The paper compares the biomembrane and classical activated sludge meth
ods of wastewater treatment and presents the influence of ultrafiltrat
ion on the activated sludge condition. It specifies the difference of
enzymatic activity of activated sludge in both systems. In effect of b
oth activated sludge performance and separation properties of the ultr
afiltration membrane, the effluent from the biomembrane system is less
loaded.