Effect of polymeric support material on biofilm development, bacterial population, and wastewater treatment performance in anaerobic fixed-film systems

Abstract

This study evaluated the performance of high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyvinylchloride (PVC), polypropylene (PP), polyvinylidene fluoride (PVDF) and polymethyl methacrylate (acrylic) when used as a support media in anaerobic attached-growth wastewater treatment systems. A combination of physical and chemical (total solids, protein, phosphorus, ammonia, chemical oxygen demand) methods, environmental scanning electron microscopy (ESEM) and Live/Dead viability assay) and genetic sequencing over a period of 81 days was used to provide an in-depth understanding of the impact of different polymer materials on biofilm formation, bacteria population, and wastewater treatment performance. The results showed that hydrophobic polymeric materials (i.e., PP and PVDF) promoted initial cell adhesion and biofilm formation (<16 days) better than the hydrophilic (i.e., ABS and HDPE) polymeric materials. However, under longer-term and steady-state operation (after 81 days), the hydrophilic materials demonstrated larger mature biofilm quantities and better wastewater treatment performance. The sequencing data showed biofilm bacterial community structures of the ABS and HDPE to be significantly different compared to the other polymeric materials tested. The data showed a positive correlation as well between the phyla present on the ABS and HDPE and COD removal. These results suggest that the type of polymeric material play an important role in biofilm development, bacterial population diversity, and wastewater treatment performance for anaerobic fixed-film systems, and ABS and HDPE performed better than the widely used PVC in the industry.

Keywords: Attachment; Biofilm; Growth; Polymer; Support media; Wastewater.