Dissertation > Excellent graduate degree dissertation topics show

Study on the Achievement of Shortcut Biological Nitrogen Removal in Continuous-Flow A/O Process and Its Stability

Author: XuHengJuan
Tutor: YinJun;ShenDongSheng
School: Zhejiang Technology and Business University
Course: Environmental Engineering
Keywords: Low C/N ratio Shortcut nitrification and denitrification continuous-flow A/O process Shocking load
CLC: X703
Type: Master's thesis
Year: 2014
Downloads: 4
Quote: 0
Read: Download Dissertation

Abstract


Denitrification process is limited by insufficient organic carbon in conventional wastewater treatment plants during the treatment of domestic wastewater with low C/N. Compared with the traditional biological nitrogen removal (BNR) process, shortcut biological nitrogen removal (SBNR) process resulted in saving25%of oxygen supply for nitrification while reducing40%carbon source requirement for denitrification. It has unique advantage for treating wastewater with low C/N. In this work, lab-scale continuous-flow A/O process with biological nitrogen removal (BNR) reactor and hybrid biological nitrogen removal (HBNR) reactor was adopted. The objectives of the study were to achieve shortcut biological nitrogen removal from wastewater with low ammonium concentration and low C/N ratio in two reactors, to investigate the properties of EPS fractions extracted from activated sludge and biofihn in the course of establishing shortcut biological nitrogen removal process, to discuss the mechanisms responsible for the achievement of shortcut nitrogen removal, and to evaluate the performance and mechanisms of shock resistance to short-term changes in C/N ratio, organic nitrogen, Cu2+of the influent in the HBNR. The primary results of this study are summarized as follow:(1) Nitrogen removal via nitrite in HBNR and BNR reactors applied to conventional continuous-flow A/O process treating low-strength ammonium wastewater was successfully achieved by controlling DO concentration of1.0～1.5mg/L in the aerobic tank. For BNR, ammonium removal efficiency (NH4%) maintained at high level(above90%), while average nitrite accumulation rate was64.5%and TN removal efficiency was74.4%under steady state. For HBNR, average ammonium removal efficiency was95.7%, the nitrite accumulation rate was63.6%, and TN removal efficiency was88.1%.In comparison to BNR, TN removal efficiency of HBNR was significantly higher than during the whole experiment. Based on mass balance for nitrogen, fates for nitrogen in HBNR and BNR were distinct from one another. In BNR most TN was removed by denitrification in the anoxic tank, whereas TN removal was dominated by simultaneous nitrification-denitrification (SND) via nitrite in the aerobic tank of HBNR.(2) EPS content and abundance of nitrifying bacteria in BNR and HBNR during start-up and steady operation periods were investigated. In both reactors, a clear change of EPS content was observed during the achievement of SBNR process, which was considered as a protective response of bacteria to the change of environment. SVI had positive correlations with LB-EPS content and protein content of LB-EPS of activated sludge. The nitrite pathway negatively impacted on the sludge settleability. Although sludge bulking happened in SBNR process, it did not influence the nitrogen removal. SOUR and qPCR assays demonstrated that AOB were dominant in activated sludge and biofihn after SBNR process established, while low DO concentration promoted AOB growth. NOB was not completely washout from the reactors, but the abundance of NOB evidently deceased in stable operation period, compared to complete nitrification period.(3) The effects of C/N ratios, organic nitrogen and Cu2+concentrations in the influent on the performance of HBNR in short-term shocking were examined. TN removal efficiency declined to15.3%and25.3%for C/N ratios of2and4, respectively. LB-EPS contents of bioflim and activated sludge were affected by the change of influent C/N ratio. The HBNR has good resistance to the shock of organic nitrogen in the wastewater, but EPS contents of biofilm and activated sludge obviously increased. TN removal efficiency declined to5.2%,9.9%and28.7%after shocking with Cu2+concentrations of1mg/L,2mg/L and5mg/L, respectively. SND was inhibited since the concentration of Cu2+was2mg/L. When the concentration of Cu2+was increased to5mg/L, TN removal efficiency was further decreased, and the HBNR can not be recovered.

Related Dissertations

  1. Pilot Plant Research on Hydrolysis & Micropore Aeration Integral Combined Oxidation Ditches in the Process of Municipal Sewage Treatment with Low C/N Ratio,X703
  2. Use Machine-made Sand to Produce High Performance Concrete in Low Ratio of Water-binder and the Performance’s Nonlinear Prediction,TU528
  3. Lower than conventional heavy liquid bubble Flooding,TE357.46
  4. Study of Seismic Data Processing Technology in Complex Low Noisesignal Ratio Area,P631.4
  5. CNOOC D field development program design,TE323
  6. Experimental Research on Low C/N Ratio Municipal Wastewater Treatment by UCT Process,X703
  7. A Study of Low Coke Yield Catalyst for Resid Fluid Catalytic Cracking,TE624.91
  8. Research on Mechanisms of Decentralized Treatment Process for Domestic Sewage,X703
  9. Test Study on shortcut nitrification wastewater with low carbon nitrogen ammonia,X703
  10. An Empirical Study of the Price-earnings Ratio Effect and Size Effect on Shanghai Stock Market,F224
  11. Reproductive Mechanism and Adaptive Significances of Hosta Ventricosa 'Excess Flowers Production, But Few Fruit Set',Q948.1
  12. Research on Nitrogen Removal of Alternating Biological Aerated Filter for Sewage Treatment,X703
  13. Response of Sewage Sludge Microbial Communities to Carbon Source Supplementary and Effects of Nityogen and Phosphorus Removal,X703
  14. Study on Nitrogen Removal Performance of Nitrosification in SBR-ANAMMOX in Compound UASB Process,X703
  15. Research on Treatment of Tailwater from Urban Sewage Treatment Plant by Biological Activated Carbon Filter (BACF),X703
  16. Study on the Characteristics of Shortcut Nitrification-Denitrification Integrated with Sludge Anaerobic Hydrolysis for Nitrogen Removal Process,X703
  17. Study on Nitrogen Removal Performance of Shortcut Nitrification-denitrification in A/O Coupled with Sludge Hydrolysis,X703
  18. Nitrogen Removal in Low C/N Ratio Domestic Wastewater,X703.1
  19. Study on N2O Production during Nitrogen Removal with Aerobic Granular Sludge,X703
  20. Development on a New Aerated Concrete of Lightweight, High-strength, Insulate Energy-saving for Outer Walls,TU528

CLC: > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Wastewater treatment and utilization
© 2012 www.DissertationTopic.Net  Mobile