Surface water environment in China was degraded rapidly in the last two decades, resulting in increasingly tighten criteria issued for municipal wastewater treatment plants (WWTPs). This paper reviewed the recent advances of process design and operational optimization for nutrients removal. Three major processes, as anaerobic-anoxic-oxic (AAO) process, oxidation ditch (OD), and sequencing batch reactor (SBR) occupied 65% of WWTPs amounts and 54% of treatment volumes of China in 2006. However conservative process designs and operational faults often impaired the process performances and energy efficiency. Therefore, typical processes were modified, combined, and innovated to meet the requirements of the diverse influent characteristics and lower energy consumptions. Furthermore, operational optimization techniques by modeling, simulation, and real-time control were also developed and applied in China to improve the process operation. Although great efforts had been contributed to improve the WWTPs performances in China, attentions should be continuously paid to the introduction, instruction, and implementation of advanced techniques. At last, the technical demands and appropriated techniques of WWTPs in China were briefly discussed. 1. Introduction In the last two decades, surface water environment in China was rapidly degraded by the booming industrialization and fast urbanization. The first large scale municipal wastewater treatment plant (WWTP) in China was constructed and operated 25 years ago [1]. In recent ten years, the construction of municipal WWTPs was catalyzed by the serious deterioration of surface water around cities, as shown in Figure 1. The reduction of ammonia nitrogen (NH3–N) and total phosphorous (TP) are also shown in the figure [2] in the unit of part per million (ppm) and also mg/L in water. The ammonia reduction was only 13.2 to 18.3？mgN/L and the phosphorous reduction was almost constant at 2.5？mgP/L from 2001 to 2007 [1], implying unsatisfied process performances in current WWTPs. Figure 1: Nutrients reduction in municipal WWTPs based on treated wastewater in China. The rapid development of municipal WWTPs and their unsatisfied performances promoted the engineering innovations, as well as the academic studies. In this paper, the recent progresses of nitrogen and phosphorous removal in municipal WWTPs were reviewed in the aspects of process design and operational optimization, the advances in academic studies, and the practices in engineering fields in China. 2. WWTP Processes in China 2.1. Features of Processes in WWTPs in China
References
[1]
National Engineering Research Center for Urban Water and Wastewater, “The state and planning of municipal sewage treatment in China,” in China Environmental Protection Industry, vol. 1, pp. 32–35, 2003.
[2]
China Statistic Year Book on Environment 2001, 2002, 2003, 2004, 2005, 2006, 2007, China Statistic, 2002–2008.
[3]
China association of Drainage and Water Supply. China wastewater treatment plants compilation. Publishing in Beijing.
[4]
L. Xu and H. Shi, “Introduction and application of the operation decision support system for wastewater treatment plants (WWTP ODSS),” Water and Wastewater, vol. 32, pp. 105–108, 2006 (Chinese).
[5]
N. Li, X. Wang, N. Ren, K. Zhang, and H. Kang, “Application of nitrogen and phosphorous removal processes in wastewater treatment plants in China,” Water and Wastewater, vol. 34, pp. 39–42, 2008 (Chinese).
[6]
J. Fan, T. Tao, J. Zhang, and G.-L. You, “Performance evaluation of a modified anaerobic/anoxic/oxic (A2/O) process treating low strength wastewater,” Desalination, vol. 249, no. 2, pp. 822–827, 2009.
[7]
G. Zeng, R. Jiang, G. Huang, M. Xu, and J. Li, “Optimization of wastewater treatment alternative selection by hierarchy grey relational analysis,” Journal of Environmental Management, vol. 82, no. 2, pp. 250–259, 2007.
[8]
Committee of Water Pollution Treatment, “Technical Development Report on Water Pollution Treatment Industry of Our Country in 2007,” China Environmental Protection Industry, vol. 11, pp. 12–16, 2008.
[9]
G.-F. He, Z.-Y. Zhou, and T.-Y. Gao, “Denitrification effect and affecting factors of activated sludge process with addition of suspended carrier,” China Water and Wastewater, vol. 19, no. 6, p. 6, 2003 (Chinese).
[10]
J. Wang, H. Shi, and Y. Qian, “Wastewater treatment in a hybrid biological reactor (HBR): effect of organic loading rates,” Process Biochemistry, vol. 36, no. 4, pp. 297–303, 2000.
