Fig. 4: Screening methods can replace large settling tanks in water treatment.

a Floc formation and trapping during screening. Conventional flocs (formed with coagulant and flocculant only) were not removed, while flocs formed with different types of fibers or Si-microspheres were easily trapped. b, c Impact of screen mesh size and type of fibers/microspheres on screened water turbidity performed at 100 mg/L fibers and 1000 mg/L microsphere concentrations. Dashed lines are included as eye guides connecting average values obtained from duplicate experiments. Shaded area (in grey) shows the industry standard after treatment (< 1 NTU). d Flocs formed with various waste fibers (cellulose, cotton, and polyester). e, f Impact of pristine cellulosic fibers on the removal of nanoplastics and microplastics. Conditions for (b–f): 30 mg alum/L, 0.30 mg flocculant/L (50% starch and 50% polyacrylamide), pH 6.5 ± 0.2.