Yearly Archives: 2012

Slow sand filters are totally sustainable, will work on gravity feed only, take out hydrocarbons, bacteria, viruses, and do not require addeed chemicals to operate. Check out the websites below. And check out the post just before this one if … Continue reading →

Filter 5, the most recent filter set up here in May of this year is now working.  The drainpipes inside the filter at the bottom of the barrel are covered by 4 inches of pea gravel. The sand directly on … Continue reading →

This is yet another update on what has been learned regarding the construction and operation of a small slow sand water filter. These are issues that stand out after experience building, testing, and operating small slow sand filters over the … Continue reading →

Some of the water quality tests done here on filter 4 and 5 are done. These tests were done with the testing kits available from Micrology Labs. The interpretation of the results of our tests are posted here along with … Continue reading →

More notes on roof water quality required for a slow sand filter: Experience here in the art of roof water harvesting and slow sand water filter construction is a continual learning experience. The newest roof water filter here (filter 5 … Continue reading →

This is an update of the previous post on slow sand filter sand sources. Instead of trying to find specialized sand sizes from a manufacturer, it can be more convenient to sift easily available sand to get the right grain … Continue reading →

A SUMMARY OF THIS POST: For a slow sand filter to work we need to use “uniformly graded” sand. “Uniformly Graded” sand means sand that has already been processed (sifted) so that the grains of sand it contains are mostly … Continue reading →

This is an update on the post about sifting sand for a slow sand water filter. I wrote about this in response to a question from a reader.  I recommended using stainless steel wire cloth to sift “play sand” so … Continue reading →

A slow sand water filter (sometimes called a biological sand water filter) works like this: Because of the pull of gravity, water flows down through a sand bed in a container about 3 feet deep from the top to the … Continue reading →