Polypropylene filter cartridges are highly retentive, graded porosity polypropylene media filters that have been specially designed for clarification and pre-filtration applications. The graded porosity design removes particles in sequence by size – larger particles by the more open outer layers and smaller particles by the tighter inner layers. The outer layers act as a pre-filter while the inner layers provide the absolute rating at the specified pore size. This efficiently spreads the contaminants throughout the media matrix resulting in superior contaminant holding capacity, lifetime, and pressure drop as compared to other media cartridges. No adhesives, binders, or surfactants are used in the manufacturing process. The non-woven media does not allow migration into the process fluid, thereby reducing the potential for extractables and downtime. Furthermore, the all- polypropylene construction provides excellent thermal and chemical compatibility with low and high pH chemicals. PureFlo polypropylene filter cartridges ensure consistent filter performance each and every time out of the package.