Abstract

Existing design approaches of methane fermentation systems employ unicriteria optimization methods, constraining the problem by using a single objective function. Multiple functions of anaerobic digestion represent a complicated and complex problem. The purpose of this paper is to present an optimization approach employing a mathematical model which includes two objective functions, subject to physical contraints. One objective function represents energy balance, and the other corresponds to total investment. Optimal solution is a trade-off curve defined by a non-inferior solution set. The non-inferior trade-off curve presented a non-convex behaviour, so it was characterized by using the k-th objective ∑constraint problem. Some preliminary results are presented to indicate the validity of the technique employed.