By Sandra Butz – 8 week intern

On Wednesday 28th September 2022, our founder Kerri, our guide Gae and Gae’s husband went to the Hot Coffee Guesthouse in Mae Na Jon to pick up seven Biosand water filters from the Rain Tree Foundation.

What is a Biosand water filter?
The Biosand filter (BSF) is a water filter that makes dirty water safe to drink. It can be used in houses or buildings, like schools. It can be made of concrete or plastic. It is filled with layers of sand and gravel that are carefully prepared to go inside the filter.

The next day, we started to install the water filters. The seven water filters were spread into different houses in the Na Klang village: at Lujet’s, Chee Chee’s, staff house, Tawahmoh’s, Ee Chur, Baw Eh’s and Kerri’s house.

What does wach part do?– Lid: The lid should be tight. It keeps
insects oud and stops other things from falling into the BSF.
– Reservoir: The top of filter where water is
poured in is called the reservoir. The reservoir can hold about 20 liters of water.
– Diffuser: The diffuser catches the water
poured into the BSF. It can be a box or plate. It has little holes in it, so the water slowly drips through to the sand. The diffuser protects the top of the sand when you the water in. If the diffuser was not there, the water would make holes in the sand and may hurt the bio layer.

– Standing water: When the water stops flowing,
there should be 5 cm of water on the top op the sand. This keeps the biolayer wet. The biolayer will die if it dries.
– Filter container: The container can me made out of concrete or plastic. It can be square or
round. It holds the sand, gravel and water. It can be painted on the outside to make it look nice – check out the one at base! 😉
– Filtration sand: The sand removes almost all the pathogens and dirt from the water. The sand
must be prepared correctly for the filter to work.
– Biolayer: The biolayer is the top later of sand where very small microbes live. You
cannot see them, they are too small. They eat the pathogens in the water that make you sick.
– Separation gravel: The small gravel stops the sand from moving and blocking the outlet tube.
– Drainage gravel: The large gravel stops the small gravel from moving and blocking the outlet
tube. The large gravel is too big to get inside the outlet tube.
– Outlet tube: Water that comes out of the ou

tlet is safe to drink. The tube can be made out

of soft plastic of copper. You must have a clean safe storage container to collect the water as it flows out of the outlet tube.

What is the most important part?
The sand! The sand removes pathogens from the water. The biolayer lives in the sand. If you do not get the right kind of sand, or do not prepare the sand properly, the biosand filter will not work well.

We spent a few days going around the homes of the villagers to install these filters, which was great fun and a new learning experience.

After the installation, there must water been filtered ones or twice a day, the upcoming 3 weeks before we can drink the water. After these 3 weeks, the village has seven more drink water taps! And how amazing is that?!

Healthy drink water = healthy life = happy life 🙂