feleke zewge - fluorosis mitigation in ethiopia
DESCRIPTION
University of Oklahoma College of Engineering - WaTER Center Speaker Serieshttp://www.ou.edu/coe/centers/water.htmlTRANSCRIPT
FLUOROSIS MITIGATION IN ETHIOPIAETHIOPIA
Feleke Zewge
Department of Chemistry,
Addis Ababa University
&
National Fluorosis Mitigation Project Office,g j ,
Ministry of Water Resources
The Challenge: High Fluoride in Groundwater
• Is serious water safety problem mainly in the
The Challenge: High Fluoride in Groundwater
• Is serious water safety problem, mainly in the Ethiopian Rift Valley Regions Ab t 10 14 illi l d t• About 10‐14 million people are exposed to fluoride‐contaminated groundwater
• Several wells failed to supply drinking water due to the presence of fluoridethe presence of fluoride
• This affects the efforts to achieve MDG• This affects the efforts to achieve MDG.
FLUOROSIS IN ETHIOPIA: DENTAL
FLUORORSIS IN ETHIOPIA: DENTAL
FLUOROSIS IN ETHIOPIA: SKELETAL
FLUOROSIS IN ETHIOPIA: SKELETAL
Issues that Need to be Addressed to Mitigate FluorosisFluorosis
Identify and exploit low fluoride drinking water sources in thefluoride endemic areas.fluoride endemic areas. Keeping record of the fluoride levels of ground water sources
Establishing regional and national fluoride databaseg g•Having clear distribution map up to village level
Setting fluoride standard for water deprived dry areas of theSetting fluoride standard for water deprived dry areas of thecountry.What should be the safe cut off level?1 5 mg/L 2 mg/L 3 mg/L 4 mg/L 5 mg/L ?1.5 mg/L, 2 mg/L, 3 mg/L, 4 mg/L, 5 mg/L ?What is the risk level in relation to the total daily fluorideintake?
Developing appropriate defluoridation technology for EthiopiaDeveloping appropriate defluoridation technology for EthiopiaIntegrating the fluoride problem with other water supply and
sanitation issues
Our ProjectsOur Projects
1 Fluoride Distribution Mapping1. Fluoride Distribution Mapping
2 Quantitative Chemical Risk Assessment2. Quantitative Chemical Risk Assessment
3 Alt ti W t S l3. Alternative Water Supply
l d ld4. Development, Optimization and Field Implementation of Defluoridation Technologies
The Ethiopian Rift
Total area of 1127000 km²
Average width of about 100 km Divides the whole country from the northeast to the southwest
Area of RV about 33000 km²
Fluoride Distribution Mapping Population at risk•14.6 % of the total
/l d kUp to 33 mg/l in drinking water
Source: RiPPLE
•Population exposed is increasing
•Prevalence of Fluorosis is increasing
Purpose of Fluoride Distribution Mapping
• To assess the extent of fluoride contamination and
p pp gProject
To assess the extent of fluoride contamination andproduce GIS maps at smallest administrative level
• To generate fluoride database at national level
• To prioritize actions and to locate the existence of lowfluoride groundwater within reasonable distance
• To know the actual number of exposed population
F Distribution: Main Rift Valley
F Distribution: East Showa Zone
Population at Risk
I
Quantitative Chemical Risk Assessment Project: To Introduce Integrated Fluorosis Mitigation Program
Fluoride in water
Fluoride in food
Identification of skeletal fluorosis
Nutritional statusQCRA
IDENTIFI Hazard identification
Overall fluoride intake
Identification of dental fluorosis
QCRACATION
High fluorosis riskDAILY >100/1000 Persons
Low fluorosis riskDAILY < 10/1000 Persons
Moderate fluorosis riskDAILY 10 ‐100/1000 Persons
M k hORWater management
Defluoridation of
Nutritional supplementDefluoridation of drinking water
Water management
MITIGATI
Risk characterization
Defluoridation of drinking water
Nutritional supplementDilutiontechnique
Rain water harvesting
ON
Risk management
Nutritional supplement
Risk management
The major activities under QCRAThe major activities under QCRA
