CL:AIRE Case Study Bulletin, CSB 12, 5 pp, 2018

The SEquential REactive BARrier (SEREBAR) groundwater treatment system is a permeable reactive barrier (PRB) that was constructed on a former gasworks site in 2003. It was one of the first biologically based PRB systems installed in the UK. SEREBAR has been in operation since 2004, and this bulletin provides a review of the system's performance over the period 2004 to 2015. This effort forms one of the longest running research projects of its kind in the world and one of the few that has provided active contamination management on a commercial scale. Except for situations where the system was vandalized, the PRB performed very effectively in maintaining hydraulic control over the contaminant plume and treating the target contaminants, including some compounds, such as cyanide, it was not designed to treat. The main issue was the original pump, but switching to a peristaltic pump improved system reliability. The GAC canisters generally provided an effective polishing step, removing residual contaminants to acceptable concentrations before discharge downgradient (overall contaminant mass removal >95%). The SEREBAR system was probably over-engineered for the expected contaminants (PAHs and BTEX), but this provided the flexibility to counter localized changes in groundwater contamination, the increasing cyanide concentration in particular. Aerating the oil-water separator proved useful in increasing the system's biodegradation capacity. https://www.claire.co.uk/component/phocadownload/category/3-case-study-bulletins?download=631:csb12-serebar-a-review-of-11-years-of-operation