How to make a good water filter

http://webarchive.cms-uk.org/water/concept.htm

End Product

Dirty water in

Clean water out

Material needed

• One large vessel, at least 32 inches tall– This will be the biological filter

• One small bucket– This will be the water supplying source

• One plastic pipe

• Stones of various sizes (see slides)

• Material to make things water-tight

Schematics of the water filter

Slow sand water filter

Water reservoir (withdirty water)

Water fit for drinking

Step 1: Prepare vessel

• Vessel must be at least 32 inches tall

• Make a hole at (about) 12 inches from the top

Step 2: Find sand/stones for the filter

• Buy/find stones/sand of various sizes

• You will need a lot of very fine sand (check Home Depot !)

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Step 3: Wash sand and stones

• It does not matter if the water is not clean, just wash them to get rid of mud that will clog the filter

Step 4: Fix the draining pipe

• Use a longer pipe if you have a taller vessel – the taller the vessel the better the filter

• Make sure the pipe reaches to the bottom

• Make sure the hole does not leak !!!

Step 5: Add sand

• Finally, put in the sand• Left 5 inch space between

the sand and the hole (where the pipe is protruding)

• The 5 inch space is used to maintain water level for the beneficial bacteria which are aquatic ! The filter is ready !

Step 6: Make water reservior

• Use (another) small vessel (bucket) as water reservoir to supply dirty water to filter

Hole

Step 7: Finishing up…

• Fasten the water reservoir on top of the filter vessel

• It is important that the sand inside the filter vessel not be disturbed after the filter is in production

How to use the water filter

• You need to run the filter for 3 weeks before drinking the water

• The beneficial microbes need 3 weeks to multiply and for a layer on the sand

• The microbes live on the top 2 inches of sand

Maintaining the filter

• After prolonged usage, the efficiency of the filter will decrease (the output flow will slow down)

• Remove 2 inches of sand from the top, wash it and put it back

Let the filter run 3 weeks before using the water for drinking !

Final advice

• Make 2 filters – in case you need to wash the sand of one of the filter, you can use the other one

• Have separate containers to store dirty and clean water – never use a container that held dirty water to store clean water

• Make a pre-filter to filter the dirty before feeding the water to the biological filter

How to make a pre-filter

• Use a 2 liter coke bottle

• Cut the bottom out

• Turn it upside down

• Prop the spout with 5 or 6 cotton balls

• Fill the coke bottle with fine sand

• Pre-filter is now ready for use – pour dirty water from top

• Wash the sand occasionally and replace cotton