| 摘要 |
PURPOSE:To provide a method of the purification of metal plating waste water, wherein to the waste water containing ESTA, HCHO, Cu, etc. are added an alkali, a mineral acid, an alkali, an oxidizing agent, a mineral acid and activated carbon in this order so that organic contaminants in the waste water can be removed with a higher elimination rate. CONSTITUTION:Chemical copper plating waste water containing EDTA, HCHO, Cu, etc. is added with an alkali such as slaked lime to adjust its pH value to not less than 12, the resulting precipitate is removed, the filtrate is added with a mineral acid to adjust its pH value to between 1 and 3, the second resulting precipitate is removed, the second filtrate is added with an alkali such as NaOH to adjust its pH value to between 10 and 13, then is added with an oxidizing agent such as hydrogen peroxide followed by its pH adjustment to between 2 and 4, and after the thus treated waste water is added with activated carbon, the solid portion and liquid portion are separated. In the present method, organic contaminants which hitherto has not been removed by a conventional method using a ferric salt, an aluminium salt, NaOH and high polymeric flocculant can be effectively removed. |
