The growing shortage of water combined with the sharp increase in population and the development of large cities due to rapid urbanization are different aspects of an important problem, and the competition among the various consumers of water increases concerns about the protection of the environment and health. Agriculture represents the greatest burden on the availability of water and most international projects dealing with water reuse are aimed at this sector. The reuse of water for irrigation cannot overlook certain risks for human health and the environment
which depend on the quality of the recycled water, its use, soil characteristics and climatic conditions. Urban wastewaters, if separated from those of industrial origin, contain concentrations of organic and inorganic compounds that present only limited problems for human health in the case of reuse for irrigation. On this
basis, the present study examines various characteristics of wastewaters coming from different urban wastewater treatment plants and surface water bodies situated in the eastern Po basin and in particular the Provinces of Bologna and Ferrara. The application of multivariate statistical methods can allow us to interpret the large and complex matrices of analytical data obtained during monitoring campaigns. In particular, cluster analysis, which discriminates data on the basis of the degree of similarity among different classes of quality, was able to characterize the quality of
the wastewaters of the various plants. Moreover, it was possible to distinguish different types of water in the surface water bodies of the sub-basins in the Provinces of Ferrara and Bologna
