Compressible synthetic dual-medium filtration of wastewater effluents for water reuse

A novel filtration process using compressible synthetic dual-medium filter was investigated for wastewater effluents reclamation. In synthetic medium filtration system, the fluid to be filtered flows through the media as opposed to flowing around the filtering media as in granular media filters. Three types of open porous polyurethane foams with different densities and pore sizes were tested to determine their performances with respect to the removal of turbidity and total suspended solids. Media with smaller porosity showed higher removal efficiency in both turbidity and total suspended solids. Second, single- and dual-medium synthetic filters were compared to evaluate their feasibilities of treating wastewater effluents for water reuse applications and determined the optimum range to meet water reuse standard of the turbidity (i.e., turbidity <2 NTU). To meet water reuse standards (i.e., turbidity <2 NTU) in this study, single- and dual-synthetic medium filters will need to operate at compression ratios of 30 (<333 L/m²·min) and 50% (<500 L/m²·min), respectively. The removal efficiency of turbidity was slightly increased with the increase in compression ratios, and the total suspended solids removal was more affected by the filtration rates than that of turbidity in the synthetic medium filtration.