Bio Sand Water Filter

Getting pure water for drinking is one of the biggest challenge in survival,so here it is a instructable to make a compact small water filter made from plastic bottle.By this filter we can easily remove dust,bacteria from water during surival.

MATERIALS NEEDED:
1.2 LITER PLASTIC BOTTLE
2.SAND
3.STONEs(5mm to 15mm)size
4.STONEs(2mm to 5mm)size
5.COTTON

Cut the bottom side of the bottle to pour dirt water and to put stones

now drill a hole on the bottle cap to get filtered water out

Before using the sand and stone it should be be cleaned properly by using some detergents and wash all the dirt's from stone and from the sand.

Now its time to place sand and stones into the bottle
~first put the large stone into the bottle up to 8cm
~And put small stone above big stones of 8cm
~now add sand above the small stones of 8cm or more
~open the bottle cap and place some cotton and close the bottle with bottle cap which was drilled

Now check the filter by pouring some dirt water at the top layer of the filter,.
The sand at the top layer will filters off dust's,dirt,and bacteria from the water .
Two layers of stone will filter off the sand at the top layer to the water at out.
The cotton at the bottle lid is finally to make sure of filtering sand and dust at water out.
Now we can get purified drinking water