[11]
J. Guo, F. Ma, C.-C. Chang, D. Cui, L. Wang, J. Yang, and L. Wang, “Start-up of a two-stage bioaugmented anoxic-oxic (A/O) biofilm process treating petrochemical wastewater under different DO concentrations,” Bioresource Technology, vol. 100, no. 14, pp. 3483–3488, 2009.
[12]
Z. Wu, Y. An, Z. Wang, S. Yang, H. Chen, Z. Zhou, and S. Mai, “Study on zeolite enhanced contact-adsorption regeneration-stabilization process for nitrogen removal,” Journal of Hazardous Materials, vol. 156, no. 1–3, pp. 317–326, 2008.
[13]
Y. Qian, X. Wen, and X. Huang, “Development and application of some renovated technologies for municipal wastewater treatment in China,” Frontiers of Environmental Science and Engineering in China, vol. 1, no. 1, pp. 1–12, 2007.
[14]
H. Lu, J. Wang, S. Li, G.-H. Chen, M. C. M. van Loosdrecht, and G. A. Ekama, “Steady-state model-based evaluation of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process,” Water Research, vol. 43, no. 14, pp. 3613–3621, 2009.
[15]
L. Ye, C.-Y. Peng, B. Tang, S.-Y. Wang, K.-F. Zhao, and Y.-Z. Peng, “Determination effect of influent salinity and inhibition time on partial nitrification in a sequencing batch reactor treating saline sewage,” Desalination, vol. 246, no. 1-3, pp. 556–566, 2009.
[16]
Y. Ben, Z. Chen, Z. Xu, and A. Jiang, “Application of immobilized psychrotrophs in ICCBR to treat domestic wastewater and its microbiological investigation,” Chinese Science Bulletin, vol. 54, no. 9, pp. 1599–1606, 2009.
[17]
K. Yang, X.-J. Yang, and M. Yang, “Enhanced primary treatment of low-concentration municipal wastewater by means of bio-flocculant Pullulan,” Journal of Zhejiang University—Science A, vol. 8, no. 5, pp. 719–723, 2007.
[18]
G. Qiu, L. Xiang, Y. Song, J. Peng, P. Zeng, and P. Yuan, “Comparison and modeling of two biofilm processes applied to decentralized wastewater treatment,” Frontiers of Environmental Science and Engineering in China, pp. 1–9, 2009.
[19]
G. Zhu, Y. Peng, L. Zhai, Y. Wang, and S. Wang, “Performance and optimization of biological nitrogen removal process enhanced by anoxic/oxic step feeding,” Biochemical Engineering Journal, vol. 43, no. 3, pp. 280–287, 2009.
[20]
J. Tong and Y. Chen, “Recovery of nitrogen and phosphorus from alkaline fermentation liquid of waste activated sludge and application of the fermentation liquid to promote biological municipal wastewater treatment,” Water Research, vol. 43, no. 12, pp. 2969–2976, 2009.
[21]
T. Kuba, M. C. M. van Loosdrecht, and J. J. Heijnen, “Phosphorus and nitrogen removal with minimal COD requirement by integration of denitrifying dephosphatation and nitrification in a two-sludge system,” Water Research, vol. 30, no. 7, pp. 1702–1710, 1996.
[22]
X. Hao, M. C. M. van Loosdrecht, S. C. F. Meijer, and Y. Qian, “Model-based evaluation of two BNR processes—UCT and A2N,” Water Research, vol. 35, no. 12, pp. 2851–2860, 2001.
[23]
H. Liu, L. Sun, and S. Xia, “An efficient DPB utilization process: the modified A2N process,” Biochemical Engineering Journal, vol. 38, no. 2, pp. 158–163, 2008.
[24]
J. Wang, Y. Peng, S. Wang, and Y. Gao, “Nitrogen removal by simultaneous nitrification and denitrification via nitrite in a sequence hybrid biological reactor,” Chinese Journal of Chemical Engineering, vol. 16, no. 5, pp. 778–784, 2008 (Chinese).
[25]
H. Pang, H. Shi, and H. Shi, “Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch,” Frontiers of Environmental Science and Engineering in China, vol. 3, no. 4, pp. 470–476, 2009.
