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Water Quality and Point of Use Treatment Study in Nepal
Team Members:Andrea Wolfe • Tricia Halsey • Andy Bittner
Kim Luu • Junko Sagara • Amer Khayyat • Benoit Maag
Advisor: Susan MurcottApril 14, 2000
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Geography
Background - Nepal
• Seventh poorest nation in the world (USAID)
• Dense and growing population in hill and Terai regions
• 70% of population do not have access to clean, safe drinking water (World Resources Institute)
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Purpose
• Water Quality:– Pinpoint some water quality problems
and add to the body of water quality data
• Point-of-Use:– Explore and design means of improving
drinking water quality on household level
Presentation Outline
• Water Quality Studies– Turbidity and Microbial– Arsenic– Nitrate and Ammonia
• Point of Use Treatment Studies– Coagulation and Settling– Filtration– Disinfection– Economics and Logistics
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Microbial Contamination of Drinking Water
Andrea Wolfe
Test Methods
• Turbidity:– 2100P Portable HACH Turbidimeter
• Indicator Bacteria:– HACH P/A test with MUG reagent– HACH MPN H2S
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Drinking Water Distribution System
Springs andStreams
Groundwater
Treatmentplants
Distributionsystem
Distributionpoints
Consumption
Kathmandu Valley
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Microbial contamination in the Kathmandu Valley water supply system – January 2000
0
10
20
30
40
50
60
70
80
90
100
well stream treatment plant treatment plant- out
distributionpoints
consumption
Perc
ent C
onta
min
ated
total coliform
E. coli
contaminant presence
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Normalized seasonal variation of total coliform in the Kathmandu Valley water distribution system.
0
0.05
0.1
0.15
0.2
0.25
0.3
January February March April May June July
J of Nepal Chem - 1988, normalized
ENPHO - 1995, normalized
N/A
Water borne diseases in a Kathmandu Hospital
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
Summer Autumn Winter Spring Summer Autumn
Num
ber o
f dise
ase
case
s
* ENPHO 1995
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Summary of Results
• Drinking water that is disinfected in the treatment plant becomes reinfected in the distribution system
• There is a lot of seasonal variation in distributed drinking water quality
• Seasonal variation in drinking water quality corresponds to fluctuations in waterborne disease
Conclusion and Recommendations
• Conclusion:– Much of Kathmandu Valley’s drinking water is
severely contaminated• Recommendations:
– Set drinking water standards– Define the roles and responsibilities of the
water supply agencies– Perform regular water quality monitoring
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Arsenic Contamination Study
Tricia Halsey
Why do we care about arsenic in Nepal?
• Toxic chemical• WHO MCL for As = 10ppb• Crisis in Bangladesh & India
– Installation of tube wells several years ago
– Unknown source generally believed to be nature
– Found in layer of alluvial deposits – Possibility that arsenic will be found
in Nepali drinking water
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Analytical Methods
• EM Quant Test Strips• Affiniti Concentration Kits• Graphite Furnace Atomic Absorption
Spectroscopy (GFAAS)– A portion of each sample preserved to 1%
acidification with concentrated nitric acid– Transported back to MIT for analysis in Ralph
M. Parsons Laboratory
59.09% 9.09% 18.18%
4.55% 4.55% 4.55%
79.52%
2.41% 6.02%
10.84%
1.20%
91.18% 8.82%
96.77%
3.23%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
% of Samples Analyzed
Parsa District
Bara District
Lumbini District
Kathmandu Valley
GFAAS Results
Non-Detect 0ppb-10ppb 10ppb-20ppb 20ppb-50ppb 50ppb-100ppb 100ppb-150ppb
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0
5
10
15
20
25
30
35
40
45
0-50 51-100 101-150 151-200 201-250 251-300 > 300
Well Depth (ft)
Num
ber o
f Sam
ples
Total SamplesSamples with Detectable Levels of As
Sample Frequency by Well Depth
35%
25%
8%
16%
33%
100% 0%
0
10
20
30
40
50
60
70
80
0-3 3-6 6-9 9-12 12-15 > 15
Well Age (yrs)
Num
ber o
f Sam
ples
All SamplesSamples with Detectable Levels of As
Sample Frequency by Well Age
15%
25%
33%
48%
0%
50%
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• No contamination found above the WHO limit in the Kathmandu Valley
• 18% of samples taken from the Terai had arsenic levels above the WHO limit (based on GFAAS)
• Samples with detectable levels of arsenic found in tube wells up to 300 feet deep
• 48% of samples taken from wells aged 9-12 years had detectable levels of arsenic
Summary of Results
• Small amount of arsenic contamination in areas of the Terai region that may be of natural origin
• Field kits provide a general indication of mass contamination, but more accurate methods should be used when detailed results are required
• Future study of the following is recommended:– testing of tube wells in other districts of the Terai– analysis of the geology of the region– possible anthropogenic sources
Conclusions/Recommendations
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Drinking Water Quality Assessment: Nitrate and
Ammonia
Andy Bittner
Nepal Nitrate and Ammonia Results
• General Results– 8.6% contaminated with NO3
- over WHO guideline of 10 mg/L -N
– 29% contaminated with NH3 over the WHO limit of 1.5 mg/L -N
– Average NO3- concentration = 2.37 mg/L -N
– Average NH3 concentration = 5.2 mg/L -N
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Nitrates vs. Depth
• Nitrates much more prevalent at shallow depths– 19% of wells shallower than 50 ft.
