The performance and microbial community in response to MnO2 nanoparticles in anammox granular sludge

• Published in: Chemosphere (Oxford) 2019-10, Vol.233, p.625-632
• Main Authors: Xu, Jia-Jia, Cheng, Ya-Fei, Xu, Lian-Zeng-Ji, Zhu, Xiao-Ling, Zhu, Wei-Qin, Jin, Ren-Cun
• Format: Article
• Language: English
• Subjects: Anammox; Granular sludge; High-throughput sequencing; MnO2 NPs; Nitrogen removal
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2019.06.006

The response of anaerobic ammonium oxidation (anammox) process and granular sludge in the upflow anaerobic sludge blanket reactor was analyzed under long-term exposure to MnO2 nanoparticles (NPs) (1–200 mg L−1). The addition of 200 mg L−1 MnO2 NPs had a significantly positive effect on nitrogen removal and this system exhibited excellent performance, with a total nitrogen removal efficiency of 93.1%. Moreover, the specific anammox activity enhanced with increasing concentrations of MnO2 NPs up to the maximum value of 657.3 ± 9.3 mg TN g−1 VSS d−1 under MnO2 NPs concentration of 200 mg L−1. This value was approximately 1.6-fold higher than that of the reactor in the absence of MnO2 NPs. The extracellular polymeric substances and settling velocity were both increased with MnO2 NPs addition. Meanwhile, the high-throughput sequencing results revealed that MnO2 NPs increased the relative abundance of dominant bacteria (Candidatus Kuenenia) from 17.3% at the absence of MnO2 NPs to 23.9% at 200 mg L−1 MnO2 NPs, which resulted in a higher efficiency of biological nitrogen removal on the anammox system. These results indicated that MnO2 NPs enhanced nitrogen removal performance of anammox process. [Display omitted] •Long-term effects of MnO2 NPs on the anammox system were firstly evaluated.•MnO2 NPs in a wide concentration range enhanced the anammox performance.•The SAA, EPS and VS had the similar variations to NRR.•“Ca. Kuenenia” dominated the community under the tested MnO2 NPs levels.