Aerobic sewerage digestion process (42 C. process)
US4026793A · kind A · utility
Inventor
Key dates
| Filing date | Aug 21, 1975 |
| Grant date | May 31, 1977 |
| Priority date | — |
| Expiry date | Aug 21, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F3/34
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An aerobic digestion process for reducing the solids content of an aqueous biodegradable organic sludge includes the steps of (a) introducing the sewage sludge into a vessel, the initial concentration of the total volatile organic solid in the sludge being less than about 2.5% by weight based on the total sludge present in the vessel, (b) maintaining the total volatile solids concentration at less than about 2.5% by weight; and (c) maintaining the temperature of the sludge in the vessel within the range of from about 38.degree. to about 46.degree. C. By processing the sludge according to the foregoing steps, including temperature maintenance within the foregoing critical limits and maintaining the total volatile solids concentration below the critical limit of about 2.5% by weight, the solids concentration of a sludge, such as a waste-activated sewage sludge, can be significantly reduced in a time period on the order of about three days. In addition to the above process parameters, it is preferred that the concentration of dissolved oxygen in the sludge be maintained at a level greater than about 3 milligrams per liter (mg/l). The waste material produced from the foregoing process …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.