Flotation is an option for the third stage of a water treatment plant installation. This is one of the most impressive techniques, especially for waste waters that are high in fats, oils and greases.
Any contaminants that are buoyant, i.e. with a lower specific gravity that the surrounding liquid medium, have a great tendency to float naturally.
Mechanically assisted flotation involves micro-bubbles or white water – these bubbles rush to the surface, assisting in the speed of flotation – this is known as Dissolved Air Flotation (DAF).
Again, there is the option of a chemically assisted technique – this involves coagulation and flocculation of smaller particles to make larger particles that can entrain air within – this generates a particle that is lighter than the background liquid and therefore floats.
A flotation system operates by generating micro bubbles which are allowed into the waste water stream at high pressure (6 bars). Upon entering the vessel, these bubbles rush to the surface taking with them a portion of solids that attach or become entrained in the bubble surface rise.
Our design also contains lamella plates to drastically increase surface area for air bubble – solid interaction.
- Plus-points of a flotation system
- Can offer solids removal rates of over 95%
- Only two moving parts – the aeration pump and scraper
- Discharge under gravity
- Minimal maintenance
- Common sense dictates it cannot fail to offer some solids removal when operating correctly
- Physically strong – steel construction, durable, long lasting
- Average cost
- No requirement for mains water or air compressor, the aeration pump takes in atmospheric air
- Includes conical base for removal of settleable solids also
- Particle size is of no significance compared to the micro bubbles which are less than 10 microns in diameter