Integrated A-B processes for municipal wastewater treatment

Abstract

Currently, the widely adopted conventional biological processes for municipal wastewater treatment are receiving increasing attention regarding their intensive energy consumption and huge amount of sludge production. However, significant improvements in energy efficiency are unlikely to be reached via further optimization of the conventional biological processes (Wan et al., 2016). Therefore, more effort should be dedicated to the development and adoption of innovative process configurations and emerging technologies for municipal wastewater treatment. In fact, chemical oxygen demand (COD) capture from municipal wastewater is critical to move towards direct energy recovery instead of biological oxidation of COD. In Chapter 2, novel technologies that are able to capture COD for energy recovery have been presented in detail. However, these technologies could not stand alone for municipal wastewater treatment due to their ineffectiveness in nitrogen removal. As such, processes for COD capture should be integrated with processes specially designed for energy-efficient nitrogen removal, and it is this configuration which has become known as the A-B process. In the A-B process, the A-stage is designed for the capture of COD for energy recovery instead of biological oxidation, whereas the B-stage is primarily dedicated to nutrient removal or recovery (Wan et al., 2016). As shown in Figure 3.1, there seem to be various combinations of the A-B process.