臭氧灭活水中枯草芽孢杆菌的动力学

Inactivation kinetics of Bacillus subtilis spores with ozone

以枯草芽孢杆菌(ATCC6633)的孢子作为难灭活微生物的代表,研究了消毒剂浓度和反应时间的乘积值(CT值)、pH值、温度对臭氧灭活水中芽孢效果的影响,并探讨了相关灭活反应的动力学特征.结果表明,臭氧灭活芽孢的过程可分为延滞期和灭活期,其灭活反应符合Chick-Watson延迟反应动力学模型.在半连续流反应模式下,当臭氧浓度在0.42—4.00 mg·L^(-1),反应时间0—20 min,pH值6—8,温度1—30℃范围内时,臭氧对芽孢的灭活效果与臭氧的CT值显著相关,与单独的臭氧浓度无关,CT值越高,所能达到的灭活率也越高.同时,温度对反应速率常数k影响较大,即随着温度的升高,灭活反应的延滞期CT_(lag)显著减小,反应速率常数k增大,臭氧对芽孢的灭活能力增强;而反应速率常数k在各pH值下基本不变,pH值对芽孢的灭活影响甚微.

In general,spores of Bacillus subtilis（ ATCC6633） would be used as potential model for the resistant microorganisms. In this study,the inactivation kinetics of spores in drinking water by ozone was investigated,and the factors such as ozone such as the numerical value of the product of the concentration of ozone and the reaction time（ CT） values,p H,and temperature which could influence the inactivation process were evaluated. Results showed that the inactivation process of spores with ozone was characterized by a lag phase followed by a logarithmic inactivation phase,and the delayed Chick-Watson model could well describe the inactivation process. In this study,the disinfection of Bacillus subtilis spores was performed in a semi- batch reactor under the conditions with the ozone concentration,reaction time,p H,and temperature ranged in 0. 42—4. 00 mg·L^（-1）,0—20 min,6—8,and 1—30 ℃,respectively. It showed that the inactivation is independent of ozone dose and is obvious relative to the ozone CT values. A higher inactivation level of spores would be achieved at higher CT values. In addition,the results indicated that the temperature could affectthe kinetic rate constant of disinfection,and the lag phase decreased and the rate constant increased with the increasing of temperature. However,the kinetic rate constant kept nearly stead under different p H,which indicated that the p H had insignificant effect on spores inactivation.