Salt groundwater use for industrial purposes in compliance with the equilibrium between freshwater and saltwater

<p>Studies on groundwater salinity stratification interested an area under a semi-arid climate located within an industrial zone in the Taranto Province (South-Eastern Italy). Fresh groundwater circulates in a Mesozoic carbonate coastal aquifer affected by salinization due to saltwater mixing. A clay formation along the coast prevents direct contact with present seawater.&#160;<br>The area is home to many companies of national and international importance that require water for their processes. The solution is to use locally available saltwater, considered a nonvaluable resource, because of the lack of surface water and use restrictions of good quality fresh groundwater.&#160;<br>The study covers the area of a company that uses its domain for both quarry and landfill activities. Because fresh groundwater resources are protected, the law authorizes the company to exploit only salt groundwater to humidify the pet-coke or lope piles stored in the landfills. The moistening is intended to avoid the atmospheric dispersion of polycyclic aromatic hydrocarbons.<br>In the study area, with ground-level elevations around 50 m AMSL, the water table is above 2.5 m AMSL. A borehole had to reach a depth of 300 m to locate saltwater. Prospecting during drilling, including temperature and EC logs, allowed the reconstruction of the saline stratification. The elevation of saltwater top and the thickness and position of the transition zone make such stratification differ from that expected from the usual simplified laws describing the balance between fresh and salt waters in coastal aquifers. The recognized density stratification likely depends on the aquifer boundary conditions (included fresh groundwater exploitation rate), tectonic assets, and karst development. Further research may provide useful information on disturbances to fresh and salt water equilibrium that may result from direct pumping of salt water. &#160;</p>