ABSTRACT:

This paper assesses possible alternatives to the use of activated carbon for the clean up of aqueous phase contaminants. The physical properties of two alternate materials; (granulated rubber and coke breeze) were found to have similar properties for bulk density, void ratio and permeability as activated carbon. Batch testing was undertaken on the three materials to assess their sorption potential for PAH, TPH and BTEX. Analysis indicated that coke breeze had a distribution coefficient similar to activated carbon for PAH, but was slightly lower for other compounds assessed. Granulated rubber was comparable to activated carbon for PAH, ethyl benzene and xylenes but was lower for benzene and toluene. Retardation factors were found to be significant for all compounds and comparable to retardation factors calculated for activated carbon. Following laboratory testing, field trials were undertaken for both materials for PAH and BTEX to assess the performance of the materials under a competitive sorption environment. The granulated rubber filter was found to perform better than coke breeze and was comparable to the results obtain from the activated carbon filter.

INTRODUCTION

Methods for the remediation of groundwater have in the past included pump and treat techniques and containment by impermeable barriers. Recently, increasing interest has focused on passive and less obtrusive methods of groundwater remediation such as permeable reactive trenches. Research has been undertaken by others, (Kershaw and Pamukcu 1997 and Smith and Fletcher 1998), to assess the potential of intercepting and passively treating contaminated groundwater in situ. Reactive trenches are constructed from suitable materials to provide an in situ permeable trench that acts to adsorb contaminants from the groundwater as it passes through the trench. Activated carbon is a material widely recognised for its sorption properties and is frequently used to remove aqueous phase organic contaminants.

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