Page 11 - Opportunities in the Treatment of Water and Other Wast Streams

• Higher operation and maintenance costs than sedimentation ponds, due to system complexity and aeration requirements
Off-site large-scale facilities use dissolved air floatation in a treatment process after coagulation and flocculation and before bioreactors and membrane filtration.
Target Contaminants:
• Oil
• Grease
• Lightweight suspended particles (e.g., transparent exopolymers) • Organic matter • Dissolved gases • Volatile compounds
Dissolved air floatation uses gas bubbles to lift lighter suspended particles to the surface of a tank for removal. The dissolved air comes out of solution: micro-bubbles rise and capture small, light particles (grease, oil) bringing them to the surface as foam to effectively filter out lightweight particles. The foam is scraped off the surface. Heavier solids are collected from the bottom of the tank.
Application:
Why: Target compounds that need to be removed for water reuse.
These systems, in combination with filtration, may meet requirements to directly reuse flowback or produced water for hydraulic fracturing.
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