“…The following supporting information can be downloaded at: , Figure S1: The variations in TN removal efficiency (%) in different SPD systems; Table S1: Primers of target genes used in qPCR analysis; Table S2: The results of ANOVA for the model (response: TN removal efficiency); Table S3: The optimized TN removal efficiency based on RSM; Table S4: The actual TN removal efficiency under optimized conditions; Table S5: Functional classification of major genera in bacterial and fungal communities. [ 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 ] of the references in the main text are from the supplementary material.…”