Field trials of the effectiveness of ceramic water filters in Cambodia over time showed a 46% reduction in diarrheal disease between filter users and non-users, a 95.1% average (and up to 99.99%) reduction of E.coli in drinking water (Brown and Sobsey, 2006). Laboratory testing has shown a 90-99% reduction in viruses (Brown, 2007). These results support other trials of ceramic water filters (Lantagne, 2001) as a highly successful means of empowering households to manage their own safe water supply.

The actions of the RDIC Ceramic Water Filters are:

1. Physical ‘straining’ of dirt and bacteria out of the water as they are too large to pass through the ceramic substrate.
   1. clay that has been vitrified through firing in a kiln changes chemically to become a slightly porous material allowing water to pass through its but straining out most bacteria, protozoa, and helminthes.
   2. burn-out material is added to produce pores that increase the rate of flow through the pots to make them a practical filtration material
2. Chemical action of silver as a biocide to kill microbes.
   1. silver applied to inside and outside of filter is absorbed into the clay pores.  Silver ions are reduced to elemental silver and form colloids within the filter body.  Silver acts as a biocide against bacteria when there is sufficient contact time.
3. Indirect sedimentation of particles within the pores of the filter.

RDIC now adds laterite to its clay mix.  Laterite, a material high in Fe oxides, the positive charges of the Fe oxides have demonstrated a removal action of the largely negatively charged virus’ in tests at RDIC.

The Handbook steps through the production process used by RDIC in Kean Svay, Cambodia.  This process can be described in 10 steps as summarized below.

The Handbook discusses relevant considerations to take into account when setting up a ceramic water filter factory including:

1. Are ceramic water filters right for you?  Ceramic water filters are suitable for treating the most common risk to drinking water quality – contamination with biological pathogens – as well as for removing general macro contaminants such as dirt and plant matter. They are not suitable for treating water whose primary health risk is chemical – such as arsenic.  They suit households, workplaces, and classrooms, and their implementation should be supported by education and a sustainable source of information and replacement parts.
2. Where to set up the factory? Locating a factory near source of raw materials, energy and water needs, near your market’s population centres, on major routes to assist distribution is valuable.  Noise and fumes of production and its impacts on surrounding community should be considered.
3. Sourcing Inputs.  Sourcing key inputs including clay, burn-out material, kiln fuel, energy, water, and plastic receptacle manufacture are major aspects of setting up a ceramic water filter factory.  Many of these choices will vary based on your location, available materials, and the costs and options will vary significantly between countries (eg the price of electricity, appropriate burn-out material, fuel for kilns).
4. Machinery.  Lists the key machinery sed in RDIC’s manufacturing process, approximate cost etc.  Machinery, excluding the kilns, flow rate testing baths, and flow rate testing racks which are built onsite can be estimated at around $13,000 US in Cambodia at this time.
5. Factory Layout Briefly Common sense approaches to factory layout can maximize efficiency of production from day one by minimizing both horizontal and vertical distances for moving items around the factory, reducing double handling, and providing surfaces that allow trolleys and wagons to be used.
6. Staffing.  Staffing policies are important considerations during the set up phase.
7. Establishing your manufacturing process.  Both flow rates, and kiln firing regimes need to be established for individual factories.

RDIC employs a number of different methods to ensure filters become accessible to community members following manufacture including through:

1. schools;
2. direct sales through private distributors and RDIC; and
3. non-government organisations (NGOs).

Whichever method of distribution is employed, education of distributors and users is integral to the success and sustainability of ceramic water filter technology.
Key issues to consider in distribution strategies are:

1. ensure appropriate training and education material is provided to the distributor in the short and long term so that they are capable of explaining the operation and maintenance requirements, and answering questions about the filter;
2. the distributor needs access to educational and instructional material to provide to the  end user to ensure correct maintenance is conducted in the long term;
3. an ongoing connection between the distributor and the community is important – such a role would provide an ongoing access point for questions and replacement supplies.  Additionally, a long term presence of the filters in a community would continue to reinforce the value of filters and remind people about the opportunity to access replacement parts or a later opportunity to buy a filter.

Ceramic water filters are not a passive resource, they require ongoing management and maintenance by users. Therefore, like computer systems in any country, an ‘after sales support’ is essential for ongoing and appropriate use of ceramic water filters.

The Handbook incorporates technical drawings of key items of machinery and facilities used to assist as anyone considering setting up a ceramic water filter factory.  Including the kiln, clay mixer, hydraulic press, drying racks.

Drawings for the clay mixer and hydraulic press are currently under review and will be added to the site once finalised.