Separation characteristics in dissolved air flotation--pilot and full-scale demonstration.

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Particle Science

Background:

• Dissolved Air Flotation (DAF) is a crucial process for water purification.
• Understanding particle separation dynamics within DAF is essential for optimizing its efficiency.
• Current knowledge gaps exist regarding the precise location and size-specific removal of particles in DAF systems.

Purpose of the Study:

• To pinpoint the specific zones within the DAF process where particle separation occurs.
• To identify the range of particle sizes effectively removed by DAF.
• To provide practical insights for enhancing particle separation in DAF.

Main Methods:

• Investigation of both pilot- and full-scale Dissolved Air Flotation plants.
• Utilisation of a light-blocking particle counter for precise particle size analysis.
• Employing an optical borescope for visualising particle-bubble aggregate formation.

Main Results:

• Particle separation is predominantly observed in the upstream sections of the DAF process, near the initial contact zone.
• The efficiency of particle removal by DAF demonstrates a positive correlation with increasing particle size.
• Visualisation confirmed the aggregation of particles with bubbles as a key separation mechanism.

Conclusions:

• Optimizing DAF performance can be achieved by focusing on upstream process conditions.
• DAF is particularly effective in removing larger suspended particles from water.
• This study offers valuable data for refining DAF operational strategies and design for enhanced particle removal.