Identification of Montmorillonite (smectite)

Clay Minerals (1971) 9, I.
Institute of Geological Sciences, 64-78 Gray’s Itvt Road, London WCI
(Read at the Spring 1970 meeting of the Clay Minerals Group
and the Basic Science Section of the British Ceramic Society, at
CambrMge; Receh’,ed 27 June 1970).

Mineralogical and physicochemical characterization of Ngaye alluvial clays (Northern Cameroon) and assessment of its suitability in ceramic production

Soureiyatou Fadil-Djenaboua, Paul-Désiré Ndjigui a, Jean Aimé Mbey b,c,∗
a Department of Earth Sciences, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon b Department of Inorganic Chemistry, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon c Laboratoire Interdisciplinaire des Environnements Continentaux, Université de Lorraine, UMR 7360, 15 Avenue du Charmois, B.P. 40, F-54501
Vandoeuvre-lès-Nancy Cedex, France

Original Article:

Characterization and assessment of Saudi clays raw material at different area

Q. Mohsen a, A. El-maghraby a,b,*
a Materials and Corrosion Lab., Faculty of Science, Department of Chemistry, Taif University, Saudi Arabia
b Ceramic Department, National Research Center, Tahrir Str., Dokki, Cairo, Egypt
Received 7 April 2010; accepted 10 June 2010
Available online 17 June 2010

Original Article at:

Assessment of saudi clays by various methods

Pot Filter Arsenic Removal with Bone Char Attachment

Link to original article:

A Sustainable and Simple Solution in Resource-poor Settings

Stephen D. Passman – Saint Louis University
Tyler J. White, MPH – Saint Louis University
Roger D. Lewis, PHD, CIH – Saint Louis University

The results suggest that the designed test filter has a significant potential for removing arsenic concentrations to below both WHO and EPA drinking water standards. In addition, the clay pot filter alone demonstrated substantial reduction in the concentration of arsenic. Further research must be done to investigate longevity and practicality of the test filter, and to explore the extent to which reduction in arsenic concentration is attributable to the additional bone char layer versus the clay pot filter.
Our research team aims to continue investigating the new design to maximize removal of arsenic, other harmful metals, and bacteria. Further development will also include finding the optimal pore size and surface area for maximum arsenic adsorption to the bone char layer and the clay pot itself. Given the variance in manufacture methods of different communities producing the clay pot filters, identifying physical characteristics that result in optimal arsenic adsorption can help promote best practices for improving the effectiveness of the filters. Finally, connecting with NGOs working in resource-poor communities is critical to improving POU clay pot water filters for enhanced filtration and better health outcomes.

Point-of-Use Water Filtration for Arsenic:

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Kiln Building: The Mani Kiln

Ceramic Pot Water Filter Kiln Building Resources

Building the Mani Kiln

Kiln building: The Mani kiln is an improved design for a wood burning kiln with a capacity of 50 ceramic pot water filters. Designed and distributed by Manny Hernandez – Northern Illinois University.

Complete drawings are included in the following PDF

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Investigation of Ceramic Pot Filter Design Variables

Original link to document:

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Investigation of Ceramic Filter Design Variables

Molly Klarman

Background: Over four billion cases of diarrhea occur worldwide each year that result in about 2.2 million deaths. Household water treatment and safe storage (HWTS) methods, such as ceramic pot water filters, are one of four proven HWTS methods and have been shown to reduce diarrheal prevalence by an average of 45% among users in a randomized control field trial. Although ceramic filters have been proven effective for improving water quality, users and implementers often express concern over their inability to produce a sufficient quantity of water due to their slow flow rate of approximately 1-2 liters per hour (L/H). If flow rate could be increased by altering the current filter design, it would improve the ceramic pot filter’s viability as a scalable HWTS option.

Objective: The main objective of this study was to determine if the flow rate of ceramic pot filters could be increased without sacrificing filter effectiveness, in terms of bacterial removal, by examining the effect of altering specific design variables.

