NIBEC, University of Ulster [email protected]
Enhancing solar disinfection of water
for application in developing regions
Dr Patrick Dunlop
FAPESP, IOP and RSC Workshop:
Physics and Chemistry of Climate Change and Entrepreneurship
Sao Paulo, Brazil
NIBEC, University of Ulster [email protected]
Presentation overview
• University of Ulster and NIBEC
• Water and Climate Change
• Solar Disinfection
• Enhancing Solar Disinfection
We seek collaborations with countries with lovely sunlight!
NIBEC, University of Ulster [email protected]
Largest university on the island of Ireland
Jordanstown campus:
Engineering, Health Science and Sports
NIBEC, University of Ulster [email protected]
Nanotechnology and Integrated BioEngineering Centre (NIBEC)
£10M purpose-built multi-disciplinary research centre
working at the interface of bioengineering and nanotechnology
Successful track record in commercialisation of research
NIBEC, University of Ulster [email protected]
Areas of research include:
- Catalyst development
- Immobilisation
- Thin film characterisation
- Commercialisation
Photocatalysis research
NIBEC, University of Ulster [email protected]
Applications:
- Water purification; estrogens, POP’s, organics
- Disinfection; water and medical devices
- Biosensors; glucose and DNA
- Solar hydrogen, solar cells
Photocatalysis research
NIBEC, University of Ulster [email protected]
Self aligned nanoporous TiO2
Room temperature, low energy input
method to TiO2 nanotubes
- Regular pore diameters
- Controllable pore size
Environmental catalysis
Photo-reduction of CO2
Hydrogen storage
NIBEC, University of Ulster [email protected]
Climate change and water
- Increased precipitation intensity
- Longer periods of low flows exacerbate water pollution
- Impacts on ecosystems and human health
- Increased water system operating costs
NIBEC, University of Ulster [email protected]
US citizens use 500 litres per day, the British average is 200
Only 1% of treated water is consumed as potable water!
Importance for food production (litres required / kilo):
Potatoes 1,000
Maize 1,400
Wheat 1,450
Beef 42,500
Climate change and water
NIBEC, University of Ulster [email protected]
“The West” can afford to waste water, however,
• 1.1 Billion people without access to safe water
• 4 Billion cases of diarrhoea (88% due to unsafe water)
• 1.8 Million die each year (majority under 5 yrs)
NIBEC, University of Ulster [email protected]
Millennium Development Goal Target 10:
“by 2015, reduce by half, the 1.1 billion
people lacking access to safe drinking
water and basic sanitation”.
WHO / UNICEF reports:
Water: $4 billion required per year
Lower-cost, point-of-use (POU)
water purification
NIBEC, University of Ulster [email protected]
Household water treatment intervention options:
• Boiling
• Filtration
• Chlorination
• Solar Disinfection
NIBEC, University of Ulster [email protected]
In Brazil: Prainha do Canto Verde north of Fortaleza
Solar Disinfection (SODIS)
NIBEC, University of Ulster [email protected]
Children under age 6 who used SODIS were 7 times less likely
than non-SODIS users to contract cholera.
Conroy RM, McGuigan KG, et al. (2001) Arch. Dis. Child. 85, 293-295.
Ch
ole
ra In
fecti
on
Rate
(%
)
Health Impact Assessment
NIBEC, University of Ulster [email protected]
Positives for SODIS:
Effective against a wide range of pathogens
Low cost (effectively zero)
Simple to use
Negatives for SODIS:
Some pathogens are resistant to SODIS
Rate of kill depends upon environmental factors
No quality assurance
Cultural / societical / political factors
Education is required
NIBEC, University of Ulster [email protected]
To demonstrate that SODIS is an appropriate, effective and acceptable
intervention against waterborne disease in developing countries
without reliable access to safe water.
SODISwater
Efficacy of SODIS against
resistant pathogens
Increasing SODIS uptake
within communitiesEnhancing SODIS
NIBEC, University of Ulster [email protected]
1. Continuous flow photocatalytic SODIS
2. Batch photocatalytic SODIS reactor
3. Photocatalytic SODIS bag
4. “Quality control” indicators for SODIS
Enhancing SODIS
Pro poor, i.e. LOW cost !
NIBEC, University of Ulster [email protected]
Photocatalysis
Cb= Conduction band; Vb= Valance band; e- = promoted electron; h+= remaining hole;
OH. = Hydroxyl radical; RH= Organic pollutant; R+= Oxidised organic pollutant
NIBEC, University of Ulster [email protected]
1. Continuous flow photocatalytic SODIS reactor
TiO2 coated borosilicate glass tubes (0.4 mg/cm2) were incorporated into the CPC-SODIS
reactors used at PSA and used as a 7L re-circulating batch system using E. coli K12 in
saline (1x106 CFU/mL) as a model test organism.
