The reuse of urban wastewater is already underway in water-stressed countries such as Namibia, Singapore and in Europe: Spain. In France, several wastewater reuse projects exist, some of them for several decades:
– 750 Ha of crops in Clermont-Ferrand
– irrigation of Noirmoutier potato crops
However, these projects take place after treatment in a wastewater treatment plant. Often located far from the city, wastewater treatment plants can treat large volumes of water but are far from many water uses. This remoteness limits projects for the reuse of treated wastewater, due to infrastructure costs such as piping that limit the economic feasibility of such projects.
An important issue in reducing the exploitation of natural resources through wastewater reuse projects is to get closer to the uses, i.e. to treat wastewater in the immediate vicinity of the uses. If we consider urban uses, treatment at the foot of the building could thus make it possible to substitute water from natural resources with clean water from an adapted treatment for the following uses:
– In homes : WC, washing machines, floor cleaning,
– At the foot of the dwellings: ornamental garden, vegetable garden, cleaning of the common areas, vehicles cleaning,
– In the city: fire water, roads cleaning , networks, freshness islands and parks.
The treatment of wastewater in the city at the foot of its use makes it possible to rethink water in the city but also the economic vision of the water service.
The reuse of wastewater is an alternative that is considered more favorably. Respondents are more open to new ways of consuming water: 86% (vs. 84% in 2017) would agree to use tap water from wastewater recycling for their domestic uses. 84% (vs. 81% in 2017) would be willing to replace tap water with pre-treated rainwater, 75% (vs. 71% in 2017) would be willing to consume vegetables watered with treated water, and 69% would be willing to have recycled wastewater used directly on tap. 53%, i.e. more than half of French people (vs. 51% in 2017) would even be prepared, this year, to drink tap water from recycled wastewater.
Emmanuelle Wargon, Secretary of State for the Ecological Transition, set a target at the end of the second phase of the Water Assizes (June 2019) to triple the volumes of recycled non-conventional water by 2025 in France.