A comprehensive framework to assess energy efficiency in urban water and wastewater systems

Abstract

Energy efficiency is inextricably linked to the sustainability of urban water services (UWS) since it corresponds to 30-40% of operational costs in drinking water and wastewater services. Energy costs are mainly associated with network pumping and aeration in wastewater treatment. A comprehensive framework for diagnosis of energy consumption and efficiency in water and wastewater systems involving four levels of analysis: overall UWS (level 1), each stage of the UWS (level 2), infrastructure component (level 3) (e.g., network distribution area, wastewater treatment facilities) and processes or equipment in each component (level 4) (e.g., pumping station, air mixing equipment). The assessment system proposed for the levels of analysis 2 and 3 and the approach for diagnosis and prioritization is explored in a water utility in this paper. It was demonstrated the potential of the framework to identify the different sources of inefficiencies and the impact in effectiveness and locate critical infrastructures for a more detailed analysis. This demonstrates the potential for applicability of the approach to other water utilities that participate in the Avaler+ project as well for general applicability.