PureULTRA II UF modules are constructed using highly hydrophilic modified PVDF hollow fiber membrane with a nominal pore size of 0.025 micron. The outside-in flow configuration contributes to easier cleaning as it keeps the solids, pathogens, and other foulants on the outside of the fibers. The fiber is designed to handle most feed water sources and tolerate solids loadings while operating within an optimal flux range.