Author(s)

S. A. Salzman, G. Allinson, F. Stagnitti, R. J. Hill, L. Thwaites, D. Ierodiaconou, R. Carr, J. Sherwood & V. Versace

Abstract

This study assessed the sustainability of utilising groundwater systems to manage an aluminium smelter’s fluoridated trade wastewater stream. Replacing ocean discharge of the wastewater with land irrigation is one option. Using a groundwater model (developed using MODFLOW incorporating parameter estimation software (PEST-ASP)), we found that most of the groundwater flow takes place through surface sands. Fluoride is adsorbed in these sands during the drier summer months, but desorption is rapid when winter rain flushes the aquifer. Underlying clays and other layers prevent significant contamination of the deeper aquifer. Keywords: groundwater flow, fluoridated trade wastewater, adsorbed, desorption. 1 Introduction Fluoride is considered to be the third most important air pollutant after sulphur dioxide and ozone because it is highly toxic to some plant species [1]. Most fluoride in or on terrestrial plants results from aerial fluoride, but small amounts will be taken up from irrigation water [2], and soluble fluoride salts can be taken

Keywords

groundwater flow, fluoridated trade wastewater, adsorbed, desorption.