Effect of magnesium oxide nanoparticles on microbial diversity and removal performance of sequencing batch reactor

J Environ Manage. 2018 Sep 15:222:475-482. doi: 10.1016/j.jenvman.2018.05.089. Epub 2018 Jun 13.

Abstract

The performance, microbial enzymatic activity and microbial community of a sequencing batch reactor (SBR) have been explored under magnesium oxide nanoparticles (MgO NPs) stress. The NH4+-N removal efficiency kept relatively stable during the whole operational process. The MgO NPs at 30-60 mg/L slightly restrained the removal of chemical oxygen demand (COD), and the presence of MgO NPs also affected the denitrification and phosphorus removal. The specific oxygen uptake rate, nitrifying and denitrifying rates, phosphorus removal rate, and microbial enzymatic activities distinctly varied with the increase of MgO NPs concentration. The appearance of MgO NPs promoted more reactive oxygen species generation and lactate dehydrogenase leakage from activated sludge, suggesting that MgO NPs had obvious toxicity to activated sludge in the SBR. The protein and polysaccharide contents of extracellular polymeric substances from activated sludge increased with the increase of MgO NPs concentration. The microbial richness and diversity at different MgO NPs concentrations obviously varied at the phylum, class and genus levels due to the biological toxicity of MgO NPs.

Keywords: Denitrifying rate; Extracellular polymeric substances; Lactate dehydrogenase; MgO NPs; Microbial community; Nitrifying rate.

MeSH terms

  • Bioreactors*
  • Magnesium Oxide*
  • Nanoparticles*
  • Nitrogen
  • Phosphorus
  • Sewage
  • Waste Disposal, Fluid

Substances

  • Sewage
  • Phosphorus
  • Magnesium Oxide
  • Nitrogen