Method for recovering phosphate from sludge and system therefor
US6338799B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Nov 10, 1999 |
| Grant date | Jan 15, 2002 |
| Priority date | — |
| Expiry date | Nov 10, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/40
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method for recovering phosphate from sludge includes the processes of treating sludge drawn from a water treatment system at a sewage treatment plant in an anaerobic condition to release polyphosphate accumulated in the sludge into solution, and recovering phosphate in the solution using a seed crystal material. A system for recovering phosphate from sludge includes a phosphorus-releasing means for treating sludge drawn from a water treatment system at a sewage treatment plant in an anaerobic condition to release phosphate into the bulk liquid, a dewatering and separating means for separating the sludge containing the solution including the released phosphate into dewatering effluent and dewatered sludge, a calcium ion concentration-adjusting means for adjusting the calcium ion concentration in the dewatering effluent, a pH-adjusting means for adjusting the pH of the dewatering effluent, and a crystallizing means for recovering phosphate from the calcium ion concentration-adjusted, pH-adjusted effluent of dewatering apparatus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.