Dissolved Air Flotation (DAF) for thinking of WAS or solids removal post MBBR process.

Solids handling remains one of the area's of a WWTP where not a lot of attention is paid yet remains a significant operator time & maintenance requirement. Waste activated sludge (WAS) typically needs to be thickened prior to going into a digester to allow for the desired hydraulic retention time (HRT) of the digester. 3-5% solids are ideal and a dissolved air flotation unit has been used successfully as a new stand alone unit or upgrading using the WWW DAG Micro-bubble technology which helps reduce HP of standard recycle pumps and eliminates the needs for older style saturation tanks. The DAF is also a perfect complement to separation of solids from a MBBR system doing BOD, Nitrification and / or denitrification of industrial & municipal wastewater. The DAF unit can provide in this case your 3 - 5% solids with the need for thickening and is in a much smaller footprint than conventional gravity clarifiers. This technology spotlight will present on a few case studies of both thickening as well as separation of secondary treated wastewater.