The management of Urban Wastewater Systems (UWS) is a critical and difficult process. Handling polluted water in UWS requires planning and decision making regarding sectors such as environmental, energetic, industrial, etc. In order to represent all the significant concepts, a powerful and flexible formalism is needed. Nowadays, there are solid approaches based on nonmonotonic reasoning which can capture dynamic domains such UWS. In this paper, we present an implementation of a real UWS in the action language Causal Calculator (CCalc-C+) which displays all the singularities of such domain and within which complex queries can be performed. The nonmonotonic causal theory, upon which is based CCalc, allows us to represent some characteristics of UWS such as nondeterministic actions and indirect effects of actions. We will capture the situations and the transitions of the UWS domain and represent them in the form of a finite state machine. CCalc allows us to perform queries regarding; the effects of actions, action planning to reach a certain state and path finding. The resultant work can be used in actual UWS to aid at the decision making process, simplifying the reasoning about actions and allowing a close representation of the real state of UWS.

Peer Reviewed