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Evaluating the effects of Zn(II) on high-rate biogranule-based denitrification: Performance, microbial community and sludge characteristics
- Cheng, Ya-Fei, Li, Gui-Feng, Liu, Ying-Yi, Zhu, Bing-Qian, Zhang, Qian, Xue, Yuan, Zhang, Zheng-Zhe, Jin, Ren-Cun
- Bioresource technology 2019 v.279 pp. 393-397
- Klebsiella, chronic exposure, denitrification, denitrifying bacteria, heavy metals, industrialization, microbial communities, nitrogen, sludge, wastewater, zinc
- High-rate denitrification is a popular and efficient process for treatment of nitrate-rich wastewater. Knowing the effect of heavy metals on denitrification is essential for industrial development. In the present study, the long-term impacts of Zn(II) on denitrifying granular sludge were investigated. The suppression threshold of Zn(II) on denitrifying bacteria was 10 mg L⁻¹ for long-term exposure. The nitrogen removal rate was decreased by long-term addition of 10 mg L⁻¹ Zn(II). Castellaniella and Klebsiella were the two dominant genera under Zn(II) stress. The relative abundance of Klebsiella sharply decreased to 4.64% after the addition of 10 mg L⁻¹ Zn(II), whereas Castellaniella was susceptible to 2 mg L⁻¹ Zn(II), revealing that Castellaniella mainly was devoted to denitrification under no or low Zn(II) stress conditions, whereas Klebsiella was effective under high Zn(II) stress.