Can Sulfide Precipitation Meet Proposed MPM Limits on Heavy Metals?

$17.50 plus tax (Refund Policy)

Buy Article:

Abstract:

In view of the stringent nature of the US EPA's newly proposed categorical pretreatment effluent standards for the Metal Products and Machinery industry, metal-sulfide precipitation was evaluated as a potential alternative to the currently used metal-hydroxide precipitation for the removal of Cu, Ni, Pb, and Zn. There were two aspects of this study: 1) theoretical analysis of both metal-hydroxide and metal-sulfide chemistry with and without ethylenediaminetetraacetic acid (EDTA) and 2) experimental evaluation of commercial sulfide-containing precipitants using wastewater samples from three Ford plants. The primary findings are:



In theory, metal-hydroxide chemistry can achieve the proposed standards in an ideal situation (i.e., no chelating agents and other constituents in water) but not in the presence of even a small amount of a chelating agent (e.g., as small as 1 mg/L of EDTA).


Metal-sulfide precipitation could achieve solubility limits lower than those of metalhydroxide precipitation over a wide range of pH. However, EDTA could still increase the limits of Ni, Pb, and Zn above the standards.


The experiments with wastewater samples showed all sulfur-containing precipitants removed Cu well while Ni and Zn were not well removed. The sample from a transmission plant was the most difficult to treat, suggesting that it might have had more chelating agents than the other samples. The commercial precipitants used did not perform any better than sodium sulfide.


Costs for using the precipitants were estimated to range <1/1000 gal to >5/1000 gal depending on the precipitant.

Document Type: Research Article

DOI: http://dx.doi.org/10.2175/193864700784608586

Publication date: January 1, 2000

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • ingentaconnect is not responsible for the content or availability of external websites

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more