The screening and scale up of ex situ physico-chemical treatment options for Cr-contaminated ground and surface waters, Glasgow, UK

A number of ex situ methods have been evaluated in the treatment of Cr-contaminated groundwater draining a site in SW Glasgow, Scotland. Sorption methods, using ion exchange and a number of waste biomass materials show some ability to remove contamination from surface waters, but offer little scope in the treatment of more highly contaminated groundwaters. Chemical reduction of Cr (VI) has been successfully applied to model groundwater solutions and real samples and a pilot-scale treatment system has been assessed. The main processing parameters found to be important were pH and residence time. There is good agreement in the processing variables in the scale up from small volumes to larger. The optimum conditions for processing Cr-contaminated waters are identified and are shown to be very sensitive to Cr:Fe ratios. The implication of these findings for treatment options at the contaminated sites in Glasgow are discussed.