Patent ID: 11945744
Assignee: SAMSUNG ELECTRONICS CO., LTD.
Field: Chemical engineering (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 8:
9. An apparatus for reusing wastewater, comprising: a first flocculation reactor configured to produce a first treated water by flocculating a mixed wastewater;
a third flocculation reactor configured to produce a third treated water by further flocculating the first treated water;
a fourth flocculation reactor configured to produce a fourth treated water by further flocculating the third treated water;
a sedimentation tank configured to produce fifth treated water and sludge by settling the fourth treated water;
an anoxic tank configured to produce a sixth treated water by performing a denitrification reaction on the fifth treated water;
an aerobic tank configured to produce a seventh treated water by removing organic matter from the sixth treated water and performing a nitrification reaction on the sixth treated water;
a separation membrane tank configured to produce an eighth treated water by removing particulate matter from the seventh treated water; and
a reverse-osmosis membrane unit configured to produce a concentrated water and a produced water by removing organic matter and inorganic ion components from the eighth treated water,
wherein the mixed wastewater refers to wastewater containing a mixture of hydrofluoric acid wastewater, other acidic wastewater, and alkaline wastewater produced from the semiconductor manufacturing process, or display manufacturing process, a total phosphorus (T-P) concentration in the mixed wastewater is 10 mg/L or less,
wherein a first chemical and a second chemical are introduced into the first flocculation reactor, a third chemical is introduced into the third flocculation reactor, and a fourth chemical is introduced into the fourth flocculation reactor,
wherein the first chemical comprises slaked lime, the second chemical comprises a hydrogen peroxide scavenger, the third chemical comprises a pH control agent, and the fourth chemical comprises an anionic polymer flocculant,
wherein a pH of the first flocculation reactor is 10.0 to 11.5, and a pH of the third flocculation reactor is 6.5 to 7.5, wherein an effluent of the separation membrane tank is adjusted to a pH of 5.8 to 6.5 and supplied to the reverse-osmosis membrane unit,
further comprising a deaeration tank configured to remove dissolved oxygen from an unfiltered water remaining in the separation membrane tank and introduce the unfiltered water into the anoxic tank, and a second return line configured to return the unfiltered water remaining in the separation membrane tank to the deaeration tank.