Clean water, cheap

University of North Carolina scientists have developed a water filtration system that is cheap and relatively easy to manufacture.

The system is based on traditional methods of filtering water through sand, which is effective to a certain degree. However, using sand or crushed rock only leaves the water at risk for certain contaminations.

UNC researchers utilize a short section of PBC filled with sand and small amounts of ferric chloride and a pH buffer. It filters water 30 to 50 times faster than more conventional (and expensive) methods. It is also easy to manufacture and requires little training to use.

The filter works because the added chemicals force contaminants to stick to the sand, leaving clean water free to run through.

Inventions improve access to water for world's poorest

The Hippo Water Roller was developed to ease the difficulty of transferring water long distances in Africa. In many parts of rural Africa, villagers have to walk up to five miles--more in the dry season--to access water.

The traditional method for water transport has been to balance a large container on the head, which can cause spinal problems. It is also difficult and time-consuming, and generally villagers can only transport about five gallons at a time.

The water roller works much like a lawn mower, but instead pushing around a blade and motor, villagers are able to push a 24-gallon barrel of water. The design makes the effective weight of the barrel 22 pounds, which is relatively easy to push.

The water roller frees up time for children to attend school and for women to attend to other domestic tasks, as well as income-earning tasks. 24 gallons of water is enough to meet daily needs for five people. The Hippo Water Roller Project also provides education about clean water practices and drip agriculture.

Another invention, known as the Solvatten (Swedish for "sun water"), uses solar energy to purify water. It has a ten liter capacity and takes several hours to reach a safe temperature. The device has been tested on water containing E.coli at high concentrations and has successfully purified it. It also contains a physical filter to rid the water of larger impurities.

A test program of the Solvatten is being run in Nepal this year, with cooperation from UNESCO and ENPHO.