[[Image:straining icon.png|right|80px]][[Image:straining with cloth.jpg|thumb|right|250px200px|A woman uses a sari cloth to strain water. Photo: CAWST.]]
[[Image:cloth filtering.jpg|thumb|right|500px|The steps of filtering water through a cloth. Diagram: CARE/CDC Health Initiative, etc. from [http://www.cdc.gov/safewater/manual/sws_manual.pdf Safe ProjectsSafe Water Systems for theDeveloping World: A Handbook for ImplementingHousehold-Based Water Treatmentand Safe Storage ProjectsEstes.]]]
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Straining water through a cloth has been widely used for household water treatment in many cultures for centuries. A common sari cloth is usually used for this in South Asia, for example (photo on right). Straining through a fine cloth can take out guinea-worm, organic matter, and help clear up turbidity. Such cloths are effective in straining out the copepods in the water. These tiny water creatures act as intermediate hosts for the larvae which transmit the disease. Some guinea-worm eradication projects supply a large-diameter drinkingstraw with a filter mesh on one end so that
copepods are strained out when water is sucked up the straw.
Old sari cloth made of cotton was found to be most effective in removing cholera based on laboratory experiments. After several launderings, threads of an old sari become soft and loose, reducing the pore size, compared with new sari cloth.
===Suitable conditions===
Cloth is available around the world, discarded cloth may be used.
===Construction, operations and maintenance===
Fold a large, clean piece of cloth seven to eight times. Place the folded cloth over a clean water container, and secure in place. Pour water through the cloth into the container. Wash the cloth in clean water before using it again.
Cloth needs to be washed in clean water after every use.
===Manuals, videos, and links===
* Manual that includes micro-filtration: MCALLISTER, SKYE. [http://www.scribd.com/doc/86078917/Analysis-and-Comparison-of-Sustainable-Water-Filters EPD 397 TECHNICAL REPORT ANALYSIS AND COMPARISON OF SUSTAINABLE WATER FILTERS.] May 2005.
* Straining using a slow sand filter with a cloth filter: [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CFsQFjAA&url=http%3A%2F%2Fwww.bvsde.paho.org%2Ftexcom%2Fdesastres%2Foxfamwfm.pdf&ei=hm3zT9fzBcis2gXKy9G9Bg&usg=AFQjCNE-pbzOnmDq0PX-5NpwgfENw0rTjA&sig2=aH4ygZJBVKywVxUT8C9cMg Oxfam Water Supply Scheme for Emergencies.]
===Acknowledgements===* [http://wwwmedia.googlegreennexxus.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CEwQFjAA&url=ftp%3A%2F%2Fftp.wpro.whowasrag/articles_of_interest/water_supply/Water_treatment/Household_Treatment_Systems/CAWST_Household_Water_Treatment_Safe_Storage_Source_Protection.int%2Fscratch%2FENH%2FHWTS%2FWHO%2520Final%2FParticipant%2520Manual%2FAppendices%2FParticipant%2520Manual_Appendix%25202_HWTS%2520Fact%2520Sheets_2011-09-05%2F3_Filtration%2FHWTS%2520Fact%2520Sheet_Straining_2011-06.doc&ei=dWDzT-eUBsqe2wWuzLj0Aw&usg=AFQjCNE2W01XfY7H6vgiYqrXUbX5fBvOsw&sig2=w5pcG7VmiOWuptaiv_3BnA pdf Household Water Treatment and Safe Storage Fact Sheet: Straining.] CAWST. Calgary, Alberta, Canada.
* Brikke, François, and Bredero, Maarten. [http://www.washdoc.info/docsearch/title/117705 Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff] or ([http://www.who.int/water_sanitation_health/hygiene/om/wsh9241562153/en/ alternative link]). World Health Organization and IRC Water and Sanitation Centre. Geneva, Switzerland 2003.
* [http://www.lboro.ac.uk/well/resources/technical-briefs/58-household-water-treatment-1.pdf 58. Household water treatment I] or ([http://www.washdoc.info/docsearch/title/120793 alternative link]). WATER AND ENVIRONMENTAL HEALTH AT LONDON AND LOUGHBOROUGH (WELL).
* [http://www.tulane.edu/~trmd700/nbaker.pdf Acceptance and use of communal filtration units in guinea worm eradication.] Tropical Medicine and International Health, January 2000.