03692nas a2200433 4500 20260818094318.0 271098s1981 th r 000| eng d .b10216352 AIT Thesis no.EV-81-7 Bravo, Helen E. Dynamics of nitrification in rotating biological contactors Bangkok : Asian Institute of Technology, 1981 69 leaves : ill. Thesis ; no. EV-81-7 A thesis 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, 1981 A dynamic model was developed to represent the dynamic responses of nitrification in a fixed-film rotating biological contactor, the key feature of which is the use of the steady state kinetic model to describe substrate-uptake in the biofilm. Results of the experiment showed that during transient operations, a pseudo-steady state concentration distribution is established after a short lapse of time, in the diffusion layer and in the biofilm with respect to the bulk-liquid substrate concentration. There was a transient rise in the ammonia flux at the biofilm surface and the shift to steady state flux level was reached after a few disk rotations. Substrate-uptake rate was observed constant once a certain critical film thickness was exceeded and was not increased by further accumulation of microorganisms on the slime. It was also observed that the nitrifying bacteria exhibited a very small lag in growth rate when exposed to sudden changes in concentration. Furthermore, when the concentration of the products accumulated in excessive amounts it was observed that the out-diffusion of products from the internal pores of the biomass to the outer surface of the film affected the rate of substrate utilization resulting to process instability especially with long term transients. Conclusion based on engineering calculations are presented to illustrate design and operational mode for a more effective control of nitrification in dynamic systems. Simple forcing functions like pulse and step functions were used to verify the dynamic model in the zero-order regime; that is at bulk- ammonia concentration greater than 3 mg/l. Results of the experiment adequately verified the dynamic models developed. Sewage Purification Rotating disc process Nitrification Watanabe, Yoshimasa, Chairperson Lohani, B.N., Co-Chairperson Chongrak Polprasert, Examination Committee The Government of the Federal Republic of Germany, Scholarship Donor Asian Institute of Technology. Thesis ; no. EV-81-7 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B21595 .b10216352 mnait x 250108 2 951012 m a x 0 mnait mnarc mnait 22 40 20 Barcode : 30050120655864 CREATED : 2014-03-02 RECORD # : i12754456 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050160084751 CREATED : 2016-04-05 RECORD # : i12968511 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050121075310 CREATED : 2023-03-16 RECORD # : i13438256 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 32167 32167 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.EV-81-7 30050120655864 2026-08-18 09:43:18 3 2026-08-18 22 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.EV-81-7 30050160084751 2026-08-18 09:43:18 2026-08-18 40 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.EV-81-7 30050121075310 2026-08-18 09:43:18 1 2026-08-18 20