A low dispersion comb filter or interleaver comprises a first birefringent element assembly having at least one birefringent element and a second birefringent element assembly having at least one other birefringent element. According to various embodiments, the system may include a performance evaluation module. The hook extends from the main body portion. The time period, during which the polycondensate remains in the extruder, after being melted therein, amounts to, for example, less than about 15 seconds. This process utilizes an ultrafiltration process for separating the steam cracker tar constituents resulting in a high recovery, low-energy process with improved separation and product properties. The inventive fiber is formed through the mixing of the fibers with a cationic or anionic polymer in one tank, the active material with a cationic or anionic polymer in a second tank, the opposite zeta potential of that used with the active material, and then mixing the active materialpolymer and fiberpolymer blends together.