Cleaning and sterilising water

Boiling

All dangerous pathogens are killed at a temperature above 160 F / 70 C within 30 minutes… the time it usually takes to boil water over a flame from cold. By the time it has reached boiling point (212F / 100C) the pathogens are killed, even at high altitude. If you can spare the evaporation that will take place boil for an extra 5 minutes.

The inactivation of the pathogens begins at 5C / 9F

Protzone cysts (Giardia,Crypto sporidium, Entamoeba) die at 131F / 55C
Bacteria (v.cholerea, e coli, Shigella, Salmonella, Typhi die at 140F / 60C
Hepatitis A virus dies at 149F / 65C

Filtering

3 phase water filter

Water can be cleaned by filtering it through a filtering system constructed from natural materials. Fill a hollow vessel or some type of container with layers of filtering materials. A container can be made by hollowing out a log, or making a sack out of cloth, perhaps a trouser leg, or the arm of a secondary top, a discarded plastic bottle would work too.

Sand: A substantial layer of sand will remove many potentially harmful micro organisms & radio-active waste.  Make the sand up to 1/4 of the total container size. In a more settled situation, use up to as much as 5 feet of sand.

Charcoal: Charcoal will remove odour, taste and even solvents. Charcoal is the black, charred, porous nougats of wood left over from a fire (ideally an earth oven, which can be built especially to make a good supply of charcoal) Use at least 2 layer of 3 inches of crushed charcoal or 2 layers (either side of the sand layer) each ¼ of the total size of the total container size.  Charcoal nougats can also be added to a container of water, agitated and left to stand before filtering.

Fresh plant material: Green leaves, plants and non toxic weeds can be added to filters t imitate natural pond filtering systems. Use at least ¼ of the total container size, crammed into the top of the container so that it can be easily replaced with fresh matter often.

Cloth: The closer the weave the better, makes a good final filter material, place this in the filtering container first.

Clay and Dung Water Filter

This water filter made from regular yellow/ red terracotta clay  found 6 -8 inches below the surface in many areas of the world has been developed by Material scientist at The Australian National University, Tony Flynn.

Clay is dug up and dried through in the sun. It is the crushed and/or pressed through a sieve to remove large lumps, into a powder.

This powder is then thoroughly mixed with equal amounts of a grainy substance: waste seed husks and crafted into a small cup/ bowl, the sides about as thick as your finger. Coffee grinds have proven to be very beneficial because of how they react in the next stage of this process, which is the firing.

A fire is then built - first a layer of grasses which will act as the starter fuel and then a layer of dung. The finished clay vessel is lain on the dung and then covered over with more dung, 30 minutes after being lit the temperature rises to approx 700C degrees – then gradually up to about 950 C in the next 30 minute, given that you keep adding dung to the fire, keeping the filter covered. The filter/s is then removed from the fire to cool. During the firing the coffee grounds burn away, leaving holes, and a small amount of Silica, which is a result of the combustion ... in the words of the inventor Tony Flyn ;

...these small voids or holes in conjunction with their silica content and the network of tiny holes that are joined in three dimensions within the clay particle mass, act as the filter structure and they are small enough to allow the simultaneous passage of water through them, while equally being small enough to remove bacteria that we tested for – in this case E-coli’.

A succession of these filters could be used.

Outdoor Survival: Learn How to Read Maps, Cross Challenging Terrain, and Find Shelter, Water and Food

Author: Garth Hattingh
Manufacturer: New Holland Publishers Ltd
Amazon Price: £9.99
Offers - Buy New From: £49.95 Used From: £2.10
Buy Now

Desert emergency-lack of water-how to find and collect water: Plants and human survival in the desert