Discharged effluent from refineries is reused in circulating cooling water systems by using water treatment techniques,such as RP-12 and RP-78, etc. After an eleven-month industrial test, the results show that the average rates of corrosion are less than 0.052 mm/a,that of scale deposition less than 6.5 mcm,and the average number of bacteria less than 1.2×10⁵mL^-1. These results are similar to those of using new water as make up water. The reusing of effluent has not only notable social benefits in saving new water and decreasing the effluent discharge,but has economic benefit for the enterprise which reuses the effluent.