Project SABRE: Source Area BioRemediation

Why is this necessary?

Chlorinated solvents have been used in large quantities by a diverse range of industries (including chemicals production, metalworking, automotive, aerospace, electronics and dry cleaning).  They are consequently extremely common environmental contaminants.

Chlorinated solvent releases into the sub-surface may result in the existence of free-phase chlorinated solvent contamination (“DNAPL”), which will persist for decades and act as long-term sources of groundwater contamination. Remediation can, therefore, be important but is usually very expensive and of uncertain result.

The Technology

Under anaerobic conditions dehalorespiring bacteria can use many chlorinated solvents for respiration, which can ultimately yield the innocuous end-product ethene. This process is effective even in the presence of chlorinated solvent DNAPL and may occur more efficiently.

To apply this biodegradation for free-phase chlorinated solvents within the subsurface, it is necessary to optimise conditions in the subsurface for the dehalorespiring bacteria, for example through the supply of organic carbon and energy sources and inorganic nutrients. The SABRE project evaluated and developed the most efficient method for doing this using appropriate monitoring to reduce uncertainty in demonstrating technology performance.

Project Activities

SABRE took place from 2004 to 2008 and involved combined laboratory and field development testing of the bioremediation technology. The following Work Packages were undertaken:

• Site Investigation:
  To characterise the test area, provide design information for the field-scale process and determine the initial quantity of contamination.
• Microbiology:
  Use of laboratory microcosm and column tests to determine the optimal conditions for the bioremediation process. Application of microbiological techniques for process monitoring.
• Test cell design, installation and operation:
  Design, engineering and installation of two field-pilot scale test areas suitable for technology demonstration and the development of design criteria for future routine technology application. Operation of these in response to data obtained.
• Performance Assessment:
  Monitoring of the process by traditional and novel geophysical techniques and evaluation of the data collected.
• Flow and process modelling:
  For process design and the development of tools to aid in the interpretation of results and for future technology implementation.
• Technical quality management:
  Ensuring that the data collected are robust and statistically valid.
• Project management

Project Reporting

SABRE is a CL:AIRE Technology Demonstration Project. Project progress and results were disseminated through a variety of channels, including:

• Technical updates
  Issued throughout the project through CL:AIRE and other channels.
• Scientific papers
  Conference presentations and peer reviewed publications.
• Project scientific conference and final report
  During 2008
• Technology guidance document and training
  Guidance on the selection, implementation, design, operation and monitoring of DNAPL bioremediation, incorporating the learning from SABRE.

Acknowledgements 

SABRE was supported through the UK DTI Bioremediation LINK programme. The project was funded through in-kind and direct financial contributions from the participating organisations and by BBSRC, DTI, the Environment Agency, EPSRC and NERC.