From conventional to advanced environmental sanitation

The basic concept of collecting domestic liquid waste in water-borne sewer systems goes back more than 100 years and became in the last century the conventional approach to sanitation in urban areas. Over the years, these sewage disposal systems had to be successively upgraded by additional sewage treatment plants increasing investment, operating and maintenance costs. Although these conventional sanitation systems could improve significantly the public health situation in those countries who could afford to install and operate them, it is highly questionable, if they are economically and ecologically sustainable. The large number of people in the developing world who still do not have access to adequate sanitation is a clear indication that the conventional approach to sanitation is not adapted to the socio-economic condition prevailing in most countries of Africa, Asia and Latin America. Advanced environmental sanitation is aiming not only to protect public health and the integrity of aquatic ecosystems but also to conserve precious freshwater and non-renewable resources. The Bellagio Principles and the Household Centred Environmental Sanitation Approach (HCES) are suggested as guiding principles and a new approach for planing and designing advanced (sustainable) environmental sanitation systems.