1. Solar Photocatalysis for Urban and Industrial Waste Water Reclamation
Sixto Malato
Plataforma Solar de Almería (PSA-CIEMAT),
Tabernas (Almería), Spain.

2. 1 5 6
1. Central receiver technology
2. Parabolic dishes + Stirling engines 4
3. Parabolic-trough technology (thermal oil)
4. Parabolic-trough technology (DSG) 1
5. Parabolic-troughs (gas) + Molten Salt TES
6. Linear Fresnel Collector 7 9
7. Solar furnaces 2 8
8. Water desalination 3
9. Water photocatalysis
10. Passive architecture 10

3. Introduction driven by solar energy Solar Advanced Oxidation Processes
“near ambient temperature and pressure water treatment processes driven by solar energy which involve the generation
of hydroxyl radicals in sufficient quantity
to effective water purification”
driven by solar energy
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4. Introduction
Wavelength, µm
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5. Introduction
CATALYSIS +
SUN
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6. Introduction
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7. Introduction 1 Sun CPCs 5/38 Turbulent flow conditions
No vaporization of volatile compounds
No solar tracking
No overheating
Direct and Diffuse radiation
Low cost
Weatherproof (no contamination)
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8. Introduction
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9. Introduction
The current lack of data for comparison of solar photocatalysis with other technologies definitely presents an obstacle towards an industrial application. Therefore, it is necessary:
Give sound examples of techno-economic studies.
Assessment of the environmental impact: life cycle analysis (LCA).
To lead to industry application it will be critical that the processes can be developed up to a stage, where the process:
can be compared to other processes.
is robust, i.e. small to moderate changes to the wastewater stream do not affect the plant’s efficiency and operability strongly.
is predictable, i.e. process design and up-scaling can be done reliably.
gives additional benefit to the industry applying the process (e.g. giving the company the image of being “green”).
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10. Examples of techno-economic studies
Sound examples of techno-economic studies:
AOP-BIO and BIO-AOP
Lanfill leachate
Treatment of Ecs
Combination NF/AOPs
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11. AOP-BIO and BIO-AOP
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12. AOP-BIO and BIO-AOP
WW characterization: TOC, COD, BOD, main inorganics, contaminants (LC-MS/GC-MS)
TOXICITY
Non-toxic or partially toxic (<50%)
Toxic (>50%)
EVALUATION OF
BIODEGRADABILITY
AOP
EVALUATION OF BIODEGRADABILITY DURING AOP 2 1 1
TOC>500 mg/L
TOC<500 mg/L
DILUTION AND EVALUATION OF BIODEGRADABILITY 2
AOP
EVALUATION OF BIODEGRADABILITY DURING AOP 1 2
BIOLOGICAL
TREATMENT 1
AOP
EVALUATION OF BIODEGRADABILITY DURING AOP
BIOLOGICAL
TREATMENT 2
BIOLOGICAL
TREATMENT 1 2
COD and toxicity<Guideline
DISCHARGE
Biorecalcitrant compounds
COD and toxicity<Guideline
DISCHARGE
AOP
1: Partially or not biodegradable
2: Biodegradable. COD>Guideline
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13. Combined photo-Fenton and biotreatment
AOP-BIO
Combined photo-Fenton and biotreatment
Non-biodegradable pesticides
Biodegradable compounds
Industrial wastewater
DOC0: 480 mg/L
Biological treatment (IBR)
Decontaminated water
DOC: 75 mg/L
Solar Photo-Fenton
20 mg/L Fe / pH: 2.8
44 % mineralization
DOCf: 270 mg/L
21 mM H2O2 consumed
DOC0: 300 mg/L
1.5 days of biotreatment
75 % mineralization
DOCresidual: 75 mg/L
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14. % Reduction combined system
AOP-BIO
Compound
% Reduction combined system
Final conc
(g/L)
Imidacloprid
96.4 25
Dimethoate
99.4 5
Pyrimethanil 81
161
Thiacloprid
84.2 88
Azoxystrobin 3
Malathion
100
< 0.1
Carbofuran
Metalaxyl
Spinosyn a
Bupirimate
Fenamiphos
Tebufenozide
1. SPE extraction 1 2 3 4
2. LC-TOF-MS
Oasis® HLB
Concentration of all pesticides decreased gradually throughout the process (mainly during the photo-Fenton process).
