Process for color reduction of dye wastewater
US5360551A · kind A · utility
17Cited by
17References
40Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 1, 1993 |
| Grant date | Nov 1, 1994 |
| Priority date | — |
| Expiry date | Apr 1, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/917
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A highly colored dye wastewater is treated by a sequence of steps to obtain a color reduction of 90 percent or more. The method requires acidifying the wastewater and adding a cationic flocculant. A reducing agent is then, optionally, added to further reduce the color value of the wastewater and produce an oxidation-reduction potential of at least -200 and, generally, about -400 to -800. The reducing agent is, preferably, either a hydrosulfite or both a bisulfite and an alkali metal borohydride.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.