Water Filtration

http://www.cleanwaterforhaiti.org/Design/HTML/filter.html

How does it work? (courtisy of CAWST)
1. Water is poured into the top of the filter as needed, where a diffuser plate placed above the sand bed dissipates the initial force of the water. Traveling slowly through the sand bed, the water then passes through several layers of gravel and collects in a pipe at the base of the filter. At this point, the water is propelled through plastic piping encased in the concrete exterior, and out of the filter, for the user to collect.

2. As with all slow sand filters, the removal of pathogens occurs in the BioSand filter due to a combination of biological and mechanical processes. When water is poured into the top of the filter, the organic material it is carrying is trapped at the surface of the fine sand, forming a biological layer or 'schmutzdecke'. Over a period of one to three weeks, micro-organisms colonize the schmutzdecke, where organic food and oxygen derived from the water abounds.

The people of Haiti live in harsh conditions and have very limited access to clean water sources. As a vulnerable population, which combined with significantly contaminated water sources that are a leading cause of disease transmission, they will only be faced with illness and death. Taking measures to reduce the dose of pathogens that they are receiving will go a long way towards reducing illness and subsequent death.