Influence of sludge retention time at constant food to microorganisms ratio on membrane bioreactor performances under stable and unstable state conditions

摘要: Abstract Food to microorganisms ratio (F/M) and sludge retention time (SRT) are known affect in different ways biomass growth, bioactivities foulants characteristics. Thus the aim of this study was dissociate effects SRT from those F/M on lab-scale membrane bioreactors performances during stable unstable state. Two acclimations were stabilized at a either 20 or 50 d with constant 0.2 kg COD  kg MLVSS −1  d . During state, higher N–NH 4 + removal rate (78%) obtained as an easier autotroph development observed. Soluble microbial products (SMPs) release double majority polysaccharides (49% total SMP). The conditions consisted changes operation without air nutrient. Autotrophs highly affected by tested disturbances SMP surface exhibited consistent performed stresses.