微生物菌剂在船舶生化需氧量快速检测仪中的应用

Application of microbial agents in the rapid detector for BOD in the wastewater from ships

摘要:

目的 针对国际海事组织对进港船舶生化需氧量(biochemical oxygen demand, BOD)检测中的特殊要求，本研究开发一种BOD快速检测仪，旨在实现对大量进港船舶生活污水进行快速检测的目的。方法 丁酸梭菌与枯草芽孢杆菌制作的生物敏感元件在检测BOD标准溶液的过程中，通过消耗溶解氧(dissolved oxygen, DO)引发电子转移，使电导率(conductivity, COND)改变。溶解氧是监测过程中的关键指标及中介桥梁。通过建立电导率与溶解氧的二次多项式拟合模型，并将溶解氧与样品浓度建立联系，由此探索电导率变化与样品浓度之间的相关性。结果 不同溶液表现的电导率变化趋势使BOD快速检测器能够区分BOD浓度超过25 mg/L (COND变化值的斜率小于-0.01)和低于25 mg/L (COND变化值的斜率大于-0.01)的废水。通过构建溶解氧与电导率值之间的高度相关性拟合曲线(决定系数R²=0.977 83)，实现了对超低浓度范围(生化需氧量BOD<25 mg/L)样品的高精度读取，并在中国河北秦皇岛的船舶测试中获得超过85%的准确率。结论 BOD快速检测仪所读取的测量数据与传统的稀释接种法所获结果高度一致，并且能够在30 min内对进港船舶生活污水中BOD进行快速量化分析，确保了检测的高效性。

Abstract:

Objective To develop a rapid detector for biochemical oxygen demand (BOD) in the wastewater from ships entering ports in response to the stringent mandates of the International Maritime Organization (IMO). The objective is to facilitate swift detection of domestic wastewater produced by the multitude of vessels arriving at the port.Methods When testing the BOD standard solution, Clostridium butyricum and Bacillus subtilis were used to manufacture the biosensitive elements inducing electron transfer during the consumption of dissolved oxygen (DO), which led to a change in electrical conductivity (COND). By treating dissolved oxygen as a pivotal indicator and an intermediary in the monitoring process, this study explored the correlation between changes in electrical conductivity and sample concentration. Through the development of a quadratic polynomial fitting model that correlates electrical conductivity with dissolved oxygen levels, and by establishing a connection between dissolved oxygen and sample concentration, this research delves into the correlation between variations in electrical conductivity and the concentration of the sample.Results The changes in electrical conductivity exhibited by different solutions enabled the detector to rapidly distinguish between the wastewater with a BOD concentration higher than 25 mg/L (the slope of the COND variation value is less than -0.01) and that below 25 mg/L (the slope of the COND variation value is greater than -0.01). By establishing a highly correlated fitting curve between dissolved oxygen and electrical conductivity (coefficient of determination R²=0.977 83), this study achieved precise reading of samples within the ultra-low concentration range (BOD<25 mg/L). The accuracy rate of the measurements exceeded 85% in the in-suit tests conducted in Qinhuangdao, Hebei, China.Conclusion The measurement data read by the rapid detector for BOD is highly consistent with the results obtained by the dilution inoculation method. Moreover, the detector is capable of performing rapid quantitative analysis of BOD in domestic wastewater from ships entering ports within 30 min, demonstrating high detection efficiency.