RETRACTED: Poly-hydroxybutyrate-co-hydroxyvalerate as solid slow-releasing source of electron donors for the reductive dechlorination of 1,2-dichloroethane in-situ

Abstract

The aim of this study was to evaluate the applicability of a biobarrier system which includes a layer of poly-hydroxybutyrate-co-hydroxyvalerate (PHBV) to enhance biological reductive processes for the passive remediation of 1,2-dichloroethane (1,2-DCA) contaminated groundwater. Preliminary results concerning PHBV fermentability and performance as slow-releasing carbon/hydrogen source are presented. The simulation of a biobarrier amended with granular PHBV was carried out using two continuously-fed columns connected in series. A mixed culture enriched in hydrogen-utilizing dechlorinators (Dehalococcoides spp. and Desulfitobacterium sp.) was inoculated in the columns to provide microbial consortia for 1,2-DCA biodegradation. Effluent samples from each column were analyzed for volatile fatty acids, pH, 1,2-DCA and its degradation byproducts. Up to 100% of 1,2-DCA removal efficiency was obtained in this passive system over a 70-days' operating period. Results indicate that continuously released electron donors from the PHBV-column can enhance 1,2-DCA biotransformation downgradient the groundwater flow. PHBV degradation kinetics appeared to be influenced by the percentage of co-hydroxyvalerate (8%mol or 19%mol) and the average particles size (powder or pellet form). These parameters affecting PHBV biodegradability can be easily optimized in order to control its fermentation rate and extend its lifetime up to suitable timeframes for sustainable (low-cost, low-maintenance) field application.