Process for dewatering of biological sludge
US4988442A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1988 |
| Grant date | Jan 29, 1991 |
| Priority date | — |
| Expiry date | Nov 7, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The present invention provides an improved biological sludge dewatering process. The process comprises the steps of: (a) heating biological sludge to a temperature of about 90.degree. to about 150.degree. C. which corresponds to a pressure of about 0 to about 55 psig and retaining the biological sludge at that temperature for less than about 15 minutes; (b) centrifuging the heated biological sludge to isolate the solids of the heated biological sludge from the liquid of the heated biological sludge; (c) chemically conditioning the isolated solids; and (d) dewatering the conditioned solids to produce a high solids biological sludge. The present process is used for dewatering any biological sludge to produce a high solids cake. The resulting high solids cake may be used as landfill, incinerated, or used as fertilizer by spreading on land and plowing said fertilizer into the soil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.