Safe Household Water Treatment and Storage using Ceramic Filtration

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• Safe Household Water Treatment and Storage
  usingCeramic Filtration

Thomas Clasen London School of Hygiene Tropical
Medicine and First Water, Ltd. Thomas.Clasen_at_lsht
m.ac.uk January 8, 2004
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Reduction in Diarrhoea from Improvements in Water
Quality
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Summary of Controlled Trials of all Household
Treatment Methods
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Summary of Mean Percentage Reduction in Diarrhoea
Morbidity by Treatment Method
Overall Median 42
Overall Mean 39
Esrey Median 16
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Household Water Treatment and Safe Storage

• There is now conclusive evidence that simple,
  acceptable, low-cost interventions at the
  household and community level are capable of
  dramatically improving the microbial quality of
  household stored water and reducing the risk of
  diarrhoeal disease and death.

Dr. J Bartram, Coordinator, Water, Sanitation and
Health Programme, World Health Organization
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Evolution of Porous Water Filters
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Basic Operation

• Clay and other materials are blended and shaped
  into vessels, disks or hollow cylindrical
  candles
• Specialized combustible material and firing
  methods can produce micron and submicron (0.2µ)
  pore sizes
• Ceramics are configured into gravity (drip),
  in-line or hand pump systems
• Microbes and other suspended solids mechanically
  reduced due to depth filtration and adsorbtion
• Ceramic may be impregnated or coated with silver
  or other bacteriostatic substance to enhance
  efficacy and prevent grow-through

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Advantages of ceramic filtration

• High efficacy in reducing microbial pathogens
• Low cost and long life
• Easy to use and maintain minimal instruction or
  need for behavioural change
• Configuration provides safe storage of treated
  water
• Visible improvement in water quality promotes
  routine use
• Operate consistently regardless of level of
  turbidity, pH, temperature
• No chemicals, mixing, batching or contact time
• Insert adsorption media in hollow candle to
  reduce heavy metals, pesticides, arsenic
• Sustainable and transferable technology leading
  to local production and commercialization
• Treated as household asset portable opportunity
  for cost recovery

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Potential Advantages for Emergency Applications

• Unlimited shelf life
• Suitable where conventional emergency supply may
  be problematic
• Flooding
• Widely-dispersed or urban populations
• Population unable or unwilling to move from
  household
• Suitable where physicals of water supply
  (turbidity, temperature, pH) are unpredictable
• Limited training (no dosing)
• High acceptability (no chemical odor or taste)
• High utilization (obvious aesthetic improvement
  reinforces use)
• Protects water from re-contamination during
  household storage
• Portable can be taken back to household for
  continued protection after emergency subsides
  (cf. Oxfam/ICRC buckets)

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Efficacy

• Measured by Log Reduction Value (LRV)
• LRV log10(untreated/treated)
• Independent test results of Katadyn (Grade A)
  candles
• Escherichia coli LRV gt 7.9
• Shigella dysenteriae LRV gt 6.9
• Vibrio cholera LRV gt 4.0
• Giardia lamblia (cysts) LRV gt 6.5
• Cryptosporidium parvum (cysts) LRV gt 3.0
• Entamoeba histolytica (cysts) LRV gt 5.9
• Independent test results of Stefani (Grade B)
  candles
• Escherichia coli LRV 4.0
• Vibrio cholera LRV 4.0
• Streptococus Faecalis LRV 4.0
• Further independent testing under way on viral
  reduction

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Cost and Quality
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Emergency Deployment
Oxfam palletized water filters (100 filters,
212kg, 120x100x150cms)
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Assembly, Use and Maintenance
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Assembly, Use and Maintenance
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Current Field Trials and Pilots
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CambodiaIDE Pilot

• 12-month pilot project with 1000 households using
  PFP design (clay painted with colloidal silver)
• 98-99...produced water lt10 FC/100ml (but only
  8 of untreated sources were gt100 FC/100ml)
• Estimated savings of US1.40/month from boiling
  (69), and US2.02 saving over purchasing
  drinking water (9)
• 10 L system refilled 2.2x/day regarded as
  sufficient by 99 of households
• 0.6 breakage/month, mostly during transport and
  cleaning

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Cambodia-Oxfam

• Takeo Province susceptible to seasonal flooding.
  Widespread use of surface and pond water.
• 238 paired samples from 96 households in 11
  villages over six months
• Over six month study period
• Mean faecal coliform count in untreated water
  1022 FC/100ml
• Proportion of samples of treated water with lt10
  FC/100ml 63 (151/238)
• Hong Phuc (Grade C) candles deteriorate faster
  than Katadyn (Grade A) candle
• Focus groups show high acceptability, ease of
  use, strong demand and willingness to pay
• Filtered water much appreciated due to improved
  appearance and palatability
• Spare candles provided by local NGO via village
  development committees

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Sierra Leone

• Victoria village, Kenema District, still
  recovering from ten year civil conflict water
  drawn from shallow wells in swamp
• One water filter issued to each household (N83)
  plus two for the school, one for the womens
  society and one for each of two mosques
• Data from randomly sampled households
• Mean faecal coliform count in untreated water
  3594 FC/100m
• Mean faecal coliform count in treated water
• May 03 9.0 FC/100 ml
• Sept 03 7.8 FC/100ml
• Oct 03 6.7 FC/100ml
• However, 15, 27 and 30 of households gt10
  FC/100 ml, apparently due to leaks and breakage
  of Hung Phuc candles/locknuts
• 10L system provides insufficient quantity for
  large households.

