3191
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
1
Reuse of dredged sediments for hydraulic barriers: adsorption and hydraulic
conductivity improvement through polymers
La réutilisation des sédiments dragués pour barrières hydrauliques: l'adsorption et l'amélioration de
la conductivité hydraulique avec des polymères
G. Di Emidio, R.D. Verastegui Flores, A. Bezuijen
Ghent University, Zwijnaarde, Belgium
ABSTRACT: Environmental management and handling of dredged sediments is important worldwide, as enormous amounts of
dredged material emerge from maintenance, construction and remedial works within water systems. Usually these materials, after
temporary upland disposal in lagoons, are disposed in landfills. The aim of this study is to analyse the possible reuse of these
sediments as a low-cost alternative material for landfill covers. The mechanisms through which polymers can improve the efficiency
of dredged sediments for waste containment impermeable barriers were investigated. An anionic polymer was adsorbed to the surface
of a dredged sediment. Hydraulic conductivity and batch sorption tests were executed to study the barrier performance and the
transport parameters of this treated soil. Polymer treatment maintained low hydraulic conductivity of the soil to electrolyte solutions
in the long term. The polymer treatment helped the soil to retain the spread of pollution.
RÉSUMÉ: La gestion de l'environnement et des sédiments dragués est important partout, parce que énormes quantités de matériaux
de dragage sortent de l'entretien, la construction et les travaux de réparation dans les systèmes d'eau. Habituellement, ces matériaux,
après le stockage dans les lagunes temporaires, sont déplacé dans les décharges. Le but de cette étude est d'analyser la possibilité de
réutiliser ces sédiments en tant que matériau alternative à faible coût pour les couvertures d'enfouissement. Les mécanismes par
lesquels les polymères peuvent améliorer l'efficacité des sédiments dragués pour les barrières de confinement des déchets
imperméables ont été examiné. Un polymère anionique a été adsorbé à la surface des sédiments de dragage. Des essais de
conductivité hydraulique et de sorption ont été exécutés pour étudier la performance de barrière et les propriétés de transport de cette
terre traitée. Le traitement de polymère maintient une faible conductivité hydraulique du sol à le solutions électrolyte à long terme. Le
traitement polymère contribué à résister la propagation de la pollution dans le sol.
KEYWORDS: reuse of dredged sediments, polymer treatment, low permeable hydraulic barriers.
1 INTRODUCTION
Soil contamination by heavy metals has been a long-term and
worldwide environmental problem generated by anthropogenic
activities of the past several decades. Heavy metals present in
soils could find their way into human and animal populations
through direct exposure or food chain/web, posing a serious risk
to human health (Garcia-Sanchez et al. 1999; Gao et al. 2003;
Ling et al. 2007). Heavy metals may be retained in clay soils by
several soil phases or mechanisms, such as exchangeable,
carbonate, hydroxide and organic phases (Griffin et al. 1976;
Plassard et al. 2000; Sharma and Reddy 2004). The factors
affecting the sorption of contaminants in soils are: (1)
contaminant characteristics, such as water solubility, polar-ionic
character, octanol-water partition coefficient; (2) soil
characteristics such as mineralogy, permeability, porosity,
texture, homogeneity, organic carbon content, surface charge,
and surface area; and (3) fluid media characteristics, such as pH,
salt content, dissolved carbon content.
Landfill sites for both chemical and industrial waste might
be a serious threat for the environment, when not properly
designed. To avoid pollution of the ground and groundwater,
landfill sites are sealed with compacted clay liners (CCLs),
geomembranes and Geosynthetic Clay Liners (GCLs). Suitable
barriers must have a low permeability. To meet this property,
the soil contained in CCLs and GCLs must fulfill some well-
known physical and hydraulic criteria (Daniel 1993, Mitchell
1993).
Next to standard CCL and GCLs, there are emerging
innovative barrier materials and systems, more efficient and/or
less costly. Alternative evapotranspirative barriers (Malusis and
Benson, 2006, Zornberg and McCartney 2010, Kison et al.
2012) or alternative barrier materials (such as, among others,
paper sludge (Rajasekaran et al. 2000) dredged sediments (Di
Emidio et al. 2006) can be necessary when: (1) high costs are
associated with prescriptive materials and methods, (2)
prescribed materials are not readily available, (Shackelford,
2005) and (3) when alternative materials are available in large
quantities. In this regard, Di Emidio et al. (2006) studied the
suitability of dredged materials to be used as alternative cover
liner material for landfills. Different dredged materials were
analyzed by means of laboratory tests, focusing on physical
properties and hydraulic conductivity performance. As a result,
acceptable zones (Daniel, 1993) based on hydraulic
conductivity were established. Test results showed suitability of
dredged sediments as hydraulic barrier alternative materials.
Therefore, the use of dredged materials for cover liners
Di Emidio G. Verast gui Flores R.D., Bezuijen A.
