Scientific Areas

Membrane Technology for Water Treatment, Desalination and Separations

Membrane-based processes (Reverse Osmosis – RO, Nanofiltration – NF, Ultrafiltration – UF, Microfiltration – MF) are already established as the dominant technology for brackish and sea-water desalination, potable water purification, and treatment of effluents of various types for clean water recovery.

Moreover, such membrane processes tend to displace many other conventional separation operations in the process and related industries. NRRE has developed expertise in membrane technology, by performing research in a broad range of topics covering all major aspects of membrane process design and operation.

This research includes in-depth studies of membrane module design, of the major operating problems of membrane fouling and scaling, and of membrane system simulation and optimization.

The development of innovative methods has been successfully pursued for on-line monitoring of desalination membrane performance, plant-wide, based on permeate water quality.

R&D studies on the important Membrane Bio-Reactor (MBR) technology are carried out, using innovative diagnostic tools, for improved operation and applications to effluents heavily loaded with compounds difficult to biodegrade.

Research is also carried out on novel membrane-based methods (including membrane distillation, membrane extraction, pressure retarded osmosis, forward osmosis).

Membrane Module – Design and Performance Optimization  

  • Spacers in Spiral-Wound Membrane (SWM) Modules: Characterization, Improved Geometrical Characteristics,Novel Spacer Designs [MEDRC project] 
  • Modeling Transport Phenomena: Spiral Wound Module, Hollow Fibers        

Membrane Fouling Studies (Organic, Colloidal, Biofouling)

  • Fouling in SWM Modules; characterization, modeling. Fouling Indices [MEDRC project] 
  • Fouling of UF, MF Membranes; pretreatment of RO feed-waters [EC projects]
  • Fouling Mitigation Methods

Membrane Scaling Studies

  • RO/NF Membrane Incipient Scaling; experiments and modeling [Saudi Aramco project III]
  • Scaling Mitigation Methods   

Development of Membrane Module and Process Simulators

  • Comprehensive simulation of steady state SWM module performance
  • Dynamic simulator of SWM and membrane desalination system performance

Membrane Surface Post-treatment

  • Post-treatment to restore/improve salt rejection [S. Aramco project I, patent application].

Membrane Element Performance Monitoring

  • SWM element performance monitoring (permeate) plant-wide [S. Aramco project II, patent application]
  • Monitoring other process parameters

Scaling propensity monitor in RO/NF plants

  • Online monitoring per pressure vessel  [S. Aramco project III]

Novel sensors for monitoring membrane processes

Αctivated Sludge Characterization – MBR Performance studies

  • Fouling studies in long-term MBR operation   [GSRT project]
  • Meta-genomics studies of sludge evolution  [Collaborationwith INEB/CERTH]
  • Development of Convenient and “Comprehensive” MBR monitoring techniques
  • MBR modeling 

Novel MBR-based Processes  

  • MBR alone, or in combination with other membrane separations (e.g. MD), adapted to specific classes of bio-processes[GSRT project]

Membrane Distillation (MD) for Water Treatment and Separations

  • MD for bio-ethanol production/separation [GSRT project]
  • Combined MD with renewable energies for desalination

Pressure Retarded Osmosis (PRO)– Forward  Osmosis (FO)

  • Innovative module design
  • Process development

Recovery of valuable products   [GSRT projects]

  •  Membrane extraction  [PhD thesis]
  • UF – NF – RO hybrid separation processes
  • Algae harvesting

Pollution Mitigation – Water Purification

Research is carried out on innovative Advanced Oxidation Processes (AOPs), which are energy efficient and need no external addition of expensive and difficult to handle oxidants, for degradation of organic micro-pollutants including recalcitrant pharmaceuticals and pesticides.

Along these lines, development of hybrid photocatalysis – UF membrane processes is successfully pursued for various applications. Other water purification techniques are also studied for potable water and industrial effluent treatment applications.

  • Electro-Fenton, Novel System for degradation of organic micro-pollutants and water purification [GSRT project – NHRON, patent application]
  • Hybrid Photocatalysis – Membrane processes for pollutants degradation

Water Characterization and filtration 

  • Natural water sources (micro-pollutants, NOM, etc.)
  • Novel filter media [Maxit project]

Removal of Pollutants; process development

  • Pesticides removal by NF-LPRO Membranes & Hybrid processes [PhD thesis]
  • Industrial effluent; treatment-reuse [GSRT – industry project]

Utilization of Agricultural Residues and other Industrial Byproducts

Research in this area currently focuses on the development of novel methods for integrated treatment of residues (mostly solid-liquid) from processing of agricultural products (fruits, vegetables). The target is to first extract valuable organic compounds and then treat the remainder for water recycling and solids utilization (energy recovery, fertilizers, etc.).

Extraction of Valuable Compounds from Agricultural Residues  [GSRT projects]

Integrated Processes for Effluent Treatment to recover valuable products and water; Hybrid Bio-Treatment/Membrane Processes [GSRT projects]

Utilization of Renewable Energy Sources

Activities are focused on maximum utilization of low enthalpy geothermal fluids, which are abundant in Greece and elsewhere, whereby sequential uses are preferable; e.g. heat recovery (heat pumps) and then utilization as potable water or for irrigation. Solar energy utilization is also studied; e.g. solar-powered desalination applications.

Geothermal  Energy Utilization  (Heat Pumps, Other Applications)

Solar Energy Utilization; Solar Energy for Water treatment and Desalination

Environmental Pollution – Impact on Human Health

Computational tools, and related monitoring techniques,are developed for assessment of environmental pollution and its effects, focused on human health impact. This research, mainly addressing toxic pollutants (e.g. pesticides), also considers various scenarios of climatic change; it is carried out in collaboration with Prof. D. A. Sarigiannis, Environmental Engineering Laboratory, Chemical Engineering Department, Aristotle University of Thessaloniki.

Assessment of aggregate and cumulative human exposure to mixtures of environmental pollutants through all environmental media [EC & CEFIC projects]

Design and optimization of  technological strategies for the improvement of public health from exposure to environmental pollutants [EC LIFE+ project].

Multi-Phase Systems – Process Analysis and Intensification

In NRRE there is long-term involvement and expertise in studies of multi-phase systems, which are encountered in a variety of process equipment. Intensification/improvement of multi-phase processes is a related research field.

Dynamics of liquid/liquid,  gas/liquid  and  solid/liquid  dispersions

  • Advanced simulation of processes involving population balances combined with spatially distributed phenomena [EC projects].
  • Simulation of evolving dilute dispersionsin process equipment.

Process improvement and intensification; packed beds, heat exchangers, separation equipment  [EC projects].