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ALUMINA REFINERY ODOUR

Forster, P.G. and Grocott, S.C.

Alumina refineries have long been known for their characteristic odour which, in the past, has not constituted a serious environmental problem. However, with the ever increasing reluctance of the general community to tolerate odorous emissions from industry, more emphasis may be placed upon odours by the environmental regulatory authorities. Alcoa operates three refineries in Western Australia and one of these (Kwinana) is located on a major traffic route south of Perth, near to some residential areas. We have embarked on a project to initially identify the extent of the odorous emissions from the refineries and ultimately to develop strategies for their control.

To that end, we have developed techniques for the sampling and analysis of odours from emission sources and also from ambient air. The odours are measured indirectly by analysis of the volatile organic compounds (VOCs) that give rise to the odours. The VOCs are typically complex mixtures of aliphatic and aromatic hydrocarbons, ketones, aldehydes and minor amounts of amines. Laboratory experiments have shown that they originate from the alkaline digestion of the organic material present in bauxite. They are released into the atmosphere as part of the non-condensible gases vented from the digestion building. A brief description of some potential control strategies is also presented in this paper.