| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating heavy metal-containing waste water which can remove heavy metals in the heavy metal-containing waste water to an extremely low level.SOLUTION: In the method for treating heavy metal-containing waste water, magnesium chloride is added to the heavy metal-containing waste water to make pH 11 or more, then a polymer flocculant is added to carry out first solid-liquid separation treatment, thereafter an iron-based inorganic flocculant is added to a treated water of the first solid-liquid separation treatment to make pH 9.5 to 11 and then second solid-liquid separation treatment is carried out. As the iron-based inorganic flocculant, ferric chloride is suitable. Since heavy metal concentration in the treated water is low, a reverse osmosis membrane does not deteriorate even when reverse osmosis treatment is further carried out. |
