U-Model-Based Active Disturbance Rejection Control for the Dissolved Oxygen in a Wastewater Treatment Process

Table 1

List of variables in BSM1.

Q0	Inlet flow rate
Z0	Influent constituent concentration
Qa	Internal flow recirculation rate
Za	Internal flow constituent concentration
Qr	Return sludge flow rate
Zr	Return sludge constituent concentration
Qf	Flow rate to the secondary clarifier
Zf	Constituent concentration of the wastewater to the secondary clarifier
Qu	Underflow rate of the secondary clarifier
Zu	Constituent concentration of the underflow rate of the secondary clarifier
	Wastage flow rate
	Wastage constituent concentration
Qe	Effluent flow rate
Ze	Effluent constituent concentration
SO,i	Oxygen concentration at compartment i
KLa,i	Oxygen transfer coefficient at compartment i
AE	Aeration energy
PE	Pumping energy
SP	Sludge production to be disposed
ME	Mixing energy
EC	Consumption of external carbon source
TSS	Suspended solid concentration
Vi	Volume of the tank i
XS,i	Slowly biodegradable substrate concentration at tank i
XI,i	Particulate inert organic matter concentration at tank i
XB,H,i	Active heterotrophic biomass concentration at tank i
XB,A,i	Active autotrophic biomass concentration at tank i
XP,i	Particulate products arising from biomass decay concemtration at tank i
r 5	Appropriate conversion rate