Research On Active Disturbance Rejection Control Application In Wastewater Treatment Process

Aerobic internal-circulation three-phase bio-fluidized bed (ITFB) is a new and efficient technique for wastewater treatment, which combines the activated sludge wastewater treatment process and Bio-Membrane technology. It is characteristic of high-volume load, fast mass transfer, strong impact resistance, small area occupied and stable operation, but its energy consumption is much higher. Besides, big inertia, nonlinearity and time-variant property of wastewater treatment make it hard to establish a mathematical model for control purpose. It is very necessary to study the closed-loop control of wastewater treatment with ITFB so that energy consumption caused by over-aeration can be reduced and ammonia-nitrogen concentration of water out can keep stable and meet the boundary.The paper mainly study closed-loop control of ammonia-nitrogen wastewater treatment with ITFB by simulation. Firstly, a brief mathematical model is established based on intensive analysis on the process and some of the experimental data, when taking aeration as input, and ammonia-nitrogen concentration of wastewater-out as output. Secondly, according to the model, one-order and two-order active disturbance rejection controllers (ADRC) of the wastewater treatment with ITFB are created, and simulation researches are committed to make the controllers work well under some disturbances. Lastly, set the output limiter of ADRCs and optimize parameters of them. It turns out that the system has zero static error and zero overshoot with settling time less than or equal to 2000s when the reference and disturbance input are step. It also shows ADRC has stronger robustness. The performance could overcome the inaccuracy and uncertainty of the object model, thus ADRC is applicable to the ammonia-nitrogen wastewater treatment process with ITFB.