Between 2019 and 2030, the global food, water, and energy demand are expected to grow by about 12%. Therefore, it is becoming more than pressing to make a better use of the water resources (conventional and non-conventional) and take advantage of the available energy sources to secure food demand while preserving the ecosystem from possible implications. In short, “How to optimize the use of all resources to guarantee, water, food, and energy security under a healthy ecosystem?”
Since 2016, Tunisia has committed to achieve the SDGs by 2030. SDG6, related to water and sanitation, is already embedded in the National Development Plan of Tunisia at the national, regional, and local levels for the period 2016-2020, more particularly in the Pillar 5 on “Green Economy as leverage for sustainable development” on the management of natural resources and mobilization of the water resources. The Strategic Study on the Water Sector “Eau 2050” will secure the availability and access to water resources in such a way that guarantees the efficient, fair, sustainable, and integrated management. The Master Plan on Reuse “REUSE 2050” will pave the road to new technologies, diversified options of reuse including crops production and better integration of the ecosystem.
The centrality of SDG6 among all the SDGs is indisputable. As WEFE Nexus components are present in 14 of the 17 SDGs, all the SDGs indicators should offer the opportunity for the development of a Nexus approach within sector-specific target. An example of relation between WEF Nexus component within the SDGs is illustrated below.
Regarding the target 6.2 related to the access to improved sanitation, data are needed on the access to sanitation to assess the amount of waste flushed, treated and the amount of water/energy needed, etc. Currently, 0.87% GDP is lost due to inadequate water supply and sanitation. The national sanitation utility (ONAS) has established a rehabilitation plan for 2030. Besides, due to the high energy cost of treatment (67%) and pumping (31%), new treatment processes are expected to save 50% of electricity thus improving the quality of treated effluents either reuse or discharged in the environment. The opportunities of the use of wastewater and its treatment by-products for energy production are still limited.
Considering the target 6.3 on water quality and reuse, there is a need of combined indicators on energy consumption, water reused/purpose, energy, and water needed to produce food. Many hurdles still exist are preventing the promotion of reuse in agriculture (to produce food), on one hand, and to produce energy, on the other hand.
By 2030, the reuse of wastewater for agricultural irrigation is expected to release pressure on water resources and reduce environmental cost. A decrease of the irrigated areas with conventional water in favor of the wastewater irrigated areas are expected to expand. Moreover, urban treatment plants using tertiary process are expected to be connected to irrigated lands. In rural areas, better performance is expected in rural sanitation. Nature based treatment and aquifer recharge using reclaimed water will be developed. The use of wastewater to produce energy is
Considering SDG6 and the Nexus approach, it is recommended to better control of the illegal withdrawal from aquifers already salinized and overexploited. Desalination of sea water and brackish water could be a solution for water supply, but it should be weighed against the drawbacks when used for irrigation. The use of renewable energy for water pumping in remote and agricultural rural areas is an option that fits with the climatic conditions. On the other hand, there is a need for irrigation water pricing for a better cost recovery and rehabilitation of the irrigation network. Finally, indicators reflecting on the WEFE nexus and its integration into the SDG6 are recommended in addition to an evidence-based strategy for the integration of WEFE Nexus and better governance of the resources.