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Conventional sanitation concepts Print E-mail
In most parts of the world, basically two options to tackle sanitation problems are applied which can be described as "drop and store" and "flush and forget" (e.g. Esrey et al., 2001; GTZ, 2003). These conventional forms of wastewater management and sanitation systems are based on the perception of faecal material, which is considered as repulsive and not to be touched. The design of the technologies is furthermore based on the premise that excreta are waste and that waste is only suitable for disposal (Esrey et al., 2001).
Water-borne sanitation as used in conventional sanitation systems (Figure 1) is based on the collection and transport of wastewater via a sewer system, using (drinking) water as transport medium. The system mixes comparatively small quantities of potentially harmful substances with large amounts of water and the magnitude of the problem is multiplied.

Figure 1: Conventional sanitation concept (Langergraber and Müllegger, 2005)

In addition, both the construction, and operation and maintenance of the necessary hardware for the "flush and discharge" options (sewer, wastewater treatment, drinking water treatment) are a heavy financial burden. Even in developed countries, these conventional systems are directly cross subsidised and the chances to ever become financially sustainable are low.

Conventional sanitation systems have even more fundamental shortcomings than their high costs such as over-exploitation of limited renewable water sources, pollution of soil and groundwater, waste of valuable components in wastewater and the difficulty for an effective removal of pollutants (Wilderer, 2001). Also in the European Union (before the EU enlargement in May 2004), still 37 of the 527 cities with more than 150,000 inhabitants discharge their sewage without adequate treatment—Brussels is a well-known example (EC, 2004).

 Looking on conventional on-site wastewater disposal systems applying the "drop and store" principles the pit latrine in its various forms is still the dominantly used device in developing countries (Esrey et al., 2001). The obvious disadvantages, like soil and groundwater contamination with pathogens, bad odour, fly/mosquito breading, pit collapse or the distance from the house make clear that this cannot be a viable alternative. However, in densely populated areas, the limits are obvious: Digging a new pit when the old one is full often leads to the question where to build the new one? Further problems greatly concern the agricultural sector. The produced nutrients on farms (in terms of food) are transported on a one-way flow to municipalities and discharged as waste. At present, this steady loss of nutrients on farms is compensated for by mineral fertiliser of fossil origin. Also, the UN realizes the limits of conventional systems and the urgent call for action: "The fact is that in contrast to the water supply system where even in urban areas the supply can be augmented through local spot sources, the sanitation problem does not have any low cost environmentally safe solution and so, focus on eco-sanitation needs to be considered" (UN, 2003).

Last Updated ( Monday, 21 September 2009 )
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