Page 12 - Opportunities in the Treatment of Water and Other Wast Streams
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Where: On-site recycling systems and off-site treatment facilities.
Target Contaminants:
• Emulsions (which are difficult to remove with chemical or filtration treatment processes)
• Suspended solids
• Heavy metals
• Natural organic matter
• Biological contaminants
• Fracturingchemicals
Benefits:
• Lower chemical demand than conventional coagulation and flocculation • Targeted treatment for water recycling
• Relatively small footprint
Limitations:
• High energy requirements
• Higher relative cost
• Maintenance required for anode and cathode plates
* Do not treat suspended solids.
Electrocoagulation.
Uses electricity to gather particles, heavy metals, oils, and grease suspended in water into a sludge that can be removed. Sacrificial electrodes of iron or aluminum are connected in parallel to a DC current. When an electric potential is applied across the electrodes, it drives off metal ions from the electrode.
These ions neutralize charged particles and form metal hydroxide precipitates that rise to the top in a foam or settle to the bottom, depending on their density.
Electrofloatation occurs when the electrical current creates dissolved gas (hydrogen or
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