US 12,351,497 B2
Methods and systems for treating phosphogypsum-containing water
Wenxin Du, Dover, NH (US); Hao Dang, Dracut, MA (US); George Y. Gu, Andover, MA (US); Michael J. Shaw, Derry, NH (US); Simon P. Dukes, Chelmsford, MA (US); and Justin Wayne Higgs, Nolensville, TN (US)
Assigned to EVOQUA WATER TECHNOLOGIES LLC, Pittsburgh, PA (US)
Appl. No. 17/276,352
Filed by Evoqua Water Technolgies LLC, Pittsburgh, PA (US)
PCT Filed Aug. 21, 2019, PCT No. PCT/US2019/047558
§ 371(c)(1), (2) Date Jun. 15, 2021,
PCT Pub. No. WO2020/041507, PCT Pub. Date Feb. 27, 2020.
Claims priority of provisional application 62/846,952, filed on May 13, 2019.
Claims priority of provisional application 62/844,173, filed on May 7, 2019.
Claims priority of provisional application 62/798,696, filed on Jan. 30, 2019.
Claims priority of provisional application 62/770,470, filed on Nov. 21, 2018.
Claims priority of provisional application 62/720,566, filed on Aug. 21, 2018.
Prior Publication US 2023/0145108 A1, May 11, 2023
Int. Cl. C02F 1/20 (2023.01); C02F 1/44 (2023.01); C02F 1/461 (2023.01); C02F 9/00 (2023.01); C05C 1/00 (2006.01); C02F 101/10 (2006.01); C02F 101/16 (2006.01)
CPC C02F 9/00 (2013.01) [C02F 1/20 (2013.01); C02F 1/441 (2013.01); C02F 1/444 (2013.01); C02F 1/461 (2013.01); C05C 1/00 (2013.01); C02F 2101/105 (2013.01); C02F 2101/16 (2013.01); C02F 2209/06 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of treating phosphogypsum-containing water, comprising:
promoting precipitation of at least one target constituent from the phosphogypsum-containing water in one or more steps to produce a supernatant water;
introducing aluminum to the supernatant water using electrolytic addition from the electrolysis of an anode consisting of aluminum to provide a pretreated supernatant water having a reduced silica level;
subjecting the pretreated supernatant water to membrane separation to produce treated water that meets at least one predetermined discharge requirement and a concentrate stream;
recycling the concentrate stream back to a source of the phosphogypsum-containing water;
removing ammonia from at least one of the pretreated supernatant water, upstream of the membrane separation, and the concentrate stream by membrane degasification;
controlling a rate of the ammonia removal to maintain or reduce an ammonia concentration of the source of the phosphogypsum-containing water to offset ammonia present in the concentrate stream that is recycled back to the source of the phosphogypsum-containing water; and
discharging the treated water.