Table 3.

Biomass yields for AOB and NOB, and an assumed heterotrophic biomass yield for mixotrophic NOB and the corresponding biomass concentration and relative community composition according to consumed substrate (37 mg COD/L; 60 mg NH₄-N/L)

	Yx/Hac	Yx/N	mg VSS/L	Community composition [%]		Reference for yields
AOB	–	0.13	8	67a	25b	(Blackburne et al. 2007b)
NOB	–	0.07	4	33a	12b	(Blackburne et al. 2007a)
Mixotropic NOB	0.4	–	21	–	63b	(Beun et al. 2001)
NOB/AOB ratio				0.5	3

Calculations based on assumption of a) autotrophic growth of nitrifiers and b) mixotrophic growth of NOB on 37 mg COD/L. _;