The operation of filtration membranes for wastewater treatment is severely affected by biofouling formation, which causes a rapid increase in transmembrane pressure (TMP) in constant rate filtration. The TMP rise is often attributed to particulate fouling within the membrane, but the external fouling layer or filter cake contributes significantly. The fouling is highly compressible, so any model must incorporate cake compression. A one-dimensional controlled rate model based on compressible cakes and accurate sludge properties is proposed to predict the TMP rise needed to maintain constant flux. Increased compressibility results in more rapid TMP rise. Model predictions were compared to pilot-plant data and showed good correlation, without assuming fouling within the membrane. Optimization of cycle times and flux rates are performed.