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Charinco, Bolivia

• Rural village using irrigation canals for
  drinking water (some rainwater harvesting during
  3 month rainy season)
• Randomized field trial with 25 households using
  Katadyn (Grade A) candles in locally-fabricated
  vessels, and 25 households continuing to use
  customary practices
• Baseline diarrheal prevalence 21.6
• Mean FC load of source water was 793 FC/100ml
  (range 10-3860) (GM212 FC/100ml)
• Medium and variable turbidity (range 5-100 NTU)

Clasen T, Brown J, Suntura O, Collin S,
Cairncross S (in preparation). Reducing diarrhoea
through the use of household-based ceramic water
filters a randomized, controlled field trial in
rural Bolivia.
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(No Transcript)
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Microbiological Efficacy
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Health Impact
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Chiñiri, Bolivia

• Rural community using combination of outdoor taps
  (80) and surface waters from irrigation canals
• Tap cost US1.26/month
• FHI hygiene and other programs underway 14
  sanitation coverage
• Four-month randomized, controlled field trial of
  60 households 20 with Stefani candles, 20 with
  Katadyn candles, 20 controls
• Baseline diarrhoea prevalence 25.4 in children
  lt5 11.0 overall
• Mean FC count of source water
• Taps 145/100ml (range 17-436)
• Surface 52/100ml (range 8-136)

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Water Quality
A.C. Dresser M. Diarrhoeal diseases in an
indigenous rural community of Bolivia contexts
of transmission and approaches to control. MSc
Dissertation, LSHTM (2003)
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Health Impact
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AcceptabilityData from Charinco, Bolivia, July
2003
J. Brown, Evaluation of point-of-use
microfiltration for drinking water treatment in
rural Bolivia, Cambridge University, M. Phil.
Dissertation, 2003
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Affordability/Willingness-to-Pay Data from
Charinco, Bolivia, July 2003
J. Brown, Evaluation of point-of-use
microfiltration for drinking water treatment in
rural Bolivia, Cambridge University, M. Phil.
Dissertation, 2003
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Cost Comparison

• Based on daily household usage of 25L.
• Assumptions
• 1. Katadyn system 8.75 per candle, plus 7.50
  for vessels and valves. 50,000L capacity per
  candle per manufacturer. Replace entire system
  after 3 years.
• 2. Stefani system 3.75 per candle, plus 7.50
  for vessels and valves. 5,000L capacity per
  candle per manufacturer. Replace candles each
  year. Replace vessels and valve after 3 years.
• 3. PUR Sachet Manufacturers suggested retail
  price of 0.10 per unit. Assumes no further
  expenditure for mixing and storing vessels.
• 4. CDS System 5.00 for special vessel, plus
  3.00 for chemical disinfectant (information per
  M. Sobsey, Managing Water in the Home
  Accelerating Health Gains from Improved Water
  Supply. Geneva World Health Organization).

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Potential for Sustainability

• Affordable
• Acceptable innovation (per E. Rogers)
• relative advantage over idea it supersedes
• compatible with perceived needs
• simple
• high trialability
• observable results
• Hardware (does not require hygiene or other
  behavioural change to achieve results)
• Potential for local production
• Compatible with micro-enterprise vendors
• Market as product or service

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Local Production

• Local production of traditional clay drip filters
  in Nicaragua by Potters for Peace
  (www.elfiltron.com)
• Local production of ceramic candles in Bangladesh
  and Nepal with assistance of MIT
  (www.purifier.com.np)
• Local production of PFP design by IDE in Cambodia
  (www.ide-international.org)

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Next steps

• Undertake larger-scale projects based on outcome
  of pilots
• Explore commercial viability and opportunities
  for cost recovery
• Explore options for commercializing filter
  systems
• Conventional distribution
• Multinational
• Regional and National
• Local
• Micro-enterprise (with support for initial
  capital)
• Investigate use of materials in core of candle
  for removal of arsenic, pesticides, herbicides,
  etc.
• Evaluate viral reduction without supplemental
  disinfectant (UNC Project)
• Evaluate use of ceramic filters as a component of
  emergency relief

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Acknowledgements

• Field Investigators J. Brown (UNC), A. Dresser
  M. (LSHTM)
• Statistical Analysis S. Collin (First Water),
  S. Cousens (LSHTM),
• Study Design J. Macy (formerly, CDC), L.
  Venczel (PAHO)
• Paper Review E. Mintz (CDC), S. Cairncross
  (LSHTM)
• Collaboration O. Suntura (Sumaj Huasi), L.
  Venczel (PAHO), P. Peterson (FHI)
• Funding First Water, Gates Cambridge Trust,
  Trinity Hall-Cambridge

Conflicts T. Clasen and S. Collin are funded
by First Water, Ltd., whose activities include
the promotion and sale of POU water treatment
devices for the emergency, aid and development
markets.