Degradation of petroleum pollutants in oil-based drill cuttings using aged refuse biofilters: A comparative study...

Oil-based drill cuttings (OBDCs) are hazardous waste generated during shale gas exploration and development, with petroleum pollutants being the primary contaminants that require proper treatment to prevent severe ecological damage. However, mainstream OBDCs treatment technologies are costly, environmentally unfriendly, and difficult to implement in ecologically sensitive areas. Based on the "waste-to-treat-waste" concept, this study utilizes environmentally friendly aged refuse biofilters (ARB) to degrade petroleum pollutants in OBDCs. The performance of three ARBs under different oxygen conditions-anaerobic (AnARB), aerobic (AARB), and semi-aerobic (SAARB)-was compared for their effectiveness in degrading petroleum pollutants in OBDCs. Results showed that after 118 days of operation, the oil removal efficiency for AnARB, AARB, and SAARB reached 48.12 %, 64.33 %, and 63.45 %. Among them, the SAARB exhibited the highest degradation rate during the later stages of treatment. Microbial diversity, community composition, and functional analysis revealed that the microbial communities in AARB and SAARB were reconstructed during ARB operation. Specifically, the unique spatial distribution of oxygen in SAARB facilitated the development of a highly diverse and evenly distributed microbial community, improved metabolic pathways for hydrocarbon degradation, and enhanced its ability to break down complex pollutants. This study demonstrates the feasibility of using ARB for OBDCs treatment and identifies SAARB as the most promising ARB for petroleum pollutant degradation. It addresses the research gap in ARB-based OBDCs treatment and contributes to the advancement of OBDCs treatment technologies toward higher efficiency, lower carbon emissions, and improved environmental friendliness.