Permeable Reactive Barriers (Proceedings of the International Symposium held at Belfast, Northern Ireland, March 2004). IAHS Publ. 298, 2005, 67-74.

1 CSIRO Land and Water, Private Bag No. 5, Wembley, Western Australia 6913, Australia

2 Chemistry M313, School of Biomedical & Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia

Abstract The use of hollow-fibre silicone (poly(dimethylsiloxane)) tubing coiled and shaped as mats has been evaluated for its potential to act as an in situ permeable reactive barrier (PRB) for the controlled and targeted delivery of ethanol, to promote reducing conditions and enhanced bioremediation of a range of contaminants in groundwater. Aqueous ethanol solutions were recirculated through the inner volume of the silicone polymer tubing to allow permeation and delivery of ethanol by diffusion through the tubing wall to a target contamination zone. Laboratory and field experiments showed similar ethanol mass flux delivery which was consistent with model predictions. This study also shows promising laboratory and field simulations of this innovative amendment delivery system to predictably deliver ethanol as a carbon source for the promotion of in situ reducing reactive zones for the bioremediation of nitrate and metal contaminated groundwater.

Key words diffusion delivery; ethanol; groundwater; mats; permeable reactive barrier; polymer tubing; remediation