• Identification of fluorosis hazard (fluorosis indicated malnutrition and analysis of food and water sample) and fluorosis hazard assessment;
• Fluoride exposure assessment (to estimate the total quantity of fluoride consumed by the community);
• Fluoride dose‐response assessment (clinical assessment);
Fl id i k h t i ti (b d l t d• Fluoride risk characterization (based on prevalence study and DALY (Disability Adjusted Life Years) calculation);
Purpose of QCRA Project
• To assess the health impacts due to excessive fluoride intake
Purpose of QCRA Project
pin relation with nutritional aspects and daily waterconsumption and finally establishing tolerable levels of risk tohuman healthhuman health
• To estimate disease burden due to dental and skeletalfluorosis in the fluorosis affected communities
• To prioritize communities that need immediate intervention
FLUORIDE INTAKE THROUGH FOOD AND( )BEVERAGES (Exposure)
40
y)
20
30 CF
MS
GW
/per
son/
day
MS
GW
0
10F (m
g/
CFfood
beveragestotal uptake
Fluoride intakeFluoride intake
CF: 1 mg/L, MS: 3 mg/L, GW: 11 mg/L
Prevalence of Dental Fluorosis (Based on Dean`s Index))
35 00%
36.00%
37.00%
Affected population by sex in Village 1
60 00%
Affected population by sex in Village 2
31.00%
32.00%
33.00%
34.00%
35.00% 52.40%
34%
20 00%
30.00%
40.00%
50.00%
60.00%
29.00%
30.00%
Male Female
Affected population by sex in Village
0.00%
10.00%
20.00%
Male Female
50%
40%
50%
60%
3
38.80%39.00%40.00%
Affected population by sex in Village 4
20.40%
0%
10%
20%
30%
33.80%
33.00%34.00%35.00%36.00%37.00%38.00%
0%
Male Female 31.00%32.00%
Male Female
Affected Population by Age in Village 1 Affected Population by Age in Village 2
Prevalence of Dental FluorosisAffected Population by Age in Village 1 Affected Population by Age in Village 2
26.50%
40.90% <18 years
37.30%
33.10% < 18 years
>18 years
>18 years
Affected Population in Village 3 Affected Population in Village 4Affected Population in Village 3 Affected Population in Village 4
29.60%
58.60%
>18 years
<18 years
51.60%
21.50%
< 18 years
> 18 years
Prevalence of Skeletal Fluorosis (Based on Physical Exercise) )
8%
8%
5.80%
Village 1 Village 2
2%
4%
6%
8 00%
8.50%
9.00%
9.50%
9 20%0%
Male Female
6.50%
7.00%
7.50%
8.00% 9.20%
7.70%
Male Female
6.00%5.60%
Village 3Male Female
Village 4
0 00%
2.00%
4.00%1.20%
Village 4No skeletal fluorosis was observed
0.00%
Male Female
PROJECT ON ALTERNATIVE WATER SUPPLY
• Low fluoride groundwater from distance villages based on distribution mappingbased on distribution mapping
• Rain water harvesting if there is sufficient rainfallg
• Provision of surface water if available (appropriate level of water treatment will be required)
PROJECT ON ALTERNATIVE WATER SUPPLYPotential of Rainwater Harvesting
250
200
150
50
100
0
50
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Nazreth Ziway Methara
Development, Optimization and Field Implementation of Defluoridation
Eawag & CDN
pTechnologies
Eawag & AAU
CDN
Catholic Diocese of NakuruD fl id ti i 1998
HEKSOSHO
Defluoridation programme since 1998
Oromo Self‐Help OrganizationSwiss Interchurch Aid
Defluoridation Materials
Aluminium oxide based methods1⇒ Sorption to surface site
1
≡ Al — OH + F‐ ≡ Al F + OH‐
Bone char and Calcium phosphate‐based methods⇒ Incorporation into mineral phase
2≡ Al OH + F ≡ Al F + OH
Ca5(PO4)3OH + F- Ca5(PO4)3F + OH-
⇒ Incorporation into mineral phase
5 3 5 3hydroxyapatite fluorapatite
Bone Char and Contact Precipitation Technology
Contact Precipitation Ca and PO4 is added to the filterContact Precipitation Ca and PO4 is added to the filter
11
Bone Char and Contact Precipitation Technology
Fluoride Removal Capacity
Bone Char
C t t P i it tiContact Precipitation
Capacity increase from ≈ 0.7 to 3 – 4 mg F/g
12
Bone Char and Contact Precipitation Technology
Uptake Mechanism?By adding pellets that release calcium and phosphate the uptake of fluoride can be increased.