[26]
S. Zhang, R. van Houten, D. H. Eikelboom, H. Doddema, Z. Jiang, Y. Fan, and J. Wang, “Sewage treatment by a low energy membrane bioreactor,” Bioresource Technology, vol. 90, no. 2, pp. 185–192, 2003.
[27]
W. Shen, X. Chen, M. N. Pons, and J. P. Corriou, “Model predictive control for wastewater treatment process with feedforward compensation,” Chemical Engineering Journal, vol. 155, no. 1-2, pp. 161–174, 2009.
[28]
P. Sun, R. Wang, and Z. Fang, “Fully coupled activated sludge model (FCASM): model development,” Bioresource Technology, vol. 100, no. 20, pp. 4632–4641, 2009.
[29]
M. Ji, J. S. Huo, Z. L. Hu, W. J. Ma, W. Y. Liu, and B. X. Zhang, “Study and application of mathematical model for activated sludge process,” China Water & Wastewater, vol. 17, no. 8, pp. 18–22, 2001 (Chinese).
[30]
L. Fan, N. Xu, X. Ke, and H. Shi, “Numerical simulation of secondary sedimentation tank for urban wastewater,” Journal of the Chinese Institute of Chemical Engineers, vol. 38, no. 5-6, pp. 425–433, 2007.
[31]
L. Guo, D. Zhang, D. Xu, and Y. Chen, “An experimental study of low concentration sludge settling velocity under turbulent condition,” Water Research, vol. 43, no. 9, pp. 2383–2390, 2009.
[32]
D. Zhang, Z. Li, P. Lu, T. Zhang, and D. Xu, “A method for characterizing the complete settling process of activated sludge,” Water Research, vol. 40, no. 14, pp. 2637–2644, 2006.
[33]
L. Fan, N. Xu, Z. Wang, and H. Shi, “PDA experiments and CFD simulation of a lab-scale oxidation ditch with surface aerators,” Chemical Engineering Research and Design, vol. 88, no. 1, pp. 23–33, 2010 (Chinese).
[34]
Y. Liu, H. Shi, and H. Shi, “Study of operational conditions of simultaneous nitrification and denitrification in a Carrousel oxidation ditch for domestic wastewater treatment,” Bioresource Technology, vol. 101, no. 3, pp. 901–906, 2010.
[35]
Q. Wen, Z. Chen, and H. Shi, “T-RFLP detection of nitrifying bacteria in a fluidized bed reactor of achieving simultaneous nitrification-denitrification,” Chemosphere, vol. 71, no. 9, pp. 1683–1692, 2008.
[36]
J. Guo, Y. Peng, S. Wang, Y. Zheng, H. Huang, and Z. Wang, “Long-term effect of dissolved oxygen on partial nitrification performance and microbial community structure,” Bioresource Technology, vol. 100, no. 11, pp. 2796–2802, 2009.
[37]
J. Guo, Q. Yang, Y. Peng, A. Yang, and S. Wang, “Biological nitrogen removal with real-time control using step-feed SBR technology,” Enzyme and Microbial Technology, vol. 40, no. 6, pp. 1564–1569, 2007.
[38]
C. Wu, Z. Chen, X. Liu, and Y. Peng, “Nitrification-denitrification via nitrite in SBR using real-time control strategy when treating domestic wastewater,” Biochemical Engineering Journal, vol. 36, no. 2, pp. 87–92, 2007.
[39]
Q. Yang, S. Wang, A. Yang, J. Guo, and F. Bo, “Advanced nitrogen removal using pilot-scale SBR with intelligent control system built on three layer network,” Frontiers of Environmental Science and Engineering in China, vol. 1, no. 1, pp. 33–38, 2007.
[40]
Y. Z. Peng, Y. Ma, and S. Y. Wang, “Improving nitrogen removal using on-line sensors in the A/O process,” Biochemical Engineering Journal, vol. 31, no. 1, pp. 48–55, 2006.
[41]
C. Huang, C. Zhang, and X. Wang, “Application of bioprocess intelligent optimization system in wastewater treatment plant,” Electric Automation, vol. 28, pp. 71–73, 2006 (Chinese).
[42]
G. O. Engin and I. Demir, “Cost analysis of alternative methods for wastewater handling in small communities,” Journal of Environmental Management, vol. 79, no. 4, pp. 357–363, 2006.
