Operational Indicators to Manage the Replacement of Electromechanical Equipment in Wastewater Treatment Facilities

Optimal management is usually at the top of the concerns in the context of water infrastructures. In the specific domain of wastewater treatment plants (WWTPs), European Directive 91/271 established the need of implementing a biological treatment of wastewater leading to an intensive construction of WWTPs in several European countries, which now present important problems of maintenance. These facilities are composed of different types of assets, which should be managed efficiently in order to optimize the performance of the processes as well as the maintenance and replacement costs of the equipment. In fact, the deterioration of these assets increases the operational risk and endangers the continuity of the service of these WWTPs. In this paper, the authors combine multicriteria methodologies (MCDM) and economic aspects of the equipment to define an appropriate technical–economical replacement policy. With the aim of developing a reference procedure in the wastewater sector, an approach has been made to blower pump, which is an equipment widely used in WWTPs to provide a continuous air flow to the reactor facilitating the elimination of organic matter and the nutrients contained in the wastewater. The proposal integrates aspects such as acquisition costs and corrective maintenance, interest rate, and amortization based on the condition of the equipment.