Evaluation of soil solid amendments for TCE biodegradation in a biobarrier system

Abstract

Permeable biobarrier systems (PBSs) are being recognized as low-cost passive bioremediation technologies for chlorinated organic contamination. This innovative technology can play a crucial and effective role in site restorations. Laboratory-scale experiments were conducted to investigate the biodegradation of trichloroethylene (TCE) to ethylene in shallow groundwater through the use of a PBS enhanced by bioaugmentation at the U.S. Department of Energy's Savannah River Site (SRS). Two composts and two plant amendments, eucalyptus mulch (EM) and corncobs (CC), were examined for their effectiveness at creating and maintaining conditions suitable for TCE anaerobic dechlorination. These materials were evaluated for their (1) nutrient and organic carbon content, (2) TCE sorption characteristics, and (3) longevity of release of nutrients and soluble carbon in groundwater to support TCE dechlorination. Native bacteria in the columns had the ability to convert TCE to dichloroethenes (DCEs); however, the inoculation with the TCE-degrading culture greatly increased the rate of biodegradation. This caused a significant increase in by-product concentration, mostly in the form of DCEs and vinyl chloride (VC) followed by a slow degradation to ethylene. Of the tested amendments, eucalyptus mulch was the most effective at supporting the reductive dechlorination of TCE. Corncobs created a very acidic condition in the column that inhibited dechlorination. O

Restoring biochemical activity and bacterial diversity in a trichloroethylene-contaminated soil: the reclamation effect of vermicomposted olive wastes

“…The difference between the two systems should also be attributed to evaporation and adsorption of TCE on the soil and on the organic amendment (Pignatello 1990;Katsenovich et al 2007). In our conditions, TCE evaporated less easily from the vermicompost than from the soil, but no TCE was detected in the layer of vermicompost after 90 days of incubation.…”

Pilot-Scale Evaluation of a Permeable Reactive Barrier with Compost and Brown Coal to Treat Groundwater Contaminated with Trichloroethylene

“…Reductive dechlorination of chlorinated aliphatic hydrocarbons (CAHs) is carried out by several different bacteria, in particular, cultures containing Desulfitobacterium, Dehalobacterrestrictus, Desulfuromonas, Dehalospirillum multivorans, and Dehalococcoides. However, Dehalococcoides are the only microorganism known capable of complete dechlorination of TCE to ethylene [10][11][12][13][14][15][16].…”

“…The use of compost in PRBs to treat TCE has been broadly documented [13,[23][24][25]. Compost has shown to facilitate TCE reductive dechlorination by improving the conditions for microbial growth, and to provide a suitable environment for creating a bioactive zone capable of decomposing TCE in groundwater [25].…”

Field Study of Enhanced TCE Reductive Dechlorination by a Full‐Scale Whey PRB

“…A wide variety of complex electron‐donor materials are also being used to enhance the rates of contaminant biodegradation (Nyer 2003). Complex carbon substrates including emulsified vegetable oil, Hydrogen Release Compound (HRC) ® , lactate syrup, mulch, molasses, and dairy whey have been employed to develop reducing conditions (Barcelona and Xie 2001) and, as sources of electron donor, to stimulate microbially‐mediated, anaerobic reductive dechlorination of CEs (Yang and McCarty 2000a; Lendvay et al 2003; Rodriguez et al 2004; ITRC 2005; Borden 2007; Hirschorn et al 2007; Katsenovich et al 2007; Lu et al 2008). Performance and cost evaluations of carbon substrate biobarriers await the comprehensive study of donor material efficiencies, loading frequencies, and application design (Barcelona and Xie 2001; Barcelona 2005).…”