Effect of chloroethene concentrations and granular activated carbon on reductive dechlorination rates and growth of Dehalococcoides spp

• Published in: Bioresource technology 2012-01, Vol.103 (1), p.286-292
• Main Authors: Aktaş, Özgür, Schmidt, Kathrin R., Mungenast, Sarah, Stoll, Claudia, Tiehm, Andreas
• Format: Article
• Language: English
• Subjects: Activated carbon; Adsorption; Adsorption - drug effects; bioassays; bioavailability; Biodegradation, Environmental - drug effects; Biological and medical sciences; Charcoal - pharmacology; Chlorides - metabolism; Chloroflexi - drug effects; Chloroflexi - growth & development; Chloroflexi - metabolism; Dechlorination; Degradation; Dehalococcoides; Dehalococcoides spp; Dissolution; Fundamental and applied biological sciences. Psychology; Granular activated carbon; groundwater; Halogenation - drug effects; Kinetics; Microorganisms; mixed culture; Oxidation-Reduction - drug effects; polymerase chain reaction; Reductive dechlorination; remediation; sorption isotherms; Temperature; Tetrachloroethene; tetrachloroethylene; Tetrachloroethylene - toxicity; Thresholds; Toxicity
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.09.119

► PCE concentrations up to 70mg/L are reductively dechlorinated by a mixed culture. ► Above 70mg/L PCE reductive dechlorination is possible only with activated carbon. ► Activated carbon decreases PCE bioavailability causing faster ethene formation. ► Thermally and chemically activated carbons show different PCE adsorption isotherms. This study focused on the investigation of (i) the tetrachloroethene (PCE) toxicity threshold of a reductively dechlorinating mixed culture containing Dehalococcoides spp., (ii) the adsorption of PCE on different types of granular activated carbon (GAC), and (iii) the bioavailability and reductive dechlorination in the presence of GAC. The abundance of Dehalococcoides spp. detected by quantitative real-time polymerase chain reaction (qPCR) was found to increase by 2–4 orders of magnitude during degradation of PCE. No degradation occurred at dissolved concentrations beyond 420μM (70mg/L). Different adsorption isotherms were determined for thermally and chemically activated carbons. The addition of GAC to biological assays reduced the dissolved PCE concentration below the toxicity threshold. The combination of microbial reductive dechlorination with GAC adsorption proved to be a promising method for remediation of groundwater contaminated by high concentrations of chloroethenes.