Assessment of energy consumption of municipal wastewater treatment plants in China

Energy consumption from municipal wastewater treatment plants (WWTPs) has brought escalating dual pressure of high expenditure and greenhouse gas emissions to environmental engineers and policy makers. In order to identify the underlying factors affecting energy usage, a comprehensive nationwide investigation program was done to analyze 1184 urban WWTPs in China over a period of 30 years (1984–2013). This investigation included a consolidated evaluation of key design parameters (scale, treatment process and effluent standard), different treatment units and geographical distribution of WWTPs in terms of energy consumption. Comparisons were also made between the statistical- and the baseline-value of unit energy consumption. These findings demonstrated the importance of the integrated effects of key design parameters on WWTPs energy consumption, and specific reference benchmark, recommendations, strategies and future development were provided accordingly. The present work can hopefully assist in understanding of how and to what extent key factors are incorporated into design guidelines, and also help decisions makers and engineers construct and upgrade WWTPs in the best energy saving way.