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Plataforma Solar de Almería
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The highest test facility for testing and development of applications of solar concentrating technologies.
Plataforma Solar de Almería
2. Parabolic-trough collector technology
1
1
2
9
7
6
4-5
3 81. Central receiver technology
5. Solar furnace (materials testing)
3. DSG Direct steam generation4. Parabolic dish + Stirling system
7. Solar desalination
6. Solar photocatalysis
9. Building materials testing
8. Solar hydrogen & fuel production
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Solar photocatalytic processes
for water disinfection
Pilar Fernández Ibáñez*, Inmaculada Polo López,
Irene Fernández García
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Overview
Water disinfection needs
Water treatment and solar photocatalytis
Disinfection of water for agriculture applications
- Irrigation water disinfection
Conclusions
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Water disinfection needsDRINKING WATER
• In communities with little or not access to safe drinking water, waterborne
diseases is the major cause of sickness and death.
• Approx. 1.8 million deaths occur per year due to a combination of
inadequate sanitation and poor water quality (WHO, 2008)
IRRIGATION WATER
• According to FAO, agriculture consumes 70% of fresh water used
worldwide (95% in developing countries).
• The daily drinking-water requirement per person is at least 2 - 4 liters, but it
is often forgotten that it still takes 2000 to 5000 liters of water to produce a
person‟s daily food requirement (FAO, 2008).
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Water disinfection needs
INTENSIVE AGRICULTURE
• The intensive agriculture activity is a very important economical sector in
Almería. There are more than 350 km2 of greenhouses.
• Initiatives to improve water management in agricultural lands are
increasingly required. Hydroponics can be adapted to arid and semi-arid
areas where the availability of water for irrigation is restricted (FAO, 2008).
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Hydroponic cultures
Hydroponics literally means “waterworks,” and includes all methods and
systems to grow plants without soil. The most common hydroponic systems are:
a) Cultivation in liquid media: plants have their roots
immersed in the nutrient solution and the type of
support depends on the crop.
b) Open-cultivation on solid: plants anchor to the solid,
inert and porous substrate and acquires the nutrient
solution by percolation.
c) Closed-cultivation on solid: the nutrient solution is
provided and drained through the same inlet. The
system is “closed” and recycles the nutrient solution.
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Hydroponic cultures• Advantages (compared to traditional agriculture):
- promotes efficient water and nutrient use.
- allows the use of poor quality water, either
moderately saline or alkaline.
- provides some protection against limiting climatic
factors such as drought and light frosts.
- modular: efficient utilization of limited volumes of
water.
- size of the hydroponic system can be adjusted.
• Disadvantages:
- high energy input.
- initial investment.
- basic water-quality analysis and training are
needed to prepare and maintain the nutrient
solutions (FAO, 2008).
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The main problem found in hydroponic
cultivation is the accumulation of
phytopathogens in the nutrient solution.
Hydroponic cultures
Fungi Viruses Bacteria
•Fusarium spp.
•Olpidium sp.
•Phytophthora sp.
•Pythium sp.
•Rhizoctomia sp.
•Verticillium spp.
•Watermelon
mosaic virus
•Tomato
mosaic virus
•Cucumber
green mottle
mosaic virus
•Pseudomonas
syringae
•Clavidobacter
michiganensis
•Erwinia amylovora
•Xanthomonas
Closed hydroponic culture
water-
recycling
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Water disnfection & solar photocatalysis
Escherichia coli
• Matsunaga et al., 1985. Lamp / TiO2-Pt slurry / 120 min
• Zhang et al., 1994. Solar radiation / TiO2 slurry / 23 min
• Rincón et al., 2001-2004. Simulated sunlight / TiO2 slurry / 20 min
• Rincón and Pulgarin 2005, Fernández et al. 2005-2009. Solar radiation /
TiO2 slurry and immobilized in solar reactors.
Candida albicans
• Seven et al., 2004. Lamp / TiO2, ZnO and Sahara sand / 120 min
• Lonnen et al., 2005. Solar simulator / TiO2 supported / 04 h
Fusarium spp.
• Lonnen et al., 2005. Solar simulator / TiO2 supported / 4 h.
• Sichel et al., 2007-2009. Solar radiation/TiO2 slurry/ solar reactor / 4-6 h.
BACKGROUND
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Damages of UV radiation on microbial cellscosmic
raysg-rays X-rays UV visible infrared
radiowaves
Far UV: 10-200 nm
10nm 100nm 200nm 300nm 400nm
UV-C200-280 nm
UV-A320-400 nm
Damages
cells DNALethal &
mutagenic Cell death
Chromophores absorb UV-B &UV-A
ROS (HO2•, H2O2,
•OH) generation
•Oxidation of proteins
•Damage of membrane
•Single strand breaks (SSB´s)
•Nucleic base modifications
McGuigan, JAM 2006, 101, 453-463.
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TiO2/ Solar UVA disinfection
0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4 2,6 2,8
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
IrradianciaSolarDirecta estándar sobrela superficieterrestre(ASTM E891-87,para MasadeAire= 1,5)
IrradianciaSolar
(W/m
2µ
m)
O3
O2
O2
O3
H2O/CO2
H2O
H2O
O/CO2
H2O
0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4 2,6 2,8
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
IrradianciaSolarDirecta estándar sobrela superficieterrestre(ASTM E891-87,para MasadeAire= 1,5)
Estraterrestrial Irradiance
Dir
ect N
orm
al Ir
radia
nce
(W/m
2µ
m)
Wavelength (mm)
O3
O2
O2
O3
H2O/CO2
H2O
H2O
O/CO2
H2O
Estraterrestrial solar irradiance
Direct solar irradiance
over the Earth surface
(Air Mass: 1.5)
Terrestrial and extraterrestrial solar spectrum
(48.2º zenit angle)
Solar radiation
Direct „cydal‟ action related with UV absorption
and increased by temperature.
