Role of surface physicochemical properties of pipe materials on bio-clogging in leachate collection systems from a...

Bio-clogging in pipes poses a significant threat to the operation of leachate collection systems. Bio-clogging formation is influenced by the pipe materials. However, the relationship between bio-clogging and the physicochemical properties of different pipe materials has not been clarified yet, especially from a thermodynamic aspect. In this study, the dynamic bio-clogging processes in pipes of different materials (high-density polyethylene (HDPE), polyvinyl chloride (PVC), polypropylene (PP), and polyethylene (PE)) were compared, and their correlation with the physicochemical properties was investigated. Results showed that the bio-clogging in HDPE and PVC pipes was more severe than that in PP and PE pipes. In bio-clogging development, the predominant factor changed from the surface roughness to the electron donator parameter (γ^-). In the initial phase, the most severe bio-clogging was observed in the HDPE pipe, which exhibited the highest roughness (432 ± 76 nm). In the later phase, the highest γ^- (2.2 mJ/m²) and protein content (2623.1 ± 33.2 μg/cm²) were observed in the PVC simultaneously. Moreover, the interaction energy indicated that the bacteria could irreversibly and reversibly adhere to the HDPE, whereas irreversible adhesion was observed in the PVC, PP, and PE cases. The findings clarify the thermodynamic mechanism underlying bio-clogging behaviors and provide novel insights into the bio-clogging behaviors in pipes of different materials, which can facilitate the development of effective bio-clogging control strategies.