Kim, Jeong-hun creator Harada, Hideki Chairperson Kim Sun-Il Examination Committee Mino, Takashi Examination committee DAAD, Federal Republic of Germany Scholarship Donor text series technical report th Bangkok Asian Institute of Technology 1991 continuing eng 79 p. Three identical small scale membrane bioreactors were operated in parallel to investigate the effect of the ratio of N/COD in the Influent on the nitrification performance. The NH4+-N concentration of the influent was fixed at 400 mg/l varying the COD concentration of that with 0, 1000 mg/l and 2000 mg/l for reactor 1, 2 and 3, respectively. The continuous experiments were conducted for 110 days varying nitrogen loading from 0.6 to 2.4 gNH-i+-N/l.d. The reactors were operated at pH 7.0-7.8 and very long sludge retention time with intermittent feeding mode to examine microfiltration efficiency and maximum allowing nitrogen loading as well as the effect of the activity of heterotrophs on nitrification Clogging did not occur when biological solids were retained in the reactor at a lower concentration. Serious clogging did occur at higher loadings in the reactor retaining a higher solid concentration. The result clearly indicate that the addition of organic matter, which provokes the growth of heterotrophs, inhibits nitrification because of loss of ammonia for assimilation of heterotrophs. Ammonia utilization rate, k, determined in batch experiments was 4. 14d- 1 when no glucose was added. The addition of glucose to the reactor resulted in a low k (2.50d- 1 and 2.30d-1 ) and 0.097 and 0.036 of the ratio of nitrifies to total biomass when the ratio of N/COD were 2.5 and 5.0, respectively. It is suggested that inhibition takes place by crowded cells of heterotrophs on nitrification. A nitrification rate of 2.51 gNH4+-N/l.d was attained with 88.1% of nitrification efficiency. More than 10% and 25% of the oxidized nitrogen in the reactors were denitrified at the same time when 1000 mg/l and 2000 mg/1 of COD were added, respectively. 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, 1991 Sewage Purification Activated sludge process Nitrification Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B17417 http://203.159.5.9/ait-thesis/detail.php?q=B17417 170399 20260818090843.0