Organo-Clay Reactive Barriers in Contaminated Site Remediation

Increased awareness of the total environmental impact and economics of many common site remediation strategies has led to interest in natural attenuation. Natural attenuation is any process that reduces the concentration or toxicity of environmental contaminants, without the aid of human intervention. The most commonly cited reasons for not utilising natural attenuation are that the process takes longer than the project timeframe and there is no guarantee that contaminants will not migrate into the air or groundwater. A barrier system could be used to allow development to continue and provide the time required for the processes to run their course. It would also provide a guarantee against further migration. Conventional barrier systems rely on minimising advective flow, however contaminants can still travel quite effectively by diffusion. Reactive barrier systems utilise contaminant reactions to reduce contaminant transport. This paper outlines some of the research being conducted into natural and organically modified clay barriers for the immobilisation of environmental contaminants.