Sludge drainage ? process overview

The sludge collected in a purification and thickening plant or a digestion tank (municipal clarifier) is extracted daily by means of a sludge pump, conditioned in a coagulator with flocculation agents and conveyed into the drainage container.

The external dimensions of the drainage container correspond with a rubble container or is designed as a tilting container. The drainage container is produced with a double base ? the top one made of perforated sheet metal. It is panelled in the interior both with a support fabric as well as with a filter fabric. Both inserts are fixed by an installed grid so that they do not fall out when the container is emptied.

Through the conditioning of the sludge it “disintegrates” in the E-Container into “solid flakes” and filtrate. These solid particles, subsequently the filter cake are retained in the E-Container while the filtrate passes through the panelling and the perforated sheet metal base and flows off.

The sludge cake is drained as a rule within 24 hours until it is hard enough to cut. TS-contents of 25-55{06105e1b926b51a75442da20d15ea774720d2c2f85a02c49b0909e09a6ae2ac9} are reached. The separated liquid phase (filtrate) can under certain circumstances be re-used for accelerating deposit processes in the tank thickening system. The sludge can also be drained in a filter press whereby up to 80{06105e1b926b51a75442da20d15ea774720d2c2f85a02c49b0909e09a6ae2ac9} dry substance are reached in the filter cake.

Benefits:

• drainage and transport in one single unit
• no mechanically moved parts
• minimum operating work
• compared with dry beds low space requirements
• Saving of flocculation agents
• Reuse of the filtrate for waste water cleaning