A method of desulfating seawater includes adding a produced water to a sulfated seawater, forming a first precipitate, separating the first precipitate from the sulfated seawater, measuring the sulfate ion concentration of the desulfated seawater, adding a precipitating agent to the sulfated seawater, and separating a second precipitate from the sulfated seawater. Another method of desulfating seawater includes determining concentrations of sulfates in a sulfated seawater and a precipitating agent in a produced water, adding the produced water to the sulfated seawater based on the determined concentrations of sulfates in the sulfated seawater and the precipitating agent in the produced water, forming a first precipitate, separating the first precipitate from the sulfated seawater, measuring the sulfate ion concentration of the desulfated seawater, adding a precipitating agent to a sulfated seawater, and separating a second precipitate from the sulfated seawater.

A process for treating frac flowback that contains barium, naturally occurring radioactive materials (NORM) and hardness for minimizing the amount of sludge produced that contains hazardous levels of NORM by employing a dual stage precipitation process. In the first stage a sulfate source is mixed with the frac flowback and barium sulfate and NORM is precipitated, the frac flowback is subjected to a solids-liquid separation process to produce a first effluent and a first sludge. In the second stage hardness is precipitated from the first effluent by addition of an alkali reagent, said first effluent is also subjected to solids-liquid separation producing a second effluent and a second sludge. The first sludge is recycled and mixed with the frac flowback and the sulfate source in a sufficient amount to maintain the NORM concentration in the second sludge at or below a threshold level.

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.

Methods and systems for removal of ions from aqueous fluids are provided. In certain embodiments, the present disclosure provides a method of removing one or more oxyanions from an aqueous fluid, including the steps of contacting an aqueous fluid containing oxyanions with an aluminum metal whereby aluminum ions are released from the aluminum metal into the aqueous fluid, wherein the one or more oxyanions in the aqueous fluid react with the aluminum ions to form one or more ettringites; controlling a rate of release of the aluminum ions from the aluminum metal; and removing at least a portion of precipitated ettringites from the aqueous fluid.

A process for treating frac flowback that contains barium, naturally occurring radioactive materials (NORM) and hardness for minimizing the amount of sludge produced that contains hazardous levels of NORM by employing a dual stage precipitation process. In the first stage a sulfate source is mixed with the frac flowback and barium sulfate and NORM is precipitated, the frac flowback is subjected to a solids-liquid separation process to produce a first effluent and a first sludge. In the second stage hardness is precipitated from the first effluent by addition of an alkali reagent, said first effluent is also subjected to solids-liquid separation producing a second effluent and a second sludge. The first sludge is recycled and mixed with the frac flowback and the sulfate source in a sufficient amount to maintain the NORM concentration in the second sludge at or below a threshold level.

Methods and systems for removal of ions from aqueous fluids are provided. In certain embodiments, the present disclosure provides a method of removing one or more oxyanions from an aqueous fluid, including the steps of contacting an aqueous fluid containing oxyanions with an aluminum metal whereby aluminum ions are released from the aluminum metal into the aqueous fluid, wherein the one or more oxyanions in the aqueous fluid react with the aluminum ions to form one or more ettringites; controlling a rate of release of the aluminum ions from the aluminum metal; and removing at least a portion of precipitated ettringites from the aqueous fluid.

Methods and systems for removal of ions from aqueous fluids are provided. In certain embodiments, the present disclosure provides a method of removing one or more oxyanions from an aqueous fluid, including the steps of contacting an aqueous fluid containing oxyanions with an aluminum metal whereby aluminum ions are released from the aluminum metal into the aqueous fluid, wherein the one or more oxyanions in the aqueous fluid react with the aluminum ions to form one or more ettringites; controlling a rate of release of the aluminum ions from the aluminum metal; and removing at least a portion of precipitated ettringites from the aqueous fluid.

The present disclosure belongs to the field of environmental protection and relates to a method for remediating groundwater chlorophenols organic contamination. The method includes determining a location of a contamination source; setting up an injection well based on the location of the contamination source; and injecting a remediation reagent into groundwater in a to-be-remediated region through the injection well so as to degrade chlorophenols organic contamination in the groundwater in the to-be-remediated region.

Precipitation or scaling may occur when combining produced water from multiple sources, such as when one produced water contains dissolved calcium ions and another produced water contains dissolved sulfate anions. The tendency toward precipitation or scaling may be decreased by treating the produced water containing dissolved sulfate anions. Such methods may comprise: providing a first produced water comprising dissolved sulfate anions; treating the first produced water with a metal salt capable of forming an insoluble metal sulfate, thereby forming a metal sulfate precipitate and a treated produced water; separating the metal sulfate precipitate from the treated produced water; and after separating the metal sulfate precipitate, mixing the treated produced water with at least one second produced water to obtain a mixed produced water, the at least one second produced water containing dissolved calcium ions, and the mixed produced water having a saturation ratio for calcium sulfate of less than 1.

A system and method retrieves liquid stream data associated with a first liquid stream that includes a set of chemical compounds. and a set of parameters. The system also retrieves reference data that is associated with a reference liquid stream, and includes a set of reference parameters. The system compares at least a first parameter of the set of liquid-stream parameters with a corresponding reference parameter of the set of reference parameters. The system also controls an output of the first liquid stream based on the comparison of parameters.