Exploiting the energy potential of municipal wastewater in China by incorporating tailored anaerobic treatment processes

Abstract

Anaerobic biotechnologies bring opportunities for energy-productive wastewater treatment processes, but the energy performances of such processes vary drastically depending on the wastewater characteristics and operating conditions. So far, anaerobic digestion (AD)-based wastewater treatment processes have been seldom applied in China due to the often unfavorable wastewater properties and suboptimal operation performances. In this study, we propose a new paradigm to achieve sustainable wastewater treatment in China by customizing the AD technologies based on the organic carbon levels in wastewater. The suitability of several AD processes for specific plants was evaluated based on the plant-resolved wastewater data, and the energy recovery potential of the entire municipal wastewater sector in China was estimated. Under optimal scenario (both organic carbon and nutrient removal are taken into account), a net energy production of 3.41 billion kWh from wastewater may be achieved in China. The process of high rate activated sludge plus sludge AD is suggested as the most desirable process (with low biogas recovery cost) for 93% of plants. This work may provide guidance for enforcing energy-sustainable wastewater management in China and may also have implications for the wastewater sectors in other developing countries.