Expert system for municipal wastewater management with emphasis in reuse

Abstract

This paper presents a methodology that uses a knowledge base and inference procedures for developing rational wastewater management schemes for small to medium size communities with emphasis in the protection of human health, the reuse of treated wastewater, and the pollution minimization of water receivers. The system provides an optimal year-round treatment/reuse/disposal plan, which maximizes the wastewater reuse for irrigation, meets the applicable minimum municipal wastewater treatment requirements and observes the water quality standards of receivers with the minimum treatment costs. The solution is dynamic in the sense that varying monthly design values can be assigned to the input variables used in the computation of irrigation requirements, assimilative capacity of receivers and performance of natural systems. The above procedure shows that the use of multiple receivers over the year is often highly advantageous; combining for example the increased treatment efficiency and reuse potential for irrigation during summer with the increased assimilative capacity of a river during winter. The expert system incorporates a number of design and ambient quality models, for which graphical solutions have been developed, so as to enable manual application if desired. The entire procedure is implemented in an integrated computer program that facilitates and refines problem solution. The expert system provides interactive guidance for collecting the necessary field information. Finally, the results of a case study for the management of wastewaters from the six communities of the Municipality of Keramoti are presented.