DIVIDE & CONQUER: Closing the loop of water, nutrient and resource management for irrigation activities

PROJECT DESCRIPTION

BACKGROUND

Water scarcity is no longer limited to a few regions of Europe, but already a concern across the EU, with one third of the EU territory experiencing water stress. Water reuse has been evidenced as the most sustainable alternative to the use of freshwater sources in terms of cost and environmental impact. However, wastewater salinity is a challenge in wastewater treatment (WWTP) and reclamation (WRP) plants where collectors receive industrial brines, agricultural runoff waters and/or marine intrusion. Conventional WWTP or WRP are not designed for salinity removal, which becomes a limiting water quality parameter in water reuse.

OBJECTIVES

The overall objective of LIFE CONQUER is the demonstration of an innovative water reclamation process based on the use of Smart Nanofiltration (NF) that will divide salinity and nitrates, to obtain a reclaimed water rich in nutrients. This will be suitable to re-use for irrigation. Additionally, with the dissolved salts removed by concentrating them into brines, the project partners will demonstrate the use of Mono-Selective Electrodialysis Reversal (MS-EDR) and three-dimensional granular anodic Electro-Chlorination (EC-3D) to transform them into valuable by-products (e.g. sodium hypochlorite) needed in industrial processes.

The project will help implement the circular economy in the field of wastewater, to comply with the requirements of the EU Water Framework Directive and is in line with the regulations of water reuse.

RESULTS

Expected results: The main result will be the demonstration of the technical feasibility of the LIFE CONQUER treatment, combining Smart Nanofiltration Mono-Selective Electrodialysis Reversal and Electro-Chlorination, to remove salinity, recycle nitrates and valorise brines in saline urban wastewaters.

Specific expected results on environmental impact are:

The volume of reclaimed water for parks and landscapes irrigation in the city of Murcia will amount to 500 000 m3/year at the end of the project. This represents 29% of the total water demand (1 750 000 m3/year) for non-potable municipal uses of the city, currently covered with 100% use of freshwater resources (55% of groundwater and 45% of potable water; 950 000 m3/year and 800 000 m3/year, respectively);

Reduction of 27% of the total water footprint of Murcia city urban irrigation system, thanks to the use of regenerated water instead of potable water for irrigation, which represents a reduction of 95% in water footprint;

Reduction of 37% (425 000 kWh/year) of total energy consumption in Murcia city urban irrigation system through the substitution of 500 000 m3/year of potable water (1.30 kWh/m3) with reclaimed water (0.45 kWh/m3). Potable water (covering 45% of the current water demand) is produced by extracting 23% from Segura River Basin (0.60 kWh/m3) and importing 77% from Tajo-Segura water transport system (1.50 kWh/m3). Accordingly, associated carbon footprint reduction accounts to 136 tn equivalent CO2/year;

Brine valorisation and consequent on-site production of 26 tn/year of sodium hypochlorite (NaOCl) for use in nearby EMUASA facilities (self-consumption). This will account to a reduction of 19% of the total NaOCl consumption (139 tn NaOCl/year) in EMUASA facilities (15 plants); and

Reduction of eutrophication potential by avoiding the discharge to natural water bodies of 1.3 tn of equivalent nitrogen/year through its recycling in Murcia parks irrigation.