Water availability, a key sustainability issue at the city, regional, and national scales, depends on the supply and distribution of portable water as well as the sewage collection networks. This research focuses on Ukraine where, currently, regions in the east and south are supplied with 25.6% of the total water volume by redistribution from wastewater treatment networks, 70% of which are worn out. In addition, the longer residence time in the water distribution system leads to a decrease in water consumption. Ultimately, the rudimentary and over-reliant water distribution and wastewater treatment networks are unable to serve the population, resulting in sewage and water leaks that are harmful to human and ecosystem health alike. In this context, the incomplete understanding of services in monetary terms associated with Ukrainian economic sectors on public water supply may lead to an underestimation of water supply impacts and omission of their indirect portion from the analysis. Therefore, LCA studies should include the full economic contribution of the national economy and the rest of the world required to provide water supply to identify the contributing products and services to the environmental impacts of drinking water and wastewater and the stability of economic sectors (contribution of each sector to the other sectors) associated with these products, and services based on the ecological goal functions (maximize power, cycling, storage, and residence time). The goal functions help to connect the stability of sectors associated with products and services of the Ukrainian economy using their flow, storage, cycling, and residence time contributions to the other sectors and, ultimately, to the environmental impacts of water and wastewater.
In this paper, an integrated hybrid LCA method is presented, which includes the water supply and wastewater treatment process (process LCA) and the exchange of contributions (activities) by the water supply and water treatment sectors (information on products and services bought and sold by the water supply and water treatment processes) and by other sectors of the Ukrainian economy including information on products and services bought and sold by non-water industries. By expanding the upstream and downstream boundaries of the analysis, this approach not only provides a missing link between the indirect economic contributions to the environmental impacts associated with drinking water and wastewater, but also directs the development of the Ukrainian economy, water supply, and wastewater treatment networks toward improving the consumption rate of drinking water and reducing the impact of wastewater on air emissions (e.g., CO2, N2O, and NOx) through the perspective of an ecological network. The results are expected to identify the sectors that require maximization of the associated goal functions to minimize their water and monetary contribution to the environmental impact of water and wastewater without jeopardizing their stability in terms of minimization of goal functions. This multi-method approach will help governments holistically manage the transition of their economies, water supply, and wastewater systems toward stability and sustainability by improving resource cycling, functional efficiency, and water security.