| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a treatment method centering around the decoloration treatment of color substance-containing waste water not requiring tertiary treatment high in treatment cost and using active carbon or an oxidizing agent, not restricted by the kind of a dye, certainly removing a color substance in waste water, not leaving iron ions or SS in waste water after treatment, lowering the water content of a dehydrated cake, improving the releasability of a cake from filter cloth and bringing the pH of the cake to about 7. SOLUTION: An aq. soln. containing either one or both of a ferrous salt and a ferric salt and an aq. soln. containing either one or both of sodium sulfide and sodium hydrosulfide are reacted to form iron sulfide, which is, in turn, used as a decolorant flocculant to treat color substance-containing waste water. Since iron sulfide is extremely good in adsorbability, easy to increase in particle size and excellent from an aspect of the formation, flocculation and sedimentation of floc, the remaining of iron ions or SS in waste water after treatment can be prevented. Further, by together using a polymeric flocculant, treatment capacity can further be enhanced.</p> |
