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Surfactant enhanced mobilisation of non-aqueous phase liquids

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Surfactant enhanced mobilisation of non-aqueous phase liquids

Duffield, Andrew (2001) Surfactant enhanced mobilisation of non-aqueous phase liquids. Masters thesis, Concordia University.

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Abstract

The remediation of non-aqueous phase liquid (NAPL) using conventional aquifer treatment technologies is limited by the low solubility of NAPLs. Surfactants can promote the enhanced removal of NAPL through mobilisation, a mechanism that relies on the reduction of interfacial tension (IFT) at the flushing solution/NAPL interface. The conditions governing mobilisation can be represented by the total trapping number (N T ), a dimensionless quantity relating viscous and buoyancy forces to the capillary forces trapping the NAPL residual. A highly reliable experimental apparatus and procedure were developed to study the effect of flow rate and surfactant concentration on the removal of a residual NAPL. Column studies were conducted to investigate the relative flushing efficiencies of very dilute Triton X-100 solutions delivered through Ottawa sand spiked with light white mineral oil. At the higher flow rate, the surfactant solutions yielded N T values greater than the critical N T , promoting greater NAPL recovery as IFT dropped. While NAPL removal at the lower flow rate should not be enhanced because the critical N T was not surpassed, variations in mineral oil recovery during flushing clearly indicate a surfactant effect. At the lower flow rate, the surfactant-induced enhancement and retardation of NAPI, removal both highlight the limitations of the N T approach. For more realistic systems where free product NAPL is present, the total trapping number approach requires further study to define its applicability as an indicator for NAPL mobilisation

Divisions:Concordia University > Faculty of Engineering and Computer Science > Building, Civil and Environmental Engineering
Item Type:Thesis (Masters)
Authors:Duffield, Andrew
Pagination:xiii, 96 leaves : ill. ; 29 cm.
Institution:Concordia University
Degree Name:Theses (M.A.Sc.)
Program:Building, Civil and Environmental Engineering
Date:2001
Thesis Supervisor(s):Ramamurthy, A. S
ID Code:1376
Deposited By:Concordia University Libraries
Deposited On:27 Aug 2009 13:18
Last Modified:08 Dec 2010 10:20
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