HARMONIZE: Enhanced Membrane Distillation and Crystallisation Technologies for Ammonia Product Recovery Approaching Zero Waste

In a circular economy scenario, water recycling, separation, and concentration technologies are crucial issues in both municipal and industrial environments. In fact, advanced separation technologies are key processes in the new Circular Economy Action Plan (CEAP II), one of the fundamental pillars of the European Green Deal, under which activities related to wastewater treatment (WWT) should seek new technologies that can recover both water and nutrients.

In parallel, the European Sustainable Process Industry through Resource and Energy Efficiency (SPIRE) plan, which focuses on actions to avoid, valorise, and reuse waste streams to create new business models and move towards a circular economy (zero waste), requires circular value chains and the development of cost-effective separation and purification operations. In this sense, membrane operations are highly relevant due to their high efficiency and low environmental impact; however, it is essential to improve membrane technologies and materials so that they can recover these value-added elements at the quality and concentration levels required by the market.

In this context, the MemTecWare project focuses on integrated and efficient solutions that contribute to minimising liquid waste (zero liquid discharge, ZLD), valorising residual streams, and sustainably producing water and energy. The project proposes the combination of advanced membrane separation technologies for the treatment of wastewater with high salinity and/or ammonia content: membrane distillation (MD), osmotic membrane distillation (OMD), vacuum membrane distillation (VMD), membrane crystallisation (MCr), reverse electrodialysis (RED), and pressure-retarded osmosis (PRO).

MemTecWare, coordinated by the Complutense University of Madrid (UCM), is divided into three subprojects: 

• Subproject 1: MemTecWare-SOMEWATER - Development of self-heating membranes (led by the Complutense University of Madrid, UCM). 
• Subproject 2: MemTecWare-PROFUSION - Implementation and optimisation of PRO processes (led by the University of Las Palmas de Gran Canaria, ULPGC). 
• Subproject 3: MemTecWare-HARMONIZE - Improvement of OMD and VMD processes for the selective recovery of ammonia and ammonium salts (led by the Universitat Politècnica de Catalunya - BarcelonaTech, UPC).

Specifically, the HARMONIZE subproject, whose main goal is to valorise the recovered ammonia both as fertiliser (e.g., ammonium salts) and as a CO₂-free fuel (NH3 (g)), will:

• Study the effects and optimise operational parameters and factors affecting ammonia flow, selectivity, and product quality in OMD and VMD configurations.
  
• Explore new OMD and VMD configurations and optimised module designs to reduce the transmembrane water flux in order to increase ammonia flow, selectivity, and product concentration.
  
• Study and optimise the crystallisation process to obtain better-quality ammonium salt crystals for fertiliser production.
  
• Develop new, more selective OMD and VMD membranes for ammonia.
  
• Extend existing physical models and develop new experimental-based models to evaluate and optimise the Opex (e.g., energy and chemical consumption, fouling, etc.) and Capex (e.g., membrane area) of the OMD-MCr process for ammonium salt production.
  
  

Budget and funding

The project is funded by the Agencia Estatal de Investigación through the State Plan for Scientific, Technical, and Innovation Research 2021-2023 (PID2022-138389OB-C33). It has a budget of €100,000 and a duration of three years (September 2023 – August 2026).