Thickener tank and equipment
Thickener tank and equipment
General information
The produced sludge, from aerobic biological processes, must be removed in certain quantities to assure stability of the system (feeding of the microorganisms) by keeping the ratio of F over Mv F/Mv constant. The removal of the sludge is necessary in order to ensure stable sedimentation rate, the desirable amount of dissolved oxygen and aeration in the sedimentation tank as well as constant rate of recirculation of the activated sludge. The produced sludge with a concentration of 10.000mg/l is too watery to be treated in a belt filterpress, therefore, it must be treated in a thickener in order to reduce the content of water. Thickeners separate water from solids and enhance the formation of dehydration in solid aggregates.
ATHANASIOS KOUTSOUKOS S.A. undertake the studying as well as the construction of a thickeners' equipment.
Thickener and equipment
1. Main thickening tank
The shape of the tank is circular and has a stable bridge to facilitate the access and maintenance of the rotary motor. The bottom of the tank is sloped in order to promote the movement of the produced sludge to the suction point. At the centre of the tank there is a base where the rotary motor and the bearing shaft of the scraper are positioned.
2. Thickening scraper
The thickener scraper has:
1. A shaft equipped with several incorporated laminas in order to promote the water removal with the least amount of trapped sludge.
2. A rotary bottomless container which has a dual purpose. First, to accept the sludge from the sedimentation tank and second to distribute the sludge evenly in the thickener tank.
3. The bottom bearing, which is made of an antifriction polymer, for the support of the shaft on the bottom of the tank.
4. The gear motor reducer.
5. The bridge to facilitate access and maintenance of the rotary motor.
6. The outlet overflow weirs.
7. The airlift pump installed on the bottom of the tank for the disposal of the sludge.
The design and construction are according to the European regulations (EN12255 “waste water treatment plants”).