Hydraulic selection to transform and improve activated-sludge based wastewater treatment

Abstract

A majority of wastewater plants in the United States use conventional activated sludge (CAS) in their treatment process. While CAS is a common practice, it is not without faults. One of its drawbacks is the difficulty in maintaining the process, as it is often prone to bulking, which is caused by an undesired build up of filamentous bacteria and results in sludge that does not settle. Additional drawbacks include limited space for WWTPs to expand and the energy costs required for aeration during CAS treatment. Because CAS infrastructure is so common, optimizing this technology is crucial for the prevention of water pollution. Some solutions for these problems have been developed including aerobic granulation, which allows the plant to have a smaller footprint; however, these advanced wastewater technologies are not easily implemented in existing WWTPs.