03320nam a2200241   450000500170000000800410001703500150005810000220007324500900009526000520018530000150023749000270025250001580027950200580043752022270049565000430272270000390276570000510280470000440285571000550289981000590295485600650301320260817171506.0011298s1998    th      r    0000|0 eng d  a.b117338461 aKarn, Sunil Kumar10aBiological nitrogen removal under inhibitory conditions in a sequencing batch reactor  aBangkok :bAsian Institute of Technology,c1998  a113 leaves1 aThesis ;vno. EV-98-14  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, 1998  aThis study was carried out to investigate the nitrogen removal from wastewater under  inhibitory conditions using Sequencing Batch Reactor (SBR). Synthetic wastewater containing  aniline was used as feed. A 40-liter laboratory scale SBR was operated with aniline containing  synthetic wastewater during the entire investigation. Aniline concentration in the feed was  increased gradually from 100 to 450 mg/l while the total cycle time of the SBR was reduced  from 12 hours to 8 hours. The cycle time was optimized by reducing the time of react phase of  the cycle. Performance of the reactor was observed at different react phases ranging from 9  hours (3 hours aerobic and 6 hours anoxic) to 3.75 hours (1.75 hours aerobic and 2 hours  anoxic). The optimal react time was achieved at 4.75 hours (2.25 hours aerobic and 2.5 hours  anoxic). At this period, removal of aniline, COD and total nitrogen was observed more than  98%, 95% and 85% respectively for the feed aniline concentrations up to 450 mg/I. The  average rate of reaction during aerobic and anoxic phases for aniline biodegradation,  nitrification and denitrification were found as 20-40, 2-4 and 1.5-4.0 mg/gVSS/hr respectively.  Profiles of pH, DO and ORP during the react phase were successfully simulated to indicate the  specific process changes as the start and end of nitrification and denitrification processes.  The effect of inhibition due to aniline was observed during the nitrification process.  Conversion of NH4 + to N0 2- by Nitrosomonas was not initiated until the concentration of  aniline inside the reactor had dropped below 4-5 mg/I. Similarly, conversion ofN02- into N03- by Nitrobacter was inhibited when the concentration of aniline in the feed was reached to  about 400 mg/I. Furthermore, as the concentration of aniline in the feed was increased over  450 mg/I, the conversion of N02- into N03- had almost ceased. Nitrobacter activity could not  be revived even after aniline concentration in feed was reduced to 300 mg/I. However, there  was no significant loss in the total nitrogen removal efficiency of the SBR due to the effects of  inhibition as N02- produced by Nitrosomonas could still be denitrified under anoxic condition. 0aSewagexPurificationxNitrogen removal1 aAnnachhatre, Ajit P.,eChairperson1 aDahl-Madsen, Karl Iver,eExamination committee1 aKim Oanh, N. T.,eExamination committee2 aGovernment of Denmark (DANIDA),eScholarship donor2 aAsian Institute of Technology.tThesis ;vno. EV-98-14  3Full-Textuhttp://203.159.5.9/ait-thesis/detail.php?q=B13469