Waste water treatment apparatus and waste water treatment method using the waste water treatment apparatus

摘要

PROBLEM TO BE SOLVED: To provide a wastewater treatment apparatus capable of facilitating the pH adjustment of wastewater, reducing the amounts of used alkali agent and oxidizing agent, and obtaining reverse osmosis membrane treated water having a very low zinc concentration, and a wastewater treatment method using the wastewater treatment apparatus.SOLUTION: A wastewater treatment apparatus for treating wastewater containing zinc comprises: a first agitating tank in which the pH of the wastewater is adjusted to 11 or more with an alkali agent; a second agitating tank in which a neutral coagulant containing food additives and a coprecipitating agent to adjust the pH of the wastewater to 10 or more and 12 or less; a third agitating tank in which an oxidizing agent is added to adjust the pH of the wastewater to 9 or more and 11 or less; a neutralization tank in which the pH of the wastewater is adjusted to 8 or more and 9 or less; a settling tank for precipitating aggregates; and a filtration device having reverse osmosis membrane filtration units. A wastewater treatment method uses the wastewater treatment apparatus.SELECTED DRAWING: Figure 1