Method of making pure salt from frac-water/wastewater

A method for making substantially pure salt from hydro-fracturing wastewater comprising:

• removing oil from hydro-fracturing wastewater selected from the group consisting of post-drilling flowback water and production brine water;
• removing solid particulates from the hydro-fracturing wastewater;
• removing large organic molecules selected from the group consisting of benzene, ethylbenzene, toluene and xylene from the hydro-fracturing wastewater;
• after removing the oil, the solid particulates and the large organic molecules, sampling the hydro-fracturing wastewater to determine an effective amount of at least one reagent to be added to the hydro-fracturing wastewater to form a precipitate comprising at least one chemical constituent selected from the group consisting of barium and strontium;
• adding the effective amount of the at least one reagent to the hydro-fracturing wastewater to produce a chemically treated wastewater and the precipitate;
• separating the precipitate from the chemically treated wastewater;
• after separating the precipitate, introducing the chemically treated wastewater to a crystallization process using a mechanical vapor recompression evaporator, multi-effect evaporator or a combination thereof to produce sodium chloride solids, a calcium chloride solution and a clean water distillate containing less than 500 ppm of total dissolved solids;
• drying the sodium chloride solids to produce over about 98% pure dry sodium chloride;
• recovering the calcium chloride solution;
• recovering the clean water distillate;
• and
• using the clean water distillate as source water for hydro-fracturing or returning the clean water distillate to the environment.

A method for making substantially pure salt from hydro-fracturing wastewater comprising:

• removing oil from hydro-fracturing wastewater selected from the group consisting of post-drilling flowback water and production brine water;
• removing solid particulates from the hydro-fracturing wastewater;
• removing large organic molecules selected from the group consisting of benzene, ethylbenzene, toluene and xylene from the hydro-fracturing wastewater;
• after removing the oil, the solid particulates and the large organic molecules, evaporating the hydro-fracturing wastewater to produce a concentrated brine containing from about 15 wt % to about 30 wt % of salt relative to the total weight of the concentrated brine and a first clean water distillate containing less than about 500 ppm of total dissolved solids;
• adding an effective amount of at least one reagent to the concentrated brine to produce a chemically treated brine and a precipitate comprising at least one chemical constituent selected from the group consisting of barium and strontium;
• separating the precipitate from the chemically treated brine;
• after separating the precipitate, introducing the chemically treated brine to a crystallization process to produce sodium chloride solids, a calcium chloride solution and a second clean water distillate containing less than 500 ppm of total dissolved solids, wherein the first and second clean water distillates are usable as source water for hydro-fracturing or returnable to the environment;
• and
• drying the sodium chloride solids to produce over about 98% pure dry sodium chloride.

A method for making substantially pure salt from hydro-fracturing wastewater comprising:

• removing oil from hydro-fracturing wastewater selected from the group consisting of post-drilling flowback water and production brine water;
• removing solid particulates from the hydro-fracturing wastewater;
• removing large organic molecules selected from the group consisting of benzene, ethylbenzene, toluene and xylene from the hydro-fracturing wastewater;
• after removing the oil, the solid particulates and the large organic molecules, adding an effective amount of at least one reagent to the hydro-fracturing wastewater to produce a chemically treated wastewater and a precipitate comprising at least one chemical constituent selected from the group consisting of barium and strontium;
• separating the precipitate from the chemically treated wastewater;
• after separating the precipitate, introducing the chemically treated wastewater to a crystallization process to produce sodium chloride solids, a calcium chloride solution and a clean water distillate containing less than 500 ppm of total dissolved solids, wherein the clean water distillate is usable as source water for hydro-fracturing or returnable to the environment;
• and
• drying the sodium chloride solids to produce over about 98% pure dry sodium chloride.