Water filter.

I happened across an article that said you can purify rainwater to 98% ~ 99% pure with a basic set up of only a drum and a bag of sand. After further investigation this is indeed the case although there are technical differences in the systems available.

In many parts of the world this is the only way the locals can have clean drinking water so I set about having a go at making a basic sand filter.

You need  a drum, some gravel, sand and a length of plastic downspout, some hosepipe approximately 1.5 times the height of the barrel and a tap connector.

The drum was recycled from an allotment and any holes were filled in with fibre glass matting and resin available from auto supply shops as only a small amount was needed. When this was set hard you will need to drill a hole to accommodate the tap at an approximate height of 2/3rds of the barrel from floor level.

Place the barrel where it is to be used permanently as you will not be able to move it once filled.

Next take the hosepipe and temporarily fix to the inside of the the tap and lay the other end on the bottom of the barrel. make an approximate mark on the pipe at a place that corresponds with where the hose meets the bottom of the barrel then remove from the tap and barrel. From this mark to the end of the hosepipe on the bottom of the barrel make holes in it all the way along. The idea is that this will allow water to seep into the hose after it has been filtered.

The next stage is to permanently fix the hosepipe to the tap and lay the perforated part on the bottom of the barrel. Cover this hose with a 4"/100 mm layer of medium sized pebbles about 3" / 75mm in diameter. If you live near a beach the size to look for is the large shingle sized pebbles.

On top of this layer place a piece of cloth the diameter of the drum as this will act as another filter.

On top of this cloth add a 6" / 150mm layer of smaller shingle such as pea sized gravel. then use another piece of cloth the same diameter as the drum.

On top of this cloth fill the barrel with yellow "builders" sand. It is better if you can use river sand as this is from freshwater rivers as opposed to builders sand which is generally from the seaside but you need to be conscious of the ecosystem that you may be destroying if you cannot buy river sand in a shop. Fill the barrel to within 6" / 150mm from the top of the barrel.

Cut the length of downspout to size and fix onto the gutter.

The best way to filter water using sand is to have a continuous stream of water running through the sand as this enables all the micro organisms stay alive but we do not have constant running rainwater  so the next best thing is to always keep the level of sand under the level of the water hence the 150mm above the sand to the top of the barrel.                                         

The water will run down through the sand, cloth and gravel to reach the bottom of the barrel as filtered water. As the level of water rises in the sand filtered water will also rise in the pipe and eventually arrive at the tap. Hey presto, clean filtered water.

OF COURSE THIS IS A SYSTEM USED MAINLY IN SUB SAHARAN AFRICA and not in the UK where we have good quality water "on tap" It is always best to leave the potable water to your local water company and don't mess around with the quality but it is also prudent to know how you can filter water if you need to.

Survival of yourself and your loved ones depends on drinking water. If, for any reason be it terrorist, man made or natural disasters you find yourself without a supply of tap water what would you do?

Knowing how to filter water and then purify it is essential. One final step if you are desperate enough to need to use the filtered water for drinking is to use a purification tablet or to boil the water and keep it on a rolling boil for 5 minutes before letting it cool.

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