NIBEC, University of Ulster [email protected]
Uncoated external
Uncoated external,
uncoated internal
TiO2 coated externalTiO2 coated external,
uncoated internal
Uncoated external,
TiO2 coated internal
TiO2 coated external,
TiO2 coated internal
Recirculating Batch
NIBEC, University of Ulster [email protected]
0 10 20 30 40 50 60 70
101
102
103
104
105
106
10:30 11:15 12:00 12:45 13:30 14:15 15:00 15:45
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50 01-04-08, Uncoated external uncoated internal
07-05-08, Coated external coated internal
Normalized time (min)
101
102
103
104
105
106 07-05-08, Coated external coated internal
29-04-08, Coated external uncoated internal
E.c
oli
conc
entr
atio
n (C
FU
/mL)
101
102
103
104
105
106
07-05-08, Coated external coated internal
29-04-08, Coated internal uncoated external
UV Data 29-04-08
UV Data 07-05-08
Local time (HH:MM)
UV Data 29-04-08
UV Data 07-05-08
UV
Irra
dian
ce
(W/m
2)
UV Data 01-04-08
UV Data 07-05-08
0 10 20 30 40 50 60 70
101
102
103
104
105
106
10:30 11:15 12:00 12:45 13:30 14:15 15:00 15:45
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50 01-04-08, Uncoated external uncoated internal
07-05-08, Coated external coated internal
Normalized time (min)
101
102
103
104
105
106 07-05-08, Coated external coated internal
29-04-08, Coated external uncoated internal
E.c
oli
conc
entr
atio
n (C
FU
/mL)
101
102
103
104
105
106
07-05-08, Coated external coated internal
29-04-08, Coated internal uncoated external
UV Data 29-04-08
UV Data 07-05-08
Local time (HH:MM)
UV Data 29-04-08
UV Data 07-05-08
UV
Irra
dian
ce
(W/m
2)
UV Data 01-04-08
UV Data 07-05-08
0 10 20 30 40 50 60 70
101
102
103
104
105
106
10:30 11:15 12:00 12:45 13:30 14:15 15:00 15:45
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50 01-04-08, Uncoated external uncoated internal
07-05-08, Coated external coated internal
Normalized time (min)
101
102
103
104
105
106 07-05-08, Coated external coated internal
29-04-08, Coated external uncoated internal
E.c
oli
conc
entr
atio
n (C
FU
/mL)
101
102
103
104
105
106
07-05-08, Coated external coated internal
29-04-08, Coated internal uncoated external
UV Data 29-04-08
UV Data 07-05-08
Local time (HH:MM)
UV Data 29-04-08
UV Data 07-05-08
UV
Irra
dian
ce
(W/m
2)
UV Data 01-04-08
UV Data 07-05-08
0 10 20 30 40 50 60 70
101
102
103
104
105
106
10:30 11:15 12:00 12:45 13:30 14:15 15:00 15:45
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50 01-04-08, Uncoated external uncoated internal
07-05-08, Coated external coated internal
Normalized time (min)
101
102
103
104
105
106 07-05-08, Coated external coated internal
29-04-08, Coated external uncoated internal
E.c
oli
conc
entr
atio
n (C
FU
/mL)
101
102
103
104
105
106
07-05-08, Coated external coated internal
29-04-08, Coated internal uncoated external
UV Data 29-04-08
UV Data 07-05-08
Local time (HH:MM)
UV Data 29-04-08
UV Data 07-05-08
UV
Irra
dian
ce
(W/m
2)
UV Data 01-04-08
UV Data 07-05-08
0 10 20 30 40 50 60 70
101
102
103
104
105
106
10:30 11:15 12:00 12:45 13:30 14:15 15:00 15:45
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50
15
20
25
30
35
40
45
50 01-04-08, Uncoated external uncoated internal
07-05-08, Coated external coated internal
Normalized time (min)
101
102
103
104
105
106 07-05-08, Coated external coated internal
29-04-08, Coated external uncoated internal
E.c
oli
conc
entr
atio
n (C
FU
/mL)
101
102
103
104
105
106
07-05-08, Coated external coated internal
29-04-08, Coated internal uncoated external
UV Data 29-04-08
UV Data 07-05-08
Local time (HH:MM)
UV Data 29-04-08
UV Data 07-05-08
UV
Irra
dian
ce
(W/m
2)
UV Data 01-04-08
UV Data 07-05-08
E. c
oli
co
nce
ntr
ati
on
(C
FU
/mL
)
UV
A r
ad
iati
on
(W
/m2)
NIBEC, University of Ulster [email protected]
V Irr
ad
ian
ce
(W
/m
22-04-08, uncoated internal uncoated external22-04-08, coated internal uncoated external10-04-08, coated external uncoated internalTypical UV data
2
E. coli
co
nce
ntr
atio
n (
CF
U/m
L)
101
102
103
104
105
106
10:30 11:15 12:00 12:45 13:30 14:15 15:00
10
15
20
25
30
35
40
45
50
55
)
Local time (HH:MM)
2. Batch photocatalytic SODIS reactor
NIBEC, University of Ulster [email protected]
Effect weather photocatalytic SODIS:
10-04-08
22-04-08
10:30 11:15 12:00 12:45 13:30 14:15 15:00
101
102
103
104
105
106
E. co
lico
nce
ntr
atio
n (
CF
U/m
L)
Local time (hr)
5
10
15
20
25
30
35
40
45
UV
irr
ad
ian
ce
(W
/m2)
16-04-08
NIBEC, University of Ulster [email protected]
Sequential batch reactor
Experiments using E. coli in natural well water (1x106 CFU/mL) were carried out to assess
the total treatment time required for sequential batch SODIS. Effect of UVA dose on total
treatment time investigated using 20, 30, 40, 60, 70 and 80 Wh m2.
