Sludge treatment

Sometimes traditional settlement clarification after the bioreactors can be quite difficult and unstable. The reason for this varies high concentration of salts in the effluent, particularly “light” biomass, de-nitrification in the secondary clarifiers, sludge bulking or a host of other reasons.

Dissolved air flotation is a good alternative to sedimentation in these cases. It allows the use of significantly higher biomass concentration in the bioreactors saving construction costs, volume and, therefore, space.

Excess biomass is also removed in the form of sludge in the biological treatment stage to allow further biomass growth. The thickening of this sludge before de-watering is another common application for DAF technology.

KWI’s Sedifloat clarifier is designed primarily for biological sludge clarification and thickening applications. Combining settlement and flotation, a specific hydraulic design and sludge recovery facility allows a deep sludge blanket to be built up for optimum clarification and better sludge thickening.

A floated sludge consistency of up to 6% is currently achieved with small amounts of flocculant being only occasionally used to cover peak hydraulic and solids loadings.