Flotation Without Dissolved Air®: Charged microbubbles for enhanced removal of suspended solids in wastewater applications.

For over a century, various forms of Dissolved Air Flotation (DAF) systems have been employed for the removal of suspended solids, and fats, oils, and grease from wastewater. The amount of air that can be dissolved in DAF systems is limited by the laws of physics and is usually less than 2 – 4% air by volume. The recirculated “whitewater” is drawn and created from underflow of flotation units, requiring high horsepower compressors and pumps that often require frequent maintenance and operator attention.

Charged microbubble flotation, specifically Suspended Air® Flotation from Heron Innovators, replaces conventional whitewater systems. Instead of dissolving air, SAF® generates whitewater (froth) at atmospheric pressure that is 40% air by volume. This froth consists of microbubbles, approximately 7 to 25 microns, and created with a charged surfactant that is ubiquitous to wastewater and GRAS approved. The charged microbubble froth is injected into the influent stream and has an electrostatic affinity to grab and lift solids to the flotation vessel surface for skimming and removal.

New SAF® systems are a fraction of the size of conventional DAF units, saving floor space and capital costs. Furthermore, because SAF® bubbles have a much longer life than DAF bubbles, a very stable solids blanket is produced, allowing for increased surface dwell time to enhance dewatering, thereby reducing disposal costs.