Sustainability assessment of sanitation systems in El Alto, Bolivia : A pre-study

Sammanfattning: The Sustainable Development Goal (SDG) Target 6.2 aims at providing access to adequate and equitable sanitation and hygiene for all and to end open defecation by 2030. Yet, 47 % of the population in Bolivia lacked access to basic sanitation services in 2012. There is a risk of actors focusing on only the construction of toilet facilities, without looking at the need for related service required for a sustainable development. El Alto is a rapidly growing city in Bolivia where the sanitation service is expanding fast. In order to enhance knowledge about the sustainability of existing sanitation systems in El Alto and to give recommendations for future development, this sustainability assessment was conducted. Two sanitation systems in El Alto were assessed against five sustainability criteria, related to: 1) health, 2) environment, 3) technical function, 4) socio-culture (institutional and user related) and 5) economy. The conventional sanitation system with sewers and an alternative small-scale sanitation system with urine-diverting dry toilets (UDDTs) were selected as system options.  Results show that the "conventional system" entails higher health risks than the "UDDT system". For example, blockages in the main sewer lines cause overflows in the streets during rainy season when storm water gets mixed with potentially infectious wastewater. The UDDT system has a higher performance than the conventional system regarding the environment criterion, which is related to nutrients recovery and removal. Results related to the technical function criterion show that the conventional system has a better capacity to endure a change in quality or quantity of input products to the system. Both systems can handle the freezing temperatures in El Alto but the UDDT system has better resilience against climate change impacts such as flooding or drought events. The levels of complexity are reasonable in a local context for both systems. If assuming that the aspiration for flush toilets is as low in entire El Alto as in the area of investigation, results show that users of the UDDT system are more satisfied than uses of the conventional system. The dissatisfaction expressed by users of the conventional system mainly derives from malodors appearing during the wastewater overflows in the streets. The institutional capacity is stronger for the conventional system, making it harder for the UDDT system to expand. In addition, the UDDT system has difficulties with financing. Recommendations for future development are to inspect and renew the sewer network and to review and expand treatment capacity of the centralized treatment plant. Financial resources should be focused on the UDDT system where there is no sewer network.