It’s all about that sand…. Really!
The old and over used acronym K.I.S.S. most certainly has a proprietary place in the world of our Bio-sand filters as their design and the science behind them is quite simple. Although the design of our filters has undergone many changes through the years, the main focus has remained constant. Our goal here at Clean Water for Haiti is to positively address the questions: Will the design and use of this filter be simple enough to understand, be simple enough that it is not a headache, bother, or extra work to use, be economical to use (as in no power or electricity usage), and be simple enough that there is little to no maintenance over the long term life of the filter. Lastly, what supplies, etc. will be needed to facilitate the use of the filter on a daily basis? In answering those questions, it is simple to understand how the bio-sand infiltration positively affects knowledge, design and use, availability, and longevity.
Simply stated, it is all about that sand ….
There are several distinct layers within the filter: Diffuser basin, water level, biological level, fine sand, coarse sand, and small gravel. The only moving part is the unclean water as it passes down through the various layers and is then pushed up through to the tube and out through an exterior water spout.
The procurement and preparation of the sand plays a vital role in the efficiency and long term use of the filter itself. The sand must be clean of debris, free of organic or bacterial contamination, and free of chemicals or compounds such as salt (as in beach sand). We purchase our sand locally which not only helps in the manufacturing of the filters, it is also a help to our surrounding communities by pouring money into their economies. Our staff has the sand selection down to a science and we strive to obtain the best sand available for the optimum use of the installed filters. The selection of sand is confirmation that it is all about that sand.
The preparation stage is also equally important. If you have ever panned for gold in the Blue Ridge Mountains of Tennessee then you are a step ahead in this stage. We wash our sand several times, all the while sifting and grading to accommodate the levels of sand in the filter. We have come a long way in the washing process, from washing by hand to the design of our sand washing equipment. The preparation stage is most assuredly all about that sand.
Finally, the sand is ready for its primary and most important function, the actual filtering of the water. Basically, as the water slowly makes its way through the layers of sand the contaminants will be eliminated through several biological processes along its travels. The simplified explanation for us non-biologist types is that as the water flows, the microbes and bacteria go through a “survival of the fittest” process. In our filters the good always wins over the bad; the good microbes will feed off the the bad ones that cause sickness and disease, thereby eliminating them. The microbes that pass through the bio-layer without being eaten can’t survive past the first four inches because there isn’t any oxygen for them past that point. The good microbes will attach themselves to the grains and will become their own little community of bad microbe eating machines.
There is one factor about the bio-sand filter that is more amazing than simple. Since 2001 Clean Water for Haiti has installed over 20,000 filters in country. In each case these communities have little or no access to clean water. With the installation of our Bio-sand filter, a resource for clean water is in their home and is ready for all of their water needs.
And, it is all about the water that drained through the sand.