You need to test each dye to see how it responds to treatment. I have 3 dye types: inorganic, organic, and organometallic. Some of the organometallics contain heavy metal (chromium) and some are heavy metal-free. Also, some dyes are very stable – 6+ hours mixing with hypochlorite, while some decompose almost instantly. So, differences in treatment, and differences in disposal.
I don’t think the following sequence will do much:
“Filterd waste water go into floculation then cogulation…”
What will filtering remove? Dyes are soluble. Coagulation must precede flocculation. Sequence should be: *add coagulant, flocculate, sedimentation, filtration.
*Maybe biological treatment should be first; it can break down soluble dyes, so subsequent coagulation, etc. can remove metals. If you coagulate w/o biological, your sediment will be highly leachable.
I suggest buying this inexpensive book:
Advances in Industrial Wastewater Treatment by P. K. Goel. 500 pages, $20-22 + ~$3 shipping. About 50 pages on treating textile effluent, plus chapters on treating tannery and distillery effluents, and a review of general processes.
How expensive are the dyes that you use? You may save money on dyes and lower WWT costs if you also buy several smaller RO units as suggested in my first post.
Ken