The sewage treatment plant consists of two stages, pretreatment and biological treatment. The pre-treatment tanks (Skimming tank – equalization tank – sludge digestion) are made of reinforced concrete and are placed underground. The biologic treatment unit Sc is made of stainless steel and is placed above ground. The method of biological treatment is attached-biomass and in particular the ‘moving bed biofilm’ technology (mbbr). The unit consists of a compact single structure. The electromechanical equipment as well as the electrical panel are integrated in the unit. The unit operation is automatic and is controlled by an appropriate automation panel.
The biological treatment unit Sc is applied to:
Unit | MBBR plant | Activated sludge plant |
Flow | Equal | Equal |
Organic loading | Equal | Equal |
Reactor volume | Smaller | Higher |
Biomass growth | Attached | Suspended |
Oxi-retention time | T = 2 | T = 6 |
Suspended solids in mixed liquor | 150 mg/l | 2.500 mg/l |
Sedimentation tank | Smaller | Higher |
Installation cost | Same | Same |
Power consumption | Smaller | Higher |