ELECTRODIALYTIC REMEDIATION OF CCA-TREATED WOOD IN LARGER SCALE _____________ *Iben

A pilot plant for electrodialytic remediation of CCA-treated wood in larger scale has been designed and tested at DTU. Several process parameters were investigated, and it was found that the use of collecting units and soaking of the wood prior to the electrodialytic process had a positive influence on the remediation process. There is a tendency towards easier remediation of wood chips < 2cm, than larger wood size fractions. The influence of the electrode distance could not be fully investigated due to the experimental setup but it is expected that the use of collecting units will keep any influence to a minimum. The best remediation efficiency was obtained in an experiment with an electrode distance of 60 cm, and 100 kg wood chips. In this experiment 87% Cu, 81% Cr and >95% As was removed. Only one other experiments was analysed for As and here 95% was removed. The electrode distance was 1.5 m and the results indicate that As may be the easiest removable of the Cu, Cr and As investigated here. This is very encouraging since As is the CCA components of most environmental concern.