Natural attenuation

The conceptual approach of natural attenuation/intrinsic remediation, which relies on natural subsurface processes rather than traditional engineered procedures to eleminate contaminants in groundwater or soil, can provide tailored measures for low-risk cases, such as contamination by petroleum hydrocarbons. In this concept, increased efforts are required both for initial studies on site hydrology, geochemistry and microbiology as well as for subsequent monitoring of the remediation success.

The concept of natural attenuation is based on processes such as biological degradation, dispersion, dilution, sorption, evaporation and/or chemical and biochemical stabilisation of pollutants. Major advantages of the concept are - as for most in-situ procedures - the avoidance of secondary waste and reduction of hazards for exposed persons compared to ex-situ treatments. Problems may arise from the long time period for reaching the remediation goals including subsequent surveillance.

Our activities focus on the development of procedures to assess the ecotoxicological potential in petroleum hydrocarbon contaminated aquifers during and after biodegradation. For this, a combination of ecotoxicological test methods is used. As a result of natural attenuation the toxicity of the substrate must not increase. Otherwise, active methods have to be applied. Bio-degradation is investigated in laboratory column studies using material from contaminated sites. Microbial degradation is examined as a function of residual oil saturation and oil composition in media of different wettability and water saturation. The intention is to provide criteria for choosing the appropriate remediation technique which instead of natural attenuation could be active ones such as enhanced bioremediation, bioventing or soil vapor extraction.

• 1-03.310V
  Förstner U.: Altlasten und Deponien - Natürlicher Rückhalt und Abbau als Problemlösung? In: Umwelt und Chemie - Innovationen und Produktdesign. Umweltagung 1998 der Gesellschaft Deutscher Chemiker, Karlsruhe, 27.-30. Sept. 1998. S. 49-51. Frankfurt/M. 1998
• 1-03.311V
  Förstner U.: Altlasten und Grundwasser - Naturwissenschaftliche Forschung für künftige Problemlösungen. Vom Wasser 91: 325-334 (1998)
• 1-03.312V
  Förstner U.: Altlasten und Grundwasser: Chemische und biologische Aspekte. In: Bayer E. et al. (Hrsg.) Umwelt und Chemie. Gesellschaft Deutscher Chemiker. Monographie Band 8, S. 175-184. Frankfurt a.M. 1997
• 1-03.326V
  Förstner U.: Langzeitprognosen und naturnahe Dauerlösungen - Ingenieur-geochemische Konzepte für Schadstoffe in Abfällen auf Deponien und in Böden. Geowissenschaften 14, 169-173 (1996)
• 1-03.328V
  Förstner U.: Reaktionen, die einen natürlichen Rückhalt bzw. Abbau von Schadstoffen bewirken. In: Franzius V. + Bachmann G. (Hrsg.) Sanierung kontaminierter Standorte und Bodenschutz 1998. S. 177-188. Erich Schmidt Verlag Berlin 1998
• 1-03.423V
  v.d. Kammer, F.; Thöming, J.; Förstner, U. (1999): Redox CapacityConcept as a Tool for the Assessment of Long Term Effects in NaturalAttenuation/Intrinsic Remediation. In: SCHÜRING, J.; SCHULZ, H.D.;FISCHER, W.R.; BÖTTCHER, J. & DUIJNISVELD, W.H.M. (Eds.): Redox ¿Fundamentals, Processes and Measuring Techniques. Springer-Verlag BerlinHeidelberg
• 1-03.428V
  Gerth, J.: Natürlicher Rückhalt anorganischer Schadstoffe.- Wasser Berlin 2000, 23.-27.10.2000, Messe Berlin 2000

Stichwörter

• ecotoxicological potential
• intrinsic remediation
• natural attenuation
• subsequent monitoring