LIFE-3E - Environment-Energy-Economy

PROJECT DESCRIPTION

BACKGROUND

European policies emphasise environmental protection, which translates into higher standards for the treatment of wastewater while encouraging water reuse. In this sense, the implementation of strategies for treated water reclamation in urban wastewater treatment plants (UWWTPS) can greatly alleviate the stress on freshwater resources, while reducing wastewater discharge and its environmental impacts. There are more than 28 000 UWWTPs in the European Union treating over 44 700 million m3 of wastewater annually, but only 964 million m3 of this treated wastewater is reused. In this context, Europe could raise its reuse rates six-fold. Coastal UWWTPs offer the possibility of linking UWWTP effluents and seawater, to harness salinity gradient energy (SGE). The water reclaimed in this way can meet legal standards for reuse; while also promoting additional benefits, such as reduced exploitation of natural water resources and minimised environmental impact associated with wastewater discharge into the marine environment. This strategy is aligned with the principles of the Water Framework Directive (WFD) and other EU policy relating to renewable energy and the environment.

OBJECTIVES

The main goal of LIFE-3E is to demonstrate the technical, economic and environmental feasibility of an innovative and efficient process for the reclamation of treated wastewater in coastal areas, with the integrated recovery of saline gradient energy (SGE). This will contribute to improving the sustainability of water resources through the efficient remediation of wastewaters in coastal UWWTPs, for urban, irrigation or industrial uses.

The project has the following specific objectives:

Process design for wastewater remediation and reuse. Within the WFD legal framework, the pilot plant defined in the project could reclaim more than 24 m3/day;

Demonstration at pilot plant scale of the viability of transforming SGE into electricity by contacting seawater with remediated water, to generate 1.6 W/m2 per cubic metre of treated water by means of reverse electrodialysis (RED)-SGE technology;

System integration in UWWTP and optimisation towards maximising the environmental and socio-economic benefits of the LIFE-3Es approach;

Assessment of the environmental and economic impact of RED-SGE application to UWWTPs through LCA/LCC tools;

Reduction of CO2 footprint associated with the energy consumed in reclaiming water in UWWTPs;

Maximisation of project outcomes through communication and dissemination.

 

The projects solution for more environmentally-friendly water treatment contributes to the implementation of the EU Water Framework Directive (2000/60/EC), Marine Strategy Framework Directive (2008/56/CE), 2020 Biodiversity Strategy, the revised Renewable Energy Directive (2018/2001/EU), and the Regulation on Minimum Requirements for Water Reuse ((EU) 2020/741). By reducing CO2 emissions in UWWTPs, the project is also in line with the EU 2020 climate and energy package.

RESULTS

Expected results:

The in-situ electricity generated from renewable SGE will reduce: i) the external energy supply in the UWWTP (from 25% for the tertiary treatment), and ii) the associated greenhouse gas (GHG) emissions (from 1.2% upwards). RED-SGE is expected to achieve 90% GHG reduction compared to conventional energy resources;

Environmental indicators, mainly global warming potential (GWP), will be reduced by renewable energy resources: i) reduction of fossil fuels-based energy (0.278 kgCO2-eq./kWh avoided), and ii) reduction of water abstraction for urban uses;

Design, construction and operation of a RED-SGE prototype to generate electricity from salinity gradient in a coastal UWWTP, leveraging the proximity of seawater with the technical objective to generate 1.6 W/m3 of treated water;

Reduction of the treatment needs of the drinking water treatment plant as a result of water reuse, thus reducing the use of chemicals and the generation of sludge from 2% upwards.