Passive Electrical Monitoring Of Aerobic And Anaerobic Processes Using Septic Systems As An Analog

Using anaerobic and aerobic septic systems as analogs, we examined whether the passive electrical potential (SP) method can be used to detect and monitor shallow biochemical reactions. High-resolution SP surveys conducted with nonpolarizing electrodes can reliably detect potential differences as small as a few mV over relatively small areas, suggesting that the technique can find wider use in monitoring biodegradation processes, mapping effluent plumes, and identifying local preferential infiltration areas. Surface SP measurements appear to respond to changes in the oxidation-reduction potential in shallow reactors, correlating best with changes in dissolved oxygen concentration and measured electrical potential within the subsurface reactors. Among the available electrode choices, including those made of carbon, low-grade steel, stainless steel, and copper, only nonpolarizing electrodes such as the copper–copper sulfate types provide the measurement stability necessary to achieve high-resolution results.