Recent efforts aimed at minimizing membrane fouling have emphasized an increasing demand for on-line monitoring in an effort to accurately predict membrane performance. To this end, an in situ bacterial monitoring system was developed that is integrated within the membrane. Because the target is bacterial monitoring, organic matter fouling must be controlled to avoid interference/masking of bacterial sensing as well as to prevent permeability loses. Combining bacterial monitoring with a membrane designed for fouling control is a novel and unique concept.