The combined effects of carbon source (HAc, HPr, Glu, Glu + HAc) and nitrate concentration (40, 80 mg/L labeling as R40, R80) on partial denitrification (PD) were discussed at C/N ratio of 2.5 (COD = 100, 200 mg/L). The optimal NO2--N and NTR reached to 67.03 mg/L, 99.14% in HAc-R80 system, and denitrification kinetics revealed the same conclusion, corresponding to higher COD utilization rate (CUR: 58.46 mgCOD/(gVSS·h)), nitrate reduction rate (NaRR: 29.94 mgN/(gVSS·h)) and nitrite accumulation rate (NiAR: 29.68 mgN/(gVSS·h)). The preference order was HAc > HPr > Glu + HAc > Glu in both R40 and R80 systems due to different metabolic pathways, however, the NO2--N accumulation and kinetic parameters of R80 group were dramatically higher than those in R40 for the same carbon source. The R80 group facilitated more concentrated biodiversity (607-808 OTUs) with Terrimonas and norank_f_Saprospiraceae responsible for high NO2--N accumulation in HAc and HPr served systems, while norank_f_norank_o_Saccharimonadales and OLB13 dominated the Glu containing systems.
Keywords: Carbon source; Microbial community; NO(2)(−)-N accumulation; NO(3)(−)-N concentration; Partial denitrification.
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