Table 1. The correlation analysis of fluorescence characteristics and sludge properties.

	Peak Ain	Peak Bin	Peak Cin	Peak Din	Peak Aex	Peak Bex
NRR	0.678**	0.648**	0.896***	0.849***	0.221	0.218
NH4+-N removal rate	0.696**	0.680**	0.879***	0.866***	0.168	0.177
NO2−-N removal rate	0.696**	0.683**	0.877***	0.823***	0.257	0.271
N removal efficiency	0.109	0.022	0.309	0.255	0.126	-0.075
NH4+-N removal efficiency	0.072	0.019	0.177	0.179	0.072	0.014
NO2−-N removal efficiency	0.258	0.092	0.274	0.151	0.316	0.082
Removal ratio of NH4+-N and NO2−-N	0.454*	0.449*	0.469*	0.369*	0.478*	0.496*
MLVSS	0.827***	0.813***	0.693**	0.650**	0.133	0.308
MLVSS growth rate	0.805***	0.501*	0.367	0.371	0.164	0.162