A Comparison of Three Nonoxidizing Biocides and Chlorine Dioxide in Treating Marcellus Shale Production Waters

Abstract

Summary Chlorine dioxide (ClO2), a relative new addition to the oil and gas fracturing industry (especially for production-water treatment for reuse), has superior microbial efficacy compared with currently used nonoxidizing biocides at their lowest and mid-range US Environmental Protection Agency approved concentrations. ClO2 is the only antimicrobial treatment to exhibit complete kill of any of the bacterial populations [except tetrakishydroxymethyl phosphonium sulfate (THPS) at 208 ppm (commodity basis) in 100% Marcellus shale production water], and demonstrated greater than 5.16 log10 reduction even at the lowest ClO2 residual tested (i.e., 1.19 ppm residual; 9 ppm dose). As a result, ClO2 should be considered a potentially viable option when selecting a biocide for treating fracturing production waters for reuse in the Marcellus shale play.