What is the requirement for treated effluent to be discharged to municipal sewage line?

Currently :

1. The effluent generated is from Aluminium Anodizing and Powder Coating Pretreatment plant.

2. Chemicals used in this process are Caustic Soda, Sulphuric Acid, Tin Sulphate, Nickel, Fluoride, Hydrogen and Titanium                    
     based chemicals and some phosphates.

3. We have an ETP with neutralization, clarifier and filter press.

4. Effluents contains Aluminum, Tin, Fluorides, Sulphates, Titanium, Nickel etc,

5. Treated water TDS is around 50000 ppm.

Could this effluent be directly discharged to the municipal sewage line? Information on regulations and  norms with respect to the discharge of treated effluent will be helpful.

Narala Surender
surender100@yahoo.com