Análisis origen-destino del movimiento de carga en el modo marítimo

has access to improved sanitation (UNICEF and WHO 2015). In Sub-Saharan Africa, only 68% of the population has access to improved drinking water sources, only 30% has access to improved sanitation, 20% uses shared sanitation facilities, 27% uses unimproved sanitation facilities and 23% practices open defecation (UNICEF and WHO 2015). In this region, only 16% of the population has a water connection in the home or on the property (UNICEF and WHO 2015) and about half of the households with a water connection has flush toilets (WHO and UNICEF 2013). Accordingly, waterborne sanitation with sewers is rare in Sub-Saharan Africa. About half of the larger cities in this region has sewer systems at its disposal (Banerjee and Morella 2011). Only in Namibia, South Africa and Senegal do some utilities offer area-wide access to sanitation (Banerjee and Morella 2011).

In 2009, 33% of the population in developing countries lived in informal settlements (UN-HABITAT 2013). This percentage is 62% in Sub-Saharan Africa (UN-(UN-HABITAT 2013). In view of this high proportion of people living in informal areas, it is clear that they have to be included in attempts to substantially increase access to sanitation.

Informal settlements are characterized by substandard housing structures (often built with non-permanent materials), high population densities and overcrowding, limited access opportuni-ties (due to, e.g., lack of surfaced roads, decaying buildings), insecure tenure and low income of the population (UN-HABITAT 2003a). It is obvious that, under such conditions, sanitation provision may not be feasible on an individual (household) level. This fact is acknowledged by a number of authors (IWA 2005; Kariuki et al. 2003; Mara 2005; Schouten and Mathenge 2010).

One option to improve access to sanitation in these areas is shared sanitation. In cases where individual provision is not possible, this approach can improve the local sanitary conditions by providing a basic level of sanitation (Bond et al. 2013; Eales et al. 2013; Rheinländer et al.

2015; Schaub-Jones 2006; Verhagen et al. 2008). Shared sanitation facilities “are proving highly effective, because they concentrate usage in one place and so make sewer connections, management and operation financially viable” (Eales 2008).

Norman (2011)distinguishes household toilets, shared toilets, community toilets and public toilets (Figure 2). Household toilets are affiliated with a single household, shared toilets are assigned to several households in a single building or plot, community toilets are shared by a group of households in a community and public toilets can be used by anybody, because they are located in public spaces (Norman 2011). However, these definitions are not fixed and vary between authors. For instance, WHO and UNICEF (2008) consider public toilets as a type of shared toilet.

In 1990, sharing was common practice for 160 million people or 7% of the world`s urban population and, in 2015, this number had more than doubled, to 394 million people or 10% of the urban population (UNICEF and WHO 2015). In earlier publications of the Joint Monitoring Programme, these numbers were even higher. According to the data in WHO and UNICEF (2013), 205 million people in urban areas were using shared sanitation in 1990 and 470 million in 2011.

Thus, shared sanitation is widely practiced. This is particularly the case in informal settlements (Schouten and Mathenge 2010) and in urban Sub-Saharan Africa, where sharing of sanitation facilities is very common: 30% of the population used shared facilities in 2011 (WHO and UNICEF 2013).

Shared sanitation facilities are not considered improved facilities by the Joint Monitoring Pro-gram (UNICEF and WHO 2015; WHO and UNICEF 2013, 2008). If shared sanitation facilities were considered improved, the world would have met the MDG of 77% (68% of the global population with access to improved sanitation plus the 9% using shared sanitation facilities, UNICEF and WHO (2015)). One reason for not considering shared sanitation as improved sanitation is the concern that such facilities may be less hygienic than private household facil-ities (UNICEF and WHO 2010). Another reason is that the data used by the Joint Monitoring Program do not allow any differentiation among shared sanitation facilities (UNICEF and

WHO 2010). It is acknowledged that this procedure might underestimate the proportion of people using improved sanitation facilities (UNICEF and WHO 2010).

Figure 2 Definition of household, shared, communal and public toilets (Norman (2011), modified)

However, a number of authors recognize the contribution that well-managed shared sanitation facilities can make in providing access to water and sanitation (Bond et al. 2013; Cumming et al. 2014; Exley et al. 2015; Mara 2005; Mosler et al. 2014; Nelson and Murray 2008; Norman 2011; Schouten and Mathenge 2010; Sijbesma 2011). Hence, the overall classification of shared sanitation facilities as being unimproved is questioned. Where individual sanitation is not feasible on a household level, shared sanitation facilities are an option for providing such services to the residents.

There are a number of initiatives that offer shared communal or public facilities to urban areas, using a comprehensive approach and emphasizing successful operation, maintenance and fund-ing. In some Indian cities, die NGOs Sulabh and SPARC (Society for the Promotion of Area Resource Centers) serve public places and poor residential areas with shared sanitation facili-ties (Burra et al. 2003; Colin and Nijssen 2007; Pathak 1999). In Indonesia, the government funds community-managed decentralized wastewater treatment systems. 77% are community sanitation centers providing water and sanitation services for 20 to 100 households (Eales et al. 2013). In Kenya, Umande Trust implements “BioCentres”. These are community latrine blocks which are owned, built and operated by the communities (Aubrey 2009). Another ap-proach, also located in Kenya, involves “Ikotoilets” (Karugu 2011; Njeru 2014; Ziegler et al.

2013). Besides sanitation services, Ikotoilets integrate other services, such as cold refreshments with snacks and newspaper vending. The NGO WSUP (Water and Sanitation for the Urban Poor) has supported implementation of public and communal sanitation facilities in Madagas-car, Kenya, Mozambique and India (Norman 2011). In South Africa, the eThekwini munici-pality is introducing community ablution blocks (CABs) as an interim sanitation service for upgrading informal settlements (Crous et al. 2013; DHS 2009).

one toilet

The vast majority of existing shared sanitation facilities is badly managed (Collignon and Vézina 2000; UN-HABITAT 2003b; WHO and UNICEF 2008). Whilst implementation of the physical structures is feasible, the main challenge is long-term sustainability and, particularly, the establishment of effective maintenance structures (Collignon and Vézina 2000; Nelson and Murray 2008; Verhagen et al. 2008). If these challenges were to be overcome, shared sanitation facilities could substantially increase sanitation coverage in regions that cannot be serviced by conventional approaches: “Without reconsidering shared sanitation, the MDG, and future tar-gets, are unlikely to be met” (Exley et al. 2015).