Waste activated sludge stripping to remove internal phosphorus
US7604740B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 1, 2008 |
| Grant date | Oct 20, 2009 |
| Priority date | — |
| Expiry date | May 11, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/906
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A method of treating a mixture of microorganisms containing phosphorus and magnesium, by first inducing the mixture microorganisms to release phosphorus and magnesium which is then tapped off as the mixture is thickened, to produce phosphorus and magnesium-rich liquid and phosphorus and magnesium-reduced treated mixture. This treated mixture is placed in an anaerobic digester where ammonia is formed but combines very little with phosphorus or magnesium as these elements have been greatly reduced in concentration. Next the high-ammonia mixture is dewatered, to produce an ammonia-rich liquid, which is combined with the phosphorus and magnesium-rich liquid. In one preferred embodiment a useable struvite product is harvested from this combination. Additionally, the production of nuisance struvite in the anaerobic digester is greatly reduced, in comparison with prior art waste treatment methods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.