미생물연료전지 셀형 센서를 이용한 유해 수질오염물질 계측시스템의 개발

Abstract

A novel hazardous water pollutions(HWPs) instrumentation system was investigated using a bio-electrochemical technique based on microbial fuel cell that converts biochemical energy generated by microorganisms to electrical energy. Microbial fuel cell was composed of cathode and anode compartment, which are separated by a cation-exchange membrane. To construct the microbial fuel cell-type biosensor, electrode-active bacteria capable of reacting with electrode were enriched in the cathode compartment. In cyclic voltammetry performed with the working electrode, at which bacterial cells have been enriched, typical oxidation and reduction peaks were generated. When stable electricity was generated between working (cathode) electrode and anode in proportional to concentration of organic materials contained in wastewater, the working electrode is possible to be used as toxic sensor. The electrochemical signal generated from microbial fuel cell is closely related to the function of electrode-active bacteria to directly reduce cathode, which can be disturbed by HWPs. The sensitivity and stability of HWPs-monitoring microbial fuel cell was improved by enlargement of bacterial-contacting area of electrode and reforming the wastewater-flowing channel, The electrochemical signal generated from the microbial fuel cell-type biosensor was disturbed in the presence of the HWPs (Cadmium, Chromium (+6), Lead, Arsenic, surfactant and organic phosphate, and PCB mixture), in which same results was repeatedly reproduced whenever the HWPs was applied. When mixture of HWPs (Chromium (+6) with Mercury, Arsenic with Cyanide, and Chromium (+6) with Cyanide) was applied to the biosensor, the detectable signals were also obtained. The biosensing-signals obtained from serial concentration of HWPs shows that the microbial fuel cell-type biosensor could be used successfully for the detection of HWPs even under interference of organic materials. To exclude effect of temperature variation, a device to maintain temperature, which is a Peltier, was developed. A control software and basic hardware were organized and constructed based on the data obtained from a series of preliminary experiments. The HWPs instrumentation system containing a back-up sensor was applied and estimated in the several practical fields including a water process company, water reservoir site for drinking, and a water treatment site in a research institute. The particle remover was also installed to prevent clogging. A customized tele-metering system (TMS) was also developed to add remote-monitoring capacity to the HWPs instrumentation system. Further experiments will be performed mainly in the practical fields to guarantee signal generation at the lower range than ppm or ppb of HWPs. The minimum alert range of cadmium was about 0.01 ppm, and the reliable operational detection ranges of Lead, and Arsenic were approximately 0.1 ppm and 0.05 ppm, respectively. The reliable alert data could be obtained within 10 to 30 minutes. The experimental results obtained from a mixture of HWPs in the practical field based on the alert signals showed that the HWPs may inhibit the electron transfer from the electrode-active bacteria to electrode, from which we suggested that the bacterial growth and/or metabolism substantially inhibited in the presence of high concentration of HWPs. The complete halt of the system caused by the high concentration of HWPs was successfully prevented using the back-up cell. According to the results in the practical fields, the HWPs instrumentation system produced reliable and sensible alert data when the HWPs was flowed in a water system. Over 180 days, the measurement system was successfully operated without any serious problem. This application showed that the HWPs instrumentation system can serve a rapid and practical way for the toxicity-warning in the various water industries.