Category Archives: slow sand water filter study and construction

Update July 18, 2016: Please refer to the comment below by Nat. There is a link to the original study. Here is a very good reason to set up rain barrels, and slow sand filters. Urban runoff is killing salmon.  It has been … Continue reading →

This study, published in 2008, explains how trees in boreal forests help to form clouds. Boreal forests are found in the northern hemisphere. Pine trees, larch trees, and other conifers make up the majority of types of trees found in … Continue reading →

An update regarding our ongoing work on slow sand filters. All of the filters here are still working. The oldest, filter 1, is working after 8 continuous years running. Filters 2, 3, 4, and 5 are still working. Here in … Continue reading →

A recent news article has warned of cryptosporidium parasites in pool water.  Another article warns of the same problem. These microbes cannot be removed or killed effectively by the use of chlorine. Ozone is effective but requires high concentrations of the chemical … Continue reading →

Back in February of this year we wrote about the lack of snow in the Cascade mountains in Washington state. We hoped for more snow – that did not happen. Now the situation is worse. Let’s hope there is not … Continue reading →

Last year and the year before, we did some work on five gallon slow sand filters. http://www.enlight-inc.com/blog/?p=1395 http://www.enlight-inc.com/blog/?p=1740 http://www.enlight-inc.com/blog/?p=1848 http://www.enlight-inc.com/blog/?p=1927 http://www.enlight-inc.com/blog/?p=2052 http://www.enlight-inc.com/blog/?p=2089 http://www.enlight-inc.com/blog/?p=2179 We set up 3 of them, ran them for a year and a half, and tested the … Continue reading →

Chlorine can be removed from water by adding vitamin C to it. This could be a way to facilitate filtering tap water with a slow sand water filter. The chlorine in tap water makes using a biological sand water filter … Continue reading →

Update, May 15: 44 percent of Washington state is in drought emergency condition From the department of ecology’s website: “24 of Washington’s river basins are in a declared drought emergency.” Some of our neighbors, who are on public water systems, … Continue reading →

We found the 5 gallon slow sand filter design to be inferior to the 55 gallon design. The five gallon filters just don’t work as well. They are less efficient at removing biological contamination at best; and actually introduce contamination … Continue reading →

When constructing a slow sand water filter, make sure the sand used is not contaminated. Make sure the sand source provides the correct type of sand. Running some chlorinated water through the filter before starting it running with unfiltered water … Continue reading →