Wu Feng, Liu Zhi, Zhou Shun-gui, Wang Yue-qiang, Huang Sai-hua
College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China.
Huan Jing Ke Xue. 2009 Oct 15;30(10):3099-103.
The 5-d biochemical oxygen demand (BOD5) test is the most conventional method to determine the concentration of biodegradable organics in wastewater. However, this method is time-consuming and usually requires experience and skill to produce creditable results, which is also not suitable for on-line measurements. This study described a single-chamber mediator-less microbial fuel cell (MFC)-type BOD sensor as an alternative method to BOD5. In such MFC, MnO2 was used as the cathode catalyst instead of Pt and the expensive proton exchange membrane was replaced with the cation exchange membrane. The factors including the external resistance, pH of anolyte, the reaction time and rinse time on BOD sensor were explored, and the results were compared with the values determined by BOD5. The experimental results showed that the optimal conditions are: the external resistance of 12 k omega, pH of 7.0, and the reaction period of 2 h and the rinse time of 2-10 min. The low detection limit is 0.2 mg/L and the precision is 0.33%. This study indicates that MFC-type sensor can be used as a reliable method to determine BOD in wastewater, supported by the good linear correlation between BOD concentration and coulombs generation (regression coefficient, R2 = 0.9992) and the small relative error of 4% between MFC-type sensor and BOD5. Such device provides a low-cost, easy-operated, fast-response, sensitive and reliable method to measure BOD in wastewater, and also is suitable for on-line measurements.
五日生化需氧量（BOD5）测试是测定废水中可生物降解有机物浓度最常用的方法。然而，该方法耗时且通常需要经验和技巧才能得出可信结果，也不适用于在线测量。本研究描述了一种单室无介体微生物燃料电池（MFC）型BOD传感器，作为BOD5的替代方法。在这种MFC中，用MnO2代替Pt作为阴极催化剂，并用阳离子交换膜代替昂贵的质子交换膜。探讨了外部电阻、阳极电解液pH值、反应时间和冲洗时间等因素对BOD传感器的影响，并将结果与BOD5测定值进行比较。实验结果表明，最佳条件为：外部电阻12 kΩ、pH值7.0、反应时间2 h、冲洗时间2 - 10 min。检测下限为0.2 mg/L，精密度为0.33%。本研究表明，MFC型传感器可作为测定废水中BOD的可靠方法，BOD浓度与库仑产生量之间具有良好的线性相关性（回归系数，R2 = 0.9992），且MFC型传感器与BOD5之间的相对误差较小，为4%。该装置为测量废水中的BOD提供了一种低成本、易操作、快速响应、灵敏且可靠的方法，也适用于在线测量。