HAP coatingF
PO4 BC
FCaF2?Influence:
BC: pellet ratioCa
ptemperature
Bone Char and Contact Precipitation TechnologyFrom lab scale tests to household units and to small
community plant
Aluminum Oxyhydroxide Technology
Characterization of AOCharacterization of AO
• Density: 2.41 (g/cm3) y (g/c 3)• XRD: Mixture of amorphous/crystalline
• BET Surface Area 37 7 m2/g• BET Surface Area: 37.7 m2/g
• SEM Analysis: • It shows that the material contains Na2SO4 having particle size ranging from 5‐10 µm and also aluminium oxide ranging from 200‐300 nm.oxide ranging from 200 300 nm.
Decrease in Surface Area as Preparation Temperature IncreasesTemperature Increases
S/N Sample name Specific surface area(m2/g)
1 Sample 1 (AO 100 oC) 38.9
2 Sample 2 (AO 200 oC) 38.2
3 Sample 3 (AO 300 oC) 37.7
4 Sample 4 (AO 400 oC) 27.1
5 Sample 5 (AO 500 oC) 12.9
Capacity of F removal = 23.7 mg F/g AO
6 Sample 6 (AO 600 oC) 12.7
7 Reference material Aluminiumoxide, TYPE150
79.9Aluminiumoxide, TYPE150
The high removal capacity compared to that of AA is an advantage, but needs further investigation
Batch Adsorption Studies/Isotherms
Continuous Adsorption Studies
1
1.2525 cm 20 cm15 cm 10 cm
0 .2 2 5
0 .3
o
2 5 cm 2 0 cm1 5 cm 1 0 cm
0.25
0.5
0.75
Ct/C
o
0
0 .0 7 5
0 .1 5Ct/C
o
00 10 20 30 40 50 60
Time (h)
00 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5
T im e (h )
0.375
0.45
0.525
0.6
12 ml/min 23 mL/min40 mL/min
0.450
0.525
0.600
10 mg L-1
20 mg L-1
0.075
0.15
0.225
0.3
Ct/C
o
0.075
0.150
0.225
0.300
0.375
C t
/ C o
recommended level for 10mg L-1
Recommended level for 20 mg L-1
00 10 20 30 40 50 60 70
Time (h)
0 10 20 30 40 50 600.000
Time (h)
Release of Aluminum Ion from AO Column
141516
1011121314 pH (F-
0 mg/L)
Al (F-0 mg/L)
F- pH (F-
20 mg/L)
56789
Con
c. (m
g/L)
20 mg/L
Al (F-20 mg/L)
12345C
Recomended level for F
0 100 200 300 400 500 600 700 800 900 1000 11001200 1300
01
BV (cm3)
Fig. Fluoride removal curves for deionized raw water with influent fluoride concentration of 0 and 20mg/L (flow rate 100 BV/day).
Release of Aluminum Ion from AO Column
12131415
pH without clacite Al without calcitepH with calcite
789
1011
(mg/
L)pH with calcite Al with calcite F- with calcite
34567
Con
c.
0 50 100 150 200 250 300 350
012
( 3)
Recomended level for F-
BV (cm3)
Fluoride removal curve for synthetic raw waterwith and without calcite at post treatment (Co = 20with and without calcite at post treatment (Co 20mg/L, flow rate 10 BV/day).
Community Defluoridation Plant Based on AO
AOCalcite
l l d h
IMPLEMENTATION OF OTHER DEFLUORIDATION TECHNIQUE
Community Scale Nalgonda Technique
Improved Community Scale Nalgonda Techniquep y g q
INTERNATIONAL COLLABORATIONS
• Swiss Federal Institute of Aquatic Science and Technology (AEWAG), Switzerland
• Oklahoma University, WaTER Center, USA
• National Environmental Engineering Institute ( )(NEERI), India
C it b ildi i t ti f diff t t k h ldCapacity building, reorientation of different stakeholders, disseminating knowledge and information, documenting best practices, technology development
A k l dAcknowledgements
• Ministry of Water Resources of Ethiopia
• UNICEF Ethiopia
• Addis Ababa University
• DFID through the National Wash Coordination Program
• Swiss National Science Foundation (SNSF)• Swiss National Science Foundation (SNSF)
• International Foundation For Science (IFS)
• Swiss Federal Institute of Aquatic Science and Technology (EAWAG)q gy ( )
• CRS Ethiopia, HEKS, OSHO
• Catholic Diocese of Nakuru (CDN)
• Water Center, School of Civil Engineering and Environmental Sciences,
University of Oklahoma