Table 2. Dominant NOB under Different Control Strategies.

strategy	reactor type	NOB	DO (mg O2/L)	SRT (days)	harsh treatment	ref
oxygen-based control	UMABR	Nitrospira	0.6 ± 0.1	infinite		(110)
oxygen-based control	MBBR	Nitrospira	0.15–0.18	uncontrolled		(111)
oxygen-based control	MBBR	Nitrospira and Nitrobacter	<0.03	uncontrolled		(112)
oxygen-based control	SBR	Nitrospira	0.2–6.5	uncontrolled to 14.4 ± 2		(64)
FNA-based sidestream treatment	SBR	Ca. Nitrotoga			>1 mg HNO2-N/L FNA	(113)
FA-based sludge treatment	SBR	Ca. Nitrotoga	1.5–2.0	15	354 ± 58 mg N/L FA	(114)
FNA-based sidestream treatment	anoxic/oxic (An/O) reactor	Ca. Nitrotoga		15	1.87 mg N/L FNA	(115)
ex situ control with harsh treatments	SBR	Nitrospira and Nitrobacter	1.5–2.0	15	4.23 mg N/L FNA and sequentially 210 mg N/L FA	(103)