A slime-forming bacterial strain N1 was isolated and purified from the Songhua River.According to the morphological observation as well as the physiological and biochemical indexes

the strain was identified as Micrococcus.Under certain experimental condition (water temperature 30℃

flow velocity 0.4 m·s-1 and microorganism concentration between 7.0×106 cfu·ml-1 and 2.2×1010 cfu·ml-1)

the fouling resistance was monitored online in an experimental device for dynamic simulation of forming fouling

and the heat transfer characteristics were analyzed.The induction period of microbial fouling in the stainless steel tube was about 57 h

which was shorter than that in the copper tube.In the contrast experiment with converging-diverging tube

it was found that flow velocity had certain influence on the formation of microbial fouling.The change of flow velocity could prolong the induction period of microbial fouling.During the dynamic experiment

many water quality parameters including pH

conductivity

total bacterial count

total nitrogen and COD were detected periodically.Based on the grey relational algorithm

the correlation for water quality parameters and microbial fouling was analyzed

which provides a theoretical basis for predicting the microbial fouling and selecting the effective measures for scale removal.