-- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing.
    no popups, no spam
on this site
current topics
topic 1602

WWT reaction tank design.


What is considered to be the upper concentration limit for chromium +6 in a given influent rate for proper chrome reduction using the standard low pH-bisulfite process? Once the metals have been pre-treated (Cr reduction, metallic cyanide oxidation), what is the upper concentration limit for metals in a given influent rate for proper hydroxide formation using the standard CaCl2, NaOH process?

Are there any good reference materials available on design of WWT process tanks, gravity settlers, etc?


John Kostura


I don't know that there is any such limit. I haven't personally treated chrome plating solutions with bisulphate, but I have treated chromating solutions (2 to 5 percent chromic acid-sodium dichromate) and the reaction is not a problem.

Similarly, I have batch treated fairly concentrated acid dumps and cleaner dumps, and the reaction is not a problem.

However, there can be a logistics problem with physical separation processes (clarifiers, sludge thickeners, filter presses) as huge loads of solids come into play. And chrome waste are difficult to filter.

I don't know of any current books on the subject, although you might try to find Clarence Roy's book "Operation and Maintenance of Surface Finishing Wastewater Treatment Systems" [link is to book info at Amazon] or you might contact AESF ( regarding the manuals from their waste ewater treatment training course.

Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Comment to THIS thread START a NEW threadView CURRENT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.