BRACKISH-GROUNDWATER DESALINATION AND DENITRIFICATION FOR SUSTAINABLE IRRIGATION: NET ZERO WASTE AND ENERGY

PROJECT DESCRIPTION

BACKGROUND

Water scarcity, a typical impact of climate change, affects at least 10.4% of the EU territory and 14.3% of the EU population, mainly in Southern Europe. Desalination, which is being applied in 150 countries, is one of the most common solutions explored for addressing the problem, with over 18,500 desalination plants producing freshwater from seawater and brackish water. It is one of the technologies, according to the Spanish Law RD1627, to obtain reclaimed water. However, the technology raises environmental concerns relating to residual brine, which can comprise up to 25% of the collected water. Brine has high salinity and contains potential contaminants, such as pathogens and nitrates from agricultural and other human activities.

OBJECTIVES

The LIFE project LIFE-DESIROWS aims to test a self-sufficient energy technology that eliminates brine from water desalination processes by means of crystallisation of salts. The aim is to improve the quality of the reclaimed water for use by the agricultural sector at an affordable price, while eliminating discharges into the Mar Menor Coastal Lagoon protected area. The goal is to decrease the negative impact of the pollutants on the fauna and flora ecosystems in the area. It also aims to recycle brine salts for use as fertilisers and road de-icing. Furthermore, the project will promote the technology among the main target stakeholders and define its potential replicability and transferability.

RESULTS

Expected results:

High-quality reclaimed water for re-use in agricultural irrigation from brine effluent from the Arcosur desalination plant, resulting in: - An increase in the total reclaimed desalinated water yield. The total reclaimed water recovery will be increased up to 98% with the incorporation of this new technology to the 1st reverse osmosis unit. The quality of reclaimed water for irrigation will increase from 90 m3/day to 118 m3/day; - Elimination of the current brine discharge to the Mediterranean Sea of 30 m3/day;

- Elimination of pathogen and nitrate discharge to the MediterraneanSea;

Production of 600 kg salt /day, which will be used in large part to manufacture inorganic fertiliser (calcium carbonate, magnesium carbonate, calcium sulphate, potassium sulphate and magnesium sulphate, up to 180 kg/day) and the rest for road de-icing (mainly crystallised CL- and Na+, up to 420 kg/day);

Energy efficiency improvement in brine evaporation by reducing energy consumption from 695 kWh/m3 under normal conditions to 40 kWh/m3; and

Emissions reduction of 9 CO2eq/m3 by integrating several renewable energy solutions to obtain an energetically autonomous system.