title: Pulsed gas injection: a minimum effort approach for enhanced natural attenuation of chlorobenzene in contaminated groundwater.
abstract: Chlorobenzene-contaminated groundwater was used to assess pulsed gas sparging as a minimum effort aeration strategy to enhance intrinsic natural attenuation. In contrast to existing biosparging operations, oxygen was supplied at minimum rate by reducing the gas injection frequency to 0.33 day(-1). Field tests in a model aquifer were conducted in a 12 m long reactor, filled with indigenous aquifer material and continuously recharged with polluted groundwater over 3 years. The closed arrangement allowed yield balances, cost accounting as well as the investigation of spatial distributions of parameters which are sensitive to the biodegradation process. Depending on the injection frequency and on the gas chosen for injection (pure oxygen or air) oxygen-deficient conditions prevailed in the aquifer. Despite the limiting availability of dissolved oxygen in the groundwater, chlorobenzene degradation under oxygen-deficient conditions proved to be more effective than under conditions with dissolved oxygen being available in high concentrations.
authors.affiliation: Department of Hydrogeology, UFZ Helmholtz Centre for Environmental Research, Theodor-Lieser-Strasse 4, D-06120 Halle/Saale, Germany. gerd.balcke@metanomics.de
authors.forename: Gerd Ulrich
authors.initials: GU
authors.lastname: Balcke
authors.forename: Heidrun
authors.initials: H
authors.lastname: Paschke
authors.forename: Carsten
authors.initials: C
authors.lastname: Vogt
authors.forename: Mario
authors.initials: M
authors.lastname: Schirmer
mesh_terms: D000332:Aerobiosis; D000388:Air; D001673:Biodegradation, Environmental; D002722:Chlorobenzenes; D052918:Environmental Restoration and Remediation / Q000295:instrumentation / Q000379:methods*; D005740:Gases; D010100:Oxygen; D014871:Water Microbiology; D014874:Water Pollutants, Chemical
chemical_list: D002722:Chlorobenzenes; D005740:Gases; D014874:Water Pollutants, Chemical; C031294:chlorobenzene; D010100:Oxygen