WATER QUALITY MEASUREMENT USING ELECTRIC POTENTIAL OF BIOFILM IN TIDAL FLATS

Abstract

 Oxidation-reduction potential (ORP) measures energy level of redox reactions in solution, and can be used as qualitative index to evaluate water quality in tidal flats with high biological activity. Conventional ORP sensors measure activity of ions that have passed through a membrane with internal electrodes, thus continuous monitoring at field is difficult. A carbon electrode, which directly measures the redox reaction without a membrane, captures redox reaction of dissolved and suspended substances such as ions, algae, and organic matters that adhere to the electrode. In this study, a carbon based ORP sensor was installed in a tidal flat to evaluate the water quality in a place with high biological activity. The results confirmed that unique potential characteristics appeared depending on the presence or absence of biofilm on the electrode surface, suggesting the possibility as new water quality parameter.