The consolidation behavior of two kinds of colloidal SiC particles (30 and 330 nm diameters) with and without phenylalanine dispersant (C₆H₅CH₂CHNH₃⁺COO⁻) at pH 7 was examined using a developed pressure filtration apparatus at 1 MPa of applied pressure. The height of 5 vol %-30 nm SiC suspension with and without phenylalanine as a function of filtration time was well simulated by a filtration model developed for a flocculated suspension rather than a traditional filtration model for a dispersed suspension. The result with phenylalanine is related to the colloidal phase transition from well dispersed particles to flocculated particles under an applied pressure of 1 MPa. The consolidation time became longer as the amount of phenylalanine added exceeded 0.1 mg/m²-SiC. However, the packing density of 30 nm SiC particles after consolidation increased from 35% for no addition of phenylalanine to 37–42% for 0.1–1 mg phenylalanine/m²-SiC. The consolidation behavior of 20 vol %-330 nm SiC suspension with and without phenylalanine was also well expressed by the filtration model for a flocculated suspension. A longer consolidation time was also measured for the addition of phenylalanine above 1 mg/m²-SiC. However, the packing density (49%) of 330 nm SiC particles increased scarcely to 52% by the addition of phenylalanine (2.68 × 10⁻²–2.85 mg/m²-SiC).