Utilization of Methane by Sulfate Reducing Bacteria: Implications for Hydraulic Fracturing

Abstract

Leakage of natural gas, particularly methane, from hydraulically fractured oil and gas wells is being implicated as a factor for degradation of groundwater. Utilization of methane by sulfate reducing bacteria in drinking water aquifers has been hypothesized, but no direct evidence has been established to link the bacteria to the reaction. A series of column experiments were performed to examine this hypothesis and to monitor the changes that occurred in the water in each column when methane is purged through the columns. Changes that were monitored include pH and oxidation reduction potential, and sulfate, sulfide, iron, and manganese concentrations. The changes were compared to changes that occurred in a drinking water well in Dimock, PA after hydraulic fracturing, and the results had similar changes, including reduction in the oxidation reduction potential, and were coupled to the loss of sulfate to form hydrogen sulfide as well as increased metal concentrations. These column experiments provide supporting evidence that sulfate reducing bacteria can utilize methane and other natural gas components to degrade the quality of drinking water wells.