Research
| Title： | High-rate partial nitrification of semiconductor wastewater: Implications of online monitoring and microbial community structure |
|---|---|
| First author： | Song, Kang; Sawayanagi, Kaoru; Numano, Tetsurou; Taniichi, Yuya; Kikuchi, Takashi; Takeda, Tomoyuki; Kanou, Hisanao; Riya, Shohei; Hori, Tomoyuki; Hosomi, Masaaki; Terada, Akihiko |
| Journal： | BIOCHEMICAL ENGINEERING JOURNAL |
| Years： | 2019 |
| DOI： | 10.1016/j.bej.2018.12.009 |
| Abstract： | The aims of this study were to investigate the feasibility of partial nitrification (PN) in a sequencing batch reactor (SBR) fed with real wastewater discharged from the washing process at a semiconductor factory, to evaluate the efficacy of online control for nitrite buildup, and to examine the microbial community composition. To this end, online monitoring of NH4+ and NO3- concentrations in an SBR was implemented to track the extant activities of ammonia-oxidizing (AOB) and nitrite-oxidizing bacteria (NOB). The results showed that the rate of NH4+ oxidation by AOB increased during the first 20 days of the operation, and were maintained as high as a maximum volumetric rate of NH4+ removal of 2.17 kg-N/m(3)/day with an NH4+ removal efficiency of 94.1-99.8%. Successful nitrite buildup (> 99.9%) has been achieved after day 20 when AOB activity was 8.11-times higher than NOB activity. High-throughput sequencing of 16S rRNA genes manifested that the relative abundance of cluster 7 Nitrosomonas species in the family Nitrosomonadaceae increased from 0.2% to 50% over total bacteria. On the other hand, the relative abundance of Nitrospira spp. as the predominant NOB decreased from 1.0% to 0.05%, indicating NOB out-selection during SBR operations. A positive correlation was noted between the abundance of the dominant AOB and NH4+ oxidation rate, suggesting that a simple nitrifier community regulated high-rate PN. |
