Organic matter contentThe particulate COD fraction (CODPART) accumulated in the con-trol systems, while being reduced or stabilizing in the systems withmicroscreens (p = 0.004, Table 2). A significant decrease in CODDISS(Table 2) over time was observed in all groups: 25–23 mg O2L−1,37–18 mg O2L−1, 34–22 mg O2L−1, and 35–25 mg O2L−1, for the 20,