Removal of ammonia from wastewater
US4689156A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 12, 1985 |
| Grant date | Aug 25, 1987 |
| Priority date | — |
| Expiry date | Nov 12, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/903
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A method is provided for removing ammonia from wastewater containing in excess of about 15 ppm NH.sub.3 (N)-T. The method comprises treating the wastewater with an alkaline reagent selected from the group consisting of lime and caustic sufficient to raise the pH to provide a free ammonia equivalence (FAE) to a value of at least about 12.4, the free ammonia equivalence being determined as follows: EQU FAE=pH+(.theta./15).sup.0.5 wherein pH is the pH value of the treated wastewater and .theta. is the temperature of the wastewater in degrees Fahrenheit. The treated wastewater is gas-stripped to lower the total ammonia content of the treated wastewater to a value of less than about 10 ppm NH.sub.3 (N)-T, the gas stripping being controlled to maintain the free ammonia equivalence of the wastewater phase being stripped to a value of at least about 12.4, following which the stripped wastewater is acidified to lower the un-ionized ammonia content to less than about 0.05 ppm NH.sub.3 (N).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.