| Microorganism that studied in this thesis as an important research object was tested in circulating cooling water of Baosteel Co., Ltd. The growth condition of the microorganism in four kinds of classic water system, including make-up water system of circulation, water system of clean circulation, water system of closed-circuit circulation , water system of turbid circulation, was strictly examined and the growth regularity along with the control methods of microbe were also explored in details. Six major contents were involved: the separation and identification of fungus in closed water system; the growth regularity of sessile bacteria on the tube surface of system; the growth regularity of microbe in different seasons; the growth regularity of microbe in different bactericide adding periods and bactericide adding intensity; the study of drug-resistance of non-oxidizing bactericide and the flexibility of oxidizing bactericide under high concentrated multiple and using study of quikly check-up SRB in FISH. Through the research, we hope to understand the microbial growth rule of the typical recycling cooling water system of iron and steel enterprises as well as the drug-fast generating rule, to improve the medicament-using plan and come up with appropriate measures so as to improve the quality control standard of bactericide usage, guarantee the secure running of Baogang's typical recycling cooling water system and save its running cost, making economic and environmental benefits for the industry and laying a foundation for the improvement of the microbial controlling technology of recycling cooling water system for the entire iron and steel industry. Meanwhile, the research is of significance of a reference for the microbial controlling technology of recycling cooling water system in other industries. The thesis consists of the following conclusions:1. Ninteen strains of heterotropHic bacteria were separated from the closed water system. They are Neisseria, Pseudomonas, Bacillus, StapHylococcus, Proteus etc.2. Studying the growth regularity of sessile bacteria: no sessile bacteria was apparently discovered in all Baosteel water circulation system, the inspection of planktonic microbe reflects the whole living condition of microbe.3. Growth regularity of microbe in different seasons: heterotropHic bacteria was considered the main microbe in all the circulation system; in summer, the amount of microbe in the system is much higher than other seasons, more control methods should be intensified to the microbe during summer.4. Growth regularity of microbe in different adding bactericide periods: the best period ofinspections is one week, and sampling before drag adding is much better. It has effect in evidence that the oxidizing bactericide and the no-oxidizing bactericide use alternatively in water system of clean circulation. Better performance of adding the oxidizing bactericide to the turbid circulation water system. The method of half reduction of dose could be available and 1,680,000 annual expenses could be saved for Baosteel Co., Ltd.5. Growth regularity of microbe in different drag adding intensity: it is not suitable to add non-oxidizing bactericide S-103 in the water system. Good effects have been proved by using non-oxidizing bactericide N-7330, 100mg/L of additive is suggested.6. The experiment of inhibition zones showed that the main factor microbile made drag-resist using the same non-oxidizing bactericide for long time in the water circulation system.The drug-resistance of the microbe to non-oxidizing bactericide S-103 which mainly induced by the drags has been proved in water system of closed-circuit circulation. The results obtained showed the drag-resistance caused by adaptation of microbile produced fast and reversibly or unstable. The experiment also gave such results that S-100 did not have the crossed-resistance which was opposite to S-103. Therefore, different kinds of bacteticide could be used in the closed water system in which the resistance was already appeared. To av...
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