Pulsed gas injection: A minimum effort approach for enhanced natural attenuation of chlorobenzene in contaminated groundwater

• Published in: Environmental pollution (1987) 2009-07, Vol.157 (7), p.2011-2018
• Main Authors: Balcke, Gerd Ulrich, Paschke, Heidrun, Vogt, Carsten, Schirmer, Mario
• Format: Article
• Language: English
• Subjects: aeration; Aerobiosis; Air; Applied sciences; benzene; biodegradation; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Biotechnology; Chlorobenzene; Chlorobenzenes; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environment and pollution; Environmental Restoration and Remediation - instrumentation; Environmental Restoration and Remediation - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Gases; Groundwater; groundwater contamination; Groundwaters; halogenated hydrocarbons; Industrial applications and implications. Economical aspects; Natural water pollution; Oxygen; Oxygen-deficient; Oxygenation; Pollution; Pollution, environment geology; Remediation; Water Microbiology; Water Pollutants, Chemical; Water treatment and pollution
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2009.02.030

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. Minimum rate gas sparging resulted in sustained biodegradation of chlorobenzene in a polluted groundwater aquifer.