after nine days (Craggs et al. 2006), approximately 1 mg of Zn together with 0.2 mg Cu per
gram of crushed mussel shell were sequestered when multiple solutions were each flowed
through a test column over 6 hours (Pickmere and Mathieson 2007), and approximately 9.9
mg of Zn per gram of crushed mussel shell was sequestered when multiple solutions of
dissolved metals were each flowed through a test column eachover a period of over 30
minutes (Macaskill 2008). In the case of flow-through experiments all of the columns for
which data are presented appear to have continuing capacity to capture Zn at the end of the
experiments, despite already being subjected to substantial loadings of dissolved metals.
Small columns of crushed shell material remained efficient at removing dissolved metals at
flow velocity of around 10 cm hr-1 and a solution:solid contact time of 30 minutes (Macaskill
2008). Higher flow rates are likely to be required for the treatment of urban stormwate r, so
the efficacy of crushed shell material at higher flow velocities needs to be determined through
further research.