KATHERINE WESTPHAL MPH CANDIDATE, 2008 The Effectiveness and Sustainability of a Low-cost Water Filter in Removing Pathogens during Long-term Household.

KATHERINE WESTPHALMPH CANDIDATE, 2008

The Effectiveness and Sustainability of a Low-cost Water Filter in Removing

Pathogens during Long-term Household Use

EARL WALL, M.S., KELLOGG SCHWAB, PHD., M.S.

Ceramic Water Filter (CWF)

Technology developed in Guatemala in 1981

Potters for Peace promotes CWF

Filters are produced by local organizations

Manufactured in 23 factories throughout 20 countries

Worldwide over 300,000 soldOrganizations promoting

CWF include Save the Children, UNICEF and Oxfam

CWF production

Made from locally available clay, screened combustible material (sawdust or rice husks) and water

Pressed into bucket shape with a hydraulic press

Fired for 8-12 hours in Mani Kiln

Filtration flow rate (1-2.5 Ltr/hr)

Painted with colloidal silver

Sold with plastic receptacle and spigot for $15 (small) and $20 (large)

Background

Research to date - Non-peer reviewed studies have found:

CWF removes between 98-100% bacteria effective in removing protozoa although the virus

removal is minimal

Concerns – Effectiveness of the filter to remove water-borne

pathogens Possible quality control issues within and between

manufacturing facilities

Research objectives

Quantify the effectiveness of the CWF to remove water-borne pathogens in the laboratory and in the field

Evaluate the long-term sustainability of the CWF

Determine if the CWF should be promoted by organizations as a POU water treatment system

Study design

3 Parts:

1.Laboratory – o tested bacteria, virus and

protozoa removal of 24 CWFs from Honduras

2.Field survey - o a cross-sectional survey of

households in Nicaragua that received a CWF

3.Field assessment –o in-situ tests of CWF

effectiveness to remove bacteria

Research findings

Laboratory (15 CWFs with silver) –

Field – 53% (23/43) of filters removed 100% of E. coli78% (34/43) of filters removed > 95% E. coli 9.3% (4/43) of households had more E. coli in filtered

water than pre-filtered water

C W F L aboratory US E PA

S tandardsB acteria 3.22 - 6.06 6.0Virus 0.27 - 1.85 4.0Protozoa 2.47 - 2.97 3.0

L og 10 R educ tion Values

Research findings

Cross-sectional survey (167 households) – 48.5% of households had stopped using filter daily Among households not using the CWF, the primary reasons

were : broken spigot ( 58.0%) broken ceramic filter (40.7%) broken receptacle (30.9%)

Even among households using the CWF, 31.4% had a broken spigot

Only 26.3% of households knew where to purchase CWF spare parts

86% of households reported that the CWF provided enough water for their family to drink

All households surveyed liked the taste of the filtered water The majority of households reported that they liked the CWF

because it cleaned the water and kept their family healthy

Sustainability

Social/Cultural People like the taste of the filtered water and appearance of the

filter Households consider the CWF beneficial enough to pay for it

Economic Provides employment for local potters A one-time cost if unit does not break

Technical Effectiveness –

Significantly reduces bacteria and protozoa in water Does not effectively remove viruses and there is no residual protection

Durability – The ceramic filter, spigot and receptacle are fragile and break easily Spare parts are not readily available

Environmental Uses locally available materials and fuel efficient kilns for firing

filters

Conclusions

Laboratory - CWF improves the quality of water but it does not

consistently remove water-borne pathogens to meet USEPA standards

Field - In general, the CWF improves household water quality Without modifications to the spigot and receptacle,

long-term sustainability will not be achieved

Overall - Necessary to consider the social, economic and

environmental constraints of a country before defining water quality standards

Recommendations

CWF - Adaptations to the spigot and/or receptacle of the CWF Increase availability of CWF replacement parts

Research - Compare effectiveness of filters across production sites Longitudinal study of diarrheal prevalence comparing

households with a CWF to those without

Quality assurance - Establish QA protocols for CWF production Develop a certification process for locally-produced

CWFs

Acknowledgements

The Johns Hopkins Center for a Livable Future

Ron Rivera, Potters for Peace

Save the Children Canada, Nicaragua

Earl Wall, Kellogg Schwab, Kristen Gibson, Stephanie Guo, Casey Branchini and Jimmy Schissler

Joan Kub and Sara Groves