Energy, water and environmental balance of a complex water supply system

Abstract

The present paper describes the analysis of water and energy balance in a complex urban water supply system. The analysis was carried out employing Life Cycle Analysis (LCA) methodologies. The LCA approach was integrated with the analysis of the system energy and water balance. For a real size water supply system, based on the results of the individual LCAs, the current baseline was constructed highlighting the water, energy and environmental (in terms of CO 2eq emissions in the atmosphere) costs of supplied water. Then, three different mitigation measures have been evaluated: the first is based on energy production by installation of photovoltaic systems; the second is based on energy recovery by means of hydraulic turbines, exploiting the available pressure potential to produce energy; the third based on energy optimization of pumping stations by installing inverter systems, replacement of rotors with optimized blade profiles and installation of automation systems and self-control. Also the possibility of substituting some of the pipes of the water supply system was considered in the recovery scenario in order to reduce leakages and recovery the energy needed for leakages transport and treatment. The analysis of the results shown that energy recovery scenario is the most reliable solution even without any pipe substitution. Thanks to the recovery of energy and limiting the environmental impact of the system, the CO2eq production per cubic meter of supplied water was reduced from 0.41 to 0.07 kg CO 2eq /m 3 of supplied water.

LCA Methodology for the Quantification of the Carbon Footprint of the Integrated Urban Water System

“…The Jato system is supplied by three wells and one treatment plant with no in-line pumps. Details of the system and the Palermo water supply can be found in Puleo et al [12]. Data used in the present study are metred annual averages for 1997-2016.…”

“…The analysis showed a certain sensitivity of the results to system variables, such as the supplied volume, and this fact may influence the reliability of mitigation strategies. In the future, uncertainty analysis approaches, frequently used in environmental analysis [12,20], should be introduced to increase the robustness of the analysis.…”

“…The LCA methodology plays a strategic role in identifying critical processes and potential improvement strategies for the urban water system. This is evident in numerous studies of water supply and transport systems, including Godskesen et al [9], where the LCA approach was applied to evaluate three different water supply systems of the water sector in Copenhagen, Denmark, to evaluate the environmental impacts of each process involved; Del Borghi et al [10], providing the analysis of potable water supply service in Sicily, Italy; Barjoveanu et al [11], analysing the water services system in Iasi City (Romania) to demonstrate the usefulness of the LCA approach as a support tool for water resources management; and Sambito et al [12], integrating the LCA approach with an analysis of the system energy and water balance in a water supply system. Other studies focused on urban drainage systems [13,14] and treatment plants [14,15].…”