Bioremediation and Bionanotechnology Part 2 Dr Russell Thomas, Parsons Brinckerhoff 19 th May 2010

Bioremediation of Groundwater Bioremediation can also be used for the treatment of groundwater. This can be in many different forms, ranging from air sparging the ground to the addition of chemicals that release oxygen or hydrogen. A novel examples of groundwater bioremediation is the SEquential Reactive BARrier project (SEREBAR). SEREBAR is a barrier based system which captures and treats a plume of groundwater contaminated with organic compounds. The site was an active gas storage depot, with an area of dense tar and plume of contaminated groundwater. A risk management system was required to mitigate the risks from groundwater pollution on the site. Appropriate geology, risk drivers, and risk management for the application of a Permeable Reactive Barrier (PRB) at the site. An excellent opportunity to undertake novel research project and at the same time develop a full scale remediation system now operational for 6 years.

Jamie Robinson, Dr Russell Thomas, Stuart Jagger and Stuart Cory Prof. Robert M. Kalin (PI), Keith Dickson, Karen McGeough, Dr Mike Larkin, Dr Andy Ferguson Dr Steve Wallace Dr Paddy Daly Prof. Chris Knowles, Prof. Mark Bailey, Dr Wei Huang & Dr Ian Thompson Prof. Stephan Jefferis, Dr Norman Kirkby, Dr Ruben Rodriquez-Quintero Dr Brian Bone Dr Simon Jackman In-Situ Bioremediation of Cyanide, PAHs and Heterocyclic Compounds using Engineered SEquenced REactive BARrier (SEREBAR) Techniques Now

Site circa 1840 Site Circa 2000’s Site Circa 1940’s Historical development of the site (study site shaded blue) Site circa 1878

Groundwater monitoring and modelling Site spatial distribution within groundwater of a) EPA 16-PAHs and b) Tar. a b

SEREBAR System SEREBAR treatment system DNAPL Recovery Wells Infiltration Well Dispersal Well Barrier Wall GAC 1 Absorption Polishing step GAC 2 Absorption Polishing step Sand 4 Aerobic Sand 2 Anaerobic Sand 3 Aerobic Sand 1 Anaerobic Oil Interceptor Aerated Infiltration Well Dispersal Well Compliance Monitoring point GAC1 Influent Monitoring point AW1

Conceptual model of SEREBAR system NAPL associated with Underground tanks and within gravels Pumped Infiltration well Dispersal well Impermeable bentonite clay wall Low permeability Breccia strata preventing vertical pollution migration Contaminant plume Remediated Groundwater Treatment chambers

SEquential REactive BARrier (SEREBAR) SEREBAR system would provide: Capture of groundwater plume by means of an impermeable bentonite clay barrier wall; Groundwater pumped into the SEREBAR treatment system; A sequential three phase system: Anaerobic treatment; Aerobic treatment; Granular Activated Carbon (Polishing step) and safety measure in case of failure. Designed as a robust and effective system for the treatment of organic contaminants (PAH, BTEX, etc.).

Installing the slurry wall and SEREBAR treatment system Completed reactor chambers. Loading of sand into reactor chambers. Gas- main Crossin g Slurry Wall

SEREBAR performance SEREBAR became operation in June 2004, Coming up to it’s 6th anniversary of operation. Monitored every two months since it became operational. Operating as a full scale industrial treatment system. The NAPL plume on the north of the site has diminished since the system was operational. NAPL now confined to the south of the site Very good performance removing organic contaminants well below risk based discharge concentrations agreed with EA. Effective hydraulic control has been maintained over the system, although changes in the flow rate have been required to ensure this. Contaminant NaphthalenePhenanthrenePyreneBenzeneTolueneEthyl benzeneXylene Conc. before treatment Conc. after treatment Remedial Action values15 to to to 12, to to 749 Average Percentage Decrease for all years98.4%96.7%86.2%96.9%70.1%91.6%78.9% Some evidence of cyanide biodegradation has also been observed.

Performance – naphthalene and phenanthrene

Future Areas? PB are currently trialling the application of Zero Valent Iron coupled to biodegradation for treating gasworks related contaminants. Working with Prof. Bob Kalin at University of Strathclyde for the application of forensic analysis techniques for investigating tar composition and evidence of Natural attenuation. Working with Prof. Jon Lloyd on the application of nanoscale iron for the remediation on contaminated sites (up next).

Thanks and Further Reading Many thanks to National Grid Property, Parsons Brinkerhoff Research and Innovation Fund, CL:AIRE, BBSRC, LINK, Prof. Bob Kalin and Onyx Environmental Trust.