Bacterial leaching process and composition
US5217615A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 25, 1991 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Feb 25, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S435/832
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The present invention relates to a process for removing heavy metals and substantially destroying indicator bacteria present in municipal sludges, which comprises: lowering, under aerobic conditions, the pH of a municipal sludge from about 7 to 8 to about 2.0 to 2.5 by adding to said sludge 10% by volume of an inoculum containing a mixture of microorganisms comprising Thiobacillus thiooxidans ATCC 55127 and Thiobacillus thioparus ATCC 55128 with 1 to 3 g per liter of sulphur, and incubating for a period of at least 40 hours where the heavy metals originally present in said sludge have been substantially solubilized and the concentration of the indicator bacteria have been lowered to a non-toxic level; and recovering the metals from the low pH treated sludge of step a).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.