contaminated with NO3- above WHO limit
– No wells deeper than 100 feet contaminated with NO3
- above 1 mg/L -N• Nitrate contamination from surface
anthropogenic sources - septic systems and inadequate disposal of sewage wastes
Nitrate Concentration Vs. Well Depth
0
200
400
600
800
1000
0 10 20 30 40 50 60 70
NO3- Concentration (mg/L - N)
Dep
th o
f Wel
l (ft)
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Ammonia vs. Depth
• Ammonia concentrations are relatively low except in deep boring wells - 200-300 m deep– Deep boring wells contain average ammonia
concentration of 48 mg/L -N• Ammonia contamination is from geologic
causes - presence of deep lignite and peat beds in an anaerobic environment
Ammonia Concentration Vs. Well Depth
0
200
400
600
800
1000
0 10 20 30 40 50 60 70 80 90 100NH3 Concentration (mg/L - N)
Dep
th o
f Wel
l (ft
)
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Nitrate Concentrations in Rural vs. Urban Environments
• Nitrates much more common in urban areas than in rural areas– Avg. urban NO3
- concentration = 3.9 mg/L-N– Avg. rural NO3
- concentration = 1.2 mg/L-N• Due to prevalence of urban NPS pollutants
such as poorly designed septic systems and inadequate containment and treatment of sewage waste
• Possible seasonal fluctuations
Nitrate Concentrations in Urban vs. Rural Regions
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
0 20 40 60 80 100
120
Sample Number
NO 3
- Con
c. (m
g/L
- N)
Rural Nitrate ConcentrationsUrban Nitrate Concentrations
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Conclusions
• Nitrates common in shallow groundwater sources from anthropogenic NPS contaminants
• Ammonia common in deep groundwater sources from naturally occurring geologic sources
• Urban groundwater sources contain nitrates at much higher concentrations than rural sources
Coagulation and Settling for Applications in Nepal
Kim Luu
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Motivation
• Preliminary phase of drinking water treatment
Coagulation Filtration Disinfection
Goals• Find optimum dosage of coagulant• Applications
– Water Treatment Plants– Point of Use
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Experiments Performed
• Coagulants: FeCl3, US Alum, Nepal Alum• Automated Coagulation
– Analysis of jartest data– Conclusions of optimum dosage
• Manual Coagulation– Feasibility
Jartest Experiments
• Rapid Mix– 30 seconds under 100 rpm
• Slow Mix– 10 minutes under 30 rpm
• Settling – 30 minutes under 0 rpm
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Analysis of Jartest Data
• Percent Removal of Turbidity – using “raw” water as control– using “zero” water as control
• Final Turbidity after Settling• Settling Tests
Turbidity Removal Efficiency vs. DosageUsing "Raw" Samples as Control
0%10%20%30%40%50%60%70%80%90%
100%
0 10 20 30 40 50 60 70 80
Dosage (mg/l)
Turb
idity
Rem
oval
Alum - BansbariAlum - MahankalAlum - GACFeCl3
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Final Turbidity vs. Dosage
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70 80
Dosage (mg/l)
Fina
l Tur
bidi
ty (n
tu)
Alum - BansbariAlum - MahankalAlum - GACFeCl3
Turbidity vs. Settling Velocity
0
2
4
6
8
10
12
0.00 0.50 1.00 1.50 2.00 2.50Settling Velocity (cm/min)
Turb
idity
(ntu
)
Blank25 mg/l30 mg/l35 mg/l40 mg/l50 mg/l60 mg/l70 mg/l80 mg/l
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Turbidity vs. Settling VelocityCloseup View
