The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 13, 1992
Filed:
Apr. 03, 1990
F Stephen Lupton, Evanston, IL (US);
Louis J DeFilippi, Prospect, IL (US);
James R Goodman, Chicago, IL (US);
Allied-Signal Inc., Morris Township, Morris County, NJ (US);
Abstract
Chromium in solid waste residues may be immobilized by reduction of essentially all of the Cr(VI) to insoluble Cr(III). The Cr(VI) is separated from the solids by contacting with an acid to produce an aqueous solution having a pH of about 6.5 to 9.5, then adding sulfate-reducing anaerobic bacteria and, as required, a source of sulfates and nutrients for the growth of the bacteria. Where the solid residues are below the surface of the soil, a continuous recirculation may be established to extract Cr(VI), treat the resulting solution above grade to reduce Cr(VI) to Cr(III), and return the treated solution to the soil.