Operation Procedure

In the central gallery, coarse screens with spacings of 15 mm, an aerated grit chamber and fat trap, fine screens with spacings of 6 mm, screw conveyors, a screenings bale press and grit classifiers are found in twin operation.
Next, there is a division in four lines: each of them has two preliminary clarifiers, one activated sludge tank with primary denitrification and nitrification as circulation basin and two final clarifiers.


 
The phosphate precipitaition is done in the third cycle of the nitrification.
The dosing device for lime milk and ferrous sulphate, the ventilation system centre with exhaust air treatment by means of a biological crosscurrent washer, the transformer box, as well as the power and control systems are built into the central gallery.
The sludge line consists of four pre-thickeners, two mechanical excess sludge drainage systems, two strainpresses, two mesophilic digestion towers, which can be operated either sequentially or parallel to each other, three post thickeners and two belt filter presses.


 
The drying plant has been in operation since 1999. Digester gas is taken from the digestion tower and used to produce electrical power in three heating power stations (150 kW per tower), the warmth is used for heating up the sludge and the galleries.
In 2004 installation of the thermal recycling plant (pyrolysis rotary kiln) followed by Start up in 2005.