Dear Sir. Concerning your issue about the discharge of dye in wastewater stream . Under the Environmental Protection and Management (Trade Effluent) Regulations, no trade effluent shall be discharged into any watercourse or land without a written permission approved by the Director-General. A person to whom a written permission has been granted or renewed shall not discharge trade effluent into any watercourse or land otherwise than in accordance with these Regulations. The allowable limits for trade effluent discharge are stated in the following below links may help you in your analysis:

http://www.nea.gov.sg/anti-pollution-radiation-protection/water-pollution-control/allowable-limits

Thanks

It depends on type of effluents - check my review papers on advanced oxidation processes you can find there an examples of dyes treatment.

Regards

G

The discharge of a dye to wastewater is regulated by national authorities in every country or state as mentions Isam Eldin Hussein Elgailani above. But common practice used is pretreatment of wastewater containing dyes in the place, where it is produced, to reduce dye concentration as much as possible. There is more reasons for such strategy:

i) The volume of wastewater containing dyes to be treated is small

ii) When dyes are diluted with other wastewater, the treatment of lower concentration of dyes but substantially larger volume of wastewater is technically and economically much more demanding.

iii) The efficiency of treatment of dyes in lower concentrations is smaller.

Best regards

Vit

https://doi.org/10.30799/jacs.188.18040304

https://www.academia.edu/download/64405174/TreatmentofDisperseBlue14RJCES.pdf

Check these publications