WAS (Waste Activated Sludge) is basically the excess sludge that is removed periodically from biological treatment processes. This excess sludge is generally pumped from the base of the biological reactor or clarifier and is low is solids content. Typically 0.3-1.5% solids.

Unlike DAF systems designed to treat industrial wastewater, which are generally sized based on flow rate and solids loadings, Waste Activated Sludge DAF systems consider several more variables.
 

Thickening of the sludge is prerequisite prior to final dewatering and is usually conducted in a DAF system.

The sizing of WAS DAF's takes into account the surface mass loading rate (ie the mass of solids entering the DAF system as a function of the surface areas of the DAF. The surface volume loading rate which is a function of the actual fluid flow into the DAF and the air to solids ration which influences the design of the recycle system.
 

WAS DAF's are generally deeper than industrial DAF systems and when compared to volume, are considerably larger. The AJM WAS DAF will always contain a bottom scraper assembly or screw conveyor system as settlement of some solids is inevitable.

AJM WAS DAF's are fabricated in either stainless steel, mild steel or concrete and all engineering is carried out using the latest AutoCAD software.