Transcript Document

Nepali Water Solutions Inc.
Point-of-Use Water
Treatment in Nepal
Advisors:
Susan Murcott, Harry Hemond
Group members:
Heather Lukacs
Luca Morganti
Chian Siong Low
Barika Poole
Hannah Sullivan
Jeff Hwang
Xuan Gao
Tommy Ngai
Presentation Outline
1. Project Background
2. Project Goals
3. Arsenic Removal
4. Filtration
5. Chlorine Disinfection
6. Tubewell Maintenance
7. Conclusion
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Project Background
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Project Background
Population
Average annual income:
Pop. below poverty line:
Access to safe water:
24 million (88% rural)
$ 210
42%
90% urban, 30% rural
Infant mortality:
Diarrheal illnesses:
Life expectancy:
75/1000 birth (5/1000 in US)
44000 child death/year
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Project Goals
Main objective:
To investigate appropriate technology to provide safe
drinking water for rural Nepal population
Criteria:
1. Technical performance
2. Social/cultural acceptability
3. Economic viable/sustainability
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Arsenic Remediation
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Introduction
• Arsenic contaminated groundwater discovered in
Terai region.
• 4% of 5000 tubewells tested have arsenic contents
greater than 50 ppb (18% have greater than 10 ppb).
• Arsenic causes
hyperpigmentation,
skin and liver cancer,
and circulatory disorder.
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Goals
• Evaluate & Test three different household arsenic
removal technologies
• Develop a comprehensive map to identify the
extent of arsenic contamination within Nepal.
• Water quality analysis to determine factors that
affect arsenic presence and removal.
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Evaluation Criteria
• Effectiveness of unit to reduce arsenic concentration below
10 ppb (WHO Standard)
• Appropriateness/Social Acceptability
- Can it be made with local material by local labor?
- Is it easy to operate and maintain?
- Can it meet the water demand (40-50 liters per day per
household)?
• Cost
- Is it affordable to average Nepali household?
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Arsenic Removal with
Activated Alumina (AA)
• Promising household unit using AA developed by
Bangladesh University of Engineering and
Technology (BUET)
• Adsorption by AA efficiently removes Arsenic (up
to 98 % removal achieved)
• Current cost per unit is $26 ($15 per unit possible
with mass production)
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Prototype Design
• Features:
- Oxidation-sedimentation
unit
- Sand filtration unit
- AA adsorption column
• Problems with the Current
Design:
- Flimsy frame
- Too tall
- Inadequate flow rate
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Arsenic Removal with
Iron Coated Sand
• Iron oxide adsorbs arsenic from water
• Iron coated sand is more porous and has a higher
specific surface area than scrap iron
• Can be regenerated and reused at least 50 times
with out loss in treatment efficiency.
• Has been effective in Bangladesh
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System Design
• Sand preparation:
- Fe(NO3)3 is dissolved
- NaOH is added, and iron
oxide is formed
- Sand is added to the
colloid solution, mixed
and baked for 15 hours
• Cost ~ US$ 8
• Flow rate 6 L/h
• 94-99% removal
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Pepperell, MA
• Well water analysis for arsenic contamination conducted
20 years ago
• Sample collection and analysis on Industrial Test System
Arsenic Test Kits
• Arsenic still present in Pepperell, MA well water
• Confirmation on Graphite Furnace Atomic Absorption
Spectrometer
• EPA has lowered the arsenic MCL to 10 ppb, and many
households are over the new limit
• We will test our technologies in Pepperell prior to field
tests in Nepal
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How to improve removal?
