title: Modeling the sustainability of a ceramic water filter intervention.
abstract: Ceramic water filters (CWFs) are a point-of-use water treatment technology that has shown promise in preventing early childhood diarrhea (ECD) in resource-limited settings. Despite this promise, some researchers have questioned their ability to reduce ECD incidences over the long term since most effectiveness trials conducted to date are less than one year in duration limiting their ability to assess long-term sustainability factors. Most trials also suffer from lack of blinding making them potentially biased. This study uses an agent-based model (ABM) to explore factors related to the long-term sustainability of CWFs in preventing ECD and was based on a three year longitudinal field study. Factors such as filter user compliance, microbial removal effectiveness, filter cleaning and compliance declines were explored. Modeled results indicate that broadly defined human behaviors like compliance and declining microbial effectiveness due to improper maintenance are primary drivers of the outcome metrics of household drinking water quality and ECD rates. The model predicts that a ceramic filter intervention can reduce ECD incidence amongst under two year old children by 41.3%. However, after three years, the average filter is almost entirely ineffective at reducing ECD incidence due to declining filter microbial removal effectiveness resulting from improper maintenance. The model predicts very low ECD rates are possible if compliance rates are 80-90%, filter log reduction efficiency is 3 or greater and there are minimal long-term compliance declines. Cleaning filters at least once every 4 months makes it more likely to achieve very low ECD rates as does the availability of replacement filters for purchase. These results help to understand the heterogeneity seen in previous intervention-control trials and reemphasize the need for researchers to accurately measure confounding variables and ensure that field trials are at least 2-3 years in duration. In summary, the CWF can be a highly effective tool in the fight against ECD, but every effort should be made by implementing agencies to ensure consistent use and maintenance.
authors.affiliation: Department of Civil and Environmental Engineering, University of Virginia, Thornton Hall, P.O. Box 400742, Charlottesville, VA 22904, USA. Electronic address: jem3w@virginia.edu.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Mellor
authors.affiliation: Department of Civil and Environmental Engineering, University of Virginia, Thornton Hall, P.O. Box 400742, Charlottesville, VA 22904, USA.
authors.forename: Lydia
authors.initials: L
authors.lastname: Abebe
authors.affiliation: Department of Civil and Environmental Engineering, University of Virginia, Thornton Hall, P.O. Box 400742, Charlottesville, VA 22904, USA.
authors.forename: Beeta
authors.initials: B
authors.lastname: Ehdaie
authors.affiliation: The Center for Global Health, Carter-Harrison Research Building, MR-6, Room 2526, 345 Crispell Drive, P.O. Box 801379, University of Virginia Health System, Charlottesville, VA 22908-1379, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Dillingham
authors.affiliation: Department of Civil and Environmental Engineering, University of Virginia, Thornton Hall, P.O. Box 400742, Charlottesville, VA 22904, USA.
authors.forename: James
authors.initials: J
authors.lastname: Smith
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D002648:Child; D003967:Diarrhea / Q000453:epidemiology / Q000209:etiology; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D008962:Models, Theoretical; D018508:Water Purification / Q000295:instrumentation*; D060753:Water Quality
keywords: ABM; Africa; Agent-based modeling; Ceramic water filters; Complex systems; Developing country; Diarrhea; ECD; HWT; Household water treatment; POU; Point-of-use; WASH; Water quality