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:
Mar. 14, 1995
Filed:
Aug. 13, 1993
Applicant:
Inventors:
Dhiraj Pal, Chicago Heights, IL (US);
Karl W Yost, Crete, IL (US);
Assignee:
Sevenson Environmental Services, Inc., Niagara Falls, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C02F / ;
U.S. Cl.
CPC ...
210710 ; 210720 ; 210724 ; 210726 ; 210751 ; 210757 ; 210913 ; 405129 ; 423 55 ; 588256 ;
Abstract
A highly flexible multi-step treatment technology for chemical fixation and stabilization of leachable chromium, particularly hexavalent chrome, in contaminated soils, solid wastes, concrete, sludge, sand and gravel and waste waters is disclosed. The process comprises reducing hexavalent chromium to chromous (Cr.sup.2+) and chromic (Cr.sup.3+) forms in the presence of water under alkaline conditions and fixing the reduced chromium forms with phosphate. The process reduces Toxicity Characteristic Leaching Procedure chromium levels below the regulatory threshold of 5 mg/l as required by the USEPA.