• Both AA and Iron coated sand work best with
As(V) instead of As(III)
• Arsenic speciation in Nepal varies
• Oxidation of Arsenic can improve removal
efficiency
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BP/I3 resin
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Benzyl Pyridinium Triiodine
Developed by Aquatic Treatment Systems
100% oxidation in 1 second
On-demand oxidant
Very stable, no by-products
Some ability to disinfect
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Arsenic map of Nepal
• Based on well info from ENPHO and Nepal Red
Cross Society
• Develop a map to show the extent arsenic
contamination
• Integrate
information
into GIS format
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To develop arsenic map
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Attend GIS class
Get relevant maps (scale, regions, details)
Get data from ENPHO/Red Cross
Obtain field data
Integrate all data into GIS format
Perform analysis on data
Print a big map
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Water Quality Parameters
• Want to investigate correlations between presence
of arsenic and other parameters
• Parameters of interest:
pH, hardness, alkalinity, turbidity, conductivity,
arsenic, iron, aluminum, sulfate, chloride, copper,
phosphate, nitrate
• Investigate the effects of these parameters on
arsenic removal efficiency by our technologies
• Can integrate these data on GIS
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Current Progress
• Accomplishments thus far
- Literature review
- Technology selection
- Contacts made
- Received some supplies and equipment
- Test kit analysis
- Arranged GFAAS analysis
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Next Steps
• Next steps:
- Obtain supplies (e.g. buckets, pipes)
- Build prototypes
- Preliminary lab tests
- GFAAS analysis
- Field tests in Pepperell
- BP/I3 Resin tests
- Water quality analysis
- Order digitized maps of Nepal
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Terafil Filter
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Terafil Terracotta Filter
• Mixture of red pottery clay,
river sand, wood sawdust
• Designed by Regional
Research Laboratory, India
• Field tested in cyclone
affected areas in Orissa,
India (Oct 1999)
• In-house test verification
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Scope of Work
In MIT,
• Carry out lab tests on Terafil Filter and Potters for
Peace Filter (PFP) (ongoing)
• Terafil and PFP Literature Review
• Compare effectiveness of Terafil and PFP Filter
• Research into ceramic manufacturing process and
local practices
MIT
Massachusetts Institute of Technology
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Scope of Work
Nepal
In Nepal,
• Carry out field tests on Terafil and/or PFP Filter
• Get involved with local filter manufacture
MIT
Back in MIT,
Massachusetts Institute of Technology
• Wrap up test results into thesis
• Possible research into other suitable filters for use
in developing countries
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Work in Progress
• Lab familiarization completed with preliminary
testing of Terafil filter
• Devise comprehensive lab tests on filter with
specific goals
• Lab tests on PFP and improvised Terafil filter
– Pre- and Post-Chlorination (Terafil only)
– Colloidal silver coating (both)
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Laboratory Testing
• Physical parameter
– Flowrate, turbidity, temperature
• Chemical parameter
– pH
• Microbial parameters
– H2S bacteria, Total Coliform/E.Coli (P/A tests)
– Total Bacteria (Microscopic Direct Counts)
– Total Coliform (Coliform Counts)
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Presence/Absence test
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Membrane Filtration
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Biosand Filter
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Biosand Filter Features
• Slow sand filtration
• Relatively fast flow rate
• Made of local materials
• Intermittent use
• No chemical additives
• Biofilm (Schmutzdecke)
• Easy to clean
• Economically sustainable
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Biosand Filter Performance
• Laboratory Studies
– Parasite removal – 100%
– Virus removal – 99.9%
– Bacteria removal – 99.5% (Lee 2001)
• Field Studies
– Bacteria removal 60-99.9%
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Biosand Project Goals
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Expand 2001 MIT Biosand work
Slow sand literature review and applicability
Global Biosand usage
Methodology development
– Maintain constant concentration input
• Laboratory study of bacterial removal
– After cleaning
– Following pause time
• Field study in Nepal
– Quantification of fecal coliform removal
(membrane filtration)
– Turbidity, pH, Temperature
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Chlorine Disinfection
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Chlorine Disinfection
Investigated Fields
1. Household Chlorination (Hannah Sullivan)
2. Chlorine Generation (Luca Morganti)
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Safe Water System (CDC)
• Point-of-Use Treatment using locally produced and
distributed sodium hypochlorite solution.
• Safe Water Storage in plastic containers with narrow
mouths, secure lids and dispensing spigots to prevent
recontamination.
