Human waste may be a topic that people generally do not or prefer not to think about. However, its capture and disposal (often referred to in terms of sanitation) play a vital role in human health and development. The importance of sanitation as a basic human need has made it an international development priority and a key target in the United Nations Millennium Development Goals. Even though since 1990 the percent of the global population with access to improved sanitation has increased (see Figure 1.), lack of improved sanitation still threatens human health and development particularly in developing regions of the world.