Modeling And Simulation Of Bi-cyclic Two-phase (bict) Biological Process

In the BICT (Bio-Cyclic Two-Phase) biological process, different micro-organisms are intensified in different reactors with two sludge systems, so the conflicts between them caused by different metabolism conditions are reduced, thereby the N,P can be removed effectively and steadily. The process is consisted of a biological selector (anaerobic), a main react region (SBR), an independent bio-film reactor and a settling tank. BICT is a compound process of suspended growth activated sludge system and biofilm system, simultaneously, BICT is also a compound process of continuous system and intermittent system. Based on Matlab and ASM2, the dissertation focuses on developing BICT mathematical model, using a supposed non-physical wastewater treatment to analyze and validate itself.The dissertation's main contents include: BICT modeling method study, BICT modeling, and model analysis and validation.Firstly, it introduces moeling method from two aspects of physical boundary conditions and biochemical reactions. Here, ASM2 is selected as the model platform for the activated sludge system (biological selector and SBR) in BICT, one-order react kinetics is chosen to describe the reactions in bio-film reactor. BICT modeling process mainly include continuous system modeling, intermittent system modeling, swith between four SBRs and connection between continuous system and intermittent system.Secondly, Matlab is selected as a mathematical calculate tool. With the tool, the model is described in mathematical way via computer programming.It introduces modularization method, dividing the program into several modules, each module completes its corresponding sub-functions. Then, an ordinary differential equation group is produced, which including 98 ordinary differential equations, and use the mathematical algorithms ode15s to slove the ordinary differential equation group. By a mass of debugging, the BICT model is compelted.Thirdly, according to certain reactor volume and run conditions, the developed BICT model is applied to simulate, analyze and study a non-entitative typical municipal wastewater treatment process. Consequently, the model is validated. Typical municipal wastewater is selected as model influent, kinetics parameters are corrected by Arrhenius equation based on typical values during 20 centigrade in ASM2. Stoichiometric parameters are given by ASM2. On the foundation of fore experimental results, contrast the curve trend of experimental results and model output, the developed model is validated.Finally, using the model to simulate the overall efficiency of BICT.It includes two areas: the influences study of fators affecting running performance, COD,N,and P's by-laws of time changes in main reactor.The results show that the BICT model based on Matlab can simulate the operation process of BICT, and it can be used as a basic tool for BICT further research, analysis and design.