• Behavior Change Techniques to influence hygiene
behaviors and increase awareness about the dangers of
contaminated water and waterborne disease.
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Promising Results
• Implemented World-wide
– Kenya, Uganda, Zambia, Guatemala, Bolivia,
Ecuador, Peru, Pakistan
• Reduces levels of bacterial contamination
• Low Cost
– Annual cost of $1.17 - $1.62 per household
Reduces incidence of waterborne disease
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Lumbini Pilot Study
Pilot Study of Household Chlorination
March 2001
• Modeled after CDC’s Safe Water Systems
• Experimental Group: 50 Families & 10 Schools
• Control Group: 50 Families & 10 Schools
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M.Eng Project
1.
2.
3.
Review of CDC’s Safe Water System Program
- History, Types of Programs, Costs, Sustainability
Evaluation of Lumbini Pilot Project
- Point-of-Use Testing
- Chlorine Residual,
- Bacterial Analysis (H2S and MF)
- Health Survey
- Social Acceptability Survey
Recommendations for Lumbini and Nepal
- Is the Safe Water Systems Approach Appropriate?
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The Problem
Chlorine is not readily available for disinfection
Chlorine disinfectant (Piyush) is produced from
imported bleaching powder (calcium chloride)
– Dependence
– Limited availability
– Export of money
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The Solution
PRODUCE CHLORINE LOCALLY
• Self-sufficiency
• Easier supply
• Generation of income for local people
HOW ?
Chlorine Generator (CG)
(Nadine Van Zyl, M.Eng.2001)
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Chlorine Generator Specs-1
• Electrolytic cell:
• Batch system:
NaCl +H2O -> NaClO + H2
easy regulation
6.0 Lb
2.7 kg
Salt consumption
per 24 h. cycle
30.0 Lb
13.6 kg
Water consumption
per 24 h. cycle
120 Gal
455 L
2.5 kW/Lb
5.5 kW/kg
Amount/day
equivalent Cl2
Specific energy
consumption
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Chlorine Generator Specs-2
Diameter
17.8 cm
Length
102.6 cm
Weight
4.1 kg
Cost
US$ 2000
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Purpose of the study
• Identify performance influencing factors (water
and salt quality)
• Define CG set-up procedure
• Learn CG use and maintenance procedures
• Test CG performance (concentration)
• Train local personnel
• Outline a micro-enterprise program
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CG Sustainability
• Economically:
– Cost of materials, energy, labor
– Reasonable price
• Environmentally:
– Energy source (solar energy)
• Socially:
– Actractive business?
– Reliable business ?
– Expanding market ?
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Tubewell Maintenance Program
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Tubewell
• Ground water is the main
source in the most of the Terai
areas
• Ground water hand pump
device
• 5 to 10 households share 1
tube well
• Tubewell water is better than
dugwell water or surface
water
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Problem with Tubewells
Past study has shown that over 70% of the tube
well water in Lumbini is contaminated by
bacteria.
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Possible Causes of the Problem
• Poor Sanitary Conditions
– Sludge drilling which uses a slurry of cow dung
– Inadequate sealing or protection of the well
– Improper drainage that causes accumulation of
wastewater in the pit nearby
– Flooding during monsoon
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Tubewell Maintenance Program
• Determination of the sources of tubewell
contamination
• Development of a plan to eliminate the
contamination and maintain the wells properly
• A study of the suitability for shock chlorination of
wells
– One-time introduction of a strong chlorine solution into
a well.
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Progress and Future Work
• Progress
– Laboratory Testing at MIT
– Contact with FINNIDA
– Literature Review
• Future work
– More literature review
– Pilot study in Butwal, Nepal
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Conclusion
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Conclusion
• Project Goals
– Technologically sound, socially acceptable, and
economically sustainable solutions
– Improved health through safe drinking water supply to
Nepali people
• Future work
– Literature Review
– Laboratory studies at MIT
– Field studies in Nepal
• Nepal in Jan, 2002!
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