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RE: Fluorides, POTW influent, & metal finishing
Perhaps obvious, hydrofluoric acid is frequently used in most processes
where glass is etched or frosted.
Related to this is a powdered chemical called "Lerite". Lerite contains
fluoride (as well as barium sulfate) and gets mixed with concentrated
hydrochloric acid to make a frosting bath for glass. (The company using
this material feels it's much safer than using HF directly.)
(Have you looked at the level of fluoride in the water supply pre-industrial
processes (or from local well water sources where the discharge might end up
at the treatment plant)?)
Raising another question, did fluoride added to drinking water supplies,
fluoride treatments at dentist offices, and the addition of fluorides to
toothpaste (or other dental/oral hygiene products) impact treatment plants
From: MARK STODDARD [mailto:MSTODDAR@dem.state.in.us]
Sent: Monday, June 05, 2000 5:15 PM
Subject: Fluorides, POTW influent, & metal finishing
I am searching for information on materials that are used in industry
that contain fluoride.
An Indiana POTW will have a fluoride limit (2 mg/L) imposed in its NPDES
permit. The POTW is concerned that it will not meet the limit due to the
average concentration (~8 mg/L which is two times the MCL of 4 mg/L) of
fluoride in the POTW influent. Downstream of the POTW discharge is an
intake for another city's drinking water.
The POTW is aware of one industrial user that etches steel using
Fluoboric acid (Tetrafluoroboric acid). The POTW would like that user to
explore other chemicals for use as an etchant whereas the industrial user
does not believe its use is contributing to the POTW's problem with
As part of the Office of Pollution Prevention & Technical Assistance, I
would like to assess other possible sources (contributions from certain
industrial sources, etc.) of fluorides to the POTW influent. Perhaps there
are industrial sources/uses that would commonly use materials that might
cause a fluoride discharge. Once I can narrow down the types of fluoride
compounds used and the types of sources using them, I want to find fluoride
subsitutes that could be considered/tested or possible use.
It would be great not only to help the POTW, but to help the POTW help
their industrial users.
Thanks for your input in this matter.
Mark C. Stoddard
<>"Watch "Echoes Through Penn's Woods" on public TV -- www.dep.state.pa.us