RÉSUMÉ
The purpose of this study was to build up a logic ranked pattern between the most important industrial activities with respect the type of water pollution and the discharge ways or managing the wastewaters in these units. For this purpose all of the statistical data have been gathered by referring to the responsible organizations. After that, by using the desk study, field work and selecting some of the industrial units as studied cases and by referring to their production processes and obtaining the curtained analytical results, the industries have been separated to several groups including Food,Textile, Pulp and Paper/, Chemical, Non-metallic mineral, Metal and Electricity and electronics Comparing the number of active industrial plants within the boundaries of Khuzestan province at 5 catchments area, indicates that Karun, Dez and Jarrahi basins with 1044. 324 and 290 active plants, respectively, are crowded with a lot of industries. Nature of the examined parameters has been selected in view of the production process type and includes pH, turbidity, electrical conductivity, chloride, sulfate, BOD, COD, TSS, iron. Results indicates that Dez river basin, being compared with the other two basins, impose the most degradable organic, nutrient substances and suspended particle loads to Dez River, and the metal pollution load at Karun basin is more than the other two basins, caused by the steel industries concentrated in Ahvaz city