Abstract: In order to further save industrial circulating cooling water,circulating cooling water simulation test was carried out under working condition of the circulating cooling water system in a power plant.The variations of fouling thermal resistance and corrosion rate after adding composite microbial agent were monitored. Testing the conductivity and pH of the circulating water,it is proved that the variation rates of fouling thermal resistance and corrosion rate in the group II that added composite microbial agent were lower than that of group I without agent. It is indicated that the composite microbial agent works well in scale and corrosion inhibition.In the process of circulating cooling water treatment,composite microbial agent is greener,more efficient and more environmental than chemical doses.It can operates stably under high concentration ratio,which is of favorable economical benifits.

Key words: circulating cooling water, composite microbial agents, corrosion and scale inhibition, environmental protection, economic benefits；fouling thermal resistance