The Research Of Bio-corrosion And Scale Inhibitor In The Treatment Of Circulating Cooling Water

Due to the constant evaporation of cooling water and the change of water quality and quantity,there are many problems occur in the industrial circulating cooling water system,such as corrosion,scale formation and microbe multiplication.To solve the above problems and high pH conditions and excessive phosphorus emission caused by chemical corrosion inhibitor,using biological competitive exclusion,nutrient limitation,advantage principle to construct an bio-corrosion and scale inhibitor,which mainly containing high carbonic adhydrase microorganisms,COD degrading bacteria and acid producing bacteria.In this paper,the microbial community structure and the performance of the bio-corrosion and scale inhibitor were analyzed.Then,the dynamic simulation experiment of circulating cooling water was carried out,and the corrosion and scale inhibition performance of biological agents and chemical agents were compared,and the change of community structure were analyzed.Finally,the industrial application of the inhibitor was carried out in the circulating cooling water system,and analyzing the environmental and economic benefits.The results showed that the main functional microorganisms of the bio-corrosion and scale inhibitor was Bacillus sp.,sphaerotilus sp.and Lactobacillus sp.The optimum pH of the biological agents was 8.0~8.5 and the optimum temperature was 30?.The Ca2+ had few effects on the performance of the inhibitor,however,the Cl-had unfavorable effects on the performance of the inhibitor and the inhibition became obvious when the concentration of Cl-was over 200 mg/l.The results of the dynamic simulation experiment showed that,compared with chemical agents,the biological agents which had better corrosion and scale inhibition performance could improve water quality index,such as pH,hardness,alkalinity,turbidity,COD and total iron ion.Meanwhile,biological agents could greatly reduce the total phosphorus content in the cooling water and achieved the purpose of phosphorus reduction.The molecular biological detection of microbial community structure indicated the functional microbes containing in the biological agents could occupy the dominant position in the system for 20 days and ensure the normal operation of the system.The biological agent also had good corrosion and scale inhibition performance in the industrial application,and solved corrosion and scale formation.Moreover,it could reduce the operation index of pH,increase the concentration times,reduce the amount of upwater and sewage,and achieve the total phosphorus reduction amount of 75.95 kg,and the rate of phosphorus reduction reach 94.10%.The above results demonstrated the possibility of using the biological agent to deal with circulating cooling water.In a word,the bio-corrosion and scale inhibitor has good performance of inhibiting corrosion and scale in the circulating cooling water,which can also achieve the purpose of saving water,saving energy and reducing phosphorus.There is a great degree of environmental and economic benefits.