As an advanced treatment technology, activated carbon adsorption can decrease COD effectively when the wastewater is reuse as make-up water in circulating cooling system.The efficiency of adsorption is related to the contact time.Ozone used before carbon adsorption can not only improve the quality of effluent further but also control the removal of total solid content and the corrosion.Pret reatments,such as flocculation and filt ration,is necessary before activated carbon adso rption so as to improve the ef ficiency of adso rption.