Research project SAFIRA

Research project: Innovative processes for groundwater remediation

(SAFIRA project network, subproject "activated carbon biology", funded by BMBF)

Problem:

Extensive regional groundwater damage, such as in the Bitterfeld area, cannot be remediated using conventional techniques. Funnel and gate processes are technologically and financially promising for long-term treatment of at least the effluent from damage sites. The proposed process combined adsorptive with biological elimination of contaminants through a two-stage anaerobic/aerobic process. This should allow a wide range of mixed contaminants to be concentrated on activated carbon and treated biologically.

Features of the process:

• High safety due to reliable adsorption behavior of activated carbon.
• Biological elimination of contaminants only useful after partial loading of activated carbon.
• Anaerobic stage for reductive conversion of pollutants that are metabolically inert under aerobic conditions; partly also anaerobic oxidation.
• Aerobic stage for continuous or cyclic degradation of aerobically useful pollutants (e.g. low-halogenated hydrocarbons).
• Significant extension of the service life of activated carbon through biological pollutant degradation, thus cost savings.
• Modular design of systems allows flexible process control and adaptation to varying conditions.

Research results:

• Laboratory tests with a model mixture of trichloroethene, chlorobenzene and benzene were successful, confirming the viability of the concept.
• The pilot plant in Bitterfeld from the SAFIRA project allowed experiments under in situ conditions (experiments ran for several years).
• Medium-term research focuses on the long-term stability of the process, performance limits depending on physico-chemical and hydromechanical boundary conditions, and the investigation of other remediation-relevant pollutant mixtures.