SOLAR ENERGY AND WATER PROBLEMS IN THE MEDITERRANEAN BASIN

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1 SOLAR ENERGY AND WATER PROBLEMS IN THE MEDITERRANEAN BASIN DR. WOLFGANG GERNJAK CHANIA, 8th APRIL 2008

2 SOLAR WATER APPLICATIONS 1. SOLAR DESALINATION 2. SOLAR DETOXIFICATION 3. SOLAR DISINFECTION +

3 SOLAR THERMAL DESALINATION

4 MEMBRANE DISTILLATION Typical distillate production: 15 to 30 L/m 2 (of solar collector) and day. The Fraunhofer Institute (Germany) is working on the development of two systems based on this process: 100 L/day (1 membrane, 6 m 2 of solar collectors) and 1000 L/day (4 membranes, 72 m 2 of solar collectors) Membrane distillation process scheme (courtesy of Memstill consortium,, Holland) Courtesy of Fraunhofer Institut

5 THERMAL MOTOR/ ORGANIC RANKINE CYCLE + RO 2 Brine effluent Reverse Osmosis is the current dominant technology when power plant is not associated with desalination Solar collector Thermal motor of positive displacement with energy recovering device Mechanical energy RO module Brine Fresh water 1 Pump 4 Condenser 3 Seawater / Brackish water

6 MED AQUASOL SYSTEM Main sub-system system components are: 14 effects MED plant (3 m 3 /h distillate prod.) Stationary CPC solar collector field Thermal storage system (water, 24 m 3 ) Double-effect (LiBr-H 2 O) absorption heat pump Smoke-tube gas boiler Solar dryer for final treatment of the brine

7 AQUASOL estimation of production in summer day: about L/m 2 1 Ha with a land occupation factor of 50% (5,000 m 2 of solar collectors) would yearly produce about a 160,000 m 3 Cost of AQUASOL produced water: 8.12 /m 3 (PSA plant / 3 m 3 /h) 0.93 /m 3 (extrapolation to a 12,000 m 3 /day plant). Land cost not considered

8 SOLAR POWER PLANT + MED/MSF Multieffect Distillation (MED) has an excellent matching with power plants when energy is supplied at low pressure (i.e.0.4 bar) Very interesting possibility to couple with solar power plants Rankine power cycle should be designed to achieve exhaust steam from the turbine at 70ºC (instead of the conventional 35ºC) Little reduction in the overall efficiency in the electricity production but all energy discharged to the ambient in the cooling system can be fully used to desalination Water to power ratio Optimising a combined cycle from 1.2 to 1.5 tons/hr of steam per each MW installed can be achieved for desalination Approximately 21,000 m 3 /d every 100 MW installed can be produced

9 SOLAR WATER APPLICATIONS 1. SOLAR DESALINATION 2. SOLAR DETOXIFICATION 3. SOLAR DISINFECTION +

10 PHOTOCATALYTIC PROCESSES TiO 2 (heterogeneous process) and Photo-Fenton (homogeneous process) photocatalytic processes have been widely reported as feasible techniques to hazardous water contaminants degradation using solar light: Heterogeneous TiO 2 Photocatalytic System: TiO + hν e + h + 2 CB VB h + H O OH + H + + VB 2 (λ< 390 nm) Homogeneous Photo-Fenton System (H 2 O 2 and Fe 2+ irradiated in the UV-VIS range): Fe + H O Fe + OH + OH Fe + H O + hν Fe + H + OH 2 (? < 580 nm) Processes based on the generation of powerful oxidant hydroxyl radicals ( OH)

11 COUPLING WITH BIOLOGICAL PROCESSES Biological treatment Photochemical treatment Toxic and biorecalcitrant Conceptual scheme of technology coupling: Solar Photocatalysis followed by Biological Treatment Courtesy of EPFL (Switzerland)

12 RANGE OF APPLICATION Photocatalytic Processes Adsorption

13 PESTICIDE CONTAINER RECYCLING Plastic granules

14 ALBAIDA DETOX PLANT Commercial plant operating since June 2004 (Almeria, Spain)

15 SOLAR WATER APPLICATIONS 1. SOLAR DESALINATION 2. SOLAR DETOXIFICATION 3. SOLAR DISINFECTION +

16 WATER DISINFECTION WATERBORNE PATOGENS VIRUS Poliovirus Hepatitis A Parvovirus Adenovirus Rotavirus BACTERIAS Salmonella Shigella Campylobacter Vibrio Escherichia coli PROTOZOOS Giardia lamblia Entamoeba histolytica Crystosporidium HELMINTOS Taenia saginata Ascaris lumbricoides Schistosoma DISINFECTION CONVENTIONAL TREATMENTS ALTERNATIVE / COMPLEMENTARY NEW TECHNOLOGIES

17 SODIS DISINFECTION Direct sunlight has no real capacity for microbiological water treatment, but it can inhibit microorganisms reproduction and photo-reparation mechanims Kehoe et al., Letters in Applied Microbiology 2004, 38,

18 SODIS DISINFECTION (EAWAG, Switzerland)

19 TiO 2 SOLAR DISINFECTION Disinfection Mechanism of Photo-assisted TiO 2 O - 2 Adsorbed TiO 2 OH e - /h + UV solar OH h + MICROORGANISM TiO 2 e - O2 - Small TiO 2 particles Suspended TiO 2 Fusarium Equiseti (fungus) inactivation after solar photocatalytic treatment

20 PSA PROJECTS & LINKS DESALINATION - membrane distillation: MEDESOL project - organic rankine cycles: POWERSOL project - MED/MSF/heat pump solar: AQUASOL project DETOXIFICATION (industrial wastewater treatment) CADOX, INNOWATECH, INNOVA-MED projects DISINFECTION (rural communities drinking water) SODISWATER, SOLWATER, AQUACAT projects INSTITUTIONAL LINKS: CIEMAT Plataforma Solar de Almería Solar Paces (SOLWATERGY task) Solar Water Disinfection