ABSTRACT
Activated sludge is the most widely used biological technology for treating domestic and industrial wastewater. After its development with 100 years of history, many novel and modified processes have been developed to meet the more and more stringent discharge and emission limits. However, most of operating systems are suffering some drawbacks, such as substantial energy consumption, excessive greenhouse gas emission, and labourintensive industry. As a powerful tool, Activated Sludge Models (ASMs) have proven to be very useful in process design, operation and optimization [1,2]. To date, ASMs for the simulation of biological nutrients removal processes have been updated from the first version of ASM1 to more compli-
cated extensions, including ASM2, ASM2d, and ASM3 [3], and further to the extended ASM3s [4-10] in order to satisfy various requirements.
