Electrochemical microbial sensor system and method of using same

Abstract

A microbial sensor, system and method that can be used to determine the chemical environment and/or substrate concentrations in saturated and unsaturated natural and environments, such as soils, aquifers and sediments are disclosed. The system may be used for monitoring municipal and industrial treatment facilities and sites where chemicals or contaminants were released to natural environments. The electrochemical microbial sensor system can be referenced using either a cathode exposed to oxygen or a reference cell (silver/silver chloride or calomel) for monitoring natural or man-made environments.

We claim: 
     
         1 . A sensor system comprising:
 a first electrode in a first environment to be monitored;   a reference cell; and   a measurement device electrically coupled to the first electrode and the reference cell, wherein the measurement device measures a voltage between the first electrode and the reference cell to characterize microbial activity in the first environment.   
     
     
         2 . The sensor system of  claim 1 , wherein the voltage comprises an open-circuit voltage. 
     
     
         3 . The sensor system of  claim 1 , wherein the reference cell is in the first environment. 
     
     
         4 . The sensor system of  claim 1 , wherein the reference cell comprises a standard reference cell. 
     
     
         5 . The sensor system of  claim 1 , wherein the reference cell comprises a silver/silver chloride standard reference cell. 
     
     
         6 . The sensor system of  claim 1 , wherein the reference electrode cell a calomel standard reference cell. 
     
     
         7 . The sensor system of  claim 1 , wherein the first electrode comprises an anode. 
     
     
         8 . The sensor system of  claim 1 , wherein the sensor system comprises a plurality of first electrodes coupled to the measurement device. 
     
     
         9 . The sensor system of  claim 1 , wherein the sensor system further comprises a second electrode. 
     
     
         10 . The sensor system of  claim 9 , wherein the second electrode comprises a cathode. 
     
     
         11 . The sensor system of  claim 10 , wherein the sensor system comprises a cathode assembly comprising the cathode. 
     
     
         12 . The sensor system of  claim 11 , wherein the cathode assembly comprises a reversible cathode assembly. 
     
     
         13 . The sensor system of  claim 10 , wherein the voltage comprises a recovery voltage. 
     
     
         14 . The sensor system of  claim 11 , further comprising a current controller to control a flow of current between the first electrode and the cathode assembly. 
     
     
         15 . The sensor system of  claim 1 , wherein the first electrode comprises a biofilm. 
     
     
         16 . A method of measuring microbial activity, the method comprising the steps of:
 providing a first electrode in a first environment to be monitored;   providing a reference cell; and   measuring a voltage between the first electrode and the reference cell to characterize microbial activity in the first environment.   
     
     
         17 . The method of measuring microbial activity of  claim 16 , further comprising a step of providing a second electrode. 
     
     
         18 . The method of measuring microbial activity of  claim 17 , further comprising a step of controlling a current between the first electrode and the second electrode. 
     
     
         19 . The method of measuring microbial activity of  claim 17 , wherein the step of measuring a voltage comprises measure a recovery voltage. 
     
     
         20 . A sensor system comprising:
 a first electrode;   a second electrode;   a reference cell; and   a measurement device electrically coupled to the first electrode, the second electrode, and the reference cell, wherein the measurement device measures a voltage between the first electrode and the reference cell to characterize microbial activity in the first environment.