Application of mathematical tools to improve the design and operation of activated sludge plants. Case study: the new WWTP of Galindo-Bilbao Part I: Optimum design

This paper presents a mathematical formulation for the optimum design of a new activated sludge WWTP. The WWTP optimum design problem has been formula ted as a Mathematical Programming problem, which is solved through a nonlin ear optimisation method. The plant model has been based on the ASM 1. The m inimum volume of the biological reactors and the minimum total cost (includ ing construction and exploitation costs) have been considered as optimisati on criteria. Some practical results are also included, using as a case stud y the design of the second stage of the Galindo-Bilbao WWTP.