Water in glass
Sustainable technology: A look at the design, construction and operation of a small scale slow sand water filter. (Building a small slow sand water filter for individual use)6
Please help support this site by purchasing, for seven dollars and fifty cents, a summary of the most important results of our research for the past 8 years, including detailed drawings of the filters, where to find sand, pictures, and an easy to understand faq of important considerations in the assembly of a small slow sand water filter. This page on our blog has the purchase area. Thank you!!

 Water Test Results 
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 Water clarity 
 Slow sand filter FAQ 
 Float Valve installed 
 First flush diverter 
 Illustrations and drawings 
 Sand size examples 
> Magnified sand size examples 
 Literature Cited 
 Slow Sand filter Blog
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  First posting 2007-08-13
  Page last updated 2013-09-05

Illustrations of sand sizes large view

sand size examples

Sand size examples
The "uc < 2" means: Uniformity coefficient of less than 2. The uniformity coefficient is a way of expressing the quality of a particular volume of sand. A smaller number means the grains are nearly all the same size; whereas a larger number means the grains of sand are all very different sizes. A larger number for the UC of sand means the sand is less desirable for water filtration. A UC of less than 2 is generally the best. The "effective size" means, in this case, the "average" size of the grains of sand in the given sample as they relate to water filtration.

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