| Summary: | 碩士 === 國立成功大學 === 環境工程學系碩博士班 === 101 === This study is aim at establishing an autotrophic biological nitrogen removal process, and scaling up the biological nitrogen removal process to pilot-scale, which are two-stage processes such as partial nitrification (PN) and ANAMMOX, based on the lab-scale processes operation parameters and experience. The target pollutant is petrochemical wastewater which contains high nitrogen and low carbon. After estimating the petrochemical wastewater quality, the effluent of ammonium and nitrate concentration were about 350-400 and 30 mg N/L, respectively. In PN, 50% of total ammonium will be converted to nitrite, and ANAMMOX process will treat the ammonium and nitrite continuously.
Inhibition of NOB and controlling the nitrite production rate are important in PN process. According to some references, PN reactor in lab-scale controlled the pH to 7.8 and free ammonium (FA) concentration at 10-30 mg N/L at 35-42⁰C. After operating 500 days, the NOB was inhibited successfully, and the AOB became the domainating bacteria. Besides, after calculating the oxygen transfer by KLa and interval aeration, the nitrite and ammonium ratio could be controlled (the ratio was 0.8-1.5 in lab-scale). Because pilot-scale PN reactor seeding source was different from lab-scale PN reactor, the microbial community is more diverse in pilot-scale PN reactor. Moreover, it was not able to wash out NOB due to reactor type of fixed bed. Therefore, to inhibit NOB, FA had to be controlled higher (20-50 mg N/L).
There are two type ANANNOX reactors, which are UASB and fixed-bed, in lab-scale reactors. The UASB type is ANAMMOX enrichment reactor, and the fixed-bed type is combined with PN reactor. For pilot-scale ANAMMOX reactor, UASB was chosen for reactor design. In order to avoid the sludge wash-out, the superficial velocity should be controlled carefully (1.5-2.5 m/hr). Because of the low growth rate of ANAMMOX bacteria, TN removal efficiency was only 5-10% after 300 days operation.
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