Sliding mode control of wastewater treatment process with activated sludge under extreme weather events

Abstract

The present climate change engender an increase of extreme weather events such as intensive rainfall, flash floods, droughts, prolonged periods of deviations from established average daily temperatures. These extreme weather events negative impact on sustainability of wastewater treatment process with activated sludge. The paper aim is to propose a sliding mode control of wastewater treatment process with activated sludge under extreme weather events is proposed. The principles of the binary control theory are used. The control design is carried out with direct use of the nonlinear model, described by three ordinary differential equations with uncertain parameters. The parameters are varied in the known intervals. These uncertainties are predetermined by the nature and intensity of the extreme weather events. The model of the sliding mode control is developed with respect to an auxiliary input variable in order to obtain the smooth signal of the dilution rate, which is need in the biodegradation processes. The good robustness of closed loop system with the designed sliding mode control in regard to various disturbances is proved through simulation investigations in MATLAB using Simulink.