Table 3.

Nitrogen removal in laboratory-, pilot- and full-scale nitritation-denitritation systems.

	Influent NH4+ conc. (mg-N/L)	C/N ratio	Operational temperature (°C)	HRT (days)	NH4+ conversion rates (%)	NRR (kg-N/m3-day)	NRE (%)	Remarks	References
1	4,559 ± 201	-	36 ± 1	-	60	-	-	250 l system	Ganigué et al. (2010)
2	>1,000	2.4	30–40		>90	-	65-95a	Full-scale system	Mulder et al. (2001)
3	1,135	2.2	30–32	2.3	80b	1.0	67	5.65 l CSTR	Fux et al. (2006)
4	1,216	1.94		1.0–1.6	95c	3.0–3.6	93	6 l SBR with continuous sludge addition
5	400–700	-	35	-	1-3d	-	95-98	7 l CSTR operated with sequencing of operations	Claros et al. (2012)
6	1750-1900b	-	-	1.86-2.71/2.71	79–98	0.63	95	Two-stage SBRs (10 l/6 l)	Zhang et al. (2019)
7	200 ± 18e	3	20–22	0.71–3.33	-	-	100	5 l SBR	Bernat et al. (2016)

^aFrom Figure 6 in the source file.

^bEstimated in Figure 2 in the source file.

^cEstimated from Figure 3 in the source file.

^dFigure 3a in the source file;

^eNO₂⁻.