Energy efficiency of wastewater treatment plants. Overview of the literature and critical discussion of energy data

Abstract

In response to strong growth in energy intensive wastewater treatment, public agencies and industry began to explore and implement measures to ensure achievement of the target indicated in the 2020 Climate and Energy Package. However, in the absence of fundamental and globally recognized approach evaluating wastewater treatment plants (WWTPs) energy performance, these policies could be economically wasteful. This paper gives an overview of the literature of WWTPs energy-use performance. Energy key performance indicators (KPIs) found are presented and critically assessed, pointing out the limits to their validity. Data from more than 430 WWTPs, together with the methods for synthesizing the information is presented. The assessment of a large data sample provided some evidence about the effect of the plant size, dilution factor and flowrate. The technology choice, plant layout and country of location were seen as important elements that contributed to the large variability observed