Sanitation in cities of the developing world
Wastewater is a collateral damage of urbanization but can be turned into a valuable asset.
Sanitation and urban growth
Urban sprawl and demographic growth inevitably lead to tensions in cities. These tensions tend to coalesce around resources – starting with potable water – then around the consequences of larger volumes of wastewater discharged because of population growth and the increase in water consumption. If used water were treated, cities needs could easily be satisfied while reducing pressure on resources. Furthermore, recycling policies must receive strong support.
Urban growth in developing countries impedes the installation of adequate wastewater treatment facilities
Most cities in developing countries do not benefit from a wastewater management system since the infrastructure is missing, failing or simply unsuitable. The rhythm at which infrastructure develops does not keep up with the increase in needs, especially in informal settlements or slum areas. However, technical solutions do exist, and can differ according to the density of the urban or rural areas, or to social and financial settings. Public authorities need to approach the wastewater issue at the same time and with the same level of priority as that of drinking water access, or they are at risk of facing irreversible pollution.
Wastewater: an alternative resource that remains to be explored
Wastewater is a resource that increased at the same pace as population growth. For a long time, it was considered as a resource for agriculture only.
If treated, wastewater can constitute a clean, largely available and safe resource. It can be used to cover agriculture needs in suburban areas or as an alternative, safe resource for the industrial sector. In many places, water is way too valuable to be used only once. In Windhoek – Namibia capital city – a water recycling system allows to redistributing about 30% of wastewater to the population.
Used water is also a much cheaper alternative to import than desalted water, and therefore a source of savings for municipalities.
Wastewater treatment and reuse are two core components of tomorrow’s sanitation schemes.
- A global perspective on sanitation must be adopted, from waste generation to waste treatment in order to neutralize its impact on the natural environment or to turn it into a reusable resource.
- Tackling this complicated challenge requires taking into account all dimensions of the problem: technical choices, financial cost, knowledge and maintenance capacity in the long term, consequences of climate change and social acceptability of the various uses.
- Sanitation certainly is costly, yet a lack of sanitation hinders cities’ development and safety and generates levels of pollution that seriously compromise emerging and developing cities’ liveability.
- Les villes émergentes doivent faire face à de multiples défis : sociaux, environnementaux, économiques. Selon les prévisions, 60% de la population mondiale vivra dans les villes en 2025, dont près de la moitié des habitants dans les villes des Pays en développement, notamment dans les quartiers défavorisés.
- A l'échelle mondiale, seulement 2% des eaux usées sont aujourd'hui recyclées pour être réutilisées.