Environmental aspects of a PRO plant effluent discharge along the coast. A case-study in the Eastern Sicily (Italy).

Laura Maria Stancanelli, Rosaria Ester Musumeci, Giorgio Indelicato, Enrico Foti

Tuesday 30 june 2015

15:20 - 15:35h at Antarctica (level 0)

Themes: (T) Water engineering

Parallel session: 6F. Engineering - Instrumentation

Recently the osmotic power technology has received a lot of attention and the Pressure Retarded Osmosis (PRO) plants have been considered among the most promising renewable energy sources (Torsen et al. 2009, J. Membr. Sci.; He et al 2014, Desalination). Although in the field of membrane science a lot of steps forward have been made, less attention has been addressed to some of the environmental issues related to the employment of such a technology. In such a framework, the present research aims at investigating the environmental effects of the propagation of an effluent discharge along the coast, with reference to a potential site for a PRO plant. The site investigated is located along the East coast of Sicily, the fresh water intake is the Simeto River and the salt water intake is the Ionian sea. The area selected is a natural reserve oasis, therefore particular attention must paid to environmental issues. The PRO discharge has been estimated according to a preliminary optimal design of the plant, based on the characteristics of the local fresh and salt water sources. In situ surveys and hydrological analysis have been carried out in order to select the osmotic pressure difference (29 bar) and fresh water availability (3m3/s). The coupled CMS-FLOW and CMS-WAVE models, developed by Coastal Inlets Research Program (CIRP) since 2006, have been applied to evaluate the distribution and the propagation of the effluent discharge under the effect of the local wave and current climate. The effluent discharge, schematized as an inlet along the coast, presents a lower salinity than the salt water flow. The simulations performed were useful for evaluating the dispersive path of the fluid of different concentrations also in order to prevent recirculation of this low salinity fluid as salt water source to the plant. Different scenarios of the plant (discharges, outflow position along the coast) as well as different wave fields and currents have been taken into account in order to achieve a low environmental impact. Results were useful in order to design a PRO plant characteristics which uses as fresh water source waters coming from a river characterized by a moderate flow discharge.