Zero net growth in a membrane bioreactor with complete sludge retention.

摘要: Abstract A bench-scale membrane bioreactor was operated with complete sludge retention in order to evaluate biological processes and biomass characteristics over the long term. The investigation carried out by feeding a plant real sewage under constant volumetric loading rate (VLR=1.2 gCOD Lreact−1 h−1). Biological were monitored measuring substrate removal efficiencies biomass-related parameters. latter included bacterial activity as determined through respirometric tests specifically aimed at investigating term heterotrophic nitrifying activity. After about 180 days imposed operating conditions, system reached equilibrium conditions VSS concentration of 16–18 g L−1, organic (OLR) below 0.1 gCOD gVSS−1 d−1 specific respiration rates 2–3 mgO2 gVSS−1 h−1. These maintained for more than 150 days, confirming that an had been achieved between growth, endogenous metabolism, solubilization inorganic materials.