0
0.5
1
1.5
2
2.5
3
0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45Settling Velocity (cm/min)
Turb
idity
(ntu
)
Blank25 mg/l30 mg/l35 mg/l40 mg/l50 mg/l60 mg/l70 mg/l80 mg/l
02468
1012
0.00 0.50 1.00 1.50
40 mg/l
80 mg/l
35 mg/l
Manual Coagulation
5 g 7.5 ml
500 ml
Applying 40 mg/l dose
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• 30 seconds under ~ 1.5 rotations per second• 10 minutes under .5 rotations per second• 30 minutes under 0 rotations per second
Water Treated through Manual Coagulation
Water Treated through Manual Coagulation
Settling Time
0 min
Raw Water Settling Time
30 minCoagulation
Regime
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Conclusions
• Optimum Dosage: 40 mg/l• Point of Use Applications
– incomplete color removal– turbidity removal much better in filters– disinfection requirement
• Filters cannot be discounted.
Filtration Study
Junko Sagara
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Indian Ceramic Candle Filter
Nepalese Ceramic Candle Filter
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Industry for the Poor (IPI) Purifier
Test Results• High turbidity removal efficiency
– Effluent turbidity<1.0 NTU (WHO - 5NTU)
0
2
4
6
8
10
12
14
Raw Water IPI Indian Nepalese
Filter Types
Turb
idity
(NTU
)
12.3
0.70 0.42 0.64
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Microbial Tests• HACH P/A Test
– Total Coliform and E.Coli
• HACH MPN Test – H2S Producing Bacteria– Similar Results Obtained
Filter Total Coliform E.ColiIPI Purifier (no Cl) + +
IPI Purifier (with Cl) - -Indian Filter + -
Nepalese Filter + +
Availability of Filters• Industry for the Poor Purifier
– Chlorine bleach not available in Nepal– Sediment and activated carbon filters expensive in
Nepal• Indian Ceramic Filter
– Widely used in Nepal among families with higher income
– Price too high for lower income families or people in the rural areas (US$10 to US$20)
• Nepalese Ceramic Filter– Very cheap (US$3)
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Recommendation and Conclusion• The Point-of-Use Filtration systems tested
achieved:– High turbidity removal efficiency– Inadequate removal of microbiological
contamination• Filter systems tested do not treat water to an
acceptable drinking water quality• Nepalese Ceramic Candle Filter with
Disinfection is recommended– Colloidal Silver Disinfection
Disinfection Study
Amer Khayyat
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Disinfection Study
• Three disinfection techniques studied and tested for possible Point of Use (POU) application– Chlorination– UV disinfection – Solar Disinfection
Selection Criteria
• Efficacy: Study local performance and compare with Laboratory and Literature Benchmarks
• Cost: Must be affordable to the lower income brackets; those less likely to have safe water
• Equipment: Focus what is locally produced/available• Regulatory: Compliance with national sanitation and
pollution policies• Socio-cultural: Acceptable to local traditions, customs and
cultural standards
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Chlorine Disinfection• IN THEORY
– Advantages: • inexpensive. • widely available • proven effectiveness
– Disadvantages• Trihalomethanes
(carcinogenic)• Requires supply of
chemicals and relatively accurate dosages
• Bad taste which may be unacceptable
• IN PRACTICE– Advantages:
• proven effectiveness in municipal applications.
