Water backpack

"PAUL" water backpack

A water backpack is a portable membrane - water filter for humanitarian aid . It enables the decentralized supply of clean water in emergency and disaster situations.

technology

requirements

Pictograms to PAUL

The filter only needs water (for example from wells or rivers) to function. No chemicals, energy, or trained personnel are required. The entire operation is shown in four pictograms so that it can also be operated by illiterate people without any prior knowledge, as a test with different population groups in India has shown.

functionality

The heart of the device is a membrane filter unit. After it has been set up at its destination, it is first filled with around 100 liters of raw water from surface waters when it is put into operation. After a waiting period of one to two minutes, filtered water will flow out of the drain hose. During the filtering process, raw water has to be topped up continuously.

Efficiency

The water pressure given by the height of about 1.15 meters presses the water through the membrane with a pore size of 20 to 100 nm and thereby filters it. Trub materials are practically completely retained , bacteria with an efficiency of over 99.999% (measurement by the Fresenius Institute, E. coli and Coliforms ) and viruses by over 99.9% (measurement by the University of Bonn, Coliphagen ).

A system based on ultrafiltration (in contrast to devices based on reverse osmosis ) cannot filter out any dissolved substances such as salts or liquids such as mineral oils, as these pass through the membrane. Therefore, water contaminated with such substances cannot be purified.

With an average filter volume of 1200 liters of water per day, a device is able to supply 400 people with the drinking water required according to Sphere standards (2011).

Use and distribution

The water filter has been developed for use in emergency and disaster situations. As a rucksack, it can be brought to the scene on foot if necessary. It was first used in March 2010 in Chile. Since September 2010, the distribution has increased significantly, so that in April 2012 around 700 copies were in use in over 30 countries.

Since the membrane has a service life of ten years, aid organizations often leave it on site permanently after an emergency. Regular maintenance or cleaning of the filters every few months is recommended or necessary depending on the degree of pollution of the raw water; the water backpack is completely filled once and then emptied through the floor outlet to flush out sediment.

In addition to the Foreign Office, PAUL is used by numerous organizations in humanitarian aid.

development

The device was developed in the civil engineering department of the University of Kassel under the name PAUL (Portable Aqua Unit for Lifesaving) and funded by the German Federal Environment Foundation. PAUL was optimized in a research project until mid-2013 and is now in use in many areas of the world.