Activated Sludge Sewage Treatment Pilot Plant 1. General
The activated sludge pilot allows the study and the comprehension of sewage treatment by activated sludge.
This treatment is an intermediate stage between the physical treatments or gridiron, defoliation and primary sedimentation
And the final sterilization and chlorination stage, in a sewage treatment station. Its purpose is to eliminate the contaminated
Organic substances which are present in the sewage water after the above mentioned physical treatment.
The organic load is measured in BOD (Biological Oxygen Demand) unit and it also causes a partial elimination of COD
(Chemical Oxygen Demand). The conditioning process takes place in a tank where the organic load is removed by microorganism (bacteria, rotifera, vorticellae, etc.) which are cultivated under aerobic conditions by blowing in air or sometimes also pure oxygen. The micro-organisms utilize the contaminated substances as necessary food for their production and their preservation. The aspect for this mass of micro-organisms is that of sludge, from which we have taken the name of the
Process. After the pollutant elimination phase it is necessary to divide the clarified water from the sludge, operation which is
Carried out in the settling tank (stating separator).
The clarified water flows down to the receiving body, or to a sterilization treatment, while the activated sludge is partially recycled within the oxidation tank in order to stabilize the elimination treatment.
This pilot plant has been designed to enable the students to learn all the fluid-dynamic, chemical-physical problems arising from the realization of an activated sludge process.
The unit is completely instrumented and arranged for the execution of tests that help to understand advanced problems which come from the modern conception of activated sludge plants such as:
1 the agitation effect in the reaction tank; the energetic saving and the reliability of the sludge recirculating system by “air-lift the effect of the work oxygen concentration on the sludge elimination and sedimentation.
