Assessing toxicities of industrial effluents and 1,4‐dioxane using sulphur‐oxidising bacteria in a batch test

1,4-Dioxane is an emerging pollutant, which widely exists in natural environments and poses potential risks to the living organisms. However, its effect on the denitrification process is still unknown. In this study, the effects of 1,4-dioxane on the denitrification process were therefore investigated by using Paracoccus denitrificans as the model denitrifier. The obtained results showed that the exposure of 1,4-dioxane exhibited remarkable lag or inhibition on the denitrification process, especially with high dose. In the control without 1,4-dioxane exposure, Paracoccus denitrificans showed high denitrification efficiency (98.5%). However, the efficiency decreased to 78.5, 63.9, and 9.3% with 0.50, 0.75, and 1.0% (v/v) 1,4-dioxane dose, respectively. The dose-induced inhibition of denitrification by 1,4-dioxane could be partially attributed to the negative effects on proliferation and viability of functional microorganisms by conjugating and disrupting the cell membranes. Furthermore, 1,4-dioxane caused biotoxicity to the intracellular activities of denitrifiers via disturbing carbon source utilization and interfering the key enzymes responsible for glycolysis. The decrease of microbial viability and activity inevitably resulted in the decline of key enzymes (NAR, NIR, NOR, and NOR) closely related with denitrification process, which could be the direct reason for the decrease of denitrification performance.

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Performance assessment of up-flow anaerobic multi-staged reactor followed by auto-aerated immobilized biomass unit for treating polyester wastewater, with biogas production

Hassan,

Kriaa,

Wahaballa

et al. 2024

Appl Water Sci

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Polyester manufacturing industries produce highly polluted effluents, containing organics, nutrients, trace metals, and 1,4-dioxane, requiring a high degree of treatment before being discharged into the water bodies. This study focused on removing complex pollutants from a diluted polyester industrial effluent (DPIE) via a cost-efficient anaerobic/aerobic combined system, with biogas recovery. The integrated pilot-scale system was composed of an up-flow anaerobic multi-staged reactor (UASR; V = 41 L) followed by an auto-aerated immobilized biomass (AIB; Vsponge = 9.54 L) unit and operated at a total organic loading rate (OLR) of 0.75 ± 0.16 g COD/L/d and pH of 7.14 ± 0.14 at 25 °C. The UASR achieved removal efficiencies of 17.82 ± 3.14% and 15.90 ± 3.08% for chemical oxygen demand (COD, total and soluble) and 15.83 ± 4.68% for total Kjeldahl nitrogen (TKN), with bio-CH4 yield of 263.24 ± 31.98 mL/g COD. Adding the AIB unit improved the overall CODtotal, CODsoluble, and TKN to 93.94 ± 2.39%, 94.84 ± 2.23%, and 75.81 ± 3.66%, respectively. The NH4-N removal efficiency was 85.66 ± 2.90% due to the oxic/nitrification condition on the sponge’s outer surface. The entire system also achieved 73.26 ± 2.68%, 77.48 ± 5.74%, and 81.26 ± 6.17% removals for Fe (3.93 ± 0.95 ppm), Zn (5.92 ± 2.32 ppm), and 1,4 dioxane (2.50 ± 0.61 ppm). Moreover, the UASR-AIB maintained removal efficiencies of 76.53 ± 8.47% and 77.51 ± 7.38% for total suspended solids (TSS: 335.95 ± 42.84 mg/L) and volatile suspended solids (VSS: 263.50 ± 36.94 mg/L). Regarding the DPIE toxicity level, the EC50 value increased from 12.9 to 39.4% after UASR/AIB application. The UASR’s microbial community at the genus level demonstrated that the synergistic cooperation of solubilization, hydrolysis, acidogenesis, acetogenesis, and methanogenesis was responsible for the degradation of DPIE components.

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Assessing toxicities of industrial effluents and 1,4‐dioxane using sulphur‐oxidising bacteria in a batch test

Cited by 5 publications

References 40 publications

Ethers and Epoxides

Ethers and Epoxides

Inhibition of 1, 4-dioxane on the denitrification process by altering the viability and metabolic activity of Paracoccus denitrificans

Performance assessment of up-flow anaerobic multi-staged reactor followed by auto-aerated immobilized biomass unit for treating polyester wastewater, with biogas production

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