Biotreatment and bacterial succession in an upflow immobilized cell bioreactor fed with fludioxonil wastewater

Environ Sci Pollut Res Int. 2021 Jan;28(4):3774-3786. doi: 10.1007/s11356-020-09231-z. Epub 2020 May 16.

Abstract

The large quantities and the persistent nature of fungicide wastewaters have increased the efforts towards a sustainable technological solution. In this context, fludioxonil-contaminated wastewater was treated in an upflow immobilized cell bioreactor, resulting in chemical oxygen demand (COD) removal efficiency even higher than 80%, whereas the electrical conductivity (EC) of the effluent was gradually increased. Organic-F was mineralized by 94.0 ± 5.2%, which was in accordance with the high fludioxonil removal efficiency (95.4 ± 4.0%). In addition, effluent total Kjeldahl nitrogen (TKN) concentration reduced significantly during bioprocessing. A strong relationship among COD removal, TKN/total nitrogen removal, and effluent EC increase (p < 0.01) was identified. Despite the adequate aeration provided, effluent nitrite and nitrate concentrations were negligible. Illumina sequencing revealed a reduction in the relative abundances of Betaproteobacteria, Chloroflexi, Planctomycetes, and Firmicutes and an increase in the proportion of Alphaproteobacteria and Actinobacteria. A shift in bacterial communities occurred during fludioxonil treatment, resulting in the significant increase of the relative abundances of Empedobacter, Sphingopyxis, and Rhodopseudomonas (from 0.67 ± 0.13% at the start-up to 34.34 ± 1.60% at the end of biotreatment). In conclusion, the immobilized cell bioreactor permitted the proliferation of specialized activated sludge microbiota with an active role in the depuration of postharvest fungicides.

Keywords: Biofilm reactor; Empedobacter; Fludioxonil biodegradation; Fungicide-degrading bacteria; Rhodopseudomonas; Sphingopyxis.

MeSH terms

  • Bioreactors
  • Cells, Immobilized
  • Dioxoles
  • Nitrogen
  • Pyrroles
  • Sewage
  • Waste Disposal, Fluid*
  • Waste Water*

Substances

  • Dioxoles
  • Pyrroles
  • Sewage
  • Waste Water
  • fludioxonil
  • Nitrogen