Rapid effective treatment of waxy oily sludge using a method of dispersion combined with biodegradation in a semi-fluid state

• Published in: Environmental pollution (1987) Vol. 319; p. 120971
• Main Authors: Yin, Qiuyue, Nie, Hongyun, Nie, Maiqian, Guo, Yonghua, Zhang, Bo, Wang, Lei, Wang, Yan, Bai, Xuerui
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.02.2023
• Subjects: Alkanes - metabolism; Alkenes; Biodegradation; Biodegradation, Environmental; Biological toxicity; High-efficiency microbial consortium; Humans; Hydrocarbons - analysis; Kinetics; Oils; Petroleum - analysis; Semi-liquid bioreactor; Sewage; Waxy oily sludge; High-efficiency microbial consortium; Biodegradation; Waxy oily sludge; Semi-liquid bioreactor; Biological toxicity
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2022.120971

Waxy oily sludge (WOS) from petrochemical enterprises has complex components and difficult treatment. Long-term large-scale stacking has seriously threatened human health and the ecological environment. In this paper, a new rapid and effective treatment method combining dispersion and biodegradation in a semi-fluid state was developed for the WOS. The degradation mechanism of the WOS in the bioreactor was preliminarily discussed. The component analysis results showed that the compounds with large molecular weight (M ≥ 282) in the WOS accounted for more than 50%. Among all microbial consortiums, the treatment effect of the consortium FF: NY3 = 9: 1 was the best for treating the crude oil in WOS, which was significantly different from that of a single strain (p < 0.05). Under the optimal nitrogen source NH4NO3 and the concentration of rhamnolipid, the developed high-efficiency microbial consortium (FF: NY3 = 9:1) could remove 85% of the total hydrocarbon pollutants in the 20 L semi-fluid bioreactor within 9 days. The degradation characteristics of WOS components in the bioreactor showed that the developed consortium has good degradation ability for n-alkanes (about 90%), middle- (77.35%)/long-chain (72.66%) isomeric alkanes, alkenes (79.12%), alicyclic hydrocarbons (78.9%) and aromatic hydrocarbons (62.78%). The kinetic analysis results indicated that, in comparison, the middle-chain n-alkanes, middle-chain isomeric saturated alkanes, alkenes, and alicyclic hydrocarbons were most easily removed. The removal rates of long-chain n-alkanes, long-chain isomeric saturated alkanes, and aromatic hydrocarbons were relatively low. The biological toxicity test showed that the germination rate of wheat seeds in treated waxy sludge was Significantly higher than that in untreated waxy sludge (p < 0.01). These results suggest that the new method developed in this paper can treat refractory WOS quickly and effectively. This method lays the foundation for the pilot-scale treatment of the semi-fluid bioreactor. [Display omitted] •High molecular weight compounds accounted for more than 50% of the waxy oily sludge.•The developed consortium has strong adaptability for different carbon sources.•85% of the hydrocarbon pollutants in the waxy oily sludge were removed within 9 days.•N-alkanes and other refractory components were removed rapidly and efficiently.•No significant difference in toxicity test between the treated and MSM-H2O group.