Environmental sustainability assessment of seawater reverse osmosis brine valorization by means of electrodialysis with bipolar membranes.

Raquel Ibañez,Antonio Dominguez-Ramos,Angel Irabien,Noy Admon,Marta Herrero-Gonzalez,Adi Wolfson

doi:10.1007/s11356-019-04788-w

Abstract

The integration of electrodialysis with bipolar membranes (EDBM) with seawater reverse osmosis (SWRO) process influences the two main environmental burdens of SWRO desalination process: climate change, accounted here as carbon footprint (CF) andassociated to the high-energy consumption, and the environmental alteration of the vicinities of the facility, due to brine disposal. EDBM powered by photovoltaic (PV) solar energy is able to meet the above-mentioned challenges that arise in SWRO desalination. In addition, HCl and NaOH, both employed in thedesalination industry, can be produced from the brines. Hence, environmental benefits regarding the potential self-supply can be achieved. The environmental sustainability assessment by means of life cycle assessment (LCA) of a SWRO and EDBM has been carried out considering four different scenarios. The percentage of treated brines and the influence of the grid mix used for electric power supply has been taken into account. The three different electric power supplies were 100.0% renewable energy (PV solar energy), 36.0% renewable energy (average Spanish grid mix), and 1.9% (average Israeli grid mix). The results showed that the CF per unit of volume produced freshwater for SWRO and the self-supply reagent production scenario for the three Spanish grid mix, the Israeli grid mix, and the PV solar energy were 6.96kg CO2-eq·m-3, 12.57kg CO2-eq·m-3, and 2.17kg CO2-eq·m-3, respectively.

Highlights

Desalination technologies have been developed to meet the increasing global demand of freshwater being the projected desalination capacity of 54 billion m3·year-1 for 2030 (Shahzad et al 2017)
The Carbon Footprint (CF) obtained in this work for seawater reverse osmosis (SWRO) and self-supply (Scenario 2) reagent production by means of electrodialysis with bipolar membranes (EDBM) for Spanish grid mix, Israeli grid mix and PV solar energy are 6.96 kg CO2-eq.·m-3 of freshwater, 12.57 kg CO2-eq.·m-3 of freshwater, and 2.17 kg CO2-eq.·m-3 of freshwater, respectively
The integration of EDBM with SWRO process influences the two main environmental burdens of SWRO desalination process: carbon footprint, associated to the indirect GHG emissions from to the highenergy consumption of electric power when the grid mix is not dominated by renewables; and the environmental alteration of the vicinities of the facility, due to brine disposal

Summary

Introduction

Desalination technologies have been developed to meet the increasing global demand of freshwater being the projected desalination capacity of 54 billion m3·year-1 for 2030 (Shahzad et al 2017). Several studies have analyzed the effects of brine disposal into the marine ecosystems (Fernández-Torquemada and Sánchez-Lizaso 2005; Gacia et al 2007; Del-Pilar-Ruso et al 2008; SánchezLizaso et al 2008; Roberts et al 2010; Yoon and Park 2011; Belkin et al 2015, 2017; de-la-Ossa-Carretero et al 2016; Fernandez-Gonzalez et al 2016; Röthig et al 2016) These studies concluded that the desired disposal concentrations are below the typical brine concentration, and this fact leads to two approaches: i) a disposal on empty areas of vegetation (Einav et al 2003), or ii) a treatment of the brines in order to reduce the concentrations and/or their valorization (Jiang et al 2014a, b; Ortiz-Albo et al 2019). Electrodialysis with bipolar membranes (EDBM) has been proved a suitable and emerging technology for treatment and valorization of SWRO brines (Koter and Warszawski 2006; Pérez-González et al 2012; Wang et al 2014; Yang et al 2014; Fernandez-Gonzalez et al 2016; Reig et al 2016)

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Discussion

Conclusion