Mathematical modeling of biofilm development has been an active research topic during the latest years. The main purpose of these models is to understand and predict biofilm growth and development. One of the first mathematical model was the so called Wanner-Gujer model, where a one-dimensional model capable of describing multiple species development was proposed. Later on, more advanced models, incorporating more dimensions, eps-production, cell-to-cell-signalling and other properties have been developed. The major obstacle when trying to predict biofilm development using these mathematical models is that a huge number of parameters are needed, such as parameters in the bacterial metabolism, growth and detachment rates. Some of these parameters are possible to measure in experimental conditions, but others are more difficult, such as the detachment rate. In this paper, we will propose a methodology for estimating parameters in mathematical models of biofilm development from comparison of model prediction and experimental data. The proposed method is based on parameter identification methods used in automatic control theory. We will especially focus on the determination of the detachment rate in the Wanner-Gujer model.