Concept formation in WWTP by means of classification techniques: A compared study

Although activated sludge process is a very widely used biological process in wastewater treatment plants (WWTP), and there are properly functioning control loops such as that of dissolved oxygen, in practice, this type of plant requires a major time investment on the part of the operator, involving many manual operations. Treatment plants work well most of the time, as long as there are not unforeseen occurrences. Normal operating situations (generally similar to design conditions) can be treated mathematically by using efficient control algorithms. However, there are situations in which the control system cannot properly manage the plant, and in which the process can only be efficiently managed thanks to the operator's experience. This is a case in which a knowledge-based system may be useful. One of the difficulties inherent to the development of a knowledge-based system is to obtain the knowledge base (i.e., knowledge acquisition), specially when dealing with a wide, complicated and ill-structured field. Among the aims of this work are those to show how semi-automatic knowledge acquisition tools could help human experts to organize their knowledge about their domain and also, to compare the power of different approaches of knowledge acquisition to the same database. In this paper are presented the results obtained from applying two different classification techniques to the development of knowledge-bases for the management of an activated sludge process.