After the combined system: totally removed, except pyrimethanil and thiacloprid, found in range of g/L
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15. BIO-AOP
Real WW
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16. BIO-AOP 14/38 INITIAL CONDITIONS (photo-Fenton)
Nalidixic acid: 39 mg/L
Initial TOC: 822 mg/L
[NaCl] : 6.5 g/L
Total degradation of the nalidixic acid
at 350 minutes (illumination time)
(65 mM H2O2)
28% of the initial TOC was removed
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17. AOP-BIO and BIO-AOP AOP  BIO BIO  AOP % TOC reduction 15/38 100 8020 40 60 80
100
% TOC reduction
AOP  BIO
Biotr. time = 4 days
BIO  AOP
t30w = 350 min; H2O2 = 65 mM
(elim.NXA)
t30w = 21 min (elim. NXA) !!!
H2O2 = 12 mM (elim. NXA) !!!
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18. BIO-AOP
LC-TOF-MS chromatograms
No DPs
Retention time (min)
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19. 3. Evaluation of toxicity
Landfill leachate
Landfill leachate (COD: mg/L; DQO: mg/L)
Pre-treatment
(Coagulation/floculation)
2. Photo-Fenton (Fe 1 mM)
3. Evaluation of toxicity
and biodegradability
3.a Respirometry activated sludge
3.b Biodegradability by Zahn-Wellens
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20. Landfill leachate
Respirometry activated sludge
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21. Landfill leachate
Biodegradability by Zahn-Wellens
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22. Pre-treatment (Coagulation/floculation) (<20 % mineralization)
Landfill leachate
TC=
15615 mg/L
COD=
42630 mg/L
DOC=
15610 mg/L
Conduct.=
77.3 mS/cm
Pre-treatment (Coagulation/floculation)
2. PHOTO-FENTON
(<20 % mineralization)
3. BIOTREATMENT
€/m3 % M1 M3
Chemicals (H202)
21.5
30.1 73 60
Electricity
0.1 1
Man power
1.4 5
CPC + facilities
6.4
11.7 22 27
Total (€/m3)
29.4
43.3
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23. CONTINUOUS INTRODUCTION
Treatment of ECs
WWTPs
NATURAL WATERS
EMERGING CONTAMINANTS
(ng-μg/L)
Until recently unknown
Commonly use
Emerging risks (EDCs, antibiotics)
Unregulated
INCOMPLETE
REMOVAL
Photochemical transformations
CONTINUOUS INTRODUCTION
INTO THE ENVIRONMENT
TRANSFORMATION
PRODUCTS
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24. Treatment of ECs
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25. Treatment of ECs 23/38 CHARACTERIZATION
LC-QLIT-MS/MS
CHARACTERIZATION
29/62 Compounds with higher contribution in MWTP Effluent
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26. Treatment of ECs 75 L, 4.1 m2, control T (35 ºC) 50 L, 0.69 g O3 h-1
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27. Treatment of ECs Solar TiO2. Solar photo-Fenton Ozonation 25/38
1-Bisphenol A; 2-Ibuprofen; 3-Hydrochlorothiazide;
4-Diuron; 5-Atenolol; 6-4-AA;
7-Diclofenac; 8-Ofloxacin; 9-Trimethoprim;
10-Gemfibrozil; MAA; 12-Naproxen;
13-4-FAA; 14-∑C; 15-4-AAA; 16-Caffeine; 17-Paraxanthine
Contaminants > 1000 ng L-1.
∑C = rest of contaminants
at less than 1000 ng L-1
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28. Treatment of ECs 26/38 Solar TiO2 photo-Fenton Ozonation
Treatment time, min
475 20 60
Accumulated solar
Energy, kJ L-1
212
2.3 -
Reagent
Consumption
H2O2
54 mg L-1
Fe(II)
5 mg L-1 O3
9.5 mg L-1
LC-MS chromatogram. Ozonation.
t = 0
t = 60 min
LC-MS chromatogram. Photo-Fenton.
