Seo, G. T. creator Chongrak Polprasert Chairperson Samorn Muttamara Examination Committee Shin, Hang Sik Examination Committee Government of Japan Scholarship Donor text th Bangkok Asian Institute of Technology 1986 continuing eng 104 p. Laboratory scale experiments were conducted to investigate the interactions between the attached and dispersed growth microbial behaviors in activated sludge reactors with sludge recycle. At a 10 d SRT, the performance of the attached growth activated sludge process(AGASP) with various amounts of contact media, such as 5%, 10%, and 20% of reactor volume, was investigated by comparing its effectiveness to the conventional one at various organic loadings of 0.81, 1.44, 2.01, and 3.18 kgCOD/m3. d. AGASP showed more effectiveness than the conventional unit (at 99% of significance level by the t-test). Oxygenation parameters, a & b in AGASP, were also obtained in the range of 0.3-0.5 for a and 0.004-0.054 for b, respectively. The kinetic coefficients k , K., Y, and Kd. for AGASP were found using the LAWRENCE and McCARTY's models and appeared to be in the range of 1-2 d-1, 20-50 mg/l, 0.4-0.8, and 0.14-0.22 d-1, respectively. Computer simulation of the performance of AGASP was also {u2022} conducted using system dynamics simulation model(Attached-Dispersed growth Microbial Interaction Model, ADMIM). Even though this model showed simple results with a little sensitivity, better simulation of the performance of AGASP can be expected by considering other important parameters of the system. A research study submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development Thesis (M.Eng.) - Asian Institute of Technology, 1986 Sewage Purification Activated sludge process Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B19639 http://203.159.5.9/ait-thesis/detail.php?q=B19639 011298 20260818143659.0