Without knowing current ...
Published by sushant kumar, Water and waste water treatment consultacy at Consultant
Without knowing current treatment scheme, influent and effluent parameters (pH, BOD, COD, TSS, TDS, Iron, Oil & Grease, Flow) I won't recommend anything. As you want solution for welfare of industry and society i appreciate your initiative, as a short cut, I can say to introduce some proven flocculants for heavy metals or bioflocculants as recommended by sarath babu. You can also suggest them to try iron removal filter as well in case only iron is issue).
I have a green solution if they can go for plant upgradation because it involves conducting treatability studies and plant installation.