t = 0
t = 20 (t30W = 14) min
Toxicity assays during ozonation and photo-Fenton showed < 10% inhibition on V. fisheri bioluminescence and in respirometric assays with municipal activated sludge
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29. of micropollutants 5000 m3/day
Treatment of ECs
Calculation basis:
90% or 98% degradation
of micropollutants 5000 m3/day
H2O2 1.1 € kg-1
Fe(II) 0.72 € kg-1
H2SO € kg-1
NaOH 0.12 € Kg-1
Electricity 0.07 € Kwh-1
O € Kg-1
Labour 18.8 € h-1
23.1 € kg O3
Solar photo-Fenton
Ozonation
€m3
90%
98%
Reagent
0.064
0.148
0.16
0.22
Labour
0.03
0.05
Electricity
0.004
0.010
0.020
Investment
0.09
0.15
0.23
0.27
Total
0.188
0.358
0.450
0.560
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30. Combination NF/AOPs
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31. Combination NF/AOPs
NF in parallel (5.2 m2).
1.4 m3 h-1
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32. Combination NF/AOPs Micropollutants at 15 µg L-1, each Ions Na+ K+
mg L-1
Na+ K+
Mg2+
Ca2+
SO42-
Cl-
HCO3-
5-7
37-60
85-100
Micropollutants
at 15 µg L-1, each
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33. Combination NF/AOPs 31/38 Inorganic ions Pharmaceuticals R (%)
Ce, CF=4 (mg L-1)
Ce, CF=10 (mg L-1)
Na+ K+
Mg2+
Ca2+
SO42-
Cl-
HCO3-
76-87
77-82
91-97
88-93
96-99
67-84
72-88
15-19
90-105
70-105
Pharmaceuticals
R (%)
Ce, CF=4 (mg L-1)
Ce, CF=10 (mg L-1)
Carbamazepine
Flumequine
Ibuprofen
Ofloxacin
Sulfamethoxazole
93-96
97-100
96-100
97-99
92-95
47-52
58-63
55-61
58-62
52-59
Solar photocatalysis
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34. r = kC Combination NF/AOPs 32/38 Fe (II), 0.1 mM H2O2, 25 mg L-1
Natural pH
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35. Ethylenediamine-N,N'-disuccinic acid (EDDS)
Combination NF/AOPs
Fe (II), 0.1 mM
0.2 mM EDDS
H2O2, 25 mg L-1
Natural pH
Fe(III)-L + hν → [Fe(III)-L]* → Fe(II) + L•
Ethylenediamine-N,N'-disuccinic acid (EDDS)
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36. Combination NF/AOPs 34/38 CF 1 4 10 Solar photo-Fenton
H2O2 consumed (gm-3)
Quv (kJ L-1)
t(min) / CPC surface(1)
17.0
22.5
90/100
4.4
5.1
120/22.6
1.9
2.8
110/12.4
photo-Fenton like
Fe (III)-EDDS complex
24.9
2.7
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6.2
0.6
10/3.3
2.5
0.5
19/2.7
Operational requirements for attaining 95% of pharmaceuticals degradation present in NF concentrates (CF=4 and 10) when solar photo-Fenton and photo-Fenton like Fe(III)-EDDS complex were applied. CF=1, no NF, only AOP.
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37. Heterogeneous photocatalytic hydrogen
generation in a solar pilot plant
Flow rate 20 L/min.
CPC with pyrex glass tubes, m2.
Irradiated volume 9.79 L.
Total volume 25 L.
Catalyst loading g/L, Pt/(TiO2-N) or Pt/(CdS-ZnS)
Sacrificial agents:
formic acid (0.05 M), glycerol (0.001 M)
and a municipal wastewater (97.7 mg/L of DOC).
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38. Heterogeneous photocatalytic hydrogen
generation in a solar pilot plant
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39. Heterogeneous photocatalytic hydrogen
generation in a solar pilot plant
0.05 M formic acid
Real wastewater, 98 mg/L of DOC
Reaction conditions: 5 g of catalyst, 25 L of aqueous solution. Data corresponding to 5 hours of irradiation.
K. Villa, X. Domènech, S. Malato, M. I. Maldonado, J. Peral.
Heterogeneous photocatalytic hydrogen generation in a solar pilot plant.
Int. J. Hydrogen Energy, 38 (29), 2013,
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40. Acknowledgements
Unidad de Tratamientos Solares de Agua (Solar Treatment of Water Research Group) .
Plataforma Solar de Almería (CIEMAT).
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