Water clarification helps remove suspended solids and particulate matter - usually with the help of flocculants and coagulants, which improve settling. Water clarification systems are either rectangular, where water flows from end to end, or circular, where flow occurs from the centre outward.
Water clarification is used in the treatment of industrial effluent, municipal wastewater and municipal drinking water as pre-treatment to further purification processes. Water clarification is also used as specialised application for grease and oil removal in industrial effluents.
In South Africa, the most popular water clarification systems from Veolia include the Actiflo™ and Multiflo™, which ensure the optimum use of space and the greatest efficiency and speed of water clarification. Both Actiflo™ and Multiflo™ water clarification systems can be retrofitted to be incorporated into an existing water purification system in order to expand the capacity of the plant. These water clarification systems can also be supplies as a pre-packaged system.
Veolia's water clarification treatments include:
- Actiflo™ Turbo
- Multiflo™ Trio
The patented high rate Actiflo™ water clarification system developed by Veolia Water Technologies has:
- Unique settling characteristics
- High overflow rates
- Short retention times
- Small footprint
These characteristics allow for clarifier designs with footprints that are five times smaller than classic lamella or dissolved air flotation clarifiers, and up to twenty times smaller than conventional sludge blanket clarifiers.
The system makes use of Veolia patented Actisand®; micro-particles of dense sand, which act as ballast for flocculants produced during the coagulation stage of the system process. This ensures that the water clarification system is capable of rapidly processing higher volumes of water in a smaller space, without sacrificing quality for performance.
Referred to as the ultimate clarifier, and based on the highly successful Actiflo™ technology. Actiflo™ Turbo incorporates the best in water clarification performance and is:
These characteristics make it ideal for municipal clarification applications across the country. The process covers numerous applications and can be integrated into many treatment chains to produce high quality potable water. The water clarification system is equipped with a flocculation tank that contains a Turbomix™ to enhance flocculation by installing a draft tube around the mixer impeller. The system provides even shorter retention times than the Actiflo™ system, and boasts an even smaller footprint.
WATCH THESE VIDEOS TO SEE ACTIFLO™ CLARIFICATION IN ACTION!
Multiflo™ technology is an advanced clarification technology which incorporates chemical precipitation with sludge thickening – this produces a thickened sludge which can easily be dewatered. The clarification technology is extremely efficient at removing high amounts of precipitated solids from water. Multiflo™ offers numerous operational benefits, including:
A small footprint
Low sensitivity to operational upsets and stop/start conditions
A low concentration of suspended solids in treated water
A high concentration of suspended solids (calcium carbonate) in the generated sludge
Lower capital and operational costs when compared to conventional clarifiers
The Multiflo™ clarification method also offers solutions for the removal of high levels of arsenic and heavy metals from water. This configuration is called the Multiflo™ Trio package and combines the coagulation, flocculation and settling stages in a streamlined process.
After oxidation raw water flows successively through two tanks equipped with propeller type mixers. Turbo Mix™, developed by Veolia Water Technologies, optimises chemical dosing, mixing and floc formation.
The flocculated arsenic and colloidal matters enter the bottom of the settling tank fitted with lamella plates. The water flows upwards, in the opposite direction to the settling flocs. The flocs are deposited along the plates and slide downwards under the effect of gravity.
This feature optimises chemical dosing and further improves sludge settling and thickening.
PERFORMANCE CHARACTERISTICS OF MULTIFLO™ TRIO CLARIFICATION
- Well adapted to high concentrations of arsenic
- Co-precipitation of other heavy metals
- Removal of suspended solids and colour
- High thickened sludge concentration
- Easy to build and operate
- Robust and proven technology