Design and Fabrication of Open-Cell Foams for Biological Organic Removal from Wastewater

Open-cell foams consist of macroporous structures are designed and fabricated in this study to be used as biofilm carriers for biological wastewater treatment. A manufacturing approach that integrates compression molding and particulate leaching is employed to fabricate the open-cell foams. Polyvinylidene fluoride (PVDF) open-cell foams prepared by sodium chloride (NaCl) as leaching agent possessed large specific surface areas with high degrees of cell-to-cell interconnectivity and demonstrated high potential for biofilm growth and protection. Moreover, PVDF open-cell foams fabricated by 80 wt.% and 85 wt.% of NaCl, showed a soluble chemical oxygen demand (sCOD) removal efficiency of up to 88%. sCOD indicates the soluble organic matters inside wastewater which have a significant role in water pollution. In the first phase of this study, PVDF foams with different porous structures and total protected surface areas were fabricated by different types (NaCl and sodium acetate (NaOAc)) and different loadings (80 wt.% and 90 wt.%) of leaching agents. The fabricated carriers were used in batch aerobic and continuous aerobic flow wastewater treatment to evaluate their feasibility to promote the growth and protect of biofilms. In the second phase, the focus was on investigating the effects of porosity, cell morphology, and surface properties of open-cell foams on the sustainability of biofilm and their performances in biological organic removal from wastewater. For this purpose, 6 types of open-cell foams with different cell sizes and different porosities were fabricated by PVDF and high-density polyethylene (HDPE) to be used in the continuous aerobic flow wastewater treatment process.