Process for reduction of sulfide from water and wastewater
US11008240B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 2017 |
| Grant date | May 18, 2021 |
| Priority date | — |
| Expiry date | May 27, 2038 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2303/22
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The instant application is directed towards methods for removing sulfide from a wastewater stream. The pH of the wastewater stream is adjusted to between 7.0 and 8.0. A first oxidizing agent is mixed with the wastewater stream, oxidizing the sulfide to elemental sulfur. The wastewater stream is then softened by mixing lime with the wastewater stream. The addition of lime further raises the pH of the wastewater stream to 10.0 or higher, and converts the elemental sulfur to soluble sulfide (S2-) and/or thio-sulfate. Calcium carbonate is precipitated and sulfide (S2-) and/or thio-sulfate is adsorbed thereon. Thereafter, the wastewater stream is directed to a solids-liquid separation process, which separates the calcium carbonate and adsorbed sulfide (S2-) and/or thio-sulfate from the wastewater stream. The solids-liquid separator produces an effluent that includes residual elemental sulfur. The effluent is then mixed with a second oxidizing agent, which oxidizes the residual elemental sulfur to sulfate, producing a treated effluent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.