The activated sludge process(ASP) was first developed by Ardern and Lockett in 1914 and has been playing the major role in the treatment of wastewater. By the end of 1999, the ASP took up 95.66% of treatment capacity in Korea and the situation does not seem to change in the near future.
The ASP is a complicated biological system which is under large or rather extreme changes of the environment. This results in the difficulty of operation, and many of the existing wastewater treatment plants report that they have difficulty to comply with the effluent quality standard. The fundamental principle of the ASP is all the same from the start, but a number of operational techniques or strategies have been proposed. Nevertheless, nearly all of them are proposed on the basis of their own experimental condition, which makes it difficult to compare them with each other and find the best practice.
In an effort to find the better or best practice of operation, this study tries to set up a simulation benchmark. Once set up, the simulation benchmark can serve as a standardized tool to evaluate the the dffectiveness of operational strategies. The simulation benchmard is composed of a simulator, standard simulation environment, the creteria for the evaluation of the simulation result, and the evaluation protocol for the whole benchmarking process.
The simulation benchmark is a common ground for the researchers and, therefore, it should be set up with a concerted effort of as many researchers as possible. The main focus of this study is to establish a methodology to develope a simulation benchmark from which any future word can start.
In this study, a whole set of simulation benchmark was defined and developed. Considering the real situation of the wastewater treatment plants in Korea, the simulation environment was set up. The aeration tank model was set up using the IAWQ Activated Sludge Model No.3. The sedimentation tank model was set up using the 1-dimensional solids fuux modelling scheme by Vitasovic with the double exponential settling velocityequation by Tak$\dot{a}$cs. The evaluation criteria was set up focussing mainly on the treatment efficiency and cost. Finally, the whole step-by-step benchmarking procedure was defined. Lots of sources and ideas are from the interim report of the Simulation Benchmark work groups of LAWQ and COST624 and from the work of Choi(1999).
As an example of the application of the simulation benchmark, three DO concentration control strategies were evaluated. The benchmarking test shows that a well-established simulation benchmark can be very useful.
