Effects of surfactants on the dechlorination of chlorinated ethenes

Abstract

The influence of surfactants on a perchloroethene (PCE) dechlorinating mixed culture was investigated in laboratory experiments. Surfactants (Steol CS-330, Aerosol MA 80-I, alpha olefin sulfonate 14 to 16, Neodol 25-7, Tween 80, alkyl polyglycoside, C16TAB [trimethylammonium bromide], and sodium dodecyl sulfate) were evaluated for their effects on the rate and extent of PCE reductive dechlorination and their potential biodegradation by the mixed culture. Limited, if any, surfactant biodegradation was observed for the surfactants tested, and all surfactants impaired dechlorination in either the rate of PCE dechlorination or the terminal dechlorination products observed. Based on initial testing, a nonionic surfactant, Tween 80, and an anionic surfactant, Steol CS-330, were selected for additional investigation. Dechlorination of PCE to dichloroethene (DCE), vinyl chloride (VC), and ethene (ETH) occurred in all Tween 80-amended microcosms, with a depressed rate of ETH production as the only adverse effect. Steol CS-330, however, inhibited dechlorination beyond DCE at all surfactant concentrations exceeding 25 mg/L. Attempts to acclimate a culture to Steol CS-330 were unsuccessful. Inhibition of VC and ETH production was reversible on dilution of the surfactant to a concentration of 10 mg/L or less, indicating that surfactant interactions with the enzyme system responsible for reductive dechlorination of DCE may be the cause of inhibition.

Development of Assessment Tools for Evaluation of the Benefits of DNAPL Source Zone Treatment

“…In their study, a dechlorinating consortium dechlorinated PCE to VC and ethene when amended with 1,000 -10,000 mg/L Tween 80 (McGuire and Hughes 2003). Our results with the OW consortium, which was derived from the same source as the dechlorinating consortium used by McGuire and Hughes (McGuire and Hughes 2003;Daprato et al 2007), also indicated ethene formation in the presence of 1,000 mg/L Tween 80. Microscopic analysis and POC measurements showed that the OW consortium contained at least 20-fold more biomass than the BDI consortium, which did not dechlorinate PCE beyond cis-DCE in the presence of Tween 80.…”

“…Despite the evidence that Tween 80 inhibits dechlorination mediated by Dehalococcoides organisms and reduces their survival, a study by McGuire and Hughes (McGuire and Hughes 2003) suggested that Dehalococcoides can dechlorinate in the presence of Tween 80. In their study, a dechlorinating consortium dechlorinated PCE to VC and ethene when amended with 1,000 -10,000 mg/L Tween 80 (McGuire and Hughes 2003).…”

“…In addition, (McGuire and Hughes 2003) reported that 40% of Tween 80 in a 1% (wt.) solution was degraded by mixed anaerobic culture after 70 days, and that Tween 80 exhibited no adverse effect on PCE conversion to VC, although subsequent transformation of VC to ethene occurred more slowly than in surfactant-free controls.…”

Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE–DNAPL source zone

“…Aquifer cell studies provide a more realistic representation of subsurface conditions compared to microcosms (Amos et al, 2007;McGuire and Hughes, 2003) and homogeneous onedimensional flow systems (Amos et al, 2008(Amos et al, , 2009Azizian et al, 2008). For example, Sleep et al (2006) observed growth of Dhc in close proximity to a tetrachloroethene-(PCE-) DNAPL source where aqueous concentrations exceeded 700 μM (115 mg/L), resulting in microbially-enhanced dissolution.…”

Surfactant enhanced biodegradation of petroleum hydrocarbons in oily sludge.

“…Surfactants including both chemical and biological surfactants have been widely reported to be utilized by pure or mixed cultures of microbial populations as their carbon sources (Oberbremer et al, 1990;Chen et al, 2001;Kim et al, 2001;McGuire and Hughes, 2003;Mohan et al, 2006). This phenomenon has also been reported to have both beneficial and inhibitory effects on bioremediation.…”