DEVELOPMENT OF MICROBIAL ELECTROCHEMICAL SENSOR FOR TOXICITY SCREENING OF INFLUENT WASTEWATER

Abstract

A microbial electrochemical sensor (MES) that is capable to detect influent wastewater toxicity was presented, having the characteristics of being quick, preventative, simple, inexpensive, on-line, and relevant to the activated sludge process. The MES was firstly optimized in terms of both sensing material (biofilm) and the transistor composed of different factors like MES configuration, size, flow conditions, membrane, external resistance, etc. The application of the MES to different kinds of toxicants and their characteristics were studied. Toxic compounds tested included individual heavy metal ions (Cu(II), Zn(II), Pb(II), Cd(II) and Ni(II)), binary mixtures of heavy metals, cyanide and organic chemicals. Both of the electrochemical and biological characteristics of the sensor were investigated. It was found that neither the viability of bacteria nor the microbial communities was changed due to the short term exposure to the toxicants. It was the inhibition of the electrochemical activity that led to the decrease of the sensor current.