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Biosand Filters
Biosand Filters
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Biosand Diffuser

What alternate diffusers can you use in Cambodia instead of metal which will cause rusting which will cause the people not to use it? 

rusted biosand filter
rusted biosand filter

Origin Story of Biosand Filter Safe Water Social Venture Projects in South Sudan & Uganda

The safe water social venture (SWSV) projects commenced in South Sudan in January 2004.  If this is of interest, the link below contains the origin story.  The South Sudanese projects had to shut down in 2016 due to the civil war there.  The resilient team members were able to restart the projects in Uganda (TEDx talk in 2nd link below).  We are presently in the process of securing Gold Standard for the Global Goals carbon offsets for the Ugandan projects (due to the avoided need to boil water).  These will allow the Ugandan projects to scale up their impact and to restart the projects in South Sudan (hopefully next year)
Catherine Francis
Senior advisor, marketing and communications, CAWST

Share your experiences with the biosand filter

The biosand filter is turning 30 in 2023. The HWTS Network is planning a celebration with CAWST, and we’d like you to be part of it!

Please reply to this post and share with us your stories from the field. They can be documents, photos, videos, links to your site, etc. Let us know what models, molds and materials you're using. Please share how they've impacted the communities you've worked with!

Whatever you share may be used in support and promotional materials for CAWST and the HWTS Network.

New systematic review and meta-analysis on effectiveness of WASH interventions

Researchers at the Emory Rollins School of Public Health, in collaboration with the WHO, UNICEF, and others recently published (July, 2022) a systematic review and meta-analysis on effectiveness of WASH interventions.

This meta-analysis provided up-to-date estimates on the burden of diseases attributed to WASH. The two previous systematic reviews were published in 2014 and 2018. This new systematic-review included 124 studies (83 observations for water, 20 for sanitation and 41 for hygiene).

The main quantitative findings are summarized below:
When compared with unimproved water source, the reduction in risk of diarrhoea were:

  • 52% for improved drinking water on premises with higher water quality
  • 50% for water filtered at Point-of-Use (POU)
  • 21% for basic sanitation without sewer connection
  • 47% for basic sanitation with sewer connection
  • 30% for hygiene interventions.

Sex-disaggregated data is very limited in WASH context, only 4% of the included studies. (In my opinion, this is a huge data gap).

Highlights, impressions and suggestions from this meta-analysis:

  1. Drinking water of higher quality and water filtered at POU are effective (up to around 50%) in reducing diarrheal risk.
  2. Basic sanitation services without sewer connection were associated with a moderate reduction in risk of diarrhoea.
  3. Sewered sanitation has a greater effect on health than on-site sanitation. (there are several explanations for this suggestion)
  4. The risk reduction of diarrhoeal disease from handwashing interventions is impressive.

It is an open access paper.

What do you think about their findings? Surprising?

Journal reference:

Wolf, J., et al. (2022) Effectiveness of interventions to improve... (More)