Naturally, material substitution is best. If that can be done, the problem is solved.
If not, additional information is needed. Preliminary questions would include:
1) What is the discharge limit for zinc?
2) Is there any existing pre-treatment done to the wastewater, including pH adjustment?
3) What budget has been established (capital on operating) to deal with this problem?
Other printers would have the same four options that are listed in the original posting. The only question to be answered is what is the best solution for this specific facility.
The following is a question posted from the PNEAC web site. I will forward responses to the originator.
We are working with a PNEAC member company on an issue regarding disposal of a process wastewater generated from a water based aqueous coating process. The wastewater contains approximately 3000 mg/l of zinc. The supplier has indicated that the zinc is
present in the coating as a drying agent.
We are discussing with the printer some alternatives for proper management of the wastewater, including material substitution, waste reduction, off-site disposal, and on-site treatment.
I would like to request any information regarding what other printers are doing to manage this specific type of wastestream. Any information regarding management alternatives and cost comparison would be helpful. Please contact me via phone or e-mail.
Thank you in advance for your assistance.