Division 1.10.2 Water emissions
United Kingdom
| Techniques | Descriptions |
|---|---|
| Chemical precipitation | The conversion of dissolved pollutants into an insoluble compound by adding chemical precipitants. The solid precipitates formed are subsequently separated by sedimentation, flotation or filtration. If necessary, this may be followed by ultrafiltration or reverse osmosis. Typical chemicals used for metal precipitation are lime, sodium hydroxide, and sodium sulphide. |
| Sedimentation | The separation of suspended particles and suspended material by gravitational settling |
| Flotation | The separation of solid or liquid particles from waste water by attaching them to fine gas bubbles, usually air. The buoyant particles accumulate at the water surface and are collected with skimmers |
| Filtration | The separation of solids from waste water by passing them through a porous medium. Sand is the most commonly used filtering medium |
| Ultrafiltration | A filtration process in which membranes with pore sizes of approximately 10 μm are used as the filtering medium |
| Activated carbon filtration | A filtration process in which activated carbon is used as the filtering medium |
| Reverse osmosis | A membrane process in which a pressure difference applied between the compartments separated by the membrane causes water to flow from the more concentrated solution to the less concentrated one |