A two-stage network optimization for sustainable treated wastewater planning

The current global availability of water resources is able to sustain human activities, however, its uneven distribution causes scarcities in some regions of the world, leading to the hindrance of industrial and agricultural operations. In addition to that, water undergoes multiple volatilities and dynamics owing to its dependence on precipitations and weather conditions which are now accentuated due to climate change. To overcome water shortage, water scarce countries have deployed tremendous efforts in enhancing their water sectors by developing novel technologies substituting the renewable water base. Wastewater reuse represents a sustainable opportunity to alleviate water scarcity in arid regions by providing additional reserves. Nevertheless, public perception is the major obstacle to implement such practices due to social constraints. This study presents a two- stage methodology to evaluate the socio-economic and environmental aspects of reusing treated wastewater (TW) generated from different municipal wastewater treatment plants in an arid climate country. The first step consists of assessing the social acceptance of TW use in different applications to preselect the highly socially welcomed ones. Selected uses are then assessed economically and environmentally using a multi-objective network optimization model that aims to reduce the cost associated with the treatment process and the transportation of TW, and to minimize the engendered environmental burden. The TW allocation is constrained by the social acceptance, the capacity of treatment and production along with the quality of the TW. Firefighting, athletic fields irrigation and street cleaning were the uses that obtained the highest social acceptance amongst the studied sample. As for the environmental and economic aspects, the network involving a high contribution of treated municipal wastewater represents the optimum plan.