N-Removal on Wastewater Treatment Plants: A Process Control Approach

A multilayered control design approach is proposed here. Starting with the Dissolved Oxygen (DO) control loop in the last aerated tank, the control of the recirculation sludge is added next. Once the limitations of this two-loop control strategy are highlighted, a cascade control loop is proposed. This cascade control is further enhanced by a feed-forward control action that makes use of influent ammonia concentration. The resulting cascade+feedforward control configuration achieves satisfactory nitrogen removal for the three influent operating conditions (dry, rain and storm.)

[1]  Evanghelos Zafiriou,et al.  Robust process control , 1987 .

[2]  Peter A. Vanrolleghem.  On-line modelling of activated sludge processes : development of an adaptive sensor , 1994 .

[3]  Mohamed Mostefai,et al.  On estimation of unknown state variables in wastewater systems , 2009, 2009 IEEE Conference on Emerging Technologies & Factory Automation.

[4]  I. Takács.  A dynamic model of the clarification-thickening process , 1991 .

[5]  Mogens Henze,et al.  Activated sludge models ASM1, ASM2, ASM2d and ASM3 , 2015 .

[6]  John F. Andrews,et al.  Dynamic models and control strategies for wastewater treatment processes , 1974 .

[7]  Adrian Oehmen,et al.  Control of nitrate ricirculation flow in predenitrification systems. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[8]  Bart De Moor,et al.  N4SID: Subspace algorithms for the identification of combined deterministic-stochastic systems , 1994, Autom..

[9]  W. Gujer,et al.  Activated sludge model No. 3 , 1995 .

[10]  N Hvala,et al.  Feedforward-feedback control of an activated sludge process: a simulation study. , 2003, Water science and technology : a journal of the International Association on Water Pollution Research.

[11]  Sylvie Gillot,et al.  The COST Simulation Benchmark: Description and Simulator Manual , 2001 .

[12]  Paul Lant,et al.  Multivariable control of nutrient-removing activated sludge systems , 1999 .

[13]  Miss A.O. Penney.  (b) , 1974, The New Yale Book of Quotations.

[14]  J. B. Copp.  The COST Simulation Benchmark-Description and Simulator Manual , 2001 .

[15]  B. Holenda,et al.  Dissolved oxygen control of the activated sludge wastewater treatment process using model predictive control , 2008, Comput. Chem. Eng..

[16]  Ramón Vilanova,et al.  Analytical robust tuning of PI controllers for first-order-plus-dead-time processes , 2008, 2008 IEEE International Conference on Emerging Technologies and Factory Automation.

[17]  G. V. Straten,et al.  A recursively identified model for short-term predictions of NH4/NO3 – concentrations in alternating activated sludge processes , 1999 .

[18]  Bengt Carlsson,et al.  Iterative design of a nitrate controller using an external carbon source in an activated sludge process , 1998 .

[19]  N Hvala,et al.  Comparison of control strategies for nitrogen removal in an activated sludge process in terms of operating costs: a simulation study. , 2007, Water research.

[20]  Pernille Ingildsen,et al.  Realising full-scale control in wastewater treatment systems using in situ nutrient sensors , 2002 .

[21]  Jérôme Harmand,et al.  Comparison of advanced control strategies for improving the monitoring of activated sludge processes , 2004 .

[22]  J F Andrews.  Dynamic control of wastewater treatment plants. , 1994, Environmental science & technology.

[23]  Norhaliza Abdul Wahab,et al.  Multivariable PID control design for activated sludge process with nitrification and denitrification , 2009 .