Preliminary study on Cr-rich groundwater treatment by membrane processes

The aim of this work has been treat Cr- rich groundwaters through membranes processes as alternative to conventional methods. Chromium (Cr) is a dangerous element for environment and human health. Commonly, the highest concentrations Cr are detected in ophiolitic areas where ultramafic and serpentinite rocks crop up and the weathering processes of these rocks are the main cause of Cr-rich groundwaters in worldwide. The sample water taken into account comes from Bonassola serpentinitic aquifer (La Spezia, Liguria, Italy) and the Cr concentration detected are 84 μg/l. This value is above to the WHO threshold for drinking water set to 50 μg/L and moreover starting from 1 January 2019 the potability threshold value for Cr (VI) was lowered to 10 μg (D.M. 06/07/2017) by Italian government. In this regards, NF/RO laboratory-scale system with membrane modules named DK (proprietary thin-film), AD (polyamide) and CD (cellulose acetate) were used to treating polluted groundwater and experiments were conducted at different operating pressure The treatment have shown a lowering of Cr concentration within the threshold values with rejection around 95%. These preliminary results are quite promising for future developments on Cr removal from contaminated groundwater in the world.