– Disadvantages:• Is NOT locally
available in retail outlets; even municipal supplies intermittent
• High sensitivity to chlorine taste and smell
• Turbid/Organically contaminated sources heighten THM risk
Ultraviolet Disinfection
– Advantages: • None to speak of in the context of this study
– Disadvantages:• Available locally as a proprietary imported luxury
item• Electric grid highly limited
– 14 % of all households 9 % of all rural households(UNDP HDR 1998)
• Water turbid esp. in the Monsoon season
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• IN PRACTICE– Advantages
• Plastic and Glass bottles widely available
• Public appeal• At worst will not
decrease water quality– Disadvantages
• No data available on solar radiation
• Turbid water and low sun during monsoon
• No residual• Large possibility for
human error
• IN THEORY– Advantages
• Free, no equipment and powered by the sun
• Good efficacy in sunny regions
– Disadvantages• Dependent on climate,
temperature and water conditions
• hard to test for efficacy• still not fully studied
Solar Disinfection
Solar DisinfectionSolar Intensity (26/1/00)
0
100
200
300
400
500
600
700
800
11:30 12:30 13:30 14:30 15:30 16:30 17:30 Day1Avg
10:30 11:30 12:30 1:30 2:30 Day 2Avg
Time of Day
Sola
r Int
ensi
ty (W
/m^2
)
Day One Day Two
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Solar DisinfectionWater Temperature vs Time of Day
12
14
16
18
20
22
24
26
28
10:35 11:47 12:59 14:11 15:23 16:35
Time of Day
Wat
er T
empe
ratu
re (C
)
Transparent Glass Transparent Plastic Blue Tinted PlasticTransparent Glass (1/2 Black) Tranparent Plastic (1/2 Black) Blue Tinted Plastic (1/2 Black)
Solar Disinfection
P/A test
Before
Total Coliform Positive
E-Coli Positive
After Untinted
Plastic
Untinted
glass
Blue Plastic
Total Coliform Negative Negative 3 Positive
1 Negative
E-Coli Negative Negative Negative
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• Chlorine– Most reliable POU in terms of efficacy– Problems remain with dissemination and dosing– Potential health risks
• Solar disinfection – Very appealing; high potential– potentially more practical than Chlorination– Still unexplored; further testing required
• Ultraviolet disinfection – Not a viable option at the present moment
Recommendations and Conclusions
Economics and Logistics of Point-of-Use Filters
Benoit Maag
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Purpose : To find ...
• Who needs POU ?• Who can afford POU ?• What are the existing products ?• How to expand use ?
POU = Point-Of-Use Treatment
Who needs POU ?
• Mountain areas : No• Populated Rural Areas : Yes & No
– No centralized system – Contaminated Water– Sanitation first ?
• Urban areas Yes– Poor centralized system– Contaminated water– Many people boil and/or filter
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Who can afford POU ?
• Populated Rural Areas : 10 % pop. ?– Affluent families
• Urban areas < 30% ?– Estimates range from 30 % to 90 %– Affluent families
What are the products ?
• Standard design <-> Mature market• Indian-made ceramic candle metal filters
– 600 ~ 1200 Rs / filter (13 ~ 30 liter capacity)– 80 ~ 100 Rs / candle (1~4 candles per filter)
• Need to be cleaned and replaced regularly (every 2 months ?)• 40 ~ 200 Rs / month
– vs :• Average income : 1000 Rs / month (Nepal average)• Kerosene : 45 Rs/month (5 liters / day)• Chlorine : 20 Rs / month (5 liters / day)
USEquivalent
$ 2000per filter
$ 200 /mofor candles
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What are the products ?
• Problems :– Small capacity
• 5 liters / day / candle -> water for 2-3 people
– Clogs with turbid waters (rainy season)– No disinfection– Candles are easily breakable– Candle fixture leaks often– Expensive
How to expand use ?
• A better product is necessary– A reliable system at current prices would be well accepted– Price is far too high for most people
• Distribution ?– Accurate
• To expand use beyond the affluent– Sponsor ?– Who will be the ‘Social Carrier of Technology’ ?
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Social Carrier of Technology ?A difficult and controversial issue
• Market Limited
• Government, Foreign Aid, NGOs No– Work on large/medium scale projects
• Para-Government (Schools, Health posts...) No– Limited staff, money and few incentives
• Humanitarian, Religious, Political groups Limited– Usually high motivation but limited scale
Conclusions
• POU is needed• Mature market• Distribution is OK• Standard products are expensive and perform poorly
• A reliable product is needed• Expanding use to the majority is difficult
– Cost– Social carrier of Technology
