents of the reactor is calculated, and the input flow of untreated water, water treatement chemical, and seed/sand are adjusted to provide improved removal of water hardness while reducing fine particulates in the outflow of softened water from the reactor.

A method for removing calcium ions from high concentration organic wastewater is provided. The method comprises the steps of: (1) introducing high concentration organic wastewater containing Ca.sup.2+, inorganic carbon and a seed crystal into a reactor with a molar ratio of Ca.sup.2+ to inorganic carbon of 1:(3.2-6.2); (2) adjusting the hydrogen ion activity α(H.sup.+) and ionic strength of the solution in the reactor; (3) sequentially stirring and precipitating in the reactor to convert Ca.sup.2+ in the high concentration organic wastewater into calcium carbonate which is then precipitated for calcium removal.

Processes and apparatus are provided for recovery of dissolved species from wastewater streams, in the form of precipitates sized by elutriation. The processes may for example be controlled so that the recovered sized solids are in the form of relatively insoluble plant nutrients, such as struvite. The extracted nutrients may for example include solid species of phosphorus, and/or nitrogen, and/or potassium.

An industrial waste salt resourceful treatment method comprises the following steps: the industrial waste salt is sequentially subject to dissolving, chemical pre-purification, deep purification, organic matter concentration reduction, adsorption and oxidation decolorization and multi-effect evaporative crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals; the crystallization temperature of sodium sulfate is in a range of 75° C. to 85° C.; the crystallization temperature of sodium chloride is in a range of 60 to 70° C.; and the crystallization temperature of sodium nitrate is in a range of 45° C. to 55° C. An industrial waste salt resourceful treatment device is further provided.

The invention generally relates to methods of removing potassium, rubidium, and/or cesium, selectively or in combination, from brines using tetrafluoroborates. Also disclosed are methods of producing potassium, rubidium, and/or cesium chlorides using ionic liquids and exchange media. This invention also generally relates to treated geothermal brine compositions containing reduced concentrations of silica, iron, and potassium compared to the untreated brines. Exemplary compositions of the treated brine contain a concentration of silica ranging from about 0 mg/kg to about 15 mg/kg, a concentration of iron ranging from about 0 mg/kg to about 10 mg/kg, and a concentration of potassium ranging from about 300 mg/kg to about 8500 mg/kg. Other exemplary compositions of the treated brines also contain reduced concentrations of elements like rubidium, cesium, and lithium.

An ion-exchange resin regeneration system includes: salt water flowing means that flows an aqueous sodium chloride solution or an aqueous potassium chloride solution into a container storing ion-exchange resin; and hard water component crystallizing means that crystallizes and removes hard water components containing metal ions from drained water arising from the ion-exchange resin through which the aqueous sodium chloride solution or the aqueous potassium chloride solution has flowed.

A zero-liquid discharge (ZLD) wastewater treatment apparatus is provided. The ZLD wastewater treatment apparatus includes a concentrator configured to concentrate wastewater to produce a primary concentrate, an evaporation crystallizer configured to concentrate and crystallize the primary concentrate to produce a secondary concentrate, a cooling crystallizer configured to cool the secondary concentrate to generate crystals from the secondary concentrate, a dehydrator configured to separate the product produced by the cooling crystallizer into a solid component and a liquid component, and a cooling system configured to cool the secondary concentrate introduced into the cooling crystallizer, wherein the liquid component produced by the dehydrator heat exchanges with a cooling medium in the cooling system and returns to the evaporation crystallizer.

A system and method for treating reverse-osmosis (RO) concentrated water with high temporary hardness. The system includes a crystallization unit, a precipitation unit, a dewatering unit, and a programmable logic controller (PLC) system. The crystallization unit, precipitation unit and dewatering unit are connected in series, and the PLC system is configured to control pumps, valves, and displays in the crystallization unit, precipitation unit and dewatering unit. The crystallization unit includes a storage tank and a crystallization reactor communicated therewith. The crystallization reactor is provided with a pH meter, a liquid-level gauge, and a stirrer. A connection pipe between the crystallization reactor and the RO concentrated water is provided with an inlet pump and a inlet valve. A connection pipe between the crystallization reactor and the storage tank is provided with a feeding pump and a feeding valve.