Pressure-controlled injection of guar gum stabilized microscale zerovalent iron for groundwater remediation

Michaela Luna, Francesca Gastone, Tiziana Tosco, Rajandrea Sethi, Milica Velimirovic, Johan Gemoets, Rob Muyshondt, Hans Sapion, Norbert Klaas, Leen Bastiaens

    Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

    Abstract

    The paper reports a pilot injection test of microsized zerovalent iron (mZVI) dispersed in a guar gum shear thinning solution. The test was performed in the framework of the EU research project AQUAREHAB in a site in Belgium contaminated by chlorinated aliphatic hydrocarbons (CAHs). The field application was aimed to overcome those critical aspects which hinder mZVI field injection, mainly due to the colloidal instability of ZVI-based suspensions. The iron slurry properties (iron particles size and concentration, polymeric stabilizer type and concentration, slurry viscosity) were designed in the laboratory based on several tests (reactivity tests towards contaminants, sedimentation tests and rheological measurements). The particles were delivered into the aquifer through an injection well specifically designed for controlled-pressure delivery (approximately 10 bars). The well characteristics and the critical pressure of the aquifer (i.e. the injection pressure above which fracturing occurs) were assessed via two innovative injection step rate tests, one performed with water and the other one with guar gum. Based on laboratory and field preliminary tests, a flow regime at the threshold between permeation and preferential flow was selected for mZVI delivery, as a compromise between the desired homogeneous distribution of the mZVI around the injection point (ensured by permeation flow) and the fast and effective injection of the slurry (guaranteed by high discharge rates and injection pressure, resulting in the generation of preferential flow paths). A monitoring setup was designed and installed for the real-time monitoring of relevant parameters during injection, and for a fast determination of the spatial mZVI distribution after injection via non-invasive magnetic susceptibility measurements.
    OriginalspracheEnglisch
    Seiten (von - bis)46-58
    Seitenumfang13
    FachzeitschriftJournal of Contaminant Hydrology
    Jahrgang181
    PublikationsstatusVeröffentlicht - 15 Okt. 2015

    ÖFOS 2012

    • 104023 Umweltchemie
    • 104002 Analytische Chemie
    • 105906 Umweltgeowissenschaften
    • 210001 Nanoanalytik

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