Abstract
This paper describes a new, two-stage model for sewer system design. In the first stage a large number of so-called main sewer systems is constructed, each of which is consistent from the engineering point of view and none of which is uniformly inferior to any other. In the second stage a pure 0–1 integer programming problem is formulated that solves the basic elements, which are the main sewer systems and wastewater treatment plants. The corresponding computer program system functions are outlined. Experiences with the model to the Lake Balaton sewer system planning are summarized. Further research directions, possible applications and relations to other sewer system planning tools are shortly given.