Optimisation de la réhabilitation hydraulique et structurale des réseaux d'égout

Abstract

Sewer systems rehabilitation is both complex and expensive problem. In the past, rehabilitation is carried out only for a major malfunction and thus on an emergency basis. Planning for the rehabilitation of sewer systems that are put in surcharge state or overflow and flood-ups, requires the development of some tools that incorporate many factors and parameters influencing the sewer pipes condition. The theme of this thesis is the development of tools for planning and optimizing the sewer systems rehabilitation. In a first work, a scheme for prioritizing sewer sections for rehabilitation was developed. A fuzzy expert system was applied with input from a combined assessment of hydraulic and structural performance as well as the consequences of potential failures. The index of overall structural performance is computed using a fuzzy logic system that incorporates the internal and external state and the site vulnerability. Another fuzzy system calculates an index of overall hydraulic performance with the input hydraulic performance, the impact of the hydraulic performance and site vulnerability. The hydraulic performance index is calculated using a global modeling upstream of each section which takes into account water lost by flooding upstream of the considered section. The overall fuzzy system uses these factors to calculate the indices of overall performance of the sewer pipes. In a second work, the structural performance indices derived using a fuzzy system are integrated into an optimization program while considering the level of disruption of rehabilitation techniques and costs associated with maintenance. An optimization procedure based on binary linear programming is then used to select the most appropriate rehabilitation method for each section, among the possible methods to improve all the system sewer performance aspects. In a third work, a new approach for evaluating the hydraulic performance of sewer pipes is considered. A problem of multi-objective optimization that considers the hydraulic and structural performance to maximize has been developed. Thus, solving the problem provides the manager an optimal solution that minimizes the overall difference of structural and hydraulic performance with a target level of performance while meeting the budget. The "Goal Programming" was used as a solving method for the multi-objective problem. Finally, the proposed rehabilitation planning tools have been validated by case studies and their results have proved convincing.

Date	19 Dec 2011
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Saad Bennis (Supervisor)