Bentonite addition enhances the biodegradation of petroleum pollutants and bacterial community succession during the aerobic co-composting of waste heavy oil with agricultural wastes

• Published in: Journal of hazardous materials 2024-01, Vol.462, p.132655-132655, Article 132655
• Main Authors: Qv, Mingxiang, Bao, Jianfeng, Wang, Wei, Dai, Dian, Wu, Qirui, Li, Shuangxi, Zhu, Liandong
• Format: Article
• Language: English
• Subjects: Aerobic composting; Kinetics analysis; Microbial community; Modified bentonite; Petroleum pollutants
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.132655

Soil contamination with petroleum significantly threatens the ecological equilibrium and human health. In this context, aerobic co-composting of waste heavy oil with agricultural wastes was performed in the present study to remediate petroleum pollutants through four treatments: CK (control), T1 (petroleum pollutant), T2 (petroleum pollutant with bentonite), and T3 (petroleum pollutant with humic acid-modified bentonite). Comprehensive analyses were conducted to determine the physicochemical parameters, enzymatic activities, removal of petroleum pollutants, microbial community structure, and water-extractable organic matter in different composting systems. Structural equation modeling was employed to identify the key factors influencing the removal of petroleum pollutants. According to the results, petroleum pollutant removal percentages of 44.94%, 79.09%, and 79.67% could be achieved with T1, T2, and T3, respectively. In addition, the activities of polyphenol oxidase (51.21 U/g) and catalase (367.91 U/g), which are the enzymes related to petroleum hydrocarbon degradation, were the highest in T3. Moreover, bentonite addition to the treatment increased the nitrate nitrogen storage in the compost from 10.95mg/kg in T1 to 18.63 and 17.41mg/kg in T2 and T3, respectively. Humic acid-modified bentonite could enhance the degree of compost humification, thereby leading to a higher-quality compost product. Collectively, these findings established bentonite addition as an efficient approach to enhance the compost remediation of petroleum pollutants. Composting serves as a viable approach for the resource utilization of agricultural solid waste, enabling the removal of petroleum pollutants. However, the suboptimal humification degree of compost products and the inadequate removal of petroleum pollutants present significant challenges in advancing this technology. In this study, the addition of bentonite effectively enhanced the activity of microbial enzymes, thereby facilitating the biodegradation efficiency of petroleum pollutants during the composting process and improving the humification degree of compost. This research offers a strategic approach to enhance the removal of petroleum hydrocarbons in fertilizer production through the incorporation of bentonite. [Display omitted] •Bentonite improved microbial activity in compost by increasing nitrogen retention.•Bentonite compost product could be used for degradation of petroleum pollutant.•Degradation of petroleum