NIBEC, University of Ulster [email protected]
Accumulated UVA dose = 33.7 W·h/m2
Total treatment time 2.5 hours … water must be kept in SODIS reactor!
11:30 12:00 12:30 13:00 13:30 14:00 14:30 15:00 15:3010
0
101
102
103
104
105
106
107
0
5
10
15
20
25
30
35
40
45
50
Ba
cte
ria
l co
nce
ntr
atio
n (
CF
U/m
L)
Local Time (HH:mm)
Tube 1. Treated water discharged
(samples stored in lab)
Tube 2. Treated water kept in reactor
(samples taken from reactor)
UV
A (
W/m
2)
Te
mp
era
ture
(ºC
)
Temperature tube 2Temperature tube 1UV Irradiance
Exposure Dark
DL
Sequential batch reactor
NIBEC, University of Ulster [email protected]
Accumulated UVA dose = 68.0 W·h/m2
Total treatment time 1.0 hour … in SODIS reactor
12:00 13:00 14:00 15:00 16:0010
0
101
102
103
104
105
106
107
0
5
10
15
20
25
30
35
40
45
50B
acte
ria
l co
nce
ntr
atio
n (
CF
U/m
l)
Local Time (HH:mm)
UV
A (
W/m
2)
Te
mp
era
ture
(ºC
)
Temperature tube 2Temperature tube 1UV Irradiance
DL
Tube 1. Treated water discharged
(samples stored in lab)
Tube 2. Treated water kept in reactor
(samples taken from reactor)
Exposure Dark
Sequential batch reactor
NIBEC, University of Ulster [email protected]
Photocatalytic SODIS Bag
Polymer bags were made from FEP, PET, PVC and LDPE (500mL and 1500mL).
Photocatalytic polymer bags were prepared in LDPE. Bags used as static batch
system with E. coli K12 in distilled water (1x106 CFU/mL) as a model test organism.
NIBEC, University of Ulster [email protected]
SODIS bag faster than SODIS bottle
Photocatalytic SODIS Bag
NIBEC, University of Ulster [email protected]
Photocatalytic SODIS Bag
Photocatalysis again increases rate of disinfection
NIBEC, University of Ulster [email protected]
Dosimetric sensors ensure “lethal solar radiation dose” has
been received, confirming water is safe for consumption.
Time 0
before exposure
Time x
Following receipt of
“lethal dose”
“Quality control” indicators for SODIS
NIBEC, University of Ulster [email protected]
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 5 10 15 20
Time (min)
Ab
so
rba
nc
e a
t 6
60
nm
Single use and repeat use sensors for 30, 45, 60 and 80 Wh.m2
Incident UVA intensity = 30 Wm2
Time taken for colour change = 5 min
UV Dose = 2.5 Wh.m2
“Quality control” indicators for SODIS
NIBEC, University of Ulster [email protected]
Low cost (25p) Large surface area:volume ratio Easy to fill
Desirable? Quality control (peace of mind) built it
Enhanced “emergency” SODIS
NIBEC, University of Ulster [email protected]
Summary
SODIS is a simple, user friendly approach to reducing mortality
where access to safe drinking water supplies is lacking
Nanotechnology (photocatalysis and sensor technology) can
enhance the efficiency and provide some quality assurance
to the end user
Cost based analysis will be undertaken to determine which
technologies will be deployed for pilot testing in Africa
Just a thought … If we inactivate the microorganisms,
but they remain in the water, could SODIS treatment act
as an oral dose vaccine?
NIBEC, University of Ulster [email protected]
Acknowledgements
European Commission for funding under FP6 INCO-DEV
NIBEC, University of Ulster [email protected]
Acknowledgements
European Commission for funding under FP6 INCO-DEV