Examples of temporary shelter and water filtration and purification

JUSTIN LAI
NOV. 19th, 2010

Temporary shelter

A view Port-au-Prince's National Stadium, where Haitians displaced by the earthquake have pitched makeshift tents for shelter.

Simple tent in Mongolia that consists of 4 long sticks supporting a large piece of cloth forming an A-shape.

Sandwater filtration system

This method can be easily made in the wilderness, utilizing mostly sand and gravel.

1. To start with, you need a container. If you can find a large, empty can, use it. Punch 5-10 holes in the bottom of the can. A large plastic bottle is also fine. Cut the end of the bottle off evenly. If there is no container available, you have to use what material that nature can provide, or that you brought with you. If you find a birch tree, make a cone of birch bark. The cone will need to have a fairly small hole in the bottom. Tie the cone with rope to keep it from opening up.
2. First, you need to stop the sand to get out of the container. Find some filter material you can place at the bottom. For instance:
           • a couple of inches (centimeters) of pebbles.
           • a grass mesh, make sure it’s nonpoisonous grass.
           • or cotton material.
3. Add a layer of gravel. The main purpose of the gravel layer is to strengthen the filter material and prevent sand mixed with the water you get from the filter.
4. Fill your bottle or cone with sand.
5. Collect some water. Pour your collected water through the filter. Catch it in another container at the bottom. Look at the water that comes out of the filter. It should be clear. If not, you may have to pass the water through the filter more than once.

This method s effective and accessible, however it still does not necessarily make the water drinkable. Purification is needed as there may still be harmful bacteria in the water.

Water Purification

A useful technique recently developed is called Solar-Water Disinfection (SODIS). This involves placing water in a grade 1 PET plastic bottle and then exposing it to direct sunlight for at least 6 hours. The UV rays from the sun interferes with the cell structure of the bacteria, thereby destroying it. It thus allows unsafe water to be drinkable. However there are several limitations to this method. It is very difficult to be effective if the water is mirky or unclear as it effects the UV ray's ability to cleanse the water. More over, you need to have an adequate source of sunlight in order for this to work. It helps if you are located near the equator line as this is where you can maximize the sunlight.

Sources 

Paris, Sophia. United Nations. “Haiti Earthquake.” Last modified February 03, 2010. Accessed November 19, 2010. http://www.unmultimedia.org/photo/detail.jsp?id=426/426984&key=47&query=subject:%22Haiti%20Earthquake%22&lang=en&sf=.

Wilderness Survival Skills for Safe Wilderness Travel. “How to make a water filter.” Accessed November 19, 2010. http://www.wilderness-survival-skills.com/how-to-make-a-water-filter.html.