Parameter Determination for Reductive Dechlorination of Chlorinated Solvents

2006 ◽  
Vol 65 (3) ◽  
pp. 411-424 ◽  
Author(s):  
Antónia Balážová ◽  
Marián Slodička ◽  
Roger Van Keer
Keyword(s):  
Reductive Dechlorination ◽  
Chlorinated Solvents ◽  
Parameter Determination

scholarly journals A Microcosm Treatability Study for Evaluating Wood Mulch-Based Amendments as Electron Donors for Trichloroethene (TCE) Reductive Dechlorination

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1949
Author(s):  
Edoardo Masut ◽  
Alessandro Battaglia ◽  
Luca Ferioli ◽  
Anna Legnani ◽  
Carolina Cruz Viggi ◽  
...  
Keyword(s):  
Electron Donor ◽  
Environmental Sustainability ◽  
Reductive Dechlorination ◽  
Environmental Remediation ◽  
Low Cost ◽  
Chlorinated Solvents ◽  
Electron Donors ◽  
Chlorinated Ethenes ◽  
Dehalococcoides Mccartyi ◽  
Wood Mulch

In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H2 availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes.

scholarly journals Hydrogeochemical and hydrodynamic features affecting redox processes in groundwater

2019 ◽  
Vol 8 (3) ◽  
Author(s):  
Diego Di Curzio
Keyword(s):  
Reductive Dechlorination ◽  
Chlorinated Solvents ◽  
Organic Substrate ◽  
Electron Acceptors ◽  
Contaminated Site ◽  
Hydrodynamic Effect ◽  
Redox Processes ◽  
Dispersive Transport ◽  
Factorial Kriging

This research deals with some hydrogeochemical and hydrodynamic features that affect redox processes in groundwater, presenting three different case studies and methodological approaches. This information is vital when characterizing contaminated sites, planning monitoring, selecting remedial techniques, and assessing health risks. In the San Pedro Sula site case study (Honduras), new insights and an advanced method for the aquifer redox zonation were provided. The Multi-Collocated Factorial Kriging, a multivariate geostatistical technique borrowed from agriculture and soil science, identified simultaneous redox processes, acting at different scales and mainly due to eutrophicated surface-water/groundwater interaction: at short-range, Mn oxihydroxide reductive dissolution and Fe oxi-hydroxide colloidal phase precipitation; at long-range, Fe mobilization. The obtained results are supported by the Principal Component Analysis and hydrogeochemical numerical modeling. The interaction among different contamination events in the VR site allowed to get a deeper insight into the competition for organic substrate among different redox processes. To this purpose, a 1-D Advective-Reactive- Dispersive transport numerical model was implemented, and its results highlighted that the reductive dechlorination is inhibited by the inorganic Terminal Electron Accepting Processes, enriching groundwater in highly toxic by-products of the reductive dechlorination (i.e. Vinyl Chloride). As a matter of fact, the bacteria using inorganic Terminal Electron Acceptors to oxidize the organic substrate are more efficient than the halo-respiring bacteria, that favor reductive dechlorination. The contaminated site of Bussi Officine case study allowed to clarify the hydrodynamic effect on the redox processes and the anoxic condition distribution. The comparison between dissolved chlorinated solvents and the inorganic Terminal Electron Acceptors distribution in the aquifer pointed out that dispersion inhibits all the redox processes because it dilutes the organic substrate concentration in groundwater. On the other hand, the lacustrine deposits rich organic matter (i.e. peat) can be considered as “chemical reactors”, that releases by back-diffusion toxic by-product of the reductive dichlorination in groundwater.

Monitored natural attenuation of chlorinated solvents—Moving beyond reductive dechlorination

2006 ◽  
Vol 16 (3) ◽  
pp. 5-23 ◽  
Author(s):  
Karen M. Vangelas ◽  
Brian B. Looney ◽  
Tom O. Early ◽  
Tyler Gilmore ◽  
Francis H. Chapelle ◽  
...  
Keyword(s):  
Natural Attenuation ◽  
Reductive Dechlorination ◽  
Chlorinated Solvents ◽  
Monitored Natural Attenuation

scholarly journals Coupled Adsorption and Biodegradation of Trichloroethylene on Biochar from Pine Wood Wastes: A Combined Approach for a Sustainable Bioremediation Strategy

2022 ◽  
Vol 10 (1) ◽  
pp. 101
Author(s):  
Marta M. Rossi ◽  
Bruna Matturro ◽  
Neda Amanat ◽  
Simona Rossetti ◽  
Marco Petrangeli Papini
Keyword(s):  
Reductive Dechlorination ◽  
Adsorption Mechanism ◽  
Biological Process ◽  
Chlorinated Solvents ◽  
Biofilm Reactor ◽  
Rrna Gene ◽  
Pine Wood ◽  
Dehalococcoides Mccartyi ◽  
Gene Copies ◽  
Physical Treatments

Towards chlorinated solvents, the effectiveness of the remediation strategy can be improved by combining a biological approach (e.g., anaerobic reductive dechlorination) with chemical/physical treatments (e.g., adsorption). A coupled adsorption and biodegradation (CAB) process for trichloroethylene (TCE) removal is proposed in a biofilm–biochar reactor (BBR) to assess whether biochar from pine wood (PWB) can support a dechlorinating biofilm by combining the TCE (100 µM) adsorption. The BBR operated for eight months in parallel with a biofilm reactor (BR)—no PWB (biological process alone), and with an abiotic biochar reactor (ABR)—no dechlorinating biofilm (only an adsorption mechanism). Two flow rates were investigated. Compared to the BR, which resulted in a TCE removal of 86.9 ± 11.9% and 78.73 ± 19.79%, the BBR demonstrated that PWB effectively adsorbs TCE and slows down the release of its intermediates. The elimination of TCE was quantitative, with 99.61 ± 0.79% and 99.87 ± 0.51% TCE removal. Interestingly, the biomarker of the reductive dechlorination process, Dehalococcoides mccartyi, was found in the BRR (9.2 × 105 16S rRNA gene copies/g), together with the specific genes tceA, bvcA, and vcrA (8.16 × 106, 1.28 × 105, and 8.01 × 103 gene copies/g, respectively). This study suggests the feasibility of biochar to support the reductive dechlorination of D. mccartyi, opening new frontiers for field-scale applications.

Degradation of halogenated aliphatic compounds utilizing sequential anaerobic/aerobic treatments

2003 ◽  
Vol 47 (10) ◽  
pp. 79-84 ◽  
Author(s):  
T. McCue ◽  
S. Hoxworth ◽  
A.A. Randall
Keyword(s):  
Reductive Dechlorination ◽  
Chlorinated Solvents ◽  
Treatment Strategies ◽  
Aliphatic Hydrocarbons ◽  
Microbial Consortia ◽  
Aerobic Treatment ◽  
Aliphatic Compounds ◽  
Groundwater Contaminants ◽  
Environmental Treatment ◽  
Anaerobic Environment

The objective of this research was to determine if either methanogenic or sulfidogenic reductive dechlorination could survive an alternating anaerobic/aerobic sequence to biologically transform halogenated aliphatic hydrocarbons (HACs), specifically tetrachloroethylene (PCE), trichloroethylene (TCE), cis-1,2 dichloroethylene (cDCE), trans-1,2 dichloroethylene (tDCE), 1,1 dichloroethylene (1,1DCE) and vinyl chloride (VC). This ability was considered to be a necessary prerequisite for complete anaerobic/aerobic mineralization of halogenated aliphatic hydrocarbons by a single microbial consortia. Chlorinated solvents, which are among the most common groundwater contaminants, have been partially dechlorinated using single-stage anaerobic environmental treatment strategies. Various types of bacteria typically reductively dechlorinate PCE and TCE to cDCE and VC in an anaerobic environment, including methanogens, sulfidogens, and homoacetogens. The problem lies in the fact that reductive dechlorination typically leads to an accumulation of daughter compounds (cDCE, VC) which are more toxic than their parent compounds (PCE, TCE). Furthermore, PCE and (to a lesser extent) TCE, are resistant to dechlorination in aerobic environments. In contrast, VC and cDCE are readily oxidized co-metabolically in an aerobic environment by methanotrophic bacteria, and others using oxygenases (e.g. toluene oxidizers). Results from this research showed that both methanogenic and sulfidogenic reductive dechlorination could resume after transient exposures to both oxygen and hydrogen peroxide (H2O2). In fact, for cycles as frequent as 10 days between aerobic treatment cycles, reductive dechlorination was observed to resume at rates at least as rapid as microcosms not exposed to aerobic treatments.

Effect of chlorinated alkenes on the reductive dechlorination and methane production processes

1994 ◽  
Vol 30 (7) ◽  
pp. 85-94 ◽  
Author(s):  
Ping Zhuang ◽  
Spyros G. Pavlostathis
Keyword(s):  
Methane Production ◽  
Reductive Dechlorination ◽  
Culture Media ◽  
Chlorinated Solvents ◽  
Threshold Concentration ◽  
Primary Metabolism ◽  
Relative Toxicity ◽  
Production Processes ◽  
Methane Production Rate ◽  
Dark Soil

Mixed, acetate-fed methanogenic cultures were used to assess the effect of increasing tetrachloroethylene (PCE), trichloroethylene (TCE) and cis-1,2-dichloroethylene (cDCE) concentrations on the reductive dechlorination and primary metabolism (methane production) processes. In addition, the effect of TCE on the rate and extent of the reductive dechlorination of PCE was investigated. All cultures were developed in serum bottles and incubation was carried out at 35°C in the dark. Soil samples from two sites contaminated with chlorinated solvents served as the inoculum for this study. All chlorinated alkenes used were supplied as saturated solutions in the culture media. The rate of PCE dechlorination increased with increasing PCE concentrations. Both TCE and cDCE showed an increase in the dechlorination rate up to a solvent threshold concentration followed by a decrease. In all cases, the methane production rate decreased as the chlorinated alkene concentrations increased. However, the effect of chlorinated alkenes was more pronounced on methane production rather than on the extent of dechlorination. The relative toxicity of the chlorinated alkenes tested in this study formed the following ascending series: PCE < TCE < < cDCE.

Sign in / Sign up

Export Citation Format

Share Document