Integrated water, energy and resources production for sustainable seawater desalination

Introduction

LIFE INDESAL tackles the challenge of supplying safe freshwater from alternative resources in a reliable way, within the paradigm of circular economy and climate change. For such purpose, it aims at developing and demonstrating a novel integrated and circular seawater desalination process, producing multi-purpose desalinated water, renewable energy, and resources simultaneously, with a low carbon footprint.

Integrated Process Overview

The integrated process consists of a high energy efficient RO system (based on low pressure multistage systems, LMS), which produces high quality water.

Brine Treatment

The generated brines, instead of being disposed of, are treated by Reverse Electrodialysis (RED), capable of obtaining energy from the salinity gradient of the LMS RO brines.

Further Treatment

The concentrated stream is further treated by electrodialysis with bipolar membranes (EDBM), generating NaOH and HCl for the desalination process itself, making the plant self-sufficient. The diluted RED effluent is recirculated upstream to the RO, decreasing the intaken seawater salinity.

Energy Savings and Environmental Impact

The targeted energy saving linked to LMS RO is 0.2 kWh/m3 and the renewable energy produced by RED is up to 0.1 kWh/m3, leading to a 7% and a 3.5% reduction over a conventional RO desalination system.

Potential CO2 Reduction

Considering a 450,000 m3/d SWRO plant, LIFE INDESAL configuration would alleviate:

1. 33 GWh/yr and 16 GWh/yr
2. Equivalent to 8,377 ton CO2/yr and 4,131 ton CO2/yr, respectively

This clearly offers great potential.

Project Ambition and Impact

The ambition and demonstrative character of the project (2-year testing at prototype scale in real conditions) together with its highly sustainable holistic approach, its transferability, and its complementarity with other R&D initiatives supported by significant dissemination efforts, will boost the implementation of LIFE INDESAL solution in new/refurbished full-scale plants.

Broader Effects

This will further multiply its technical, socio-economic, and environmental impact. Moreover, its modularity and transferability to other industrial areas will catalyse its effects.