Every year, a large amount of mineral processing wastewater is discharged from various industries into the environment which is considered a challenging task not only because of its large volume, but more importantly, its hazardous components, while its reuse as feed water without proper treatments causes great harm to the final product of these industries. Cost-effective methods are required to treat a wide range of industrial wastewater in a diverse range of conditions. In this study a combined hydrocyclone-electrocoagulation system is tried to treat the wastewater for industries with high water consumption and high pollutants such as paper industry, iron and metal forming industry and marble and granite industry. The effects of the hydrocyclone operational parameters, such as feed inlet pressure, feed inlet diameter, vortex finder diameter, apex diameter, and feed solids content were investigated. In the case of paper industry wastewater, the following optimum conditions, (P=4.5 bar,D_O=15.8 mm,D_u=6 mm,D_i=4 mm and c_s=2.3 %) were achieved and an overflow of about 90.58 % water recovery and 21.45 % solid at 75.92 % separation efficiency were obtained. The results showed that the hydrocyclone-electrocoagulation treatment has efficiently treated the three different types of industrial wastewater and reduced the Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total solid (TS), Total suspended solid (TSS), color and turbidity, sharply and met the effluent discharge or reuse standards. In addition, compared with the hydrocyclone-treated wastewater, hydrocylone-electrocoagulation-treated wastewater was found to be more enhanced.