Ceramic Filters Description
Ceramic filters have
micro-scale pores that are effective for removing
bacteria from water. The filters are made from clay
that is often mixed with materials such as sawdust
or wheat flour to improve porosity. Colloidal
silver, an antibacterial agent, can also be added
to the filters. A low-cost colloidal
silver-enhanced ceramic water filter; the Filtron
There are two main types of ceramic filters, disk and candle, with multiple variations of each. A disk filter consists of a removable ceramic filter sandwiched between two containers. Candle filters consist of one or more candle-shaped ceramic filters and two chambers.
Filtron Development:
Potters for Peace
There are two main types of ceramic filters, disk and candle, with multiple variations of each. A disk filter consists of a removable ceramic filter sandwiched between two containers. Candle filters consist of one or more candle-shaped ceramic filters and two chambers.
Filtron Development:
Potters for Peace
Performance
Amount of Water Treated
Disk filters typically have a flow rate of 1 to 11 liters per hour and candle filters have a flow rate of 0.3 to 0.8 liters/hour. Under ideal filter conditions and 12 hours of continuous refilling, a filter with a flow rate of 1.7 liters per hour would provide less than 4 liters per day per person for a family of five.
Contaminant Removal
Disk and candle filters are generally effective for removing turbidity, iron, coliforms, fecal contaminants, and E. Coli from water. In studies, disk filters with colloidal silver have exhibited a 93 to 100 percent bacterial removal rate, and those without silver have shown an 80 percent removal rate. Candle filters with colloidal silver generally exhibit 100 percent bacterial removal, and those without silver average at 85 percent removal. Disk filters range from 83 to 99 percent turbidity removal. Ceramic filters are generally not effective for removing organic contaminants.
Ease of Use
Ceramic filters are easily assembled, and no component construction is required of the user other than placing the filter into the container. Scrubbing the filter with a toothbrush is required monthly as maintenance. Annual colloidal silver recoating is also recommended. Filters typically come with illustrated instructions. The fragility of ceramic filters can make their transport difficult.10 Field studies have also indicated that heavy subsidization or free distribution of filters may result in maintenance negligence. The production of ceramic filters is a lengthy process that requires skill and quality control. Quality can be affected by variations in clay composition across geographic regions. Variability in weather conditions also makes long-term production planning difficult, and lack of storage can complicate stockpiling of filters.
Disk filters typically have a flow rate of 1 to 11 liters per hour and candle filters have a flow rate of 0.3 to 0.8 liters/hour. Under ideal filter conditions and 12 hours of continuous refilling, a filter with a flow rate of 1.7 liters per hour would provide less than 4 liters per day per person for a family of five.
Contaminant Removal
Disk and candle filters are generally effective for removing turbidity, iron, coliforms, fecal contaminants, and E. Coli from water. In studies, disk filters with colloidal silver have exhibited a 93 to 100 percent bacterial removal rate, and those without silver have shown an 80 percent removal rate. Candle filters with colloidal silver generally exhibit 100 percent bacterial removal, and those without silver average at 85 percent removal. Disk filters range from 83 to 99 percent turbidity removal. Ceramic filters are generally not effective for removing organic contaminants.
Ease of Use
Ceramic filters are easily assembled, and no component construction is required of the user other than placing the filter into the container. Scrubbing the filter with a toothbrush is required monthly as maintenance. Annual colloidal silver recoating is also recommended. Filters typically come with illustrated instructions. The fragility of ceramic filters can make their transport difficult.10 Field studies have also indicated that heavy subsidization or free distribution of filters may result in maintenance negligence. The production of ceramic filters is a lengthy process that requires skill and quality control. Quality can be affected by variations in clay composition across geographic regions. Variability in weather conditions also makes long-term production planning difficult, and lack of storage can complicate stockpiling of filters.
Benefits & Drawbacks
Benefits
Ceramic filters are not able to achieve maximum effectiveness without silver colloid, which can not be produced locally in all regions.
- Simple
- Excellent microbial removal
- Can be constructed of local materials
- Income generation
- Fragile
- Low flow (1-2 litres / hr.)
- Requires frequent cleaning
Ceramic filters are not able to achieve maximum effectiveness without silver colloid, which can not be produced locally in all regions.
Costs
Disk filter units cost about $3.50 US, and
replacement filters range from $0.49 to $1.02 US.
Disk filters need to be replaced every 5 years.
Candle filter units cost about $2.29 US, with
replacement filters averaging about $0.46 US.
Candle filters need to be replaced every 6 to 12
months. Additional labor and maintenance costs are
minimal.
Projects
Resources
References
& Links
- Household ceramic water filter evaluation using three simple low-cost methods: membrane filtration, 3M Petrifilm and hydrogen sulfide bacteria in norther region, Ghana [http://hdl.handle.net/1721.1/34669]
- Development of a Ceramic Water Filter for Nepal [PDF]
- Resource Development International
- Engineering for Developing Countries
- Practica Foundation
Contact Information
- Potters for Peace
Peter Chartrand
Email: pottersforpeace [at] yahoo [dot] com - Reid Harvey
Kathmandu, Nepal
Email: pottery [at] wlink [dot] com [dot] np - SBL Ceramic Water Filtration
System
Solutions Benefiting Life
Sudbury, MA USA
Email: info [at] solutionsbenefitinglife [dot] com
