16 th International Conference on Environmental Science and Technology Rhodes, Greece, 4 to 7 September 2019 CEST2019_00576 Preliminary study on Cr-rich groundwater treatment by membrane processes Fuoco I. 1 , Figoli A. 2 , Brozzo G. 3 , De Rosa R. 1 , Bloise A. 1 , Criscuoli A. 2 , Apollaro C. 1,* 1 DiBEST – University of Calabria, Via P. Bucci, cubo 15b, I-87036 - Arcavacata di Rende (CS) Italy 2 Institute on Membrane Technology (ITM-CNR), Via P. Bucci cubo 17c, I-87036 - Rende (CS) Italy 3 ACAM Acque S.p.A., Via Alberto Picco 22, I-19124 - La Spezia, Italy *corresponding author: Apollaro Carmine: e-mail: carmine.apollaro@unical.it Abstract The aim of this work is to treat chromium (Cr)-rich groundwaters through membrane processes as alternative to conventional methods. Commonly, the highest Cr (VI) concentrations into groundwater are detected in ophiolitic areas due to water-serpentinite interaction processes. In this work, the water sample treated comes from Bonassola serpentinitic aquifer (La Spezia, Liguria, Italy), in which a Cr(VI) concentration of 84 μg/l was detected. To lower down this value under the threshold established by law, NF/RO laboratory- scale system with membranes named DK (NF polyamide membrane, GE Osmonics) and AD (RO polyamide membrane, GE Osmonics) and CD (RO cellulose membrane, GE Osmonics) were used. The experiments were conducted at different operating pressures. Membrane process treatment was able to lower the Cr concentration within the threshold values, and rejections around 95% were registered for each used membrane. These preliminary results are quite promising for future developments on Cr removal from contaminated groundwaters. Keywords: Chromium, groundwater, ophiolitic rocks, membrane processes 1. Introduction Chromium (Cr) is a dangerous pollutant that has a strong impact on environment and ecosystem when it is released into natural water bodies. Although anthropogenic Cr-sources are widespread due to the common use of chromium in a large spectrum of industries, natural Cr pollution is the environmental issue of worldwide ophiolitic areas (Apollaro et al., 2019). Indeed, these rocks contain high amount of Cr(III) which, if mobilized during the weathering processes, can be oxidated to Cr(VI) form which is more dangerous and toxic for human health. Naturally occurring Cr(VI) in groundwater has been increasingly reported at concentrations exceeding the World Health Organization’s threshold for total Cr in drinking water, which is set to 50µg/L (WHO, 2011), whereas some countries as Italy, have lowered the limit value of Cr(VI) fixing it to 10 µg/L. The improving of living standards is becoming an urgent challenge and in this context, suitable and efficient remediation plays a crucial role. The techniques commonly used can be recognizable in precipitation, adsorption, solvent extraction with amines, ion-exchange, activated car-bon adsorption, electro deposition, biological processes and membrane tecnologies (Di Natale et al., 2015 and reference in therein). The latter can be view as innovative methods which fall within the Best Available Technologies (BAT) considered the high performance, in terms of costs and advantages, for instance environment protection, reduction of energy consumption by improving productivity and/or production quality (Figoli et al., 2017). In this work, the high performance of RO/NF membrane processes were tested to treat Cr-rich groundwater with the purpose of lowering the concentrations below the law limit. 2. Geological Setting The analysed water sample is coming from La Spezia province (Liguria, Italy) where the high-Cr content of natural water is due to the extensive weathering process affecting the ultramafic rocks outcropping in the area (Fantoni et al., 2012). Ultramafic-gabbric basement is mainly represented by its ultramafic portion, consisting of serpentinites, whereas gabbros are a subordinate portion. From these rocks emerges the Vivaio spring (Bonassola - La Spezia) and the water circulation in the serpentinitic rocks occurs in fractures originating in the superficial portion of the rock mass.