02364nam a2200253   450000500170000000800410001703500150005810000280007324500760010126000520017730000140022949000270024350001560027050200580042652012370048465000480172165000430176970000390181270000400185170000460189171000490193781000590198685600650204520260818144927.0271098s1981    th      r    0000|00eng d  a.b103891670 aChalermraj Thanantaseth10aKinetic model of biological oxidation in rotating biological contactors  aBangkok :bAsian Institute of Technology,c1981  avi, 64 p.1 aThesis ;vno. EV-81-17  aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development  aThesis (M.Eng.) - Asian Institute of Technology, 1981  aThe major problem of the treatment efficiency for nitrification is the existence of BOD5 in the wastewater. The model was developed to explain  the phenomena occurring in the rotating biological contactor unit base on the property of substrate diffusion and the degree of zero order biological  reaction within the biofilm. The active biofilm are divided into outer layer of heterotrophic and inner layer of nitrifying microorganism due to lower diffusion coefficient but higher biological reaction of organic carbonaceous substrate than the ammonia-nitrogen, and so, the nitrification rate will depend on the oxygen and ammonia-nitrogen concentration, on the  nitrifying surface, left from the heterotrophic utilization.  Experiments with low influent BOD5 concentration were carried on to prevent oxygen limitation in the heterotrophic layer and to be able to observe the reduction of oxygen penetration into the nitrifying layer. The experimental variables were hydraulic loading, influent BOD5, and the type of organic carbonaceous material. Experimental results show that higher BOD5/N ratio together with higher hydraulic loading caused the lowering in  nitrification rate. These were adequate explained by the proposed model. 0aSewagexPurificationxRotating disc process 0aSewagexPurificationxNitrogen removal1 aWatanabe, Yoshimasa, eChairperson1 aNguyen, Cong Thanh, eCo-Chaiperson1 aSamorn Muttamara, eExamination Committee2 aRoyal Danish Government, eScholarship Donor2 aAsian Institute of Technology.tThesis ;vno. EV-81-17  3Full-Textuhttp://203.159.5.9/ait-thesis/detail.php?q=B21614