Apparatus for treating wastewater and method of treating wastewater

An apparatus for treating wastewater, the apparatus comprising:

• a collecting tank configured to store wastewater including sulfate ions;
• a stirring tank configured to form sulfuric acid crystals by stirring (i) the wastewater including the sulfate ions and (ii) a solvent;
• a solvent supply device configured to supply a solvent to the stirring tank;
• and
• a separation tank configured to separate the sulfuric acid crystals and treated water from each other, from a mixture solution of the sulfuric acid crystals and the treated water,
• wherein the treated water is the wastewater from which the sulfuric acid crystals have been precipitated, and
• wherein the solvent is hydrophilic but has low affinity for the sulfate ions.

A method of treating wastewater, the method comprising:

• supplying, to a stirring tank, wastewater which includes sulfate ions and sodium ions and is stored in a collecting tank;
• supplying a solvent to the stirring tank into which the wastewater is supplied;
• forming sodium sulfate crystals by stirring the wastewater and the solvent supplied to the stirring tank;
• and
• supplying, to a separation tank, a mixture solution of the sodium sulfate crystals and treated water which is the wastewater from which the sodium sulfate crystals have been precipitated, and separating the sodium sulfate crystals and the treated water from each other in the separation tank,
• wherein the solvent is hydrophilic but has low affinity for the sulfate ions, and
• the separation tank comprises a precision filter.