+ TiO2 Indirect „cydal‟ action due to photocatalytic
effect of TiO2 generating hydroxil radical whcih attack
the cell membrane. Also, a decrease of Coenzyme-
A levels by photo-oxidation, which induces celular
death.
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TiO2/ Solar UVA disinfection Blanco, Fernandez-Ibáñez,
Malato,J. Solar Energy
Engineering 129 (2007) 1-12.
40 nm 300 nm >1mm
TiO2 TiO2-aggregates cells
TiO2
h+
OH•
e-
O2-•
Solar UV
e-/h+
Very small particlesof TiO2
suspendedTiO2
OH•
O2-•
Adsorbed TiO2
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Macroconidia of Fusarium equiseti before (left) and after (right) 5 hours of
photocatalytic treatment.
TiO2
C. Sichel, et al. Appl. Cat. B:
Environ., 74 (2007) 152-160.
TiO2 nanoparticles adsorption on
Fusarium macroconidia
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TiO2 nanoparticles adsorption on
Fusarium chlamydospores
Fusarium solani chlamydopores after
6h of solar exposure without TiO2.
TiO2
Fusarium solani chlamydopores after
6h of solar exposure with TiO2.
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TiO2 nanoparticles adsorption on
Phytophthora spores
Phytophtora after 5 h of solar
exposure without TiO2.
Phytophtera after 5 h of solar
exposure with TiO2.
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0 2 4 6 8 10 12 14
1
10
100
1000
Co
nce
ntr
atio
n (
CF
U/m
L)
QUV
(kJ/L)
F. equiseti
F. antophilum
F. verticillioides
F. solani
F. oxysporum250 mL
Bottlereactor
200 mL fungal
suspension
Glass cover
irradiating light
irradiating lightirradiating light
250 mL
Bottlereactor
200 mL fungal
suspension
Glass cover
irradiating light
irradiating lightirradiating light
Glass cover
200mL suspension
of fungal spores
Magnetic stirrer
Solar ligth
Inactivation of Fusarium spores
C. Sichel, et al. Appl. Cat. B:
Environ., 74 (2007) 152-160.
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Pilot plant design with CPC modules, catalyst
sedimentation tank filters for post- treatment.
Design of a solar prototype
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Solar CPC reactor for water disinfection
20 Borosilicate glass tubes
Irrradiated collector surface of 4.5 m2
CPC moduleRecirculation tank
pH, Temperature, Dissolved Oxigensensors
Settling tank
Glass tube (L:1500mm, di:50mm thickness: 2.5mm)
CPC mirror (aluminium annodized quality MIRO SUN)
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Radiometer
4. Solar collector covering.
2. Inoculation of culture & catalyst.
3. Dark recirculation.
1. Catalyst preparation.
5. Remove the cover.
6. Experiment starting.
7. Spread in malta agar.
Incubated: 2 days, 28 ºC
8. F. solani colonies counting
Methodology
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Inactivation of Fusarium solani microconidia
WELL WATER
TiO2 concentrations: 0, 50, 100, 250 mg/L
30 L/min
V = 60 L
11:00 12:00 13:00 14:00 15:00 16:00
100
101
102
103
0 mg/L TiO2
100 mg/L TiO2
DL
Controls
F. s
ola
ni
Co
nc
en
tra
tio
n (
CF
U/m
L)
Local Time (HH:MM)
50 mg/L TiO2
41,2
kJ/L
QUV
needed to Detection Limit
41,5
kJ/L
DISTILLED WATER
11:00 12:00 13:00 14:00 15:00 16:00
100
101
102
103
DL
Controls
F.
so
lan
i C
on
ce
ntr
ati
on
(C
FU
/mL
)
Local Time (HH:MM)
QUV
needed to Detection Limit
0 mg/L TiO2
250 mg/L TiO2
50 mg/L TiO2
100 mg/L TiO2
30 k
J/L
41 k
J/L
52 k
J/L
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Inactivation of Fusarium equiseti spores
30 L/min
100 mg/L of TiO2
11:00 12:00 13:00 14:00 15:00 16:0010
0
101
102
DL
Controls
F.
so
lan
i C
on
ce
ntr
ati
on
(C
FU
/mL
)
Local Time (HH:MM)
39,4
kJ/L
30,4
kJ/L
Solar disinfection
Well water
QUV
needed to Detection Limit
Distilled water
28
,5 k
J/L
MACROCONIDIA
11:00 12:00 13:00 14:00 15:00 16:0010
0
101
102
DL
Controls
F.
eq
uis
eti
Co
nc
en
tra
tio
n (
CF
U/m
L)
Local Time (HH:MM)
45,3
kJ/L
37,2
kJ/L
Well water
Distilled water
QUV
needed to Detection Limit
Solar Disinfection
36,4
kJ/L
CHLAMYDOSPORE
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Conclusions
This study showed that Fusarium spores in distilled and
well water can be inactivated with TiO2 slurry in a CPC 60-
L photo-reactor.
The reactor was also evaluated to find out the best
operating parameters, which were found to be a flow
regime of 30 L/min and optimal TiO2 concentration of
100 mg/L.
We demonstrated that it is possible to scale up the
photocatalytic treatment for further use and reuse of water
for hydroponic culture when the catalyst recover is done by
different methods like sedimentation, filtration, etc.
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Acknowledgements
FITOSOL project, AGL2006-12791-C02.
Spanish Ministry of Education and Science
Thanks for your attention