Methods: At the FilterPure ceramic manufacturing facility in the Dominican Republic, eight new filter designs were created by changing one of three design variables: 1) type of combustible material, 2) the ratio of combustible material to clay, or 3) the size of the screen used to sift combustible material. These eight new filter designs were produced in triplicate, along with six control filters. Local river water was passed through the filters daily, and they were tested once a week for five weeks for total coliforms (TC), turbidity, pH, conductivity, and flow rate. 

Results: The flow rate of all filter designs increased from the first to fifth week by an average of 44.1%. The filters made with alternative combustible materials (coffee husks and rice husks) had average flow rates of 9.9 and 5.0 L/H and average TC reductions of 96.1% and 97.6%. The control filters had an average flow rate of 0.95 L/H and average TC reduction of 99.8%. As the proportion of clay to combustible material decreased from 60% clay:40% sawdust to 40% clay:60%sawdust, the average flow rate increased from 0.38L/H to 5.9L/H and the percent reduction of TC decreased from >99.9% to 98.1%. Once initial flow rate increased above 1.7L/H, TC reductions fell below 99%.

Discussion:Minor alterations in filter design or raw materials can affect the performance of locally produced ceramic pot filters to thepoint where their ability to produce safe drinking water is compromised. The results of this research suggest that the maximum initial flow rate for a properly functioning FilterPure filter is 1.7 L/H. None of the alternative designs, that had faster flow rates had better TC reduction than the control filters. This indicates FilterPure should not produce filters with a clay to sawdust ratio lower than 53% clay to 47% sawdust and different combustible materials cannot be used interchangeably without first identifying optimal proportions.



The author of this thesis is:
NAME: Molly Klarman
Address: 32 Lovejoy RD
Andover, MA 01810
The advisor for this thesis is:
NAME: Christine Moe, PhD
Rollins School of Public Health
ADDRESS: 1518 Clifton Road
Atlanta, Georgia 30322
Other committee members for this thesis are:
NAME: Daniele Lantagne, PE
Centers for Disease Control and Prevention
ADDRESS: 1600 Clifton Rd.
Atlanta, GA 30333

Molly Klarman
BA Lewis and Clark College

A thesis submitted to the Department of Environmental and Occupational Health and the Hubert
Department of Global Health
Rollins School of Public Health
Emory University
in partial fulfillment of the requirements
for the degree of Master of Public Health
May, 2009


Open Source Receptacle Design – Vhembe


This open source receptacle design was the outcome of a Masters in Industrial Design, from the University of Johannesburgs Department of Industrial Design. The Vhembe Water filter receptacle was designed by Martin Bolton, who lectures at the University of Johannesburg.

This WIKI was created as an open-source showcase of Design Development, Design Sketches as well as all relevant Computer Generated Models which can be used for design refinement/ prototyping, tooling, mass production etc.

It is suggested that the MTech dissertation be read to allow for the understanding of how and why this product was developed. Furthermore, all field research, data gathering, data analysis and development of design requirements will be evident.

Design and Development of Ceramic Pot Water Filter Receptacle – Vhembe

Independent Appraisal of Ceramic Water Filtration Interventions in Cambodia: Final Report

Joe Brown and Mark Sobsey
University of North Carolina School of Public Health
Department of Environmental Sciences and Engineering
Submitted to UNICEF – Cambodia, 5 May 2006

This study is an independent follow-up assessment of two large-scale implementations
of the household-scale ceramic water filteration after 2 and 4 years in use.
Approximately 1000 household filters were introduced by Resources Development
International (RDI) in Kandal Province from December 2003 and 1000+ filters by
International Development Enterprises (IDE) in Kampong Chhnang and Pursat provinces
from July 2002. The American Red Cross, CIDA, AusAID, UNICEF, and the World Bank
Development Marketplace Programme have supplied support to these two NGOs for
various parts of the production and distribution cycle of the filters.

In October 2003, IDE completed a field study of the ceramic water filtration devices after one year in use,
yielding promising results. The study used bacterial analyses of water samples and user
surveys to measure the performance, acceptance and use of ceramic water filtration devices in 12 rural villages.
The field study also assessed health improvements, time savings, and expense savings.
In August 2005, RDI completed a similar internal study for the filter distribution in Kandal
province, although findings from this assessment have not yet been released. The
present study follows up on these previous assessments and represents an independent
appraisal of the performance of the ceramic water filtration projects undertaken by IDE and RDI. It is
hoped that the findings produced will aid in assessing the water quality and health
impacts of the ceramic water filtration interventions to date and yield useful information on the
sustainability of the filters as implemented.

The study was carried out in two parts:

(1), a cross-sectional study of households
that originally received filters to determine uptake and use rates and associated factors;

(2), a nested longitudinal prospective cohort study of 80 households using filters and
80 control households to determine the microbiological effectiveness and health impacts
of the filters in household use. We measured (i) the continued use of the filters over
time as the proportion of filters still in use since introduction, and identified factors
potentially associated with filter uptake and long term use; (ii), the microbiological
effectiveness in situ of the filters still being used, as determined by the log10 reduction
values of the indicator bacterium E. coli; and (iii), the health impacts of the filters as
determined by a prospective cohort study using data on diarrheal disease prevalence
proportions among filter users versus non-users. We also collected a variety of other
survey data intended to elucidate successes and challenges facing the long-term
sustainability of this intervention in Cambodia. Stratified analyses, logistic regression,
and log-risk regression with Poisson extension of generalized estimating equations
(GEE) were employed in analysis of cross-sectional and longitudinal data to determine
factors associated with long term filter use and effectiveness of filters currently in use.

Major findings are that (i), the rate of filter disuse was approximately 2% per
month after implementation, due largely to breakages; (ii), controlling for time since
implementation, continued filter use over time was most closely positively associated
with related water, sanitation, and hygiene practices in the home, cash investment in the
technology by the household, and use of surface water as a primary drinking water
source; (iii), the filters reduced E. coli/100ml counts by a mean 95.1% in treated versus
untreated household water, although demonstrated filter field performance in some
cases exceeded 99.99%; (iv), microbiological effectiveness of the filters was not
observed to be closely related to time in use; (v), the filters can be highly effective
against microbial indicator organisms but may be subject to recontamination, probably
during regular cleaning; and (vi), the filters were associated with an estimated 46%
reduction in diarrhea in filter users versus non users (RR: 0.54, 95% CI 0.41-0.71).

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Particle Size Distribution Analysis for Ceramic Pot Water filter production

Maria del Mar Duocastella and Kai Morrill

Potters Without Borders, Enderby, British Columbia, Canada – September 2012

Abstract: To develop a standard Particle Distribution Analysis testing protocol for use in Ceramic Pot Water Filter factories.

Introduction: Ceramic Pot Water filters are generally manufactured from sources of raw clay that vary in their consistency, some factories have begun using particle distribution analysis to qualify clay batches, as well as for blending multiple clay sources in order to maintain a more homogeneous clay body. In order to promote common testing methods between factories, we have begun herein to develop testing protocols that utilize widely available apparatus and materials. It is desirable to develop an effective test that is easily accessible to individuals with limited laboratory experience. This test must be able to be performed in extremely rudimentary conditions with limited resources while presenting reliably accurate results. We hope that by establishing stabilized testing standards specific to filter production the test data will be useful in comparing clay bodies between all participating filter factories. We find that difficulties in ensuring that identical lab equipment is used (cylinder dimensions) may make it difficult to accurately compare results across different factories. Several standards already exist for soil classification; particles can be classified into categories of Clay, Silt or Sand. These categories are demarcated recognizing that suspended particle size is in direct relationship to settling time. For our purposes, we established a baseline for classification by comparing other standards and examining the results of our tests.

Although it is useful for general comparisons to define the samples by the three categories (Sand, Silt, Clay), for the purposes of detailed clay sample comparison, it is better to collect data from various particle sizes, thus developing a curve of particle size distribution. For this reason we tested samples at 13 different time intervals: 30 seconds, 1 minute, 2 minutes, 5 minutes, 10 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, and 24 hours. Having this expanded range of sample data allows us to compare samples in greater detail. These times were also chosen in order to complete the test within an 8 hour work day. *Note 1: Samples in Appendix 2 (Raw Data) which fall outside the standard testing procedure (Those prepared 24 or 48 hours before testing) were excluded from the final averages as there was significant variation in their results. It would have been interesting to use the results gathered to compare particle distribution results to burnout mixture ratios used in the participating factories. This proprietary information did not receive specific approval prior to publication.

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Creative Commons License
Particle Distribution Analysis for Ceramic Pot Water Filter Production by Potters Without Borders is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Based on a work at

Best Practice Recommendations for Local Manufacturing of Ceramic Pot Filters for Household Water Treatment

The Ceramics Manufacturing Working Group
June 2011
First Edition

Recommended Citation: The Ceramics Manufacturing Working Group (2011). Best
Practice Recommendations for Local Manufacturing of Ceramic Pot Filters for Household Water
Treatment, Ed. 1. Atlanta, GA, USA: CDC.

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Comparison of Silver Impregnated and Conventional Spigots in Ceramic Water Filters Devices

Marlyn Mendoza*, Monica Krakue** and Vinka Oyanedel-Craver*

*Department of Civil and Environmental Engineering; **Department of Chemical Engineering


Ceramic filters water filtres (CWF) are a promising point-of-use water treatment technology in the developing world that can be made with local materials and labor.  Currently CWFs are manufactured by pressing and firing a mixture of clay and a combustible material such as flour, rice husks, or sawdust prior to treatment with AgNPs.  The filter is formed using a filter press, air-dried, and fired in a flat-top kiln, increasing the temperature gradually to about 900 ˚C during an 8-h period.  This forms the ceramic material and combusts the sawdust, flour, or rice husk in the filters, making it porous and permeable to water.  After firing, the filters are cooled and impregnated with a silver solution (either AgNPs or silver nitrate) by either painting with, or dipping in (Rayner, 2009).  After painting with the antibacterial solution the ceramic component is commonly placed in a five gallons bucket. The contaminated water is placed inside the ceramic component from where it percolated through the porous matrix of the ceramic removing pathogenic microorganism (Oyanedel-Craver, 2008; Bielefeldt et al., 2009). The clean water drip into the plastic bucket where is stored and can be accessed through the spigot located at the bottom of the plastic receptacle. The CWF are capable to remove between 3 to 4 log of the microbial load in the influent water, however is has been observed that re-growth can happen after several month of usage (Kallman et al., 2012). The spigot has been identified as a potential sources of re-contamination of the purified water (Cohen, 2011).

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Design of Water Filter for Third World Countries

Louis Chan
Marcus Chan
Jingwen Wang
A thesis submitted in partial fulfillment
of the requirements for the degree of
Date: March 26th, 2009
Supervisors: W. Cleghorn / J. Mills
Department of Mechanical and Industrial Engineering

The residents in third world countries battle against waterborne diseases every day. It is a luxury
to have access to safe drinking water. However, it is extremely difficult to invest on a water filter
with minimal annual income. A low cost water filter can serve as a subsidy such that every
family can take advantage of this luxury. In this thesis, literature reviews on existing water
filters have been completed and design of a dual level water filter with ceramic and activated
carbon is developed. Water flow rate tests are carried out to optimize water filter design.
Further, the filter effectiveness in diminishing various contaminates is analyzed by a licensed
sampling laboratory. A manufacturing line to produce the dual water filters is proposed and the
cost of manufacturing a unit is calculated to be $1.53 USD, which is an affordable price for
people in third world countries. With a low cost water filter available, residents in the third
world countries could enjoy having safe drinking water and improve quality of life.

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Evaluating the impact of production variables on on the effluent water quality of Ceramic Pot Filters

Evaluating the impact of production variables on on the effluent water quality of Ceramic Pot Filters

April 10, 2011

Kristen Jellison, Julie Napotnick, Natalie Smith, Kyle Doup (Lehigh University)

Justine Rayner, Jesse Schubert (PATH)

Vinka Oyandel-Craver (University of Rhode Island

Daniele Lantagne (CDC, Harvard University)

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Current Practices in Manufacturing of Ceramic Pot Filters for Water Treatment

Current Practices in Manufacturing of
Ceramic Pot Filters for Water Treatment
by Justine Rayner
A research project report submitted in partial fulfilment of the requirements for the award of the
degree of Master of Science of Loughborough University
August 2009
Advisor: Brian Skinner, BSc, MSc, CEng, MICE
Co-Advisor: Daniele Lantagne, PE
Water, Engineering and Development Centre
Department of Civil and Building Engineering

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Optimizing Performance of Ceramic Pot Filters in Northern Ghana and Modeling Flow through Paraboloid-Shaped Filters

Optimizing Performance of Ceramic Pot Filters in Northern Ghana and Modeling Flow through Paraboloid-Shaped Filters
Travis Reed Miller
B.S. Environmental Engineering
State University of New York at Buffalo
June 2010
©2010 Travis Reed Miller. All rights reserved.


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Quantification of the Lifetime of Ceramic Pot Filters

by L. A. Hubbel, (Department of Geological Engineering, Missouri University of Science and Technology, 1400 N. Bishop Ave., 124 McNutt Hall, Rolla, MO 65409 E-mail: and A. C. Elmore, (Department of Geological Engineering, Missouri University of Science and Technology, 1400 N. Bishop Ave., 124 McNutt Hall, Rolla, MO 65409 E-mail:

Document type: Conference Proceeding Paper
Part of: World Environmental and Water Resources Congress 2012: Crossing Boundaries
Abstract: Ceramic pot filters (CPFs) are effective, low-cost household water treatment devices. CPF lifetime is assumed by the manufacturer to be one year; however, there are no definitive studies which quantify CPF lifetime. The objective of this preliminary research was to quantify the lifetime of a CPF in terms of the amount of water that can be filtered before the flow rate becomes unusable. Constant head flow rate testing, porosity testing and water quality testing were performed in a laboratory using three CPFs to establish baselines for comparison with field tests using six CPFs manufactured in Antigua, Guatemala. Interviews with 17 CPF users were performed in Guatemala to obtain information on their water and CPF usage. The limited laboratory and field testing showed that flow rate values decreased with increasing cumulative volumes of treated water. The field test data was compared to the laboratory data to estimate the volume of water that would be filtered before the flow rate decreased to an unusable rate. This volume was found to be approximately 1,500 L, which corresponds to a six-month time for a family of six using World Health Organization estimates of daily water consumption. The water quality data collected in the field showed that turbidity decreased after filtering through the CPFs while conductivity and hardness both increased slightly. This increase in conductivity and hardness may be due to rainwater being used as the water source, which typically has low mineral content with very little dissolved solids and hardness to begin with. The number of families interviewed is too small of a data set to provide conclusive results. But the anecdotal data collected from the interview process suggests that the subject families did not believe that a single filter could provide enough drinking water for a family for one year. The large number of CPFs in use throughout the world means that the technology has the potential to have a significant impact on large number of people, and it is recommended that a formal study involving large numbers of filters be conducted to quantitatively estimate CPF lifetimes.

Investigation of the Critical Parameters in the Production of Ceramic Water Filters

Isabelle Gensburger

October 2011

The flow rate can be increased by:
1. increasing the porosity of the filter, by increasing the quantity of burn-out material in the clay mix; and
2. increasing the pore size, either by

changing the particle size distribution of the burnout material, or by

changing the maximum firing temperature.

The bacteria removal effectiveness is only compromised when increasing the pore size

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