Integrated evaluation of the performance of a more than seven year old permeable reactive barrier at a site contaminated with chlorinated aliphatic hydrocarbons (CAHs).

An important issue of concern for permeable reactive iron barriers is the long-term efficiency of the barriers due to the long operational periods required. Mineral precipitation resulting from the anaerobic corrosion of the iron filings and bacteria present in the barrier may play an important role in the long-term performance. An integrated study was performed on the Vapokon permeable reactive barrier (PRB) in Denmark by groundwater and iron core sample characterization.

Microbially mediated clinoptilolite regeneration in a multifunctional permeable reactive barrier used to remove ammonium from landfill leachate contamination: laboratory column evaluation.

This study focuses on multifunctional permeable reactive barrier (multibarrier) technology, combining microbial degradation and abiotic ion exchange processes for removal of ammonium from landfill leachate contamination. The sequential multibarrier concept relies on the use of a clinoptilolite-filled buffer compartment to ensure a robust ammonium removal in case of temporary insufficient microbial activities. An innovative strategy was developed to allow in situ clinoptilolite regeneration.

Design of a multifunctional permeable reactive barrier for the treatment of landfill leachate contamination: laboratory column evaluation.

This study describes a laboratory-scale multifunctional permeable reactive barrier (multibarrier) for the removal of ammonium (NH4+: 313 +/- 51 mg N L(-1)), adsorbable organic halogens (AOX: 0.71 +/- 0.25 mg Cl L(-1)), chemical oxygen demand (COD: 389 +/- 36 mg L(-1)), and toxicity from leachate originating from a 40-year-old Belgian landfill.

Positive impact of microorganisms on the performance of laboratory-scale permeable reactive iron barriers.

Degradation efficiencies of zerovalent iron (Fe0) containing different bacterial inocula, i.e., an iron(III)-reducing Geobacter sulfurreducens strain and/or a bacterial consortium, were compared to degradation efficiencies of noninoculated Fe0 in a laboratory-scale column experiment.

Impact of microbial activities on the mineralogy and performance of column-scale permeable reactive iron barriers operated under two different redox conditions.

The present study focuses on the impact of microbial activities on the performance of various long-term operated laboratory-scale permeable reactive barriers. The barriers contained both aquifer and Fe0 compartments and had received either sulfate or iron(III)-EDTA to promote sulfate-reducing and iron(III)-reducing bacteria, respectively. After dismantlement of the compartments after almost 3 years of operation, DNA-based PCR-DGGE analysis revealed the presence of methanogenic, sulfate-reducing, metal-reducing, and denitrifying bacteria within as well as up- and downgradient of the Fe0 matrix.