Evaluating the effects of Zn(II) on high-rate biogranule-based denitrification: Performance, microbial community and sludge characteristics
2019
Cheng, Ya-Fei | Li, Gui-Feng | Liu, Ying-Yi | Zhu, Bing-Qian | Zhang, Qian | Xue, Yuan | Zhang, Zheng-Zhe | Jin, Ren-Cun
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.
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