Feature selection and feature weighting methods in supervised domains have been thoroughly discussed in the literature. On the other hand, very little work has been done for unsupervised domains, probably due to the assumed hypothesis that their performance would necessary be substantially worse than the supervised method performance. One method found in the literature, in addition to the new methods proposed are detailed in this paper. The methods have been tested and compared in a data base coming from a Wastewater Treatment plant, with good results. Also, the integration of the new software into the GESCONDA tool is detailed.