Method for stabilizing and conditioning urban and industrial wastewater sludge
US7497956B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 2002 |
| Grant date | Mar 3, 2009 |
| Priority date | — |
| Expiry date | Apr 27, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/928
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The invention concerns a method for stabilizing and conditioning wastewater sludge. The invention is characterized in that it consists in treating sludge in an acid environment (3.0≦pH≦5.0), with an inorganic acid and two oxidizing agents, that is a ferric iron salt and hydrogen peroxide. The ferric iron salt is used in such an amount as to obtain a concentration ranging between 5 and 40 kg of Fe per ton of dry sludge; the hydrogen peroxide is used in such an amount as to obtain a concentration ranging between 5 and 40 kg of H2O2 per ton of dry sludge; mixing the treated sludge for a time interval sufficient to stabilize the sludge and improve its dehydrability; then flocculating the stabilized sludge by adding an organic polymer; then dehydrating the flocculated sludge. Said method enables to significantly improve the dehydrability properties of the sludge while increasing the dry solid content during its mechanical dehydration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.