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Even in at very low concentrations, heavy metals in industrial waste constitute environmental and health risks. The U.S. Department of Health and Human Services has recognized as chromium compounds and defined carcinogens the level acceptable in drinking water as being only 0.05 ppm. The objective of this work was the electrochemical reduction of hexavalent chromium Cr (VI) to Cr (III) ions in a dilute synthetic solution of K2Cr2O7 and Na2SO4 (0.05N). A plug-flow reactor with an RVG 4000 graphite felt (Le Carbone Lorraine, France) electrode was used for this work. Its morphological characteristics such as specific variables surface, porosity, average fibre diameter and permeability were determined. The influencing process selectivity such as initial concentration of Cr (VI), solution pH, current intensity and conversion yield are considered. The fractional conversion achieved in the plug-flow reactor in the present work, was about 90%

-The use of electroflotation in emulsified oil wastes was studied. A rectangular electroflotation cell was designed and constructed in acrylic with stainless steel cathode and DSA ® anode with a nominal composition of Ti/Ru 0.34 Ti 0.66 O 2 . The variables studied in the present work were current density and oil, flocculant and electrolyte (NaCl) concentrations. The experiments were carried out in accordance with 2 4 full factorial experimental designs with two center points. The STATISTICA 5.5 software was used for calculations in order to relate experimental data to a statistical model. The best results, yielded 99.71% oil removal were obtained from 1050ppm of emulsified oil feed.