Characterization of broom fibers for PRB in the remediation of aquifers contaminated by heavy metals

Abstract

Abstract. The present level of pollution, increasingly involving ground waters, constitutes a serious risk for the environment and also for human health. Therefore the remediation of saturated and unsaturated soils to remove the pollutant materials is required more and more frequently. In the present paper, the possibility of removing the specific pollutant typology constituted of heavy metals by permeable reactive barrier (PRB) from the groundwater, carried out with natural fibers, specifically with broom fibers, is investigated. Once shown the economic benefits deriving from the use of this plant, a hydraulic characterization of the broom fiber mass was performed, determining the permeability and the porosity in correspondence to different levels of compactness of the fibers. Having verified the effectiveness of these fibers for some heavy metals, the results of some experiments, carried out in the laboratory for this purpose, are shown. These experiments were carried out utilizing broom fibers obtained in different ways and, limitedly to the considered pollutants, showed the high capability of these fibers to reduce their concentrations. The best results were obtained for the broom fibers extracted by a particular chemical-physical process. Moreover, the behaviour of this fiber with time was investigated, determining the kinetic constant of degradation.