Improving the sustainability of granular iron/pumice systems for water treatment

Stafania Bilardi (1) , Paolo S. Calabro (1) , Sabine Caré (2) , Nicola Moraci (1) , Chicgoua Noubactep (3, 4)

1 Mechanics and Materials department MECMAT, Reggio Calabria
2 navier umr 8205 - Laboratoire Navier
3 Department of Applied Geology [Göttingen]
4 Kultur und Nachhaltige Entwicklung CDD e.V

Metallic iron (Fe0) is currently used in subsurface and above-ground water filtration systems on a pragmatic basis. Recent theoretical studies have indicated that, to be sustainable, such systems should not contain more than 60% Fe0 (vol/vol). The prediction was already validated in a Fe0 /sand system using methylene blue as an operational tracer. The present work is the first attempt to experimentally verify the new concept using pumice particles. A well-characterized pumice sample is used as operational supporting material and is mixed with 200 g of a granular Fe0 , in volumetric proportions, varying from 0 to 100%. The resulting column systems are characterized (i) by the time dependent evolution of their hydraulic conductivity and (ii) for their efficiency for the removal of CuII ,Ni II , and ZnII from a three- contaminants solution (about 0.3 mM of each metal). Test results showed a clear sustainability of the long term hydraulic conductivity with decreasing Fe0 /pumice ratio. In fact, the pure Fe0 system clogged after 17 days, while the 25% Fe0 system could operate for 36 days. The experimental data confirmed the view that well-designed Fe0 PRBs may be successful at removing both reducible and non-reducible metal species.

Mots clés: Hydraulic conductivity; Column study; Pumice; Zerovalent iron; Reactive walls

Domaines: Matériaux; Sciences de l'environnement; Electrons fortement corrélés [cond-mat.str-el]; Physique Atomique [physics.atom-ph]

Stafania Bilardi, Paolo S. Calabro, Sabine Caré, Nicola Moraci, Chicgoua Noubactep. Improving the sustainability of granular iron/pumice systems for water treatment. Journal of Environmental Management, 2013, 121, pp.133-141. ⟨10.1016/j.jenvman.2013.02.042⟩. ⟨hal-00809731⟩