So What's the difference?

WOULD YOU USE A CLARIFIER OVER A FILTER PRESS AND WHERE DO SLUDGE DRYERS COME IN?

Well the short answer is that you generally would not use a clarifier over a filter press.  They would be used sequentially.  The clarifier provides step one of the solids settling process while the filter press condenses the accumulated solids.

In a clarifier, the solids settle into a slurry by gravity feeding the wastewater from the top of the unit directed to the bottom through an underflow weir.  The water would flow back up through the inclined parallel plate pack and the solids settle in the bottom cone(s) as thickened slurry.

The solids from the clarifier are then either pumped into a holding tank to allow additional settling or directly from the bottom clarifier cone into a filter press.  Utilizing a sludge thickening tank is generally accepted procedure as this will allow the operator more time and options to run the filter press.

When the solids have settled into thickened slurry, they are then pumped into the filter press via a diaphragm pump.  A filter press is used anywhere there is a need to separate heavy solids from a liquid.  Once the slurry is compressed in the filter press, a filter cake is formed and the water that gets pumped out of the press can go back through to the system for further treatment to ensure complete compliance.

The clarifier and filter press combination drastically reduce sludge disposal costs by reducing the sludge volume.

If you want to reduce volume even further, you can add a sludge dryer at the end of the process.  It will take filter press cake and dry it to a consistency of kitty litter.  In some cases, sludge